c20xe crank

[greene94]

I have a c20xe and the bottom end went I got another crank but its no better. im thinking of getting the crank ground and putting over sized bearings in wats everybody's opinion. Im a fast driver would the engine still take the abuse?

[Bubba]

0.25 grind. its a fraction off. +0.25mm bearings will be fine too

[philip]

.25 or .5mm will be fine. Machine shop will need bearings or get them to supply as they tend too be wider on the thrust bearing so need grinding too suit.

[greene94]

will the engine still take the same abuse?

[philip]

Bottom ends go due too not looking after them. I run 8.5k rpm and 600 bhp on cranks ground .25. You wont have any problems on a road car.

[BRoadGhost]

Are you destroying rods too?

[greene94]

iv only have the car about 2 months and the bottom end has went but I have the engine out and striped so I think I will get the shaft ground and put oversized bearing in. but im just worried that the engine wont stick the abuse

[philip]

Build it right and it will. Ive got lads racing on engines I built 4+ years ago. There a solid motor built right and looked after.

[meritlover]

iv only have the car about 2 months and the bottom end has went but I have the engine out and striped so I think I will get the shaft ground and put oversized bearing in. but im just worried that the engine wont stick the abuse

taking 1/4 if a mm off the journal will have virtually zero effect on the crank. You did not mention if its the mains or big ends which need ground. i take it you have measured them all for squareness and size? this will determine the size of the grind required. Always grind as little as you can get away with and to the next available bearing size.

As Philip says, its not the size of the journal, but the quality of the grind and the oil clearence which is what makes it effective.

the important thing is the root cause of the failure. is it bad tuning (detonation), poor oil pressure(surge?), bad balance, high RPM, bad build or bolt stretch which is loosing the wedge in the first place? No point in spending money on a grind and bearings for it to happen again.
if you get it back from the grinder, remember and FULLY flush the oil ways out!!

[greene94]

thanks for all the comments really helping me. it was the big end bearings went when I let the clutch out and the pressure went on the engine you could hear the big ends rattling.

[greene94]

the oil pump is ok because I checked it was putting it up to the cams.

[mowgli]

for god's sake, just cos it is pumping a little oil to the cams does not mean the pump is ok....

your engine will be at least 21 years old. it will have been thrashed to within an inch of its life too.... it needs a bottom end rebuild.

a crank grind won't knacker anything. it would probably need new piston rings & at a minimum, a new oil pump relief valve.

all of the above will result in improvements in performance too, as they will help get it back to where the factory had it.


if I were you, I'd strip & clean the head, re-lap the valves etc..

[greene94]

ive done the head and I have piston rings for it so I will get the crank done and get it finished.