Bought a brand new crate engine from a very well know engine guy in Phoenix and he said his Pump gas 383,s normally run 480,500hp with Afr,s and hyd roller cams.

Shipped it all the way to Australia put it on a dyno and was struggling to get 430hp
after 1 hour or adjusting things and sticking a 1 inch spacer on it it ran 439hp

brand new GM 4 bolt block, Scat 4340 kit 10.5 comp pistons hyd roller 1.5 rollers, Rpm edelbrock 750 Hp setup properly.

AFR CNC 195,s.

engine showed 150lbs cylinder pressure.
It ran i guess as expected as parts suggested,, 10.5 comp, Hyd Roller cam, Duel plane intake.??

We ran on 95 UPL
Possible problem
I should have asked for 11.5 comp, solid cam and victor JR intake.

car is a stripped out 82 Running no AC or emissions
1 3/4 headers a 2500 stall YH350 and 3.44 eaton trutrac.

car did run 13.0 @ 107 mph in 1/4 with old 408 and vortecs.
i feel this 383 will struggle to run 12.5,s but i have spent $8500.

could have had a good engine built here but parts are 30% more expensive.

Dyno is Very Accurate,,,, and has been on the money for years,,it is reliable.

When the engine was shut off,, the crank rotated for a few revolutions before it stopped. Engine was not still running, it was shut down but crank still ran a bit,,i never saw this before.
they normally stop dead.

When it was built i was sent a video of it running and you couldnt see much,, it was a waste of time.
Before we ran it here we checked the spark plugs and they were light grey like it had been run on Sunoco race fuel or something,, the spark plugs were also short reach retracted,,
we put a new set of NGK,s in it and ran on our 95 pump gas...

Dont buy crate motors even though this wasnt a production line crate motor or a massed produced item.
Its got no more power than the ZZ383GM crate motor. But for the price i paid $7500 what do you expect.

not good


expensive

 

What cam is in it?

 

THATS the BIG BIG BIG thing i wanted from the engine guy a CAM CARD and a few numbers so we can tune the thing,,i constantly asked for a cam card i imported the engine and got nothing.

Cam info is all i wanted... in saying that,, no matter how many cam cards he gave me doesnt change it as it is BUT it would have let us know where we are at and thats critical. in my view.
It would have eliminated a lot of guess work. and head scratching.

He engine builder had it running 40 degreese
We at the dyno yesterday backed it off to 38 and it seemed better.. oil pressure was 100lbs!! at 4500rpm,,wow.. crazy,, something working i guess.

 

my guess is the cam isn't big enough. How much vacuum are you pulling at idle? Say 700 rpm?

 

Yikes. Horror stories like this always scared me when dealing with shops that offer crate engine packages. I only ever bought one assembled short block and never had an issue. Rest of my motors have come from other shops machined checked and ready for assembly. I always assemble my own when i can or now that i have a good local contact for my machine shop stuff, have had him do work.

idk what you mean by engine rotates over after shut off. Like it keeps spinning and slow to come to a complete stop? Sure it aint dieseling abit? How much effort does it take to turn motor over if you put a socket on the crank bolt and attempt to turn it?

150 psi sounds slightly low but depends on how big the cam is

theres no reason they shouldnt have given you all the detailed parts information with the motor. That’s crazy to not have cam info. From the hp peak it probably is in the 220-224 deg at .050 range. Afr 195’s can get up to 480-500 hp range but need cams in the 230’s deg and some lift to really shine.

Maybe they could tell you what type of dyno they used and what dyno headers/intake/carb system they used? Not all dynos read the same and even though they are suppose to be calibrated they dont always get serviced or checked and then again there are differences in design, and dyno pull rpm rates. I dont know but being down 40-50 hp seems odd if they have done the combo before and its made 475+

40 deg of timing is way too much on afr 195 heads in my experience. 34-35 is usually all they need

lastly, 100 lbs of oil pressure is bad! Thats way too much. What weight oil and do you know what clearances? A high volume pump is not needed for a sbc.

