crankshaft and conrod end float

PostPost by: MartinH » Sat Feb 04, 2023 12:23 pm

I have pulled the engine and gearbox to fit a replacement gearbox. While I have the engine out I will replace the sump gasket and generally clean everthing up. I havent had the sump off in over 20 years of ownership.

I was surprised to find my sump is baffled. I doesn't work that well as on very hard right handers on a track day I loose most of the oil pressure for a second or two. Note the wear mark from where the oil pick up rubs

When I checked the end float on the conrods they are at the limit of the tolerances in the manual 0.010
On the Crankshaft the endfloat is way over the upper limit from the manual more like 0.020 vs the 0.008 quoted

I've attached some pictures to make sure I am measuring at the correct place.

I don't want to do a complete rebuild right now of what seems to be a tired as engine as I would like to have it running in March. I think it will take longer than the available time to have it completely rebuilt. Can I get away with just replacing the various thrust washers as a temporary fix to see me through to next autumn?

The engine has 60psi oil pressure on start up and typically runs at approx 40/45 PSI when cruising at 3.5-4k rpm.

The engine is a lightened and balanced 711 block with approx 140 BHP

Any feedback/comments gratefully recieved
Martin
Attachments
sump.jpg and
end float crank.jpg and
end float conrod.jpg and
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PostPost by: rgh0 » Sat Feb 04, 2023 12:37 pm

Its hard to measure crank end float in the Ford blocks with feeler gauges as the thrust washers are just a half circle and located in the upper half in the block and you appear to be meausring on the bottom half where there is no thrust washer which is what is probably causing the high measurement. You really need to measure with a dial gauge the crank movement as you push it forward or back or pull off the centre main cap to reach down between the thrust washers and the crank.

Measurement of the conrod end float as you are measuring is the correct location and the actual dimension is not adjustable and not very critical as long as it is not to tight and it does not normally wear in any case.

The wear on the sump bottom from the oil intake strinaer is normal as the spring holds the strainer hard down on the sump and vibration causes the wear marks. Running without oil pressure for even a few seconds can cause catastrophic engine failure but you appear to have good oil pressure so unlikely you have damaged the bearings so far. If tracking the car and loosing pressure I would upgrade the baffling or put in a accusump oil accumulator.

cheers
Rohan
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PostPost by: MartinH » Sun Feb 05, 2023 10:56 am

Thanks Rohan for the very fast reply. I would have responded sooner but had to watch the now customary victory for Scotland vs England in the 6 nations match. Which resulted in several large whiskies being enjoyed.

I will go and pull the centre main cap as suggested to measure the end float and explore the sump baffle upgrades you suggest.

Regards
Martin
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