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Discussion Starter · #1 ·
Hi Guys,

I wont explain the story, but basically (as some of you may know from previous threads) I've bent my exhaust valves. The engine wasn't running at the time, I just manged to make the timing belt skip (without knowing), turned the engine over and got a loud bang!

Anyway, Im going to be stripping the valves out to assess the damage, but I was just wondering what damage to look for? I know about the valves (obviously!) and the valve guides, but its there anything else? Ive heard valve seats mentioned - what would the damage to these look like - would they eb dented, scored etc?

Cheers
Mike
 

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Worst case,damaged pistons,head,seats,guides.Seats might be able to be re-ground,depending on how bad they are.
Good luck,hope its not too bad.:eek:uch:
 

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Discussion Starter · #3 ·
Thanks for the that mate. The pitons heads look ok to me. Theres a bit of carbon removed, but no damage to the metal surface. At least thats one less thing to worry about.

When you say damge to the 'head' do yuo mean the piston head, or the cylinder head? If you mean the cylinder head, how could this be damaged? Are we talking warped (something which I have checked and all seems ok), or are we talking something more severe?

Thanks again
 

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How damaged are the valves, smashed or just bent?
If so you may have damaged the piston rod too. Unlikely though if the piston head itself is not damaged.
 

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You have to take all the valves out to inspect .

Roll them on a flat surface to check for wobbles.

Then after, onto this stage


This is really when you need a small lathe.

Put valve stem in a 4 jaw chuck on the lathe and indicate stem so it runs true .........then indicate the head to see if its concentric with the stem.

Or you could just put the valve back in its place on the head and use engineers blue to see if the seat/face of the valve is touching all the way round....when its spun .......if it lifts contact in the spin .........dont use



but first check the valve guides are OK ...they pert-rude in a little bit .........you may be able to see splits in the guides or distortion.

ideally valve should touch the seat all the way round and guide should be checked..............if OK ...then that one passes ..move onto next one.


to check for bent conrods ........in-situ
you need a dial test indicator and stand.

http://search.ebay.co.uk/search/search.dll?sofocus=bs&sbrftog=1&from=R10&satitle=dti&sacat=12576%26catref%3DC6&bs=Search&fsop=1%26fsoo%3D1&coaction=compare&copagenum=1&coentrypage=search&fgtp=&sargn=-1%26saslc%3D3&sadis=200&fpos=LL197NG&ga10244=10425&ftrt=1&ftrv=1&saprclo=&saprchi=


........bring each piston up to the top of its stroke and note reading...do the same on all four pistons ...all should be equal.....


all the best.....mark
 

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Discussion Starter · #7 ·
Thanks for the pics Mark, that helps a lot!

The valves are bent at the side which lies closest to the piston head (the outer edge of the combustion chamber). They aren't broken at all, apart from the bending and some slight buffing of the valve face where its come into contact with the piston, all else looks ok - although I haven't had the valves out to check the guides yet; thats the next job.

Thanks for all the info guys - useful, as always!
Mike
 
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