Looks like I'll be getting a new cam since my old one (which was only 3 months old) suffered damage recently when I broke a rod in half. I was considering just getting the same one, a Comp NX 276. It ran well, and had a slightly choppy idle. Here's the specs:

"Hydraulic Roller-Street Machine with 125+ Nitrous system or small supercharger. 2200 stall with lower gears"

RPM-Range: 2000 to 6000
Lobe-Center Angle: 113
Intake Centerline: 108
Duration @ .050" Lift: 224/236
Valve Lift: 502/520

I recently mailed in a recommendation form, and a custom grind was recommended. Here's the specs that was sent:

Part#: 12-000-8
Grind#: CS 3313/3315 HR113+2
Duration @ .050”: 218/230
Lift w/ 1.5 Ratio: .495/.510
LSA: 113
Advance: +2

This is for a SBC Gen 1 400 (+.040) , 9.2 compression, 200cc Dart Iron Eagle heads with 72cc chambers. About 8 pounds of roots blown boost max. (see sig for more details)

Which would you choose for mostly street driven use, 5 speed manual trans with 3.70:1 rear gears and 27-28" tall rear tires? And why?

Both cams seem awfully close to me, except the part "Advance +2" -which I'm not sure what that means, whether it has 2 degrees of advance ground in, or I have to install it 2degrees advanced..

 

I would go with the recommended cam because it will be slightly tamer, but more importantly, make much better power!

I was recommended a 236/248 cam with a hair of .600 lift. on a 113 LSA, I love it!

 

[QUOTE=TraviZ;4470943]I would go with the recommended cam because it will be slightly tamer, but more importantly, make much better power!/QUOTE]

Well, that's just it. The NX 276 was the cam Comp recommended when I first put the blower on. I think the only thing I put down different on my cam recommendation request this time was that I'd like a smooth idle. So now they recommend this custom grind.

The custom grind seems a bit tamer - agreed - but - will the tamer cam put out more torque at a lower RPM? I couldn't get traction with the NX 276 as it was.

I guess I'm trying to figure out what will be different so far as driving characteristics between the two.

TraviZ - I'm guessing you're runninig higher boost on a centrifugal blower and the cam you have would see max power in the upper RPM range - maybe 6500 plus and has a very lopey idle. - more like a race cam -is that accurate??

 

honestly you will probably feel about the same performance, I just like the new recommendation because it has a wider duration split, which is better for scavenging those high cylinder pressures better, so you will see on a dyno better hp and torque across the rpm range.
yes, im running 13-15 psi now and its built for a 3-7k rpm range

http://www.youtube.com/watch?v=It7Q6-DSFro

first time getting the motor running, long time ago, but thats the kind of idle you get with my cam

 

please please please give Cam Motion a call and see what they recommend for you. Big companies like Comp Cams don't always have the most knowledgeable of people recommending camshafts... A good indication of this is that if you resubmit the same exact recommendation form chances are they will reply with a totally different recommendation each time!

 

I know it has been awhile since anybody has posted in this topic,but what camshaft did you end up going with Confuzed1?

 

I ended up going with the same one I had in it before I snapped the rod. The NX276HR with the duration at 224/236 @ .050....I called Comp again and asked them about the differences between the two as far as torque and HP went, and they felt that the torque from the milder cam would come in lower in the RPM range...well, that was enough to make me choose the one I had in it previously, because on the chassis dyno it had plenty of torque (495 ftlbs) and traction issues already.

The only reason I was looking for a different cam in the first place was because HP fell short of my expectations and maxed out at 376...BUT..... I only had 5 pounds of boost, a 650 CFM carb on it and I was still running a CAT in the exhaust when I dynoed. I'm hoping a bigger carb and no CAT will help it breath a little better and I'll get a bit more HP from it this time around....we'll see!

