Valve Clearances too tight? ..and strange spots

[RobertoBlanco]

I've bought the car (T350) a couple of month ago with a full 12k service done by a reputable, known garage. Since i want to get the valve cover cleaned and possibly painted i checked the valve clearances since i was there already. BTW I did 2000 miles since the 12k service.

I noticed that the inlet side is more on the "tight" side having 4.5ish thou on some valves (4thou got through easily, 5 thou was kind of hard to push through) and 4thou on cylinder #6.

Wonder now, if the difference of -0.5thou or -1thou requires a change of shims, since the gap should be 5-7thou. I'm not to familiar if we are talking about critically low numbers. Probably someone was "overly caring" and put in shims too thick, since they wear anyway.

So whats your opinion on this?


Aahh, one more thing. I noticed some strange dark spots on the can shaft near cylinders #5 and #6. Any ideas what this is and if its something is amiss (see pic)?

[330p4]

Robert if the gap is 5-7 thou I aim for 6 thou I do not like to run on the smallest gap. Also correctly hardened shim should not wear easily but the valves recesses into the head and closes up the gap.
Ian

[PetrolHeadPete]

I'd measure them again just to be sure. Make sure the feeler gauge is under the foot of the follower, the part that presses the shim. You can measure under the actual lobe but its much harder to judge the clearance.

If they really are over tight and you're up to it, then skim them with 600 wet and dry on a flat surface...rotate as you go and clean thoroughy

Black spots...no idea!

[RobertoBlanco]

Thanks for the replies.

I measured again, and guess what? I got different readings. I measured with the feeler gauge between shim and follower, like Pete described. Did that the first time exactly the same way.
I really took my time, tried to get a better feel for it and voila! All the inlet clearances are >5 thou.

But now on the outlet side 3 of the clearances are 13 thou. So 1 thou over. Doh!
So it seems like i have to replace the three outlet side shims.

But anyhow I wonder why this hasn't been properly done at the last 12k service?! I do not see, that it would change that fast after 2000 miles after the 12k.

[Basil Brush]

Not an expert by any means but it's tended to be my ex valves that have closed up between checks so I probably wouldn't change them for 1 thou.

[SergSC]

RobertoBlanco said:

Thanks for the replies.

I measured again, and guess what? I got different readings. I measured with the feeler gauge between shim and follower, like Pete described. Did that the first time exactly the same way.
I really took my time, tried to get a better feel for it and voila! All the inlet clearances are >5 thou.

But now on the outlet side 3 of the clearances are 13 thou. So 1 thou over. Doh!
So it seems like i have to replace the three outlet side shims.

But anyhow I wonder why this hasn't been properly done at the last 12k service?! I do not see, that it would change that fast after 2000 miles after the 12k.

There was a thread posted on here warning of some cheap soft shims, maybe they found their way into your car at the 12k?
I'd ask said reputable garage about it.

[twinreal]

Robert,

on the outlet side 1-2 thou should be ok, even on the last cylinder (that's what varley writes in his bible), so maybe this clearances were already at the 12k Service.
Did you take a look to this thread http://tvr-forum.de/viewtopic.php?f=16&t=4738&... in tvr-forum ? All in there :-)
Btw. you should accurately clean/remove ALL the leftovers of the cam cover sealant

Thomas

Edited by twinreal on Sunday 5th January 17:28

[RobertoBlanco]

Thomas,
i remember browsing through that thread. I guess is hould read it again. Thanks for the heads up.

[Edit] I guess i'm kind of naive, thinking that at the 12k the garage would try to adjust the clearances to optimum values.

[Quentin1]

Yes, Robert,
that IS a bit naive...
Oh, and always measure between follower and shim, because that is the place where you adjust.

Björn.

[RobertoBlanco]

Quentin1 said:

Yes, Robert,
that IS a bit naive...
Oh, and always measure between follower and shim, because that is the place where you adjust.

Björn.

Thanks for the reminder Bjoern.

Originally i bought from a garage and not from a private seller because i wanted peace of mind concerning all technical things. But as it turns out there are some more, lets say, questionable things, which means i cannot be sure if all service work was carried out or what was only ticked off on the service schedule.
At least i have a warranty. *rolleyes*

[X13]

O n the subject of shim removal, has anybody got a few photos how you remove and replace

[330p4]

Gary I use a small pry bar and lever the valve cap down lightly then use a magnetic pickup to pul the shim out. DO NOT lever against the cam lobe.
Ian

[RobertoBlanco]

Another method is to, where possible, carefully push the lever against the horizontal spring with a screw driver and "park" it slightly beneath the spring plate, jamming it (red arrow). Then you can easily grab the shim with a magnetic pickup. After measuring the shim and possibly changing with another one you just put it back into place and let the lever carefully slide back in its place.

Be sure to seal the spark plug holes and the oil drains with cloth or anything like it, that the shim can't get into the engine, when dropped. Else you have to go fishing for the shim or even worse have to take the sump apart to get to it.....

I take it you know, that you have to crank over the engine at the pulley to get the cams' pointy end face upwards, where you want to measure the clearance.