Engine build-up Questions

joshbea6

Registered User
Gentlemen....(I use that term fairly lightly:D )

I recently had a "sit-down" with the performance engine shop that I am working with to set goals for my engine rebuild.

Just to give those of you whom I hope to hear responses from a little bit of history on the project...

The 1990 SC had 169K miles on it when I took it apart. The engine was leaking fluids through all of the gaskets (Head Gaskets were still intact however, no coolant passing between water jackets and cylinders). I pulled the engine out, and down and took it to a shop here (Columbus, Ohio) called Performance Research. They have been building custom blower motors for boats for years (at least 20).

The minimum goal for the project is to have approximately 550 HP at the crank.

The block and heads have been magnafluxed (No cracks) and they also have the heads pulled down and are going to be decking both the block and heads.

I purchased a set of Wiseco pistons from Supersix Motorsports about a year ago, and was waiting on funding so that I could get a set of ARP bolts for the stock rods. My engine shop recommended that I get a set of aftermarket rods due to the the issue that by the time I had purchased the bolts, and they had set-up the rods, cleaned them, installed them on the pistons, and installed the bolts, that getting a better set of aftermarket rods would be a better solution for me and that way they were going to be right from the start and would require NO prep time.

In speaking with Tom at Supersix, he mentioned that the Scat 351 rods that he uses could be used with the pistons that he sold me, but that I would need to have the machine shop take material off the top of the piston so that it would have proper valve clearance, as the 351 rods are longer than the stock 3.8L rods. I understand all of that, and that he can't take the pistons back into his inventory (after all the purchase was made about a year ago).

In speaking further with the guys at the Engine shop, they recommended that instead of using Nitrous on the motor, that I use a CO2 injection into the intercooler to reduce the boost temp to gain HP. Now I am going to be using an aftermarket intercooler such as the MP, or I may try and adapt an intercooler such as the one for the F350 as I have the car completely bare-bones and there is literally NOTHING on the car as it is headed for the dip tank this fall, so there is NO BETTER TIME to do this than now.

Furthermore, I am also looking for opinions on the following:

1. Camshaft profile (so I can get the proper one ordered, and also the proper
springs)
2. Autorotor, or MPIII, so that I can give the proper SC specs to the engine
shop for matching flow capacities.
3. Engine Main Bearing Cap Girdle/ Windage Tray, who's got the best one,
and do I even need one for 550+ Crank HP (I'm thinking err on the side of
caution on this one and just do it the first time)
4. Exhaust Manifolds, ported stock to high-flow cats, or headers to high flow
cats?
5. Should I go with a new piston rod combo, if so, whose combo to use, or
should I stick with the stock rods and ARP bolts

I have given the Engine shop block, heads, and intake manifold as well as the crank, new pistons, and old piston/ rods.

As far as the rest of the project goes for this 90-95 SC Hybrid project, I am going to also be tackling the following:

1. Tremec 6 spd transmission (due to the fact that my M5R2 needs new shift
forks and that the parts like shift forks are getting VERY hard to find)
2. Balanced Aluminum Driveshaft
3. 3.27 Gears with an Aluminum Diff case
4. IRS rebuild (strengthening, and bracing like Rich at MN12 Performance did
with his car)
5. Chassis bracing for strength along the uni-body
6. Front Strut Tower Brace
7. Rear Strut Tower Brace

Another question that I have on this project, is with the HP from the engine, I guess that I should expect close to 400-450 HP at the wheels? With that kind of power, will I need a rollcage, and if so, how many points?

I'm looking for opinions on all of this as this is my first performance engine rebuild project and I want to get the best "Bang" for my buck, and I want to only have to do this once........God willing that I don't throw a rod.....or a crank.

Thanks in advance....
 
joshbea6 said:
...
The 1990 SC had 169K miles on it when I took it apart. The engine was leaking fluids through all of the gaskets (Head Gaskets were still intact
...
The minimum goal for the project is to have approximately 550 HP at the crank.

The block and heads have been magnafluxed (No cracks) and they also have the heads pulled down and are going to be decking both the block and heads.

Heads are aluminum, so the can only pressure test them. But you got the point right... no cracks.


joshbea6 said:
...
In speaking further with the guys at the Engine shop, they recommended that instead of using Nitrous on the motor, that I use a CO2 injection into the intercooler to reduce the boost temp to gain HP.

You're never going to get as much power from CO2 injection as you would nitros. But with a MPIII or for sure the Autorotor, mid 500 crankshaft horsepower shouldn't be an issue with a proper cam and head work.

joshbea6 said:
1. Camshaft profile
2. Autorotor, or MPIII, so that I can give the proper SC specs to the engine
shop for matching flow capacities.
3. Engine Main Bearing Cap Girdle/ Windage Tray, who's got the best one,
and do I even need one for 550+ Crank HP (I'm thinking err on the side of
caution on this one and just do it the first time)
4. Exhaust Manifolds, ported stock to high-flow cats, or headers to high flow
cats?
5. Should I go with a new piston rod combo, if so, whose combo to use, or
should I stick with the stock rods and ARP bolts

I'd go with the Scat H-beam rods and have the pistons milled to zero the deck and get the proper compression ratio you want. Super-Six will have to help you with how much can safely be taken off those pistons. If not already done, I'd have those skirts moly coated at the least.

Scat H-beam rods come with ARP bolts already installed.

Camshaft profile is a bit of a black magic yet. I'd suggest you consult with XR7 Dave (Dave Dalke, Supercoupes Unlimited Inc. mdkracing@alltel.net) who sells re-grinds, and new grinds of SC camshafts, or Victor at http://www.spinningwheels-sc.com/ who also sells new camshafts. Both folks, I believe, would rather talk to you about what you're doing before just throwing out any cam numbers for a generic engine.

Personally I'd go with the auto-rotor, but from what I've seen, the MPIII would probably get you to the HP goal you have, without nitros. The auto rotor could take you beyond that for sure.

Personally, I think you could get away without the girdle. But if you have the budget for it, I can't see how it could be a bad thing to have. My feeling is simply from those that have already put down that HP number and survived without a girdle.

Wynn at www.texasthunderbirds.com has been working on fairly custom long tube headers for the SC. I saw the prototypes, but haven't seen them on anyones cars yet. If you can get in touch with him, I get the feeling his headers would be the best bet.

Good luck with the project. It sounds fairly significant.
 
Mike, thank you for your weigh-in.

I could really use some discussion on this one so that I do it right the first time and don't sink a fortune in the "wrong" areas. I've been doing plenty of reading on people here who have sunk a fortune in areas that they regret, and are resenting ever owning an SC because of their frustration.

Please let me know opinions/ etc. so that I can get this project rolling again.

-Josh
 
Have you seen this thread in the members area? I was planning to go for under 400rwhp and got lots of great useful input from some of the smartest guys around here.
http://www.sccoa.com/forums/showthread.php?t=54274

By shooting for a bigger number, all I'm doing is going with forged pistons, h-beam rods, and a new cam with ported heads. I hope to bolt on a Auto rotor here in the next 10-12 months but will drive it this summer with the stock M90.
 
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