Not up on engines so basic questions.
Why do you need to break a cam in and what actually causes them to fail,and why only one part fails and not all off it
Sometimes it happens because people dont run the engine long enough, once started they **** themselves and turn it off/engine dies, too late, the cam lube has gone.
Valve spring press plays a part also
If you dont run it for 15mins or so,there is a danger the vortex of oil wont lube the friction points correctly.
I have built over 1500 engines and never had a cam fail, maybe i'm lucky.
Once the hardened face has gone off the cam its game over in a short while
^^^ I think that's what often happens.
I remember when I got a NOS 10.5:1 Rover short motor, fitted ported SDi heