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So it's time to turn my attention to the engine being replaced. Remember, my car had a perfectly functional clutch when it gave up the ghost.
I need to figure out the condition of the clutch I was using up to now, and to see if the stuff on my car can be re-used (pressure plate, disc, flywheel, bearings). I'll definitely buy new bolts, seals, and bearings to re-assemble it.
But I need to do that quickly so I can get the clutch parts on order right away in case I need a new clutch altogether.
My engine makes 140 ft-lbs of peak torque, although that could change, of course. Just a point of reference.
Also, if I buy an aluminum flywheel that's lighter, does that affect the crankshaft balance? Is the crankshaft balanced internally?
I'll be calling SPEC directly I guess, to ask other questions such as whether the stock flywheel bolts are compatible with the aluminum flywheel, does the AL flywheel come with new bolts, etc....
I imagine that the disc material is free in 944cup class. Do you have any opinions/recommendations on what "stage" is most appropriate?
I'll be doing the lightweight stuff, I think. Mostly because my car is already so illegal for 944cup classing that I can't imagine bringing it back... I think it would make more sense to just buy someone else's 944cup car if that's what I wanted to run.
My car's already got 968 spindles, rotors, and calipers (4-pot). Fancy adjustable swaybars by Kokeln. Not one 15" wheel in the garage. So it would be pretty expensive to bring it into 944cup rules compliance.
In Performance Touring classes, lightweight flywheel, clutch assembly, and torque tube are all no-points modifications.
GTS class doesn't even care what you do to the drivetrain, so long as it's a block from a German car.
So I might as well do what I can while I'm at this point. I think it'll make a difference, and the fun clutches don't seem that much more spendy than new OEM clutch kits, depending on where you source them.
I got a response back from SPEC regarding my inquiry into their clutches.
They said all of their stages exceed my torque requirements, and that I should choose based on feel. All are built for track use.
So I think I'm going to go with Stage 1, in the hopes that a more progressive clutch engagement will be kinder to the rest of the driveline, especially the transaxle.
They also answered my concern about the billet aluminum flywheel. It includes a race bolt kit for the pressure plate. And it is compatible with the OE crankshaft bolts. Mine are in exceptional condition so I see no reason to buy new ones.
I successfully removed the flywheel and exhaust last night, because it was too stormy to be working outside. No broken bolts or issues at all!
The oil cooler seal kit and timing belts arrived this morning, so those items are next up for this engine.
This morning I towed the car up my driveway to its work area in front of my tiny garage, so tonight I hope to get under the car and do some real damage assessment on the broken engine.
The oil pan is off the engine and the rods are all intact.
There is a bit of wiggle in the #2 rod bearing if I move it by hand. So that definitely needs replacement, but it doesn't explain the dramatic loss of power I experienced on my last lap or so on track.
I'm now thinking it's a valve... the chunks in the pan look thicker than that of a bearing. And the crankshaft looks too good for them to have come from it.
If something happened that was preventing the valve from closing all the way, the seat would quickly burn. That could potentially be chunks of a roasted seat. Was the car running on all 4 pots when you pulled it in?
The crankshaft looks similarly marred, but it isn't deeply scored or beat up, which I guess is good. I don't know anything about how much wear can be tolerated before the crank is considered scrap or unworthy of reuse.
One thing that concerns me is that I was trying to turn the crank but I couldn't budge it even with the plugs out. It may mean other bearings are bad too... This engine is coming out, and will be rebuilt this winter.
IMHO ANY wear in a crank that can't be polished out (read: Anything more than light discoloration) = scrap metal. +1 bearings + cost of machining costs too much imho compared to how cheap a good used crank is. If it's marred in any way, I'd be looking for a new crank.
This is especially true for damage to the main journals.
wire wheel all the rust off. Weld up any cracks, holes, ect and weld the piece that broke off. Spray the entire thing with a good rust neutralizer, then high temp prime and paint it. Good as new.
Also, good work! I finished up my NA motor rebuild about 2 months ago and just started my 951 engine rebuild today. it feels good to make progress!
09-07-2016, 12:29 PM
