Noisy cam follower / tappet.

[rogermassey]

Hi, I’ve recently purchased a 1970 4 door Morris Minor 1098cc The engine was replaced 10 years ago with a rebuilt unit from a specialist rebuilder, the engine has covered 9,742 miles since being fitted. The car is in extremely good condition and has been treated well from new, as evidenced by the file showing all the repairs over the years. The issue I have is that the engine runs smoothly but has an intermittent metallic clinking noise that relates to the cam / tappets / followers. It is most noticeable on the deceleration of the engine, blipping the throttle then letting the engine slow to idle, it’s on the return to idle. With the engine ticking over, the clinking comes and goes, I’m wondering if a follower is pitted and worn through the hardened skin but not all the way across. Tappet clearances set at 0.012”. I’m going to change the followers and pushrods over the next few days to see if this fixes it, definitely not timing chain, although I have bought a duplex to fit once the clinking is resolved. sound familiar to anyone? Roger.

[philthehill]

To me it appears more of a timing chain issue than cam followers but as it is not a hard job to change the cam followers I would do as you have suggested and change the cam followers and if that does not cure the problem change the timing chain to a duplex set up.
The simplex standard set up with the rubber ring tensioners does not have a reliable long life and after a few thousand miles the rings can become ineffective leading in some cases for the timing chain to wear through the timing chain cover.
The duplex set up gives better service and longer life.
When fitting the duplex you will need the flat oil thrower plate and the two 1/4" UNF hex headed screws replaced with two 1/4" UNF countersunk screws. Allen headed preferably and loctited in place. The front engine plate will need countersinking to accept the countersink head of the screws.

[rogermassey]

Thanks for the input Phil. I agree with the fitting of the Duplex set up, I’ve got everything including the 1/4” UNF X 5/8” Countersunk Allen screws, I don’t have the flat oil thrower plate though. I thought the concave one could still be used? I’m not convinced it’s timing chain though as I’ve had quite a few minis in my past, the rattle of a loose chain is distinctive and more easily identified as coming from the front of the engine. My clinking is more to the rear, I’ve replaced the distributor with a new one as I thought it could have been the drive, it made no difference, drive gear was good. Once the followers and pushrods arrive, they will go in. I will post the result. I’m 50/50 on the noise stopping, if it’s still there, then timing chain next. Valves and springs are good, cold compression test 160psi on all 4 cylinders. If still there, engine rebuild over winter. Roger.

[philthehill]

You will need the flat oil thrower plate. It is marked ' F ' for front.
The duplex crank pulley pushes the oil thrower forward and the concave fouls the timing chain.

[philthehill]

Here is the plate required:-
http://www.minispares.com/product/Class ... o%20search

[philthehill]

Amended/Duplicate post as unable to amend above post.
The duplex crankshaft sprocket/gear pushes the thrower plate forward which allows the concave thrower to foul the timing chain cover.

[philthehill]

Here is a flat oil thrower plate for sale. The usual suppliers all appear to have this part on back order.
https://www.ebay.co.uk/itm/162561347802 ... R7T2qsKqYg

[rogermassey]

Thanks for the info Phil, and for the link to the flat oil throw plate. Best regards, Roger.

[philthehill]

Just a thought:-
It may be advisable to check the drive shaft located between the camshaft and the distributer. I removed a drive shaft once and the teeth on the drive shaft were so worn they were sharp as a knife.

[philthehill]

Just went to add a photo and the post is closed. Note the time between the two posts above.
Something is not quite right.

[svenedin]

Just went to add a photo and the post is closed. Note the time between the two posts above.
Something is not quite right.

Are you accessing the forum on a tablet or phone? I am sure I noticed your issue a few days ago but when I tried on my laptop I could edit as normal.

Stephen

[philthehill]

I am posting from my desktop.

[philthehill]

No edit icon shown for the above posts!!!

[svenedin]

I am posting from my desktop.

Well this happened to me too a few days ago and I assumed the forum was on the blink. Coincidentally I did an update and rebooted my machine (which is a Mac running the Safari browser) and it worked again.

Stephen

[rogermassey]

Hi, removed pushrods and 7 of the 8 cam followers without issue. No2 cam follower was tight coming out, I ended up removing the manifold to get a better grip of the follower. Replaced all 8 pushrods for new and fitted 7 followers with ease, the 8th new follower would not enter the final 5/16” in number 2 follower bore, it wouldn’t contact the cam lobe. I measured the old follower, it was 0.003” undersize to the old (and new) followers. I have put the old follower back in until I can get a reamer to clean out the bore. I’m thinking the follower is too tight, it doesn’t slide very easily. Anybody know where I can get a reamer from? I guess it will be a special. Roger.

[rogermassey]

I checked the Distributor drive shaft / gear when I fitted the new distributor, it’s in good condition.

[philthehill]

The standard bore of the cam follower hole is 0.812" with a 2.5 degree inclination from vertical towards the crankshaft centre line.
Instead of trying to ream the cam follower hole I would be tempted to move the cam followers around and see if the problem can be overcome as not all currently produced cam followers are the same diameter or have parallel sides.

[rogermassey]

Hi Phil, tried all 16 cams, only the one that came out went back in. The one that fits measures .8085” to .810” so undersize and oval, it does rotate so I think the oval it’s is causing the intermittent clinking, all the other cams measure .811” to .812” the cams that came out are a mixed set, some have drain holes, some don’t. If reaming doesn’t work, I will probably get a cam ground centreless ground to .8075” probably one with a drain hole.
I think this engine has been worked on previously, I looked at removing the front bumper and grill panel to fit the replacement duplex chain. All the bolts are clean and look to have been replaced recently. I bought the car due to it having an exceptional chassis, no welding at all, and good bodywork. I heard the noise when I bought it and expected to need to do work on the engine.

[rogermassey]

Update on noisy tappet /cam follower, after much “process of eliminations” I finally pulled the engine and stripped it down to check everything. Crank journals and shells near perfect, pistons, perfect, bores, although liners fitted, perfect with no wear or top lip. Checking piston ring gap in bore at mid position, 0.037” gap!! Checked piston diameters to bore, 0.0135” clearance. To verify measurements, I can slide a 12 thou feeler blade between the bore and piston. Seems that the noise was severe piston slap on an engine that hasn’t covered 10,000 miles, admittedly over a 10 year period but very surprised to finally find this build error, I can’t say it was an error by the very well known engine remanufactured as 10 years is a long time for things to happen, as no locking tabs were on the mains or big ends, it’s anyone’s guess. I fitted another rebuilt engine and rebuilt a spare gearbox to go with it. The Car now purrs. I will rebuild the original engine as it now has duplex timing chain, I will rebuild into a replacement block, bored to suit original pistons etc. Head already converted to unleaded so all is well that ends well.