 

Cool! Keep us posted,dad is getting ready to start building his 383 with the MP122 supercharger,hope it runs well!! Here are some specs:

383 sbc
Brodix Iron Killer 180cc aluminum heads,2.02/1.60 valves,64 cc chambers
4340 Forged 3.750" staroke crank(dual keyed)
Scat 4340 H-Beam rods
JE Extreme Duty pistons,Total Seal rings
8.5-1 compression
Comp NX274 hydraulic flat tappet
230/244 dur.@.050" .488"/.501" lift 113* lobe seperation
Quick Fuel 750 DP carb, Mech secondary, manifold referenced power valve
Edelbrock E-Force supercharger MP122(not sure about boost yet,we have the pulley that came with it,whatever size it is, and a 3.1",and a 2.8" to try,we are looking for around 7-8 lbs.)

Keep us posted on how it go's!!

Brian

 

Wow...that's a pretty simular setup to what I'm running except my comp ratio is a bit higher at 9.2:1 since I have 72cc chamber Darts and SRP -21cc SRP forged pistons. If you want anything near 7 pounds of boost, you'll probably end up going straight to the 2.8 pulley...

 

Hey Confuzed,what number belt you run with the 2.8 pulley? Also what kind of timing curve you run with it,is your distributor locked out,or do you run a timing curve?(like how much initial timing,how much total timing,and what rpm does it have full timing? We have a timing advance kit,comes with all the different colored springs,but we didn't know what would be best to run. I would really appreciate the info,

Thanks,
Brian

 

huh... I really don't get where TraviZ was going with his responses... both the cams you listed as well as his all have 12* lobe split (the exhaust lobes all have 12* more duration) and an LSA of 113. Even procharged's cam isn't that different, it's got a 14* split and the same LSA.

The +2 degrees just tells you where the lobes are located. Most SBC cams are ground with a few degrees advance, typically 4 (that's what it looks like the first one was ground with), the difference is that the cam with less advance will typically move the power band up by closing the valves later. Really, the second recommendation is basically the same cam with one step smaller lobes which would lower the power band some, but with less advance which would raise it back up a little. Not sure why they bothered to do that like that unless they thought that leaving the exhaust lobe open 2 degrees longer but not adding timing was more beneficial that just going with a bigger lobe.

Honestly, based on what you've said here I would have suggested something in the range of Procharged cam for your combination, and I would suggest something like your cam for Procharged's smaller displacement and edelbrock blower (I just think that 230/244 is getting a bit aggressive for a blower like that, which is really just a big eaton blower, originally intended for lower rpm street use). Also, your higher compression will tolerate more cam timing without loosing driveability, as well as bleed off some cylinder pressure down low which would also bleed off some cylinder pressure down low allowing you to run a little more boost with your highish compression.

 

We are thinking about going ahead and running the NX276HR cam like confuzed is running if we can get a reasonable deal on a set of hydraulic roller retro-fit lifters. It seems to fit our engine great,seems to be better sized for our 8.5-1 compression,and 180cc heads,over the NX274 flat tappet we were gonna run,and would probably be more enjoyable to drive since this is a daily driven deal,although dad runs the NX274 hydraulic flat tappet in his 86 Trans Am with a 383 sbc and AFR 195 heads with a D1SC Procharger,and isn't that radical at all,drivability don't seem to suffer,but it does have 9.3-1 compression.

Brian

 

Brian - You need a 6 rib belt, NAPA Micro V 25-06480 and let me tell you, I had to make 3 different trips to get the right one. It's a tight fit, and you'll hardly need to use the slot at all to increase tension. They tell you that serp belts don't stretch, but they're full of it. It'll loosen a little over time.

I doubt you can set your initial just like mine since all engines act differently, especially since you're running different heads, pistons and compression than what I have. In general, I run 12 initial and limit total to 32 degrees. I run a small cap ACCEL street billet distributor with 2 light silver springs. There may be a better curve yet, since I'm still testing myself, but it ran well on the dyno with the above.

I also have a boost retard box that allows me to take an additional 1-3 degrees of timing out per pound of boost if I happen to get crappier gas, but I've never really used it yet.

