anyone know about these cams? ive heard a few good things

 

I think they are manufactured well. I have used ONE and was happy with the quality.

They are older tech and as far as fuel injection goes it's really more of an older carb design.

 

Well, turn up the volume and hear another good thing:
MINE with an Isky.
They offer a wider power band than higher lift cams and a little nastier idle.

 

"They are older tech and as far as fuel injection goes it's really more of an older carb design."

Ditto's according to Big Joe Sherman.

 

I certainly do like the sound and power in a carb'd street engine. I was very happy with mine. Mine was in an older Buick GS 350, not a third gen.

 

Oh, I forgot. You have to be 30 years old or older to buy one.
They're not for kids...

 

i dont see why they are "carb" cams...looking at some of the hydraulic rollers theyoffer for our blocks, they got some VERY aggressive lobes with fuel injection cars should like.

225/234 duration at .050" cam with advertised duration 272/282. Comp cams xfi fuel injection shafts have 268 advertised and 218 at .050", have 276 advertised and 224 at .050" and 280 advertised and 230 at .050".

I'd say those Isky cams would work well in the right supporting aplication.

 

Look again at the LSA and valve lift. The Comp and Crane cams will have more lift and wider LSA.

Quoting Obi Wan Kanobi from the movie Star Wars:
"These aren't the cams we're looking for"
"move along now..."

 

thats not necessarily a feature that you need for EFI. if you use 1.6 rockers those cams turn into decent lift values. most street heads dont flow that much more after .550 lift and getting close to that value is what u want
the one cam looks to have an lsa at 112 which is very popular.

 

Without knowing what lift value isky uses to measure their advertised duration at, that's almost a meaningless comparison. If they use .008" then it'd SEEM like they have wicked fast ramp rates. Same way cranes cams ALWAYS seem like lazier rates vs comp, comp uses .006" and crane uses .004". GM uses .001" IIRC, so their cames seem SUPER tame.

But I agree, I don't think ISKY's roller cams are very popular. I think there are a few people using their solid roller designs though. Same with Crowers, but their off the shelf flat tappet stuff is almost unheard of (except the older generic grinds).

FWIW i'm buying an ISKY solid flat tappet similar to Supervisors, but more MANLY (240@.050"). I like ISKY's 108LSA and relatively tame lift (valve train lives longer). But then again i'm using 1.6 rockers so...

 

The Z-25? You will definately need a vacuum reservoir. There's a lot of difference between 110 and 108 LSA. Remember, that is in cam degrees not crank degrees. Good springs and ignition are a must because it will still be making power after 6000.
This will be a good experiment so there can be a direct comparison between "old school" and "new school". Get a 1/4 mile time nailed down on the high lift one you have now, so we can see which one is faster and how streetable the Isky is or isn't.
Besides, if you don't like it, you can always give it to me. (be sure to keep the lifters matched to the lobes when you pull it out)
EDIT: VOTC for the Z-25 is .141" with 1.5's. If you put it in let us know what the VPC measures with your setup. See attached.

 

i was gonna say they use a .002 but i mis read, the card specs say they use a .020".... damn, those are pretty lazy lobes.

 

Engine is partially torn down now, I don't think i'll get a chance to do a back to back comparison on the compxe268H and the Isky cam.

I've upgraded the ignition, but springs are yer-basic 1.25"OD 100/300 springs. I might replace those later if need be.
With the stickshift, I use engine braking a fair bit, so my vacuum level is high in those conditions for my brakes. That's another wait-and-see purchase I think.

I don't think i'll buy their kit to measure VOTC, but I can take some measurements with a digital caliper and dial gauge when building the engine again...

 

The only time i've seen a cam company measure duration at lift as high as .020" is with a solid cam, since it probably uses .020" lash. That's pretty normal. If that cam is solid, then you can't compare it's duration and lift to a hydraulic cam.

 

they had it under hydraulic rollers on their website.

see here
http://www.iskycams.com/timingchart....ber=211265/272
they say the above timing is checked at .020" doesnt say anything else

 

You may be able to shim the springs to get the needed 115-120 lbs on the seat and not be close to coil bind at .512 lift with the 1.6's.
With the head on the engine all you would have to do is roll the engine to TDC and remove the 2 springs & rockers. Then with a dial indicator, measure using each valve, the distance from the seat to the eyebrow. The .141 VOTC becomes .150 with the 1.6's, .1" clearance is needed. So if it is 1/4" (.250) or more from the valve seat to the piston, it's good to go.
Since you're going to be using the 1.6's, I would recommend 120lbs seat pressure as a minimum. I still have the holesaw I can loan you if you should decide to "spring" for the 6105 springs (1.430" OD) and 507-STA retainers (if they will clear the rockers).

