C4 383 - 100 Horses Sleeping at Rear Wheels

[delnic]

My 1985 383 has not run like it should since I had the engine installed on 12/21/01. It only pull 315 horses on the dyno at the rear wheels. It has a Lingenfelter super ram, 58 mm throttle body, Lingenfelter 219/219 hydraulic roller cam and 1 & 3/4 full length headers, CompCams 1.6 roller rockers, underdriver pullies, AFR 190 full competition heads with 2.02/1.60 and 63 chambers for a compression ratio of 10.7:1, Keith Black flat top pistons, MSD 6A, 26 pound Accel injectors, adjustable fuel pressure regulator, high output fuel pump, 3.54 rear, 700-R4 tranny, B&B TriFlow cat back with high flow cat for an 86 vette, K & N filter, Accel super coil, and Gen VII Accel computer with wide band O2 sensor. The long block four-bolt 383 came from Golen Performance Engine Service. The car only ran right once, and it smoked the tires from 25 - 65 MPH. It has not run like that since. I shipped it to Formato's Faster Proms in Tampa, FL from Virginia a year ago. It still did not run right. It has been in Tony's Corvette Shop in Gaithersburg MD. Now the car has been at one of the best tuners in the Northern Virgina area since 7/15/03 and he has not figured it out yet. He said it is not a fuel problem. Any ideas, please because it should be pushing around 400 HP at the rear wheels???

Also, does anyone know what parameter valve covers will fit my 85 with 1.6 roller rockers and clear the windshield wiper motor for the left (driver side)?

One other thing, since the car is no longer MAF, but rather speed density, will the larger air snorkel and filter box for a 93 Vette work on my 85? It needs more air.

Thanks :confused

 

[-=Jeff=-]

Have you done a compression test or leakdown test? Also how well is it in tune? Have you also checked the timing to be sure it is correct?

As for an Airbox, the 90-later have a slanted radiator so the airbox will not fit in your vette. I would suggest the TPiS Racing intake and then replace the MAF with a piece of tubing. That is what I did.

I have a feeling you car has either a computer problem or the timing is off.

Good luck

 

[vader86]

Something is really wrong, LPE SR 383s put out over 440 crank HP with D-port heads, yours with the AFRs should be putting out well over that.

Either you have a serious internal problem or the computer system is all F'd up, I know the Accel DFI can be hard to get a handle on, I suppose its not installed correctly (wiring wise).

Compression test, you might have to go in diassembling things too if its not the computer.

It should be putting down ALOT more power than that with the current intake, which is very capable of feeding it.

 

[delnic]

The timing is right on the mark. The tuning is fine. The compression is fine. Formato's FasterProms initially burned the custom chip, but it only made 290 HP at the rear wheels. Howie Cronice in Tampa also had the car.

Dynotech of Woodbridge, here in VA told me that the problem was in the chip and that he would be able to properly tune it with the Accel Gen VII. The guy at this place has a lot of experience tuning Gen VIIs. The Gen VII is connected to the original computer via an interface that I purchased from Fast Track Performance in California. Before I had the Gen VII installed, everything on the stock computer checked out OK. Could a bad module in the distributor cause a loss of power?

The engine does not show any signs of internal problems.

This thing really has me frustrated. I will contact TPIS for the racing intake.

Thanks. Any other ideas would be appreciated

 

[tntcorvette]

I do not know much about Accel DFI, but you have the DFI connected to the original computer too? So you have 2 computers in your car? The accel DFI & the OEM '870 ecm?

My understanding is that the DFI is stand alone and does not need the oem computer at all. Where is the timing set at? I run 10* timing on my 357 sbc w/o any detonation problems.

Do yourself and your car a favor. Dont bounce it around from shop to shop. Try and stic with one.

Is your cat. converter clogged?

I really do not know what to say because with DFI, I always assumed (yeah, its a bad thing to do) that as long as the a/f ration was where you wanted it, the DFI did the rest. Maybe you have a bad camshaft. Where does your hp peak at? Can you post or show us via typing what your dyno numbers look like including hp & torque and at what rpms?