 

Due to the cost of parts here a good 427 dart would have run $15,000 Aussie dollars,, and i am selling the car this year,,
the 383 was supposed to have a detailed list and all the documernts that come with the parts used in an envelope.

i cant even get a cam profile off this guy and the shop is right up there with the reyer morrison type shops,, its a famouse speedway shop in phoenix Az and even AFR reccomended them so did Hahle and
i think i just got taken a bit and its got 150 cyl pressure,, my old 35 year old 400 2 bolt had 170 ..
i dont want to pull it apart and do pistons.. we will pull the cam and use Cam Doctor to see what it is if its got no markings on it.. see where we are At .

we will get a custom solid cam made here.. based on what the rest is..we should get another 25hp and a victor Jr may be added if its still no good..

 

Dyno is good,, builder here often builds control engines for confederation of Australian motor racing and its all callibrated ..

reason i didnt want him to do me an engine is i didnt have enough to build a 427 and he told me not to waste my time with a 383 but i was short of cash and this is what happens!!

 

I'd say, without a whole lot of other detail, this nails it. To make HP overall, you at least have to make lbs/ft down low. This compression pressure may confirm that isn't happening.
With 10.5:1 SCR (assumed, not measured?), and half decent heads, a well spec'd cam should let you make that advertised HP. And a well spec'd cam is going get higher cylinder pressure than 150. So something is out of whack.
All of that isn't necessarily the case in all instances (to save me from getting burned here) but for the most part it holds true for your average 10.5:1 Gen 1 SBC.
It wouldn't take much for you degree the cam and figure out where the ICL is and what the LSA is. That'll give you any info that the cam card might and let you decide if the cam is just wrong or something else isn't right.

EDIT: It's worth repeating that the ICL is going to go a long way into determining the cranking compression.

 

WHOA WHOA WHOA. Hit the brakes.

None of this matters then. You've got a receipt for a brand new engine from xxxxx speed shop. And most people are going to think the car goes like hell. So keep your mouth shut about YOUR discontent and let the potential buyer wear a silly grin from ear to ear.

DO NOT tear into a freakin' brand new engine that just raised the value of your car a factor of 3. If it's running and will shred the tires then leave it the hell alone and put the 'For Sale' sign on it and don't talk. Even better, have your wife sell it for you.

 

the car is worth $25,000 here,, if it runs low12,s its worth $40,000.
its just been painted brand new,,

i could get $45,000 if it screams.. 490hp will get me 45k

 

That must be Australian math where '+' and '-' is opposite the northern hemisphere.

You can't make money buying crate engines. If you could then there would be more crate engines than cocaine.

 

Lol exactly. Im in the wrong business then.

anyway do what skinnyz says, put a degree wheel on it and check valve lift at the rocker. Check what the .050” lifter lift durations are (at the valve that will be .050 times your rocker ratio) record the open and close figures and see what you come up with. Do intake and exhaust lobe. Should get you an idea.

 

sent an SMS to Engine buy in AZ,,, he will send cam specs,,
i think lack of compression
lack of cam
mydraulic roller
duel plane intake.
the rest is good.

Another thing these AFR 195,s have 3/8 rocker studs!!! a bit lame i thought

we will need a stud girdle or change the rotten things. FAR OUT..
This is what happens when you are trying to drink Whisky from a Bottle of Wine.
Its no good flogging a dead horse.

I should have bought an $1200 Eagle rotating assembly a set of Brodix Ik200 heads and put the old 408 back in it to sell.,,it flew with a stock bottom end and Vortecs..

not a bad idea,, if this 383 is crap i will sell the car with the old 400 as above.

 

The afr’s are great they just needed ordered withthe right parts. 3/8 is ok for most things tho. I like 7/16 for the heavier hyd roller springs they offer but should be ok

is it a performer rpm dual plane? That should be a good intake. Its capable of power. Port matched to afr port, carried into the runner some. They are proven

 

That dyno curve looks funky just by the numbers.

The torque peaks at 4900rpm, but the HP flattens out by 5300rpm.

Its almost like its choking past 5000. I'd expect an engine that makes peak torque around 4800 to carry the power upwards around 6200.

