over revving damage?ie 4th to 1st gear!

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inferno

Guest
Today i called the motersport company whos stickers are on my R. They advised me that the previous owner was only running 1bar of boost, and that it was mechanicly sound. However i brought it with the head in the boot, from some1 else who advised me there was piston damage.

Now theres no sign of movement in the pistons, and the motorsport company advised me it had been revved high, ie dropped from 4th into 1st, then it still ran but with popping sounds, he said there was bent valves, the guy i got it from mentioned the popping.

so as the head was off, i filled the chmbers with petrol and after leaving a few hours i cant see any sign of fuel seeping past valves. i thought there was at first, must of been the weather!

Anyway i just wanted to know what other checks i should carry out before i spent a lot of time and money on a rebuild. has anybody done anything similar?!

im waiting for the electronic manuals, but untill then what should i look for?

cheers. tom
 
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paulrandy

Guest
To be honest you'll probably notice a bent valve quite easily but if you've got the head off anyway it's not too much work to remove them and re-lap them into the seats.

IMO the most likely point of damage would be to the big ends and mains, rotate the crank by hand and make sure 'A' the crank rotate FULLY fairly smoothly with NO tight spots(which would be a bent crank(most likely)) and 'B' make sure all 4 pistons reach EXACTLY the same height in the cylinders, if not it's a big end or rod.

I take it you never heard the engine running in this state?
 
Fast Guy

Fast Guy

Moderators
Staff member
If the head is still on, a leak down test would also test valve sealing.

If you do take the head off, it may be worth having the timing chain, rod bolts and big end bearings replaced anyway. ie anything that could have been stretched/damaged by over revving.
 
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