 

Hmm. Ok, i'll measure the "VOTC" at TDC and see what i've got.
I'll remove a spring and use my vice and a bathroom scale and see what i've got as far as pressure when open and solid length, then go from there.
I was hoping to avoid jumping up to bigger springs for now

You can just use a holesaw to fit for larger springs? or is this their specific 1.43" OD hole saw?

 

Just for clarity of future searchers, you will be measuring the VPC (Valve/Piston Clearance) at TDC. The VOTC (VALVE OPENING AT TOP DEAD CENTER) is the amount that the valves are off the seat at the end of the exhaust stroke due to the cam holding the exhaust open late and opening the intake early during overlap. The VOTC amount is subtracted from the VPC to determine how close the valves will actually be to the piston when the engine runs.
With the springs, if you measure the installed height and it's close to normal, the spring manufacturers specs should tell what the seat pressure is.
What you need to measure with the scales is how much shim would be needed to get 120lbs seat pressure. If you subtract that from the spring specs for max lift and still have .512 left, they will work shimmed.
About the holesaw: The 6105's are double springs. They have a smaller ID than the stock spring. The holesaw also trims the "fat" stock bosses for the valve guides so the inner springs will fit on them.
They also open the spring pocket OD in the head to accept the 1.430 springs.
Some "thin" stock castings are a problem with the springs at each end of the head being too close to water jackets.
Or you can just get some "bee-hive" springs...
Long story short, if they recommend 115 lbs with .480 lift, you'll want 120 lbs with .512 lift using the 1.6's. I don't think 100lbs will get past 6K and still have stability. FWIW, I set mine up with about 124lbs on the seat and I'm running .465 to 6700. It's probably a little overkill, but with a retainer change (and cam) it would run 7K with no problem. (oh, I forgot about the stock rods, cast crank, and 2 bolt block)
BTW, Has anyone seen the original poster after we hyjacked this thread?

 

Yea, the thing is I don't have a box or receipt for the valve springs. My machinist put them on for my as part of a cylinder head re-do package. Machined for 1.94 valves, valve guides, decked it lightly, and assembly. I told him my Voodoo 60103 was going on, and it needed 110/320 or something, and he just kept nodding and saying it would need a "normal" aftermarket 1.25" OD spring. It didn't bind at .530" lift with my 1.6 rockers and voodoo cam, so I should be ok going forward. That being said, I don't know what the *exact* specs for these springs are, so i'll get an analog scale, my vise, and my digital caliper and should be able to come up with a good measurement.

I'm running entry level aftermarket rods, factory turned crank, and no balance job - so I don't intend on running it past 6000RPM. I do however want the absolute best 3000-6000RPM, which is where this engine will spend the majority of it's life. Now that I have a DD, this car can be decently gnarly to drive, and if I don't like it, I can take the Oldsmobile to the store to get milk. But when I want to SHRED SOME ASPHALT this'll do it
The ported 416's will stay for the interim, but in the long term (a year at least) a set of Dart 200cc heads with some porting will go on there.

Good point, the original poster didn't even mention which Isky cam he was looking at. A pity when you don't take advantage of the help you get on a forum. tsk tsk.

 

I thought you had stock rods. Bottom end should be ok.
You'll see. You ain't gonna want to shift at before 6500. It'll be humpin' it's butt off as it sails past 6K. You get 120 lbs on the seat and it should be just fine.
About all I can say is, it will be different.
Glad to hear you have a DD. (I have 2, counting the Co. vehicle, and not counting the MRS.'s 2005 Caddy)
My 3rd gen is "pure toy". And when I get it out to play... the neighbors notice.
BTW, I will be offline 11-24-07 until 12-03-07, cruising the caribbean. Costa Maya, Cozumel, and Belize. Scuba diving.

 

I'm mostly worried about the no balance job. I used ARP rod bolts on Ohio I beam rods, and ARP main bolts in the 2 bolt main caps.
I get pretty scared seeing the tach up that high and hearing the engine SCREAMING. We'll see how it goes.
Bah, it's still summer at your house, why bother going to a warmer climate? I'm going *snowshoeing* for my christmas vacation. Ahh trudging through 4' deep snow in the dark - now that's fun.