 

[Mad-Mic]

i know Tony and he does fantastic work! but i'm not sure if he works alot on aftermarket DFI setups.

you might want to contact www.JimsPerformance.com he is in elkridge area and has done a DFI on my friends 86 in late fall last year. i know he does some crazy modding and am sure he can find your problem.

 

[delnic]

The Gen VII DFI controls the engine and the factory computer controls the dash gauges. Fast Track Performance sells an interface that enables you to keep all of your gauges working the same except you lose the instant fuel mileage readout.

The timing was set on 8 degrees the last time I saw the car, which was 7/15/03. It has been in the shop ever since. I am not sure what the total timing is set on now since John Sealock at Dynotech of Woodbridge installed the DFI, but it had pretty significant detonation with the Formato's FasterProne chip in it and did not seem to want any more than 34 degrees total timing them.

The cat is a new high flow catfrom Catco for an 86 Vette because the 86 cat is larger than the one that comes on the 85. I inspected the cat before it was installed and it was not clogged.

I changed from the first hydraulic roller cam that came in the engine and installed the Lingenfelter 219/219 hydraulic roller cam in it because I thought that maybe the 210/220 with .500/.510 lift by CompCams may have been the problem. At the same time, I changed from the Edelbrock Performer RPM bowl ported heads with LT1 springs to the AFR full competition 190s because I thought that the Edelbrock heads might have also been holding it back. I upgraded the injectors to 26 pounders and installed a Walbro 255L per hour pump. All of that only netted a 4 HP increase on the dyno. Unbelieveable!

Before making all of the upgrades that I just described, my dyno figures at the rear wheels were as follows:

HP - 290 @ 4700 RPM with air fuel ratio of 12.3 at peak horsepower reading
Torgue - 414 @ 3000 RPM with air fuel ratio of 14.4 at peak torque reading

I don't have the dyno printout for the latest 315 horses at the read wheels with the DFI, but these are the rear HP figures after the upgrades noted above with the Formato's custom chip specifically designed for the upgrades:

HP - 305 @ 5100 RPM with air fuel ratio of 13
Torque - 357 @ 3900 RPM

The car actually put on it very best performance once prior to all of the upgrades. Then it felt every bit as strong as any 383 has a right to feel. It ran so hard that it fried the rear tires from 25 to the point that I could smell the burning rubber inside the car with the windows up while accelerating up to 65 MPH before I got off of it. That was the only time that it ran that way -- the horses layed down and went to sleep after that.

 

[delnic]

Mad-Mic, I just visited Jim's website. It looks like he is capable of doing impressive work. And yes, Tony does impressive work. I had him to change my cam and heads. He did not do any tuning for me because Formato's was burning my custom chip.

I want to leave the car with John for a while longer because he has an 85 Vette with a 396 stroker in it that he is working on for another customer. It has basically the same setup as mine except the owner has a TPIS mini ram on it. John is going to compare the dyno result of the 396 stroker with my 383 and try to pinpoint the problem. However, he has had my Vette over 6 moths now.

 

[tntcorvette]

I dont know what to say....looks like your hp is peaking around where the 74219 combo's do. Is the cam installed straight up or advanced or retarted?

 

[delnic]

The cam is installed straight up.

I just spoke to John, who has my Vette in his shop. He said that when he put his other customer's 396 85 stroker Vette together, it immediately went to where it should be in only five pulls on the dyno in terms of HP. The 396 pulled 398 HP at the rear wheels and it is nearly identical to my 383 except it has a more radical cam in it.

 

[tntcorvette]

Maybe your transmission is slipping and you are loosing h/p there. How does the tranny feel? Maybe that time you got on it you broke something????

Just a thought because it sounds like a mechanical issue somewhere.

 

[tntcorvette]

also have you performed a compression check?