 

Thanks for the info!! We really appreciate it, how much boost did you say yours pumps on your 406 with the 2.8" pulley? At 6000 engine RPM, the blower will be spinning 16,071 RPM,we were kind of nervous spinning it that much,but maybe it doesn't hurt it? We only spin our B&M 144 13,400 RPM at 6000 engine RPM,and B&M says not to turn it over 14000 RPM. I have read alot of people that spin the magnuson 122 around 17000 RPM,so I guess it doesn't hurt it,we just have fear that the rotors will hit the case and gauld it,since it is a new blower,but I guess it isn't supposed too,the guy at maguson thinks it will be alright.

Also do you run the 32* total on 91 or 93 octane? All we can get around my town is 91 octane. Sorry for so many questions,just like the info

Thanks,Brian

 

I ran 6.5 to 7 pounds of boost with the smallest pulley available. That's why I said if you want anything close to 7-8 pounds, you'll most likely need to go right to the smallest pulley for a 383.

Even with that being said, how much boost you get with any size pulley is not just cubic inch dependant. The biggest variable is how well your setup breathes. With the stock pulley, I only got 2 pounds of boost, and to be honest, increasing boost from there only showed small gains in additional power from there.

Ideally, I'd want to get 2 pounds of boost with the smallest pulley - that means my engine is actually USING the additional boost...instead of stacking it up in the intake.....if that makes sense. But who am I telling this to...1300 HP Procharged..

Magnuson doesn't have a problem with it spinning at 16,000 rpm, so niether do I. The charge HAS to be a bit hotter though, so I'd watch out for how much total advance you give it to start out with. Be conservative and only give it 28 total and test it from there. I use premium only with the blower...If memory serves me, gas octane here is 87 for regular unlead, 89 for mid-grade and 92 for premium (up to 10% garbage ethanol added).

 

Hey,Thanks Again Confuzed,I have one other question,what brand lifters do you run in your motor? We are going to go ahead and run the NX276HR cam like you are running,and our Brodix heads have the Comp 987 springs on them,it just so happens that is what Comp says to use with that camshaft. We have 130 lbs. seat pressure,320 open pressure(at max lift of .575"). We are looking at the Lunati #72330 street series retrofit hydraulic roller(we are using an older block),they are supposed to be good for 6500-6800 RPM,and found them for $329.00,another set we were looking at are the Howards street series lifters,they say they are good for 6500 RPM,they are $275.00. I do know that the Lunati lifters are "Morel" lifters marketed under Lunati,which is what we run in our race car,but they are solid rollers in it,and the Morel lifters are supposed to be one of the best lifters you can buy,besides Jesel,but I wasn't sure about the Howards,they just say the are USA built,but they are $30.00-$40.00 cheaper than the Lunati.

EDIT: I have been doing some research and it looks like the Howards lifters are also Morel,so they should be the same lifter as the Lunati,summit has them for $297.00 Howards #91164N,supposed to be good for 6500 RPM,we won't turn this motor over that ever.

Thanks,
Brian

 

Well,my dad got the cam and Lifters on the way,ordered them last night! Went with the Comp NX276HR #12-415-8 camshaft and the Howards Street Series Retro-Fit hydraulic roller lifters #91164N. I have read and read some more,and everybody says the Howards lifters are "Morel" built lifters,which are the same as the Lunati,Herbert,PBM,Bullet,Cam Motion,and so on..... lifters,just boxed in different boxes with different prices.

Can't wait to get both cam and lifters so I can gaze at them,seems to be a well matched camshaft for dads combination!! I am glad he went with the NX276HR hyd roller over the NX274 flat tappet,I think the NX276HR will be more friendly in a street blown 383 than the NX274 flat tappet,and I think it is better suited for his Brodix 180cc head port and his 8.5-1 compression. This will be the first hydraulic roller cam my dad has ever ran,has always wanted to try a hydraulic roller cam,but because of the price of the Retro-Fit stuff,he has always ran hyd flat tappet stuff,but he bit the bullet this time. I think it going to be an excellent combination,we will see.

