Cambelt & Bent Valves

[Warren]

For those following my other thread I decided it was prudent to change the cam belt. I also needed the car further up the drive and in the corner so it could go on stands. An attempt to start it with a flat battery put paid to that plan so I went off to get a belt while the battery charged.

On my return I noticed the belt riding high on one of the cams, I assume it jumped while trying to start. Anyhoo I tried to align TDC manually and it looked about 20-30 degree out on the cams. So I decided to further turn the engine once manually via the bolt on the crank pulley to see if alignment came back but within 1/4 to 1/2 a turn it locked up. I'm guessing this is valve and piston contact.

SOooooo, whats likelyhood of a bent valve under poor battery cranking and what's the chances turning it manually bent the valve/valves??

Also, I didn't really want to turn the drive into a scrap yard so can the heads be removed with the engine in? That way I can check valves and reassemble with correct timing.

If it has to come out then I'm wondering what parts availability is going to be like, i.e. new valves, etc, maybe even pistons if it's made a real mess.

Next is apart from the RV8 option what other engines are peeps fitting if I decide to go non-original (I can hear the traditionalists groaning now) you've got to be realistic, these cars aren't worth that much in their prime.

Advice and helpful pointers appreciated.

Warren

[Sparky]

Eeeeek!

Starter cranking is enough to mess things up. Depends how good/bad the battery was. Again, cranking manually, it's all down to how much grunt you gave it if you tried to overcome the lock. Possibly worth getting the timing right (very carefully) and tensioning a belt correctly to see if there's any damage (manual crank first)?

Removing heads insitu is perfectly possible, but almost as much effort as pulling the engine, as you need to dismount the lump and lay it over to get the heads/manifold to clear the body/chassis past the head studs.

[Stokey]

Hi Warren,

Engine parts are readily available, I did my head not that long ago (headgasket failure - thought it a good time to overhaul everything whilst I was at it). Yes you can take the head off with the engine in situ no problem, the exhaust manifold nuts are a knuckle skinner though LOL. People reckon it is best to support the engine then remove the engine mounts so that you can move the engine over a bit to get at the studs, I would definately do that next time around.

Jase.

Edited September 17, 2010 by Stokey

[andydclements]

I'm with Sparky. Don't assume the worst but be prepared for it.

Set the belt, turn it over by hand with plugs out. If you get air movement via the plug holes and there are no signs of the engine locking up it's good so move to next stage. Put a compression tester in and turn over using the starter and ascertain the state of the vales by the compression readings.

[Sparky]

Whoops - shouldn't have assumed it was an Esprit - sorry! Yup - much easier in the Eclat.

I have an Eclat (well, half of one) to renovate too - will watch with interest!

[Stokey]

I am with everyone else here! I had a 16v Honda twincam which decided to snap it's belt on a dual carriageway whilst accelerating, I mean of course under the speed limit Ahem!!!!!

It was supposed to be impossible to not bend valves with this engine if this happened, but I had nothing to lose other than a belt and time. Put the belt on turned it over by hand first with no problems so turned the key and hey presto started first time and never a mention after that.

Go for it!!!!!!!!!!!!!!!

Jase.

[Warren]

First time with these twin cams, am I right in thinking that I can take the cam carriers off so that all valves all closed. Get the engine to mid and re-fit and torque the cams down to exert pressure on the valves into the right position. Set the cams then TDC, then stick the belt on to try it??

Cheers

Warren

[Sparky]

Potentially much easier than that - if you can get the crank to a point where all pistons are roughly midway (90deg either way off TDC), then you can dismount the belt and turn the cams to their markers, then bring the crank round to TDC, without fear of interference.

[Warren]

OK I'll give that a try this weekend.

Cheers

Warren

[Dunc]

what's the prognosis Warren?

[Warren]

Sorry guys no progress as yet, the business is taking all my attention at the moment. I'm having the folks over next weekend for some fireworks etc so will get the car moved to were I want it on the drive because once I start removing things it ain't sifting again until its ready for paint.

I have been grabbing the odd part here and there off evil bay but that's it. I'll keep y'all posted, I haven't given up yet!!

W

[USAndretti42]

I think I would be tempted to set the engine at the "Safe position" i.e. 90 degrees away from TDC, and check the valve clearances. If they are all OK then there is a good chance the valves aren't bent as any bent valves won't close properly.