ralphw

Set the tension to the spec in the service manual regardless of new or used. The tension on the belt is specified to ensure there is always load on the belt. When the tension drops too much, then the belt sees load reversals which causes most of the damage. Personally if the belt is off, I would always put a new one on Cheers Ralph

Looking at the broken ends of the belt, did the break go straight across the belt or was it at 45 deg. If its straight across its been crimped and the cords have been damaged, if its at 45 deg then it has seen a lot of load. An 18 month old belt should be OK for normal running so I would advise that you look for a mechanical problem before putting another belt on. If the crank pulley (drives the belt) is in good condition then the increase can only come through the pulleys driven by the belt eg oil pump pulley or the cam pulleys. I have seen a lot of belt failures, but rarely seen one break without it being extremely old and work hardened or a mechanical fault. I have even run belts on dyno engines and the teeth have sheared off because the belt has been aged so much, but they have continued to run quite happily. Strange sight to watch. Cheers Ralph

See you at the Dog, Norton. May be a bit late depending on traffic out of London Dont know about the rest of you but I will be eating and yes the Dog burger is tempting Cheers Ralph

There is no reason why you cant use the frequecy method on the trap belts but they will have a different frequency to the round belts. I worked it out some time ago and posted it but I dont have time at present to go looking. The frequency method is the most accurate but it must always be done in the same place with the engine position eg 30deg otherwise you will get errors. It may not show up so much on the mechanical setting tools but mainly because of their degree of accuracy. As for the twist method, my experience is it is less accurate than the mechanical setting tools unless you get lucky or one of the few with a calibrated finger. Cheers Ralph

SHould be OK for the 19th but cant make Larling, Cambridge, Ancient Shepards is good, where were you thinking in Suffolk, the Dog at Norton? can just about make that one. Cheers Ralph

Arte Another thing to check. I come across some engines the other day (not Lotus) where the block machining was incorrect. To be specific, the threads in the block for the head bolts didnt finish deep enough, consequently the bolts were cutting the last 2 threads so the torques seemed ok / a fraction high but the head gasket blew because the clampload was insufficient. You have said that the bolts have probably been reused and may have stretched, the head has been skimmed, etc. Check that there is enough thread engagement to cope with these changes (or the bolts are close to bottoming out) before you screw it back together. Cheers Ralph

Black Bull thurs 5th OK with me. Are we just going to turn up or will a booking be needed. Next prob, I cant book at present, dont get home to Thursday morning. Cheers Ralph

Yes the issue is cooling around the exhaust valves in number 3. I remember doing some work on this years ago and due to core shift in this level of casting, it is possible that the flow around the guide on the exhaust valve can be poor, especially on the exhaust manifold side. My Sunbeam has done exactly the same thing, same valve. Cheers Ralph

I used to be involved in the testing of Brake fluids and Castrol always come out on top. Never used anything but Castrol since then Cheers Ralph

Cant do the 4th but otherwise OK Cheers Ralph

Im in, but the last week of Apr, first week of May be a bit difficult. Will check work stuff and come back. Cheers Ralph

Artie I will assume for the minute the head is OK and you will have the nip checked. Do you have any pictures of the offending headgaskets. Where have they failed, is it the same place each time, what is the failure mode. You mention head bolts, have you checked the stretch against a new bolt. I havent checked if these are torque to yield, if they are and have been reused several times the clamp load may be inadequate. Are you using the correct fasteners to hold the head down. I have found cases on other engines where the under head profiles are different to spec and consequently give a different torque reading. This could result in the torques appearing to be to spec, but with insufficient stretch to give the required clamp loads. Also check the condition of the faces on the head where the bolt heads mate as that could also contribute to torque and hence clamp load issues. Also another thought, if you are running at this higher boost and the clamp loads are incorrect, that would be enough to give the headgasket issues. Other owners running lower boosts may have the same clamp loads but the lower cylinder pressures and temps they have may be insufficient to give the same issues. By the way, the gear to measure the nip isnt too expensive and a useful addition to the toolbox as once you have it you will find other uses for it. Hope this gives you ideas to think about Regards Ralph

Thanks for letting the blue Focus pull in front of you. I was Already late for an appointment Ragards Ralph

Gavin The trapezoidal profile doesnt lend itself to that very well. The logical thing to do is to upgrade to the later pullies and belt. I have the same issue on my Sunbeam Lotus and will convert that in due course. I will never the less give your suggestion some thought, but at this time the modifications I would have to do to the belt with such a shallow tooth profile would increase the risk of belt jump and I really dont want to go down that route. Cheers Ralph

Darren Email me and we can discuss off-line [email protected] Cheers Ralph