 

Tell your Dad I feel his pain...going to retro roller was a hard decision for me to make also due to the additional $$, but there are better grinds out there for the rollers.

I run a set of Crane retro-roller lifters myself, but if you ask Comp they'll tell you to run their brand of lifter with thier cam. If I had the extra $$, I'd run Crower stuff since I've had nothing but good luck in the past with their parts, but they're just too pricey to justify the added expense. But maybe if I ran their rods, I wouldn't be in the mess I'm in now...

I think the NX276HR cam will work well in a 383. Did you get it ground on a small base circle? I did for ease of mind - just to make sure I'd have no clearance issues....

BTW, I just dropped my engine between the fenders yesterday!! Should have it up and running within a week.

 

Great!! Can't wait to here how it runs again. We didn't order it with a small base circle,but the Scat H-Beam rods he is using are supposed to be cam clearance already,so hopefully it will work!! I think it will. Thanks for the info again,it's much appreciated.

Brian

 

In hind site, I wish I would've gone with the H-Beam rods instead of the I beams I have.......even though most everyone I've spoken to say the Eagle SIR rods are tough. Well, I proved them wrong unfortunatley....

I tried to get my engine running but hit a few snags...I had some wiring issues I had to straighten out which set me back a few days that had to do with my MSD boost retard box. It's all good now I think.

I was really trying to make it to Thirdgen Fest this year for the first time, but it looks like I won't have it all together by then due to this 12 hour rotating shift schedule I work...

 

Well we have most of the 383 put together,we did have to have the rods clearanced some to get our .050" rod to cam clearance for the NX276hr cam,but wasn't a big deal. We got all the short block put together,heads on it,and the cam in it and degreed. We had to by a Cloyes Hex-A-Just billet timing chain so we could get the cam were it is supposed to be installed. We still have to set the cam endplay,we are going to be using the Cloyes Quick Button cover with the built in cam button. I hope dad likes the NX276HR cam in his 383,it seems like it is a well matched combo for a daily street driver,at least in my opinion. Confuzed... how does this cam idle in your 408? We are hoping for a good sounding idle,not smooth,but not to radical either,i do understand that it will be a little more pronounced in a 383 than a 408,but a 224/236 duration cam doesn't seem that big for a 383 either. We set the E-Force 122 supercharger on it just to see what it looks like on there,and man does it look impressive! can't wait to hear it run,i'll try to get some pics and post them.

 

Just got mine running again the other day. Idles well at 750 RPM's - you'll love the idle...at least I do. Good to hear you had enough clearance with the cam. Not sure why you needed a hex-adjust timing spocket, I installed mine straight up with no issues. Did you set yours advanced 4 degrees?

I used to run a XE288HR cam in my car, which I beleive was 236/242 duration and the idle was more choppy than most would like on a street car (at least I thought so). I couldn't really get it to idle well below 900 RPM''s with that cam. Yeah, post a few pics!

I have a few pics posted towards the bottom of this thread: https://www.thirdgen.org/forums/tech...ne-damage.html

 

Hi Confuzed,no we didn't advance it 4 degrees,we degreed the cam in to were it is opening and closing the valves(valve events)exactly were the cam card says they should open and close,and we found out with this particular camshaft,it had to be installed at 105.125* intake centerline to open and close the valves at the proper time listed on the cam card. We first installed it "straight up" at 108* intake centerline,and checked it,and it wasn't opening and closing the valves at the right time. So although it looks like we have it advanced almost 3*,from 108* to 105.125*,it really is put in there were they want it,which would still be considered "straight up". now a person can advance or retard from this point,but we are going to leave it alone.

I will try to get some pictures posted in a bit...

EDIT: I was looking at your pictures in the above thread you listed and noticed you have the larger blower pulley back on it,are you gonna put the 2.8 pulley back on it? Just curious,we already put our 2.8 pulley on ours.