 

Oh, that's different. I thought it had been balanced. BTW, I'm in Tampa FL right now and it's 71 degrees F. at 8:30 at night.
I can't wait for temps in the 80's and that constant breeze across the deck of the ship. I better go check my suntan oil supply...

 

And back from the dead. Now i'm finally assembling my engine here (it stopped snowing!!! Well, slowed down at least...)
I book marked this thread so I could reply with my VOTC number, to give this thread 'closure'

I have #1 cyl at TDC now (+/- 2* lets say). I measured from a basepoint, to the top of the valve spring, zero'd my caliper, then had my brother push the valve down until it hit the piston. Boy this would have been easier without valve springs on . Anyway, .343" on exhaust, .329" on intake. So it looks good to go.

Just so you have any idea as to why I have those numbers, the hardware is:
1976 350, 010 block. Decked ~.010". Speed pro hyper pistons are .015" in the hole. Steel shim gasket from Mr gasket, spec'ed at .018-.020" compressed. Stock 1.94" valves stolen from a set of 993 heads, and fresh new 1.50" valves. Valve job (so the valve seat is probably a shade deeper).

However I ran into another problem, but since I doubt it's related to the original thread here, so i'll kindly start a new thread....

 

Well finally got the damn thing running here... Hydraulic clutch wasn't going to work for me, had to fight that thing pretty hard...

Anyway, 240/240 on a 108LSA is not enough for power brakes. No way no how. Gotta buy a vacuum can. More info to come Supervisor. Thanks for the help!

 

I kinda thought so. Get it settled down and post us an audio/video clip of it at 6K. You did say it would be more "manly". (I bet it sure is) It's going to have an "attitude" anyway... Is that a circle track cam?
p.s. welcome to the world of Isky cam owners

EDIT: Oh! I forgot. I know you prefer ported vacuum to the distributor, but give straight a try along with at least 18° of base timing.
It will help with the idle and off-idle characteristics.

 

I pulled the springs and weights and used a zip tie. It's 36* full timing. It's a BEAR to start...
I had to get it pushed into the exhaust shop. The battery dies before I can get it fired up. I'm not sure if i'm flooding it or what. The carb tuning is so far off now it's not even funny. I think I need a different power piston spring.

I think it's considered a circle track cam yea.

I'll try the manifold vacuum then too.....

It was manly alright - with open headers... good lord! It ran like a bag of smashed a*holes though, the carb/timing is WAYYY off. I did get to remember how well the thing handles though. It's a lot different from my oldsmobile!

Will know tommorow. Exhaust shop wanted to re-do my y-pipe, since apparently I have a 2 1/4" y (BS those liars... it's a hedman 2 1/2"!).... And the dynomax ultraflow welded has to come from out of town... Having them build me 3" tailpipes to match...

Steering wheel is no longer level, since I put in the new steering gear. Buying hotpart strut mounts, then getting it aligned too. Got a vacuum reservoir can in the mail now too.
Boy, $1000 or so now to get it running...

 

If you have the advance locked out, it's going to be hard to start.
You can use the stock big weights and one weak az stock spring and it will be all in by 750 rpm (which is below idle). Think of it as a "start retard".
Definately.
It's got to be able to pull it down with the lower vacuum level. If it stays open the primaries will be way too rich.
Woo Hoo!
Remember if you decide you don't like it, keep the lifters matched to the lobes...
...for me.

 

haha, yea, I still have my xe268he if I decide to sissy out... but that's not gonna happen!
Well the starter spins the motor ok, it just doesn't catch. I think it just needs the spark/fuel tweaked at idle.

And yea, i've got a collection of power piston springs. I have an extra q-jet body, to use as a tester. So i'll hook up my manifold vacuum to the spare q-jet, and find one that seems to work well, then swap to that one.

Tonight and tomorrow are going to be pretty busy!

 

Yea but cam lope sounds ssoooo cool

 

Got it running today, many bugs to work out... I think the crank pulley is bent, it's got a mean wobble... It tossed the alt belt at about 6000RPM this morning... got home, and I only had the PS belt.... No trace of the other one. I'll be damned. Also ran the PS pump dry. All the fluid got pulled into the new PS gear I suppose...

