Lifters!

[garethcolley]

I bought a LET off Chris Astley a while ago which has had new lifters in (fitted by him). However its really noisy which makes me think there is a problem? Since ive got it the head has cracked which ive just replaced with a new one thats been rebuilt but with the existing lifters, its even worse now and seems to get louder the hotter the engine is, any ideas? Dont think the ones he sells are GM.

The oil im runing is Millers Oil 10w/60 CTS motorsport stuff as recommended by the technical engineer there as an upgrade oil for a 90k turbo and bottom end.

[burgo]

sounds like an oil pressure problem to me

[garethcolley]

sounds like an oil pressure problem to me

It seems to hold good pressure though, on my digi dash it rarely drops below 3 bars even when its hot (thinner).

My rocker gasket is slightly leaky near the cam belt cover which might not be helping.

What is standard maximum LET oil pressure at full whack?

[Stuart]

bet the "cheap" lifters were used.... you know, the silly cheap ones you see on ebay. Best of with proper GM ones, ok they cost a lot but are a hell of a lot more robust/reliable.

whose technical engineer, where?

[AlexW]

One of my lifters are noisy on my 8v they were new not long before i brought them but i was warned one was noisy, i just forgot which one.

What your saying does sound like mine, it gets louder with temp and oil pressure seems well.

[garethcolley]

bet the "cheap" lifters were used.... you know, the silly cheap ones you see on ebay. Best of with proper GM ones, ok they cost a lot but are a hell of a lot more robust/reliable.

whose technical engineer, where?

I phoned the technical department up at millers oil to speak to an engineer there. He brought up the C20LET spec and said i can run anything from 5/40 to 10/60. He then said because the bottom end and turbo was 90k++ i should use a 10/60 fully syn for extra protection. Id explained my head had been rebuilt but he still said use that. Apparantly most turbo places recommend 10/60 for the K16's aswell. They were Chris Astley lifters which he apparantly sources from down south, he said he hasnt had a problem with them before. I would estimate they are 900 miles old max.

[garethcolley]

One of my lifters are noisy on my 8v they were new not long before i brought them but i was warned one was noisy, i just forgot which one.

What your saying does sound like mine, it gets louder with temp and oil pressure seems well.

What lifters are they? GM?

[garethcolley]

Also Autovaux say there are 2 different types of GM lifter for early and late. Aftermarket ones are the same for both. Ive taken them out of my GM cracked head and put in my early coscast head. Chris Ast says he can only get one type anyway so that put to bed my theory that it has got worse since they have been in the coscast because they are meant for a late GM head.

[Stuart]

10W60 CFS is the nuts. I'm running it in my 2.2, its nice and stable + the car dosent use a drop of oil :D

[burgo]

isnt fully synth abit much for such an old engine? id use semi synth personnely

[garethcolley]

Well thats what ive been told t use so went along with it really. Think factory spec is 15/40semi? What do you mean by 'a bit much' ?

[burgo]

factory spec oil sounds alot more like what id use. by abit much i mean your oil i would use in a modern high performance engine. which yours isnt

[garethcolley]

Fully synthetic only means its not mineral based hence as chemical additives, i cant see it been too far off the mark, i reckon the guy at millers knew what he was on about...regardless of semi or fully the only issue i can see is viscosity problems from running 10/60, would a thicker oil make them tap more? I know thinner oils can escape the lifter known as leakage which also causes tapping. I think maybe i should borrow somebodys lifters and put them in mine to see whats going on. It would also be nice to try and isolate which lifters are making the noise (if not all of them).

[garyc]

All oils contain additives. If you have a decent synthetic base stock then it will have less additives because it will have better resistance to oxidation, better viscocity properties etc. mineral oils onthe other hand are less stable and also thin out more. I'd stick to mineral if your tight (but change it more often) and go to full synthetic if you can afford it.