 

Also,dad wants to know what number spark plugs your running in your motor so we can try the same ones in our motor,except we will have to have them in the long reach style for aluminum heads. Thank you

 

I was using NGK UR5's. They recommend a plug 1-2 steps colder than stock but I dunno what difference it really makes. I tend to just go with whatever doesn't foul on me.

Why the bigger pulley? Basically Edelbrock screwed me. I sent my blower in under warranty to get checked out while I was rebuilding my engine anyway because I could hear a light, slight "knock" in the drive section while it was idling cold so I was worried a bearing was going bad.

I also noticed there was some play between the rotors and pulley. I could hold the rotors still, and the pulley had some play in it. I found out that Magnuson puts a spring type coupling in the drives, so a slight slop in the drive is normal. That may have been the source of the light knock it had I thought, so I told the guy at the Warranty dept. at Edelbrock that I was OK with his explanation, but I wanted my warranty extended just in case I did have a bearing going bad. I also found out that Edelbrock cut all ties with Magnuson within the first year they sterted marketing the blowers. Edelbrock now manufactures the entire thing.

They told me that they would just go ahead and change out the drive section on the blower and send it back to me. It took them two full months to do that, and when I asked them why it took so damn long, I got some excuse that all thier engineers where busy developing new blowers for the Mustangs....which is no excuse in my book.

So - it finally arrived at my house. I open the box and it no longer has the spring type coupling on it - now it's a solid connection. But the biggest thing they didn't mention when they changed it out was that they altered the drive shaft in a way that it's now some type of pressed on fit for the pulley, and now none of my smaller pulleys will work at all. I don't even think that big pulley can even be removed...theres no nut or keyed shaft on it anymore...They have royally pissed me off. I've called them 10 times and got an answering machine, left my callback number etc. ...because I can't change pulleys now and I want my old drive back...but they haven't responded. So now I'm stuck with only 3-4 pounds of boost thanks to Edelbrock. I'm so done with them.

If you look at thier web site, there not one email address I can send a complaint to. I'd love to write a note to Vic himself...

 

Yes,that is a bunch of BS on Edelbrocks part,it seems thay are starting not to care about their customers,kinda reminds me of Holley,they are all getting to big,all they care about is that "mighty" dollar rolling in to them,and don't give a chit about the customer,and trying to help with what they can. If they were really interested in helping the customer and being loyal,they would have people hired that answered the phone of every phone call that came into the place,and if they have problems with the people they hire not answering the phone and helping customers who have bought thousands of dollars worth of parts from them,then fire them and hire someone who gives a chit about helping their cutomers that have put food on the table for them and thier familys. We have ran in to this alot being into drag racing,it is really tough to get any parts and info that you need now days,in any decent time at all. It's funny how most everybodys income is down in the country right now,but you still can't get anybody to opereate their buisness right,which you would think they would want to do,so they could sell as much product as they could. It's kinda funny,the more the prices keep climbing on most everybodys products,the less customer service we get. That right there shows you all they care about is the money!!

OK.....sorry for the rave,just wanted to express my opinion also,now what I have said above is not true for all companys,there are still companys out there that do try to help their customers all they can,but they are getting more scarce everyday it seems like.

Confuzed.....I apprecitae all the info you have given me throughout our build,it has really helped out alot,and it takes people like you and me and everybody else on these forums to help out each other with good info and experiance,because more than likely you aren't going to find any with these big companys any more,because some how they don't even know much about their own product,it just blows my mind!!

Again,thanks for all the help and information,

Brian

 

Brian - You're welcome anytime! I don't mind a bit giving out what little info I can, considering I just don't have all the knowledge that people like you and '83 Crossfire have (and many others) on this board. I'm just a backyard mechanic that's learned things the hard way on too many occasions...lol

I'm glad you agree about these big companies not giving a crap about thier customers and not knowing about products they sell. Even though I bought this blower from Edelbrock, I had to call Magnuson to find out more about pulley changes, compression and cam choices. Thier service department is the exception, not the rule from what I've experienced.

