free hit
counters
Damage to cam follower bore - Engine/Ancilliaries - The Lotus Forums Jump to content
NR2k

Damage to cam follower bore

Recommended Posts

As we were cleaning the cam carriers we noticed one follower bore had some damage. About 5-6mm round and deep enough to feel with a fingertip. The follower itself looks fine, and moves freely in the bore. 

Is this something we should be concerned about?

Is it possible to get the bore ground out and fit an oversize follower?

Standard 910 engine in 84 turbo.

IMAG1392_1.jpg

IMAG1392_1.png

Share this post


Link to post
Share on other sites

Upgrade today to remove Google ads and support TLF.

Is that an indention into the bore wall? In your pic it almost looks like it's proud of the surface of the wall as if a stray piece of metal was mashed between the follower and bore...


1995 S4s

Share this post


Link to post
Share on other sites

If the follower moves ok and the mark was an indentation (as I presume it must be) since it is all dosed with oil as it is running, I would clean up with some emery so it was pretty invisible. Check with bore gauges to make sure that there is not something else more untoward. Out of round etc.

Not ideal, but it would work.

As Jim asked, it would be interesting to know is it was a piece of metal that got mashed up in there?

  • Like 1

All we know is that when they stop making this, we will be properly, properly sad.Jeremy Clarkson on the Esprit.

Opinions are like armpits. Everyone has them, some just stink more than others.

Share this post


Link to post
Share on other sites

Difficult to see in the picture but its an indentation. Looks worse in the pic too, it can just be felt with a fingertip.

Only clue as to cause is that the valve had contacted the piston in that cylinder.

Just finished completely rebuilding the bottom end, head etc. Thought we were on the home straight. 

Share this post


Link to post
Share on other sites

As Ramjet says when lubricated with oil that area should be fine,  However after going through all the hassle  of rebuilding the bottom end, I would take the cam housing to a local trustworthy machine shop and get it cleaned up.  

You can get away with marks on castings in engines while rebuilding but not knowing if this is a contaminent i.e something embedded in the alloy is another matter.   Air on the side of caution on this one imo as it better to spend a couple of extra pounds getting it cleaned up now than spend a few thousand pounds maybe a little further down the line when it possibly comes back to bite you on you on the bum :)


A

Share this post


Link to post
Share on other sites

Looks like a seizure, imho. All very well talking about taking it to a local machine shop for them to clean up....but what can they DO?? They can't bore it out, you'd need an oversize follower and such things don't exist. Poking at it to see if anything can be dislodged you can do yourself. I don't think anyone would be prepared to take money for "repairing" that and become liable for any subsequent failure.

Having said that.... if the bore is round and the follower is, too, and the fit is acceptable, slides up and down without wobble...and you have cleaned up the bore around the blemish with fine grade wetordri and then given it a good scrubbing to get rid of any particles....then I think I'd put the whole thing back together, using the Lotus recommended Graphogen grease, and all will probably be well. Otherwise....replace the cylinder head ? Ugh.

Personally, I'd reassemble the thing and expect it to be OK...but it's your choice.

  • Like 2

Scientists investigate that which already is; Engineers create that which has never been." - Albert Einstein

Share this post


Link to post
Share on other sites

My two-pennyworth - If the follower slides well enough, and the surface of the alloy is smooth, then I'd drop it back in again. It does look like it's had a bit of debris to cause the localised damage, though some very fine paper would clean it up. I think there's more than enough good surface area left for it to run, and yes, the cam follower bores can be sleeved if deemed necessary. Someone like H.T. Howard in Slough would do that, but there are many other cylinder-head machine shops around, too.


Margate Exotics.

Share this post


Link to post
Share on other sites

I'd reuse it and not worry too much.   However, as this is just one of your cam towers, I don't think a good 2nd hand replacement would be particularly expensive or hard to get in the grand scheme of things <£100?       

Share this post


Link to post
Share on other sites

If the follower is undamaged and it is an indentation then I'd probably just leave it as it is. After all, how may miles has it been like that? If you wanted to repair it you could get the bore white metalled then have it bored and honed back to the specified diameter.

Share this post


Link to post
Share on other sites

Thanks for the helpful comments. 

Will try cleaning it up and go from there.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...