 

[delnic]

It may be possible that I broke something when I got down on it, but the transmission shows no signs of slippage. John, who has my car, said the transmission is fine. The compression is also fine with no problems.

 

[tntcorvette]

I do not think there is a way to check if the transmission is slipping or such like there is a way to check if the compression on a engine is fine.

Like I said earlier it sounds mechanical. I'de try to lean out the afr to around 14:1 and see what happens.

Good luck.

 

[-=Jeff=-]

OKay you stated you had a compression test done..

What about a leakdown test. sometimes the leakdown will find what a compression test cannot

 

[tntcorvette]

OKay you stated you had a compression test done..

What about a leakdown test. sometimes the leakdown will find what a compression test cannot

jeff what is a leakdown test? Looking for a blown head gasket or such?

 

[delnic]

John, who is working on my Vette, told me that the leakdown results were fine.

 

[-=Jeff=-]

jeff what is a leakdown test? Looking for a blown head gasket or such?

Yeah, checks for that and valves if they are not sealing properly

 

[delnic]

I found out the cause of the lack of power in my 383 and it is not good. As a matter of fact, problem is terrible. Golen's Engine Service sold me a bad engine that was bad when it arrived at my door steps. I am grateful to John Sealock of Dynotech of Woodbridge because he ran a compression leak-down test and also decided to pull the oil pan. He found the following after he dropped the oil pan:

1. The engine is a 2-Bolt Main block, not at 4-Bolt Main block that I ordered and paid for as stated on Golen’s Engine Service build sheet.
2. There are three different kinds of rods in the engine, all of inferior quality.
3. The crank shaft is not an Eagle Steel crank as I ordered and and paid for as indicated on the Golen’s Engine Service build sheet. Instead it is an inferior quality “scat,” crankshaft which that is the cheapest crank shaft on the market.
4. Instead of the block being properly notched as required for a 383 stroker application, Golen’s Engine Service machined the ends of the rod caps for block clearance. The numbers on the rod caps have been machined away until the point that no numbers are visible, making it highly probable that the rod caps would be miss-matched if they ever have to be pulled off and put back on.
5. A couple of the rod bearings are not hitting round, which is an indication that there is a serious problem with the crankshaft, which is the central part of the lower engine’s components.
6. When you rotate the crank shaft, there is a “tight” (friction) spot during the rotation that is not suppose to be there, which is evident that the crank shaft is either not properly ground or is improperly balanced.
7. There is an anti-freeze stain on the bottom of the number 8 piston.
8. The results of the compression leak-down test follows:

• Number 1 Cylinder - 60% leakage going into crankcase
• Number 3 Cylinder – 90% leakage going into crankcase
• Number 5 Cylinder – 12% leakage going into the crankcase
• Number 7 Cylinder – 20% leakage going into crankcase
• Number 2 Cylinder – Headers too close to attach tool
• Number 4 Cylinder – 18% leakage going into crankcase
• Number 6 Cylinder - Headers too close to attach tool, but blowing over into #8 cylinder
• Number 8 Cylinder – 60% leakage; head gasket blowing over into #6 cylinder

On top of this, though Golen's Engine Service (advertised in Super Chevy, Chevy High Performance, Hod Rod, Car Craft, Popular Hot Rodding Magazines, etc.) had to admit that they did not put everything in my 383 that I ordered and paid for, they tried to discredit my master machanic. Since they could not convince me to agree with them, they refused to provide me with another engine. I am going to have to settle this matter in court. I would not wish this on anyone. I am insulted that such a screwed up engine was installed in my Vette. I am angry that I was deceived. This was suppose to be a new engine. Make very sure that you are careful when you buy a crate engine. All of them are not what they appear ro be, or what you may pay for.

 

[tntcorvette]

Welcome to the "i've been screwed over by somebody who is allegedly reputable" club.

It happens to the best of us.

Glad you found out what is wrong with the car. Personally i'de ask your mechanic for a local engine builder who is reputable and go from there.

Good luck.