Valve clearances opening up

[promotor]

Probably a stupid question, but can you not get the sleeves removed and new sleeves fitted?
Tim

Yes. QED sell the sleeves in STD and 0.005" O/S on O/D.

But take it to someone who has done loads of these and knows how to do it properly - the tolerance is something like 0.0005-0.0014" which doesn't leave much margin for error. The sleeves need machining out or splitting to remove them, and the head needs warming up to install new sleeves.

[shynsy]

Makes sense. Just had a look. Guessing wilcox should know how to do this. Would rather get it done once and properly.
Tim

[2cams70]

What is the condition of the other followers? If it’s just one that looks like that you need to investigate further to establish why it’s just one. Marks like that can also be due to poor lubrication so you need to check the oil ways to ensure they are all clear etc. Measure the diameter of the followers too to see whether they are already oversize. Make sure it’s got a proper Lotus jackshaft with 4 oil slots and not a crossflow camshaft. As a matter of interest is it an aftermarket steel or original cast follower? Should not matter but interesting to know. Cast followers have a thicker wall.

[shynsy]

What is the condition of the other followers? If it’s just one that looks like that you need to investigate further to establish why it’s just one. Marks like that can also be due to poor lubrication so you need to check the oil ways to ensure they are all clear etc. Measure the diameter of the followers too to see whether they are already oversize. Make sure it’s got a proper Lotus jackshaft with 4 oil slots and not a crossflow camshaft. As a matter of interest is it an aftermarket steel or original cast follower? Should not matter but interesting to know. Cast followers have a thicker wall.

[shynsy]

What is the condition of the other followers? If it’s just one that looks like that you need to investigate further to establish why it’s just one. Marks like that can also be due to poor lubrication so you need to check the oil ways to ensure they are all clear etc. Measure the diameter of the followers too to see whether they are already oversize. Make sure it’s got a proper Lotus jackshaft with 4 oil slots and not a crossflow camshaft. As a matter of interest is it an aftermarket steel or original cast follower? Should not matter but interesting to know. Cast followers have a thicker wall.

Certainly there is the same wear patern on all the exhaust valve followers. I Don't think oil flow is an issue. There is plenty in the head area. I suspect the issue was with corroded liners. Not sure if the followers are iron or steel. Will check when i am back home.

[2cams70]

Certainly there is the same wear patern on all the exhaust valve followers. I Don't think oil flow is an issue. There is plenty in the head area. I suspect the issue was with corroded liners. Not sure if the followers are iron or steel. Will check when i am back home.

It is probably an incorrect setting of the follower to sleeve clearances then. Someone may have attempted a bodge by fitting oversize followers to worn sleeves without machining the sleeves properly to fit. If you take a few measurements you'll find out more.

[shynsy]

Am away for a week, so will look later. But what do you think of the corrosion visible at the top of the sleeves. Is this normal?
Tim

[rgh0]

The corrosion is absolutely not normal and the rust particles will contribute to the wear seen on the follower and could contibute to the follower jamming. The grooves on the top of the retainer are also not normal and suggest it has been machined for some reason ?

regards
Rohan

[rgh0]

Looking closely at the photos its clear that the engine has been stored unused for an extended period in a damp environment and corrosion has occured on the sleeves and followers. There may as a result be other issues with corrosion elsewhere in the bores or the crank. From the start of this thread it appears the engine history is unknown and you have only done 500 miles with it. Is this the engine that came with your plus 2 you purchased a year ago or a different engine ? The thread started with you retightening the head bolts, was this because head work had been done or some other reason ?

Without knowing more it is hard to recommend what to do but I think the next step is to take head off and rectification be done of the sleeve and follower issues as a minimum. Close examination is also needed to determine if a more extensive amount of engine work is needed for either the head or block.

Wilcox is an engine builder but I dont think he does his own machining. He should be able to assess any issues with your head and is more likely to offer to rebuild your head. He would then farm out the specialist machine work to whoever he uses. He is a race engine builder so his services are understandably not cheap.

regards
Rohan

[shynsy]

Looking closely at the photos its clear that the engine has been stored unused for an extended period in a damp environment and corrosion has occured on the sleeves and followers. There may as a result be other issues with corrosion elsewhere in the bores or the crank. From the start of this thread it appears the engine history is unknown and you have only done 500 miles with it. Is this the engine that came with your plus 2 you purchased a year ago or a different engine ? The thread started with you retightening the head bolts, was this because head work had been done or some other reason ?

Without knowing more it is hard to recommend what to do but I think the next step is to take head off and rectification be done of the sleeve and follower issues as a minimum. Close examination is also needed to determine if a more extensive amount of engine work is needed for either the head or block.

Wilcox is an engine builder but I dont think he does his own machining. He should be able to assess any issues with your head and is more likely to offer to rebuild your head. He would then farm out the specialist machine work to whoever he uses. He is a race engine builder so his services are understandably not cheap.

regards
Rohan

Hi Rohan
Thanks for the comments. Sage as ever..
Have had the car less than a year and I know the last owner had work done on the engine in good faith. I have been chatting with him by email throughout. It was fitted immediately so I wonder if the corrosion is an old issue. I think for my peace of mind the best route is for the head to be checked and new sleeves and followers to be fitted.
Tim

[2cams70]

A common cause of internal corrosion is an internal leak of coolant into the oil. Either through the head gasket into the combustion chamber or through the front cover into the sump. If the quantity of leaked coolant is enough the lubricating properties of the oil are destroyed hence the galling of bearing surfaces such as on the followers. It’s difficult to assess that sleeve properly and examine the extent of the problem without removal of the valve first. To me it looks like a lubrication or clearance (insufficient clearance) problem.

https://blog.spectrosci.com/guide-to-co ... st-methods

[shynsy]

Ok folks. So took the head off and thing I now know why the valve clearances on number 3 opened up.
Foreign object, probably a spring washer, in cylinder 3.. remnants embedded in the cylinder head.

Some got under the valve at some point I suspect. Perhaps some light piston to valve contact and slightly bent valve hence not closing repeatable. This last para is supposition.

Luckily no obvious damage to the bores which are in good condition.

So cylinder head off for recon. Hopefully it can be sorted.

Tim

[rgh0]

I would also have a close look at the piston and rod in the affected cylinder to see if any damage like s bent rod or cracked piston. The big end bearing in that cylinder may also be on its way out.

cheers
Rohan

[RichardHawkins]

A long time ago my girlfriend (now my wife) had a valve guide break up and go through the combustion chamber, a BMC A series engine. The engine still ran, lots of smoke and the damage to the piston had trapped the piston rings in their grooves.

Hope this is not the case, but worth checking,

Richard Hawkins