Yet another 3.2/3.4 rebuild thread ...

[Jnikic]

I've owned my targa for the past three years. During that time, I caught a disease for which there is no known cure: the track. Her previous owner was a PCA instructor and I've put in 30 or so days myself. And though she's never left me stranded - or even wept a spot of oil on my floor - my last track days didn't go so well.

Heading in, I was already experiencing some blow by at the rings/out the breather. But we figured one more day wouldn't hurt. About that - I ended up leaving after my second session for fear of making it the 300 miles home. I did make it home, but just barely. And so that leaves us here ...

The motor is being torn down by my wrench - I'm neither talented nor handsome enough to do the work myself, so the doctors at Rennwerke in Elmsford, NY are taking care of the real work - and we'll know this week whether or not I need new pistons cylinders. The motor was rebuilt several years/30k mostly track-miles ago with 98mm JE pistons and some machine work (supposedly, a boat-tailed case), but I don't have any more details except that it retained the stock SC cam - which is odd because I bought the car with Webers and its currently running 46 PMOs (with Electromotive crank fire).

The Plan. Depending on the condition of the pistons/cylinders, I want to end up with a reliable, race ready motor that wont need attention for another 30k track miles and can be driven to races. The rest of the car is being developed to run in NASA GTS - since this is a power/weight class, specifically which class I'll run in will depend on the final build.

I'm hoping to minimize my costs and be able to reuse the pistons/cylinders to stay somewhere around 200-210rwhp (dialing down the advance to stay within class), but if we need new pistons/cylinders, I may opt to run higher compression with twin plug ignition and something like a GE-60 cam to hopefully end up around 240rwhp. (When we send the heads out for machining, I'll likely have the additional plugs machines even if I decide to stick with the single plug).

Lots more to come over the next few weeks - I look forward to everyone's advice. But for now, some pics ...



Looks like I had a bit of an exhaust leak ...


Weeping at the case








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[Jcslocum]

Watching with interest!

[Jnikic]

Short update after quick conversation with the wrench ...

Looks like the cylinders are within spec, but the pistons suffered from detonation. So those would need to be replaced. We'll need to solve why this occurred and take a thorough look at every thing else.

So ...

10:5?
11:5?

I'll twin plug the heads while they're being reconditioned.

Cam suggestions when paired with 46PMOs?




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[blockhed]

Gorgeous car

[camgrinder]

Check out this combination...
Another RSR Clone Project - Dyno Day

[Jnikic]

I'm not a mechanic, but something tells me this isn't good ...




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[cgarr]

No not good, but that 912 head looks nice!

[Jnikic]

It feels like a lifetime ago, but my heads finally arrived from the machinist. And we're back on track - the car will be ready this weekend ..

Along the way, we learned a few things:

- The previous owner was under the impression the motor was rebuilt with JE 98mm cylinders/pistons. He was wrong. It was rebuilt with 95mm Mahle cyclinders and JE pistons.

- Those pistons had a pretty high dome, so it appears that's what cause the detonation - this motor should have been twin plugged at the same time.

- Thankfully, the rest of the motor had very little wear: we reused many parts, replacing what we had to and upgrading others. Stiffer valves springs, GE60 cam, rods, etc ...

- Cylinders showed very little wear and were right within spec, so we replaced only the pistons with a 10.5:1 set from Woosner. There was visual evidence of piston slap on JE's.

- I added a little lipstick to the motor, powder coating the upper valve covers and fan/housing in a satin, "prototype" grey, and adding a brush stainless alternator strap and engine mount from Rennline.

For now, here's the motor on the stand:






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[chrisbruck]

AHhhh... thanks for the motor porn pics....

[87 930]

Looks Purdy!

[Jnikic]

A couple more shots along the way ...




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