I have a healthy cam, and the AFR195 street ports. In all the logging I've done peak torque is right around 5000rpm, and the power curve doesn't flatten until 6500rpm.

 

It probably is.

OP what kind of exhaust is on the car? Long tubes? What size air filter? If it can’t breathe it isn’t going to make power.

 

Looks to me like that dyno is an engine dyno, not a chassis dyno. Probably run with open headers or some dyno long tubes.

GD

 

I agree with Thirdgen89TA. That's enough head and intake to make power up to at least 6,200 RPM, but the torque plummets after 5,200 RPM. This looks like, be a v to me anyway, toalve control issue. What valve springs are in the engine? It's worth pulling a valve cover and check the install height and spring pressure at installed height.

 

I initially thought valve control but the power does not fall off early, it holds power fairly well. Its almost like intake restriction for it not wanting to peak higher

 

I'm mildly confused. That dyno sheet is for the 383? The sheet says Sun Aug 27th 06. Has that been around that long or is that a different engine that was dyno'd? Just sake of wrong date?
Peak torque at 5k and hp peaking at 5700 seems strange for sure, though I have no explanation.

 

Might cost a little more, but unless you can accurately measure the cam that is in there, I'd stick a cam in it that actually will deliver the numbers you are looking for. I'd also pull a head and measure deck height, gasket thickness, piston cc, etc., and actually verify actual compression ratio. Cheap insurance, relatively speaking to what you have spent, and you will sleep better at night.

 

A 383 with AFR 195's (current eliminators) should easily reach 500hp at the crank without having to spin to astronomical RPM. A 350 can do it, though the RPM is a bit excessive for and the street manners of such a cam are far from what most people would consider friendly.

Though, my GTA isn't too terrible considering the cam has 66* of overlap. Going over the data logs between 700-900rpm it averages about 18" of vacuum according to the MAP sensor from one datalog where TPS = 0% and Speed = 0mph.

 

18” is alot. My last two turbo cars had cams that made closer to 12” at 1000 rpm idles lol. I like cam in my cars lol

 

I only make 8" vac on my setup. Being that it is a street-show-drag-autocross car I worked the power brake booster too hard and caused it to fail after 8 drag race days and 3 autocross days this summer. I am going to put on an electric vacuum gauge this winter but if the Op has 18" of vacuum that is awesome. Does seem like a lot!

 

Exactly. That and what headers were on the engine as tested in Oz.
Or did somebody accidentally put a restrictor plate in there...?

Agreed. 66° of overlap is easily managed. What's the timing at idle when you're seeing 18" of vacuum?
At 71° I can pull up 10-11" idle vacuum @ 750 RPM (with a wheezy worn out shortblock and too low a CR). That's with 30° timing. Remember though that the difference is not just 5° of overlap but also the area exposed by the opened valves. With the greater overlap comes lift points that are further along than if the LSA was tighter.

This may have been discussed in your thread but I'll ask here for comparisons sake. What's your overlap at advertised duration? And what's your idle timing? 8" seems somewhat on the low side.

 

I was surprised, when I built the engine a long time ago it was only 14-15" on a vacuum gauge. Maybe the ECM reads it differently than the vacuum gauge did. I suppose I can hook up the gauge again and look.

I still need to open up the IAC hole though, I have a big split BLM issue. Common prob on LT1s with bigger cams. Definitely doesn't like to idle cold and IAC steps are usually near maximum.

 

Lt1’s should have injector offsets for individual cylinders

 

OT, but the one of the reasons the LT1s have split BLM's at idle with large cams is that the IAC passage isn't large enough. The PCM does have individual cylinder control, but one of the required fixes is to actually drill out the IAC hole in the TB to allow for more air. I just haven't done that, so my idle split BLM issue is largely because of that. One of these days I'll take the TB out and drill it larger. That'll also bring my IAC step counts down at idle and let the car start without dying so easily.

 

Sounds a lot like an old school carburetor trick with big cams. A couple of 1/16th - 3/32nd holes in the primary butterflies allowed the throttle to be more towards a closed position thereby restoring the carb to a more normal operating spec.