engine post-mortem (with pics)

engine post-mortem (with pics)

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renn68

Original Poster:

281 posts

217 months

Tuesday 6th February 2007
quotequote all
What better to do on Waitango Day butstrip down my engine that failed while racing in December.

This fell out when we initially got the car on the hoist



Failure was 8 laps into a 1 lap race while changing from 5th to 6th. There was no warning; I'd just done a PB the lap before. Oil level was checked immmediately before the race and is always run at full and has never been run low while I've run the car. I use Redline 15W50 and it is changes frequently. Oil pressure is logged on the MXL and starts off at 5bar (warm) dropping to 3.5bar when running hard and the oils hot. Pressure does spike down half a bar through some corners.

In September I had a couple of occurrences with bolts coming loose, on the alternator and the power steering pump at which point I had the balance shaft timing checked and they were found to be 180degrees out. In hindsight, I should have dropped the bottom off the engine and replaced the oil pickup.

The engine did a further 500 race miles before this failure.

View thru the sump - #2's not looking good



Sumps off - its not getting any better



At least it stopped on the down stroke - no apparent piston/ valve contact



Closer inspection of the oil pick-up - just a wee crack



I'm hopeful that the head is OK since there doesn't appear top be any piston/ valve contact - I'll get it checked out and freshened then plonk it on the replacement motor.

The replacement motor has been re-bearing'd and ringed, sump baffled and a new pickup with suction ring. I've put an oil temp channel in and the MXL data shows its right up there at 260F (3.5bar), so more cooling is called for.

GravelBen

15,696 posts

231 months

Tuesday 6th February 2007
quotequote all
Ouch. And good luck with the new motor thumbup

kylie

4,391 posts

258 months

Tuesday 6th February 2007
quotequote all
That is serious carnage! Glad to see you have found a new motor to go in so quick. We watched a bit of targa on tele the other night which had awesome coverage. We were hoping to see a glimpse of ya, but as per usual they concentrated on crashes, skids and front runners. So this year could you please wear chicken suits, get one wheel up going round corners and do a few skids for the crowds