The only thing Edelbrock could tell me all along is that going to a smaller pulley will void my blower warranty....guess they took care of that in the end. I'm glad my car is running well and has great power even with 4 pounds of boost, but still, Edelbrock has basically taken away my choice to get any further potential from this blower.

I'd love to see a few pics of your Dad's 383 and hear how it turns out!!

 

Heh, those of us that have any clue what so ever have learned all too many lessons "the hard way" doing it in the backyard, basement, garage...

Who the heck told you they don't stretch, and if they didn't then why do v-belt tensioners have ranges marked on them that the belt is supposed to be replaced when the arrow/dot is outside the marked range?

UR6's are 2 steps colder (most other companies have 2-3 steps between those 2 plug ranges, and are still warm enough that even a stock car won't foul them if you run the thing hard once in a while.

all these things started as eaton parts. They originally had a coupler with some give in them because they were intended to be driven by the accessory drive that has other things going on and to dampen the assorted changes in load... without it you end up with the gears and even the actual rotors going through a harsh, loading and unloading slamming parts around. That thing when it started getting a little worn, or even when brand new if you suddenly change the load on it tends to make a clanking sound (which doesn't hurt anything, you should here the racket the old prototype M90 that I have floating around makes).

I guess magnussen started replacing them with some sort of solid coupler to get rid of the noise (I would worry about durability without some sort of give in the drive), and I'm not really sure what any of them ship with, just that the OEM ones still have a drive that has some give in it to meet warranty requirements.

Sounds a lot like whoever you talked to on the phone just didn't know what they were talking about exactly or were just trying to sell you the latest parts in their parts bin... that sucks.

 

Hey everyone.

I got good news about the blower! I contacted Magnuson about the issues I had with Edelcrock sending my blower back under warranty in the condition as I described above (I quoted my previous post) - and they're willing to help me out - BIG TIME!! Talk about great customer service, and I didn't even buy it from them!!

IF I ONLY PAY FOR SHIPPING, they're willing to replace my stupid pressed on shaft that Edelcrock stuck me with back to the original keyed shaft!!! This is GREAT!! Now I'll be able to use my smaller pulley(s) again so I can run 5 or 7 pounds of boost!!

I was actually on my last straw when I wrote to them and I was actually getting ready to replace the entire blower since Edelcrock's pressed on, non-replaceable pulley stuck me with only 3 to 3.5 pounds of boost, but now, I don't have to! Magnuson said they'd be happy to help me out and replace the shaft!!

I even asked if they could give me the "Magna-Charger" stickers that go on each side of the blower when they send it back to me, so there's no reference anymore to that crappy Edelcrock company. They said OK to that too!

Guess my season for driving the Camaro is over till spring since I'll be pulling this blower off to send it to them by Monday - but it's SO WORTH IT!!

Magnuson's customer service ROCKS!! And I didn't even buy the blower from them. Great people at Magnuson!!!

 

if you are still looking for a blower cam, I have a brand new isky blower cam in the box that has never been used. It was a custom grind cam for a 383 here is the specs. 226/240 560/558 114 let me know if you are interested. I think i paid about 375 for a custom grind. I will let it go for 250.00

 

No thanks....I stuck with the nitrous cam.

 

Well, Magnuson isn't the ones that decided to change my blower over to a pressed on shaft with a rigid coupling - Edelcrock did. Edelbrock cut ties with Magnuson shortly after they ventured together and sold the blower under the Edelcrock nameplate. I'm just guessing that Edelcrock bought the rights to the design, and now buys just the rotors from Eaton. Vic has everything else made at his own foundry.

The 2 things that really sucked was getting my blower back from Edelbrock with a keyed on shaft and rigid coupling without telling me they were going to change it, along with the excuse they gave me for taking two months to put the thing back together. Their excuse (if you want to call it that) is that the same guys that work in the warranty dept. on blowers were too busy developing new blower models for Mustangs and Challengers to take care of my warranty claim.

Magnuson is doing me a big favor by changing it back to a keyed shaft and spring type coupling like it had to begin with. I can't say I've been totally disappointed with how the car runs being limited to 3.5 pounds of boost....it's running great, but now when I get it back I'll be able to add more boost once again and have more potential.

 

This is great to hear,I am glad you got something figured out with it!! If we ever have to send it in,it will be goin to Magnuson for repairs....got another question for ya...we are putting dads motor in right now and was wanting to know what fuel pump and line size your running with yours? We have a 130 gph holley mechanical pump with just the stock 3/8" line from the tank to the pump,the a 6an line from the pump to the Aeromotive 13205 regulator,then 6an line to each bowl from the regulator..this setup worked fine with our mild 350,but not sure if it will be enough for our 383...just curious what your fuel system consist of? Also,what fuel pressure you run with it?

I am so glad you got somethin figured out with your blower,magnuson is a great company for doing that,they will for sure get are buisness....not edelbrock!!

Again,thanks for the help

Brian

 

Hey Brian!
i thought you would've had that thing tearin up the streets by now! I think you'll be fine with the fuel setup you have already. I'm running (I hate to say it) - an Edelcrock victor series race pump (130 GPH) with an Aeromotive 13301 bypass regulator piped in to the stock lines. Everything between the regulator and carb is the 8AN braided stuff. I have the regulator set at about 8 PSI, but my stupid pressure gage bounces around so much it's hard to tell, but it's in the ballpark.

Edit: Dave at Magnuson gave me call Friday and said my blower is ready to go! It's being shipped back to me on Monday!!

 

Thanks a lot!! We figured we would have it running by now too lol,but just been so busy with work and everything.....and getting the race car goin our way...but now the 383 is finally getting put in...I will keep you updated on how it goes,shouldn't be long now!!

Again,thanks for the help...

Brian

 

Well, I got the blower back late yesterday!! Good as new, and now I can go back to 6 pounds of boost!!
First pic is what Edelcrock left me with, and the last 2 are how it should have been set up. Edelcrock had the big pulley pressed on so tight, Magnuson broke it trying to pull it off!! Didn't matter to me since I don't use pressed on pulleys anymore!

 

Hey Confuzed,does your plugs look coal black just running it at idle and reving it a little? We haven't driven it yet but have ran it here in the driveway some,and have adjusted the four corner idle circuit for the best vacuum and everything,timing is right,we have it set at 18* initial with 18* more mechanical for a total of 36*,then we are gonna pull it back to 30* under boost. I just wanted to know what your plugs look like,ours are coal black,porcelain,ground strap and all,and have only ran it a bit in the driveway....the throttle responce seems to be a little smothery feeling,you can rev it to about 2500 or so and rev it from there and seems to be more responsive...also we have all the timing in by 2500 rpm....we are using the same carb and ignition we used on the previous motor,a quick fuel 750 DP with 74/84 jets and manifold referenced power valve...I have had people telling me that its normal to have black plugs with a street blower motor....we didn't think so,so I thought I would see how yours look..

Thanks,Brian

 

Hey Brian! How's the beast sound? I had no idea how mine looked, so I pulled one and took a pic for ya. I'm using a different plug other than the usual NGK's for a change, instead I have Accel 5765's in it now. They're a little carboned up, I suspect it's from how the A/F ratio is set at 12:1 - You might have yours a little on the too rich side, but I wouldn't worry about it too much yet until that engine is broken in a little - so long as it's not "pig" rich and washing down the cylinder walls.....

I would highly recommend a chassis dyno to get the timing curve and A/F dialed in better anyways. Unless you have a wideband and are good at tuning (I'm not).... I thought mine was good when I brought my car to the dyno, but it was a bit rich (10:1) and on the first run it was detonating bad in the upper RPM's. - I took a pic of my plug on #2 cylinder, it's black but not wet..

 

Thanks for the info and picture Confuzed.....I really appreciate it...ours looked black like that with 18* initial timing and we had people telling us to bump it up into the mid 20*'s for initial timing and others just told us to lock it out at 30*'s. we changed the initial up to 24.5* and it seems the plugs have cleared right up in it,they aren't sooty black anymore like they were with 18,although we can't boost it because it will have to much total timing with 24.5* initial and 18* mechanical....but works to see if it has any effect in the plugs and it does!! We are gonna have to limit the mechanical to like 11.5* to get to our 36* total since the biggest bushing they have is an 18* bushing,will have to weld it and file it till its right....then we will pull it back to 30* under boost...it sounds good at idle,its pretty smooth actually with a little bit of sound...but then again I am used to our procharger drag radial car,its pretty radical,the cam in it has 279/283 dur at .050" with 312/316 adv dur and .776"/.776" lift and 112* lobe seperation,so its just a hair more radical....lol

again,thanks for the help,how is yours running?

Brian

 

Well, that's good to hear! Now I'm thinking I need to follow the same route with mine also since my plugs looked like yours....hate to admit it, but it's the 1st time I looked at them since I got my engine together!
One thing I changed since the engine blew, was I added a Mallory Unilite distributor which obviously isn't dialed in yet. It came with a somewhat lazy timing curve, and it's not all in until 3K RPM's, plus the mechanical is only 22 degrees, so I have my initial set at 8 degrees and make up an additional 9 degrees using the vacuum advance, so it's at 17 degrees at idle. It's the first time I tried doing it that way, and I intend to change it by limiting the mechanical and try bumping up the initial to 20+ where yours is and try it. I'll change the vacuum advance to the timed port also.

I think I can probably go to 32 degrees total and get away with it, and go with lighter springs so it's all in by 2200. I have a boost retard if it detonates at 32....

All that being said, it's running pretty darn good although I know I'm running it pretty conservative at the moment. - There's even more I'm leaving on the table and I know it.... still can't get decent traction as it is anyway.

You're gonna love the instant tire shredding response when you hit the go-fast pedal with that blower!!

 

Hey Confuzed,glad to hear you got it back up and running...we have been tinkering with dads motor and have noticed if the motor idles a little slow you can hear what seems to be q knocking sound coming from the blower and sometimes you can hear it when its idling normal.....this thing is brand new...with very little run time,you can put your hand on the blower snout right near the front of the blower were the input shaft goes into the coupler and feel it when it does it....does yours do this? Is it normal? You don't here it at all just above idle....

 

YES IT'S NORMAL!! Mine did that exact same thing and I thought my blower had problems too, and that's EXACTLY how my saga began with Edelcrock. There is a spring-type coupler in these blowers. If you hold the rotor still with your hand, and twist the drive pulley back and forth, you'll notice some "play" in it.

83 Crossfire TA mentioned it in this same post, I'll quote him:
Edelcrock also confirmed what 83 Crossfire said in this post and they told me that these blowers also have that same type of spring coupler but they couldn't tell me what function the spring couplers actually served when I asked them.

I then understood that the noise I was hearing could conceivably just be coming from the coupler, but for some reason, the guys at Edelcrock didn't want to actually check the drive bearing to disprove for sure that it wasn't a bearing issue. - I didn't think it was too much to ask since they had it in their hands and all.

So - since they didn't intend to do ANYTHING with it, I asked them to extend my warranty since they weren't going check further about the noise or replace anything....well, they called me a couple of days after that and said they decided to go ahead and just change out the whole snout on mine...

What they DIDN'T tell me was that they got rid of the spring coupler and replaced it with a solid coupler (which wasn't a big deal) - but they also didn't replace it with the same type of shaft mine originally had which allowed me to run smaller pulleys.....and you know the rest....

It took sending it me sending my blower in to Magna Charger to straighten it back out. Magnuson's customer service is by far the best I've ever dealt with.