Picked up a new project - 1993 Coupe

TTSaleen

Active Member
Apr 27, 2025
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Picked up a new project.
1993 Coupe - Twin Turbo, LS engine, TH400 trans. Has ran 5.40's in 1/8th and 8.60's in 1/4.

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View: https://youtu.be/tcpDDyBVBms
 
@86HO5.0 - I live outside of Raleigh in a town called Willow Spring.

Tore it apart to figure out the issue.
Determined the pistons were hitting the heads, effectively pushing the heads off the block and blowing the head gaskets!
Gotta fix that and repair the head that got torched and then put back together.
This setup should allow the car to go faster than previous 5.40's/8.60's to something like lower 5's such as 5.20's to 5.30's on these GT3582 turbos.

So the plan is to fix it and race it and squeeze some impressive track times out of it.

Here's the problem I found today.
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View: https://youtu.be/PJJZTiP6x9A
 
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Yeah i would go blind if i saw that engine in that car,lol,it is a beautiful car though and a beautiful shop,if i had that i would never stop working on cars.

Those are some big valves in those heads,what caused that piston to hit that head? was there something rolling around in there? When you have Axles that look like that is when you know you are putting serious power to the ground, is that head fixable or is it junk? sorry for all the question,im just a curious person.
 
Yeah i would go blind if i saw that engine in that car,lol,it is a beautiful car though and a beautiful shop,if i had that i would never stop working on cars.

Those are some big valves in those heads,what caused that piston to hit that head? was there something rolling around in there? When you have Axles that look like that is when you know you are putting serious power to the ground, is that head fixable or is it junk? sorry for all the question,im just a curious person.
Thanks. Yes the shop has definitely enabled me to work on stuff much easier!
They are 2.04 intake valves and 1.57 exhaust valves.
The interference was from the piston crown touching the head. My new engine builder (Redline Speed Shop) said they can massage the pistons slightly to clear and/or run a thicker head gasket. Will know when they fix my heads (they said that is no problem) and reassemble it to check piston to valve clearances.
So I should have this engine back together in about 3 weeks (waiting on parts).
Ryan
 
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Cool, i hope you get it running good ,since one piston hit the head how come the other ones didn't? im guessing the builder didn't check piston to head clearances in the manner he should have? ive built a couple of engines before but basically copy and paste stuff, nothing radical.
 
Cool, i hope you get it running good ,since one piston hit the head how come the other ones didn't? im guessing the builder didn't check piston to head clearances in the manner he should have? ive built a couple of engines before but basically copy and paste stuff, nothing radical.
Each head showed marks where each piston was hitting in the same area. He did check it and had over .010" of clearance. However he didn't take rod stretch into account. Basically a thicker head gasket would have been a way to fix it.
I'm getting the entire engine gone thru to ensure the block deck surface is flat in addition to other things since water went thru the oil.
Minimally it will have all new bearings, oil pump, timing set, plus head repair and all clearances checked/verified.
I predict it will be a monster when I get it back in the car.
Ryan
 
The 31 spline axles I have used in many cars seem huge to me... I can't imagine bending those splines on 35 spline axles.... Really sticky tires with some big horsepower....
 
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Almost got the car ready to fire up. Sent injectors off to Fuel Injector Clinic to flow/test them before completing car.

For now, got my Bogart RT wheels on it (17" front, 16" rear) and adjusted the front coil overs down about 5 turns.
Also installed LED lights in the gauge cluster, a V8 tach replacement for the 4 cylinder one, and Makers Garage license plate housing with LED lights.

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The fact that the machine shop got you knocked out in less than a week is unheard of. Go buy a lottery ticket while youre at it. I like the LEDs, I need to do that. I had a Chinese LED company reach out to me on Instagram and offer to send me a set for free to review. Havent responded yet, not sure how I feel about it...
 
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