F20C rebuild

General engine tech -- Drag Racing to Circle Track

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turbo2256b
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Re: F20C rebuild

Post by turbo2256b » Tue Oct 03, 2017 10:11 am

Under sized bearings dont do well with higher RPM and compression rather have a std crank. Extra strong rod bolts a must for higher RPM . balancing the rotating assembly a must. 14 to 1 compression dosent increase power that much compared to somewhere around 11 to 12 to 1. Unless your running E85. How much oil pressure were you running at those high RPMs

turbo2256b
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Re: F20C rebuild

Post by turbo2256b » Tue Oct 03, 2017 11:30 am

Factory rods might not even be strong enough. Even the block main web areas could be too weak. Have watched blocks twist on dynos with special paint and strobe lighting. Which gave me insight on how to design blocks that the stress analysis guys couldnt figure out

pamotorman
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Re: F20C rebuild

Post by pamotorman » Tue Oct 03, 2017 2:20 pm

wrightcomputing wrote:
Mon Sep 25, 2017 7:59 am
So bearing I ordered were the correct ones I guess they are undersized. Unfortunately I do not have an oil pressure light, the only gauge I have is AFR. In Autocross you never have time to look at the gauges. I plug in my laptop for diagnosis.
Unfortunately I do not know what caused the loss of lubrication. However by installing a drysump I replace the oil pump and pan. As long as the engine is clean that should fix the issue.
When I de-stroked it I used the stock rods and pistons from the F20C. This time I decided to get new pistons and rods and increasing the compression is one of the few ways for me to gain power. The new parts are on order and I will be balancing them once the arrive. 12.5:1 is from the manufacturers spec sheet, they would be 13.1:1 in the F22C with the longer stroke. I'm not sure the exact compression ratio matters as the tuning will be the same regardless.
wire a low oil pressure switch to the ignition so it kills the ignition if the oil pressure drops

Zmechanic
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Re: F20C rebuild

Post by Zmechanic » Tue Oct 03, 2017 2:34 pm

Did you lose oil pressure while corning/accelerating/braking? Are those the 'occasions' you are referring to? That might be your first clue. An accusump might need to be in your future if that's the case. Or a dry sump, as you mention.

wrightcomputing
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Re: F20C rebuild

Post by wrightcomputing » Tue Oct 03, 2017 7:47 pm

I had a good long chat to the guys at Inline Pro who are very experienced with the S2000 engines, they gave me some great tips. He is pretty sure that the failure was due to oil starvation caused by the baffle pan that I made. I am going to ship them the block and they are going to bore it to repair the cylinders, then custom make some pistons to match the new bore. The said I can get any compression, so I told the to go as high as possible which is probably 14.5:1.

I have been in touch with my tuner and we are going to set the engine up with flex fuel and larger injectors (Already in hand). I will set up the base tune using E100 (canned race fuel). Then at local events run on pump E85 and for big events run run canned race E85 or E100.

He also mentioned that the undersized crank will probably not last. I have a good F22C crank so I will try to arrange a swap with someone. Then next time I take the engine out I will go back to the OEM crank.

I have also purchased aftermarket rods they are Skunk2 units. I currently only have an AFR gauge on the car but plan to install Oil pressure with dummy light, engine temp and maybe fuel pressure.

turbo2256b
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Re: F20C rebuild

Post by turbo2256b » Tue Oct 03, 2017 9:53 pm

OIL TEMP WOULD BE A GOOD IDEA ALSO

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