Anyway, getting the idle/mixture figured out. I put in a 5-7"vac power piston spring, gotta take it for a spin now. Have about 8-9" vacuum at 900RPM idle. I DO have brakes.
But the idle was a tad low, so after a high RPM run, the car stalled So I bumped up the idle. Seems ok now. Gotta play with it some more, will post back.

Very nice idle. Oh yea...

 

(hee hee) Now we're getting somewhere...
So, was it still pulling strong at 6K?

 

had to be... it didnt have the alternator drag to deal with

 

oh yea, it doesn't run out of fuel anymore (installed an electric helper pump), and it also pulls a lot harder above 5000RPM vs the comp xe268h I had before. That seemed to run out of breath...
I can't stand to hear it ROAR that loud, so I shift it at about 6000RPM. No idea how accurate the tach is though either...

 

If it's anything like my stock tach, that was about 3500rpms.

 

Get a decent camera and shoot some video!
Don't want my Isky to be the only one they hear SINGING do ya?

 

Yea, not sure where I'd be able to find a decent video camera though... Might be able to borrow one from work, but obviously the sound from a digital camera moonlighting as a video camera is going to be... less than average.
Will see what I can do!
Broke the shifter rod out tonight, have to pick up another pitpack for my hurst shifter... fun limping it home in second gear...


Quick question - after a hard WOT run through a few gears, I pop it out of gear and just let it coast down.... The idle always drops low, and usually stalls - what gives? Is this a pretty common big cam thing or what? Should I just break myself of this nasty habit (taking it out of gear) or is there a solution? ie, higher idle speed, etc?

 

I've run bigger and not had that problem. More than likely it needs a little more inital timing (which means you may not have the right springs in the distributor) or a higher idle speed.

 

I would steer clear of a higher idle. This leads to "run-on" (dieseling) when you try to turn it off. Remember it's preignition, not detonation when this happens. (preignition being much more destructive not to mention embarassing)
I would use an old fashoned dashpot. No hoses or wires and they still work. They make the throttle landing back to idle gradual.

 

dashpot? I'm trying to picture this...?
Where do I buy one?

 

Here's a universal one but it is kinda pricey.
Universal Dashpot

I'm sure there are some cheaper.

 

Here's another ONE:

 

http://store.summitracing.com/egnsea...nresults=false

 

"These Holley carburetor dashpots are designed to be used on manual transmission vehicles. They will prevent engine stalling on sudden deceleration, fits most Holley dashpot brackets."

No way!!! So i'm not the only one! I'll be damned! So basically when you snap the throttle shut from 3/4 or more open (lets say), then it slows down it's closing? Huh... I'd probably have to fab up my own bracket type of thing to hold it in place, since i've got a q-jet...
Hmm, I'll hold off on this until I get it totally dialed in, but if I can't fix this own my own, that's what i'll get.
Damn, talk about an oddball part...

FYI to the guy who suggested timing - I have the timing locked out at about 35* with no mechanical advance. I have about 8* of vacuum advance, on manifold right now. That's on top of the 35*, so about 43* or so total.

My 1-2 shifter rod fell out, and I need a new hurst pit kit. While the car was down today I started wiring up my vacuum gauge (a-pod mounted) and my wideband setup.

I'll be using those this coming week to dial in the q-jet more. Then i'll probably fab up my CAI, then bring it to a dyno for some real world answers.

Thanks for all the help so far guys!

 

Hell, I thought you were running an Edelbrock or holly. (I don't know why I thought this)
I got lots of old solenoids with brackets for the Q-jet.
You can do like I did and set your idle where you want on the solenoid and have it close the butterflies when you turn off the key.
(it shuts the engine down FAST!) They were used to bump the idle up when the A/C came on "back in the day".
(it's one of my "run 11:1 on 93 gas" tricks)
lemme know and I'll post pics of some old dirty parts...

 

Here's my sig to refresh your memory then.

Oh yea, I know I could use one of those A/C kicker solenoids to control my idle, but I don't think I need to. I don't want to bump up my idle too fast. Right now at 900RPM or so, it doesn't diesel at all. That wouldn't really solve my problem would it? Oh, also, having my throttle blades open too far tends to give me an off idle stumble, since it's already running on the primary circuit instead of the idle circuit. I have a surprisingly steady idle now actually...


You have the other kind of solenoid for a q-jet though? A dashpot? If so, let me know. I'll grease your palms for one of those with a bracket.

