Tuesday, August 13, 2013

More on engines (and Moron engines)

The engine that Tim built for this season's racing ran into a number of issues. The engine came out of a 1993 900S purchased for parts. The car was pretty rusty, but had a good engine. Unfortunately it also had an automatic transmission. On the plus side we figured we could strip the car, sell off the transmission and some other parts, take the remains in for recycling, and recoup our investment with a small profit.

For those who have followed the saga of Fart-hinder Racing (a.k.a. V.I.A.G.R.R.A.), you may recall that we have had several other engines, all 2.1-liter normally-aspirated from 1991-93 Saab 900s. The engine that we ran last year at Road America was Engine #3. It had about 200,000 miles on it when it was put in the racer, and has about 40 racing hours between Iowa (2011) and R.A. (2012) on top of that. It puffed a bit of smoke out the tailpipe when shifting. A compression check indicated that cylinder #1 was weak.

At least it looked good.
We will refer to this latest as Engine #4. The compression and leakdown tests looked good, but the 900 it came from had 195K miles on the odo. It was decided to renew the internal wear parts, the seals, gaskets, bearings and timing chain. An engine from the first season (Engine #1) only had about 15 racing hours on it, and the bearings and timing chain looked great so they were placed back into service. In addition, the head from that first season was chosen as it had been planed and cleaned up, and was in better condition than the other heads.

Bolt for A/T on the left,
for manual gearbox on the right.
Unfortunately the re-assembly of Engine #4 met some setbacks. The only flywheel bolts Tim could locate were from the flex plate for the automatic transmission. The unfortunate part was that they are about 1/4" longer than those for a manual gearbox flywheel. They came out the back side of the rear crankshaft flange and jammed against the #5 main bearing housing. Once the proper bolts were installed, the engine turned over, but it never felt quite right.

With only a short amount of running time on the "new" engine, water was discovered in the oil. That turned out to be a couple of timing cover bolts that are hidden behind the water pump pulley. And they are critical bolts, sealing an area where a major water passage feeds the water pump. Under pressure, water from the cooling system could leak into the oil, which it did. Replacement of those bolts did not take, so we chose not to race rather than risk destroying the engine.

Circles are where the flywheel bolts pushed against
the rear bearing housing
Post-race inspection indicates that the #5 main bearing housing was slightly warped when the wrong flywheel bolts were torqued into place. Not much, maybe a few thousandths of an inch, but enough that Tim decided to give up on that engine block. And the water in the oil apparently condensed on the camshafts which caused them to rust, enough that they probably should not be used again. The engine builder is a moron..

So Engine #3 is back in play. A teardown revealed rather worn rod bearings (down to the copper), and mildly worn main bearings, but the crankshaft looks pretty good. New bearings, new seals and it should be running. Not certain yet which head will be used. Either take the cams from a good head and use them in the planed head, or take a head into the machine shop and have a full valve job done.

As if that were not enough, Mike at Hanover European Parts has offered us a running engine. That would be engine #5. It would be nice to have a known running engine as a backup.

We have decided to take the car to an Open Track Day at Brainerd in early September. They have a special rate for ChumpCar teams, and we can have up to five drivers. Looks like we have a full slate lined up already, with five of us hoping to get some track time.