Charles A. Toupin

Hi Guys,

I want to ask the guru's out here. Here's the picture:

1) My engine has to be partly redone. It has about 1000 racing miles on it. 25% leakdown on three cylinders, 100% on #3. The heat shield between the turbo and the brake master was not put back at the time of the rebuild. At Watkins Glen last May, something on the outside of the brake booster caught on fire and the rest of it got sucked into the head, most probably leaving a valve open, thus the 100% leakdown on that particular cylinder. Furthermore, when it had about 250 miles on it, a valve stuck open and hit piston #1. The piston does not weight the same as the others as material has to be removed (the engine had been blueprinted at the time of the build)

2) Specs of the engine:

- 100.5mm Arias pistons;
- Steel sleeved block (not the Darton, only the thin ones);
- shotpeened rods;
- lightened and khife-edged crank;
- 968 piston squirters;
- ported head but stock air intake;
- Vitesse MAF with custom chip;
- Speedforce stage one intercooler;
- Speedforce complet 321ss headers and downpipe;
- 38mm Tial WG;
- Speedforce 57mm turbonetics

I want to race it again this year. I have to work on the head and I would change the pistons and rings, polish the sleeve...

Cheap rebuild?

Now I'm there, could I sleeve it with Dartons (3.0L), buy a 2.7L head, buys new pistons and rods, another crank (which one?), send the chip to John at Vitesse for that new configuration and slap all the other parts that I have?

Or I can't? And how about my rods? Good or not (for racing)?

And buy new 100.5mm pistons/rings, use a non turbo head that has been race prepped, maybe add a stroker crank and just go that way?

Currently running 17/18 PSI with race gas. The car could do 2:05 at WG, this is if it would last more than 30 minutes without getting on fire

TIA

c.

NB: I can move the car under its own power, albeit running a bit rough.

Tom M'Guinn

Of course you can. Here's your shopping list:

104mm block (they're cheap and reliable)
Mahle motorsport pistons
88mm crank from S2 or 968
Carrillo or other strong rods (somewhat optional)
2.7 head with turbo exhaust valves
turbo to taste (Vitesse Stage 5 is nice)
Vitesse reflash
Clutch to hold power
All the other bits you'd need to redo your existing motor.

rlm328

I am in the process of building a 3.0 l. The heads to the 104mm (2.7 or 3.0) cylinders are different around the water goose neck. So the 2.5 and 2.7 heads are not interchangeable without some work. I will have a crank available out of the donor engine as I was running a 2.8 l before. The Darton MID sleeves for the 2.5 l block can be machined to 104 mm, but that doesn't allow for a future re-build. If you are in the northeast, you are in Chris White's area and I would definitely give him a call for advise or to do the work. If you keep the 2.5 block I would have windage ports put in while I had the motor apart.

Charles A. Toupin

Thanks guys,

I was thinking of Chris White already. Although I'm in Canada (east)... Since I want to run high boost (18 psi at least, maybe more, max 20), I want something reliable. Maybe I should keep the 2.5L head/block, have it sleeved with dartons, buy your stroker crank, new pistons and rods and an NA 2.5L heavily ported head and just go with that.

The turbo, although quite new, leaks oil like crazy. And has major lag. Any replacement options to reduce lag?

What you guys think?

TIA

c.

reno808

If i were you i would just rebuild what you have and save the money when things come up during the race season. Seems like you already have a good build. just check why your engine got a fire

Charles A. Toupin

I know why there was that small fire: turbo heat. Because the heat shield was not there anymore.

I absolutely want to change the pistons. I have to work on the head, so I'll take off all the good parts and I will use an NA head.

Can I keep the stock shotpeened rods?

If I buy RLM328 stroker crank, do I have to change the rods?

Will rebuilt the turbo and use it as is.

c.

Adonay

Rods are good with the 3L crank but you will only need custom pistons. Then you need a ecu retune.

Charles A. Toupin

Thanks. I'll go that route and I'll send my chip back to John at Vitesse. And I need an heat shield

c.

Adonay

Ask john about pistons as well he supply those and know what are the correct ones.