I'm going to have to borrow my sister or coworkers digital camera to get a short video. I'll also have to video tape the dyno run....

 

The A/C kicker solenoids are not strong enough to open the throttle. Once the go-pedal opens it then the solenoid will hold it open.

IOW: if at idle and the A/C turns on, the solenoid will be activated but won't open the throttle. Once you open the throttle it will then hold it.

Between that and the sudden decel stalling, makes EFI look at that much better. . . .

BTW: I'm running an Isky cam in the current engine. And have used their springs and lifters in many others. Great parts.

Rbob.

 

I didn't keep any of the dashpots, the rubber in them would be rotten by now anyway. I was thinking that we could use the bracket from one of the solenoids to mount one of these
on, but the big ones have about a 7/8" hole that the coil mounts on with a giant nut.
The smaller ones, the coil is made onto the bracket...
Maybe you'll get it settled down and it won't be needed.
EDIT: (if it gets to idling too nice, the lifters probably need adjusting; as the lash increases, duration & overlap decrease and "nice-idle" returns.)

 

oh... damn... I hope it doesn't idle too nice hahah, I've got poly locks and all that, so I don't think it'll happen too soon...
It's crazy, I can't even tell it's a solid cam, I can't hear the tick or anything. Ahh good old loud exhaust.

Couldn't get it to start tonight, so i'll be trying more stuff on it tomorrow. I think I may need to shim the starter...

 

Did you install the ignition power interupt switch yet?
Plug the vac into ported timing.
With the big cam, your stock QJET may need a IFR/ idle air bleed tweek. A bit complicated on a Qjet. (requires special hard to get long precision drill bits)
{last ditch thingy to dial in the idle.}
A AFR meter makes things a lot lot easier.

When you have the vac adv on full man vac, when you come off the throttle, timing flashes to full timing max mechanical + full vacuum.

If you use ported as a source, you avoid this.
How much manifold vacuum do you now have at idle?

You can create your own home brewed "idle eze" to allow proper idle throttle blade position and idle speed with a pep **** on the PCV hose to adjust the airflow/idle speed at idle. (as opposed to drilling throttle blades), if you need to.

Don't be afraid to experiment with the idle timing, throttle blade opening, "idle eze" adjustment to fine tune it . I only suggest the locked out timing as a starting point. Your 240° cam is sort of middle ground, not a mild cam and not quite a race cam so the required idle timing will be somewhere in the middle too.
24 ish 26 ish 30 ish.
Once you've found the right balance, it should not stall on you as your come off the throttle after a high rpm WOT blast.
It is not a good idea to declutch or pop a auto/trans into neutral during deceleration. Some race tracks prohibite this.

By the way there is nothing old school about Isky cams.
When you make something right the first time, you don't need to change it every week. Iskys published catalog grinds are in no way all he's got to offer.
the stuff in the catalog are stuff that works for the majority of people that are building typical stuff. If you want something beyond this give em a call. They like/prefer to custom grind stuff for your application as a whole system. Getting the right cam grind and kit makes all the difference in the world.
They have lots of radical state of the art lobe designs and know how to apply them for the right purpose.
Their stuff does and always did make excelent power including the hyd roller stuff with excelent durability especially when used as recomended.
They seem to gear their marketing to the serious oval guys more than the street crowd.

 

No ignition power interrupt yet.
I am having trouble with my starter wiring. Either the wire from the battery to starter is faulty (had to fiddle with that last week...) or the starter is jamming, and needs some creative shims to re-check that. It won't kick over at all now.

Hmm, ported vac eh? Well I can give that a try I suppose.

idle air bleed tweak - i've heard about that. I've heard I can remove the idle air bleed tubes, then drill them, and press them into an allen plug or something, and thread them back into place. That way they are removable for future re-drillings... Might look at that soon.

I have about 9" of vacuum at idle. It flicks around 9-10" or so.
Hmm, a pet-**** on the PCV hose eh? Huh, wouldn't have thought of that... A controlled vacuum leak basically eh? Hmmm... Well right now i've got 1/16" holes in the throttle blades, and i've got a pretty nice idle, but I might play with that idea in the future.

Ok, for now i'll avoid pulling out of gear after a high RPM blast then....

Right now I need to finish wiring up my wideband AFR (I hate wiring so much...), and check the starter wiring/engagement.