Another valve clearance question.......

[TailHappy]

My cerb is a 4.2 with 4.5 crank/pistons/liners, rebuilt about 7000 miles ago when it was owned by its previous owner. Im told it still has the 'clatter' cams fitted.

Although it has the clatter cams it seems to have quite a loud tappetty noise when warm(more than i would think the clatter cams gives). When cold its reasonably quiet. When driving the tappetty noise is most apparent around 2000-3000 rpm especially on over-run.

I decided to check the valve clearances tonight, all the cam lobes look in good condition, no flat spots, scoring or signs of wear. The clearances were as follows ;-

Cylinder----Exhaust---Inlet
---1--------0.008"----0.004"
---3--------0.010"----0.004"
---5--------0.010"----0.006"
---7--------0.010"----0.006"

---2--------0.008"----0.008"
---4--------0.010"----0.006"
---6--------0.008"----0.004"
---8--------0.010"----0.004"

Reading through some of the posts on here, my clearances seem too tight.
Has anyone experienced similar and does anyone know if too tight clearances can cause an overly tappetty noise?

Thanks in advance.

[Boosted LS1]

I'd have thought excessive clearance would leave slack and that that would cause clatter. Others will be along shortly who will know better.

[TailHappy]

Boosted LS1 said:

I'd have thought excessive clearance would leave slack and that that would cause clatter. Others will be along shortly who will know better.

That was my thinking too. When i started checking i expected the clearances to be huge but its not the case.......

[HarryW]

Strange one, quiet when cold certainly can be an indicator that the clearance has closed up, are you sure it is actually louder when warm .
I always understood the more clattery noise of clatter cams was more down to the sharp nose profile, more akin to banging the valves open and closed as opposed to lifting and lowering them. If like the race cams they will have a higher lift too.

[TailHappy]

HarryW said:

Strange one, quiet when cold certainly can be an indicator that the clearance has closed up, are you sure it is actually louder when warm .
I always understood the more clattery noise of clatter cams was more down to the sharp nose profile, more akin to banging the valves open and closed as opposed to lifting and lowering them. If like the race cams they will have a higher lift too.

It is a strange one, Ive set clearances before but only when they have gone bigger than spec and were noisy.

Its definitely louder when it warms up. Im unsure whether if they are too tight it causes anything else to happen.
Ive had a look through the history and its had a new set of valves with the rebuild so maybe the stems have stretched slightly while bedding in. Ive got the shims out now so will get them ground and hopefully that will sort it. If it doesnt at least they will be to spec. I'll post the results.

[TailHappy]

Thought i would update on where i got to. Ive now reset all the clearances to the recommended gaps taken from previous posts on here.

Unfortunately the noise is still there. It may be normal for a 'clatter cam' engine but i think a trip to TVR Power is in order to get a 2nd opinion.