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whats happened to my follower and why

Engine 
5K views 34 replies 14 participants last post by  advinnie 
#1 ·
Hi striped down my engine and found one of the cam followers looking like this. Can anyone tell me how it's got like this and why. Cheers all the engine has done less than 2000 miles.
 
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#5 ·
Lost compression on number 2 cylinder and had a clicking sound at 1/4 engine speed and if you was to turn the engine over by hand it would spin easy for all most a full rotation then go stiff then spin easy again so I thought I would investigate :)
 
#13 ·
Not sure....
You can see the TDS for this oil here: http://www.epc.shell.com/Docs/GPCDOC_Local_TDS_United_Kingdom_AeroShell_Oil_W_15W-50_(en-GB)_TDS.pdf

Couple of clues...it states:
AeroShell Oil W 15W-50 is not recommended for use in
automotive engines
. For automotive engines converted for use
in aircraft, the specific engine manufacturer or the conversion
agency should be consulted for proper oil recommendation.

Also, they describe it as "AeroShell Oil W 15W-50 is a unique blend of high quality mineral oil and over 50% synthetic hydrocarbon base
stocks, plus the AeroShell Oil W ashless dispersant additive system.".
To me "ashless" means zero ZDDP (any chemists out there please correct me if I am wrong). They claim Ash content of 0.006%m, which is pretty much zero.

So, I don't know what their magical anti-wear ingredient is, but it doesn't appear to be something you want to put in your car. ;)
 
#15 ·
I don't want to rub salt in anyone's wounds, but it interesting to try and work out why this oil isn't suitable. On the face of it you might think it was a good choice.

However, I did notice that it has quite a low flash point.
That is fine with aero engines as they get plenty of cooling air (for obvious reasons).
If your engine has been too hot the oil may well have started to combust.
Oil starts to break down if it gets too hot....

For car engines, especially air-cooled ones, you really need to look for oil with a high flash point.
 
#18 ·
By the way if anyone is interested I found out why the cam lobe went flat and why two of the followers broke up. One of the exhaust valve guilds had slipped outwards in to the head and that valve was only moving 5mm open before it jammed but the valve should of been opening 12mm so because the valve was only capable of moving get 5mm the cam lobe first had to destroy the follower so the cam could turn and then slowly ground it's self down :-(
Happy days
 
#28 · (Edited)
This is a fine theory, however I believe that catastrophic failure, rather than accelerated wear, would have been the result of the loss of 7mm of valve travel. This would surely have wrecked the relevant pushrod before anything else, even if the engine could turn over to start. Further, why two followers and not just the one on the offending valve, and if the valve guide
was loose enough to 'slip' why could not the valve have pushed it back again?

The pitting effect is typical of surface fatigue failure (as seen on aged or overloaded rotating bearings) so I feel we should be looking a bit deeper here.

Cheers, Carl.
 
#20 ·
Yep all sorted now I ended up building a junk yard 2054cc engine with stock size 35x32mm valves and aftermarket heat exchanges with a 1 3/8" header and a pair of Dell 40 carbs and the bloody thing really does go although it will only rev to 5100rpm due to the heads but it has sh#t loads of torque from idle to 4500rpm. God knows what this engine will go like with bigger valved heads?
 
#22 ·
Cause this engine runs so well I may just get some large valved heads and see what happens but on a side note my other bug me to take all our old junk down to the tip today and I'm glad I did meet this bloke getting rid of a 1 1/2" merged header with a mondo muffler it's in pretty good nick as well, ask him why he was getting rid of it and his answer was it was left in the garage they have started to rent so offer him a £5 and now it's mine. Don't know if it's going to be to big for my motor or not? What you think?
 
#25 ·
Hi mate, I've just seen your reply.

Thanks for going into such detail and asking around.

It wasn't what I was hoping to hear but I've had a few days to think about stripping it down now and I'm getting used to the idea.

Will keep you posted.

Thanks again.
 
#31 ·
Hi mate I'm at work so I'm rushing what I'm writhing.
Right the valves that destroyed there followers should of be opening 12mm like the rest of them but these two would only open about 5mm before they jammed. They physical can not open any more than 5mm not even if you hit them with a hammer for some reason they just jam why I have no idea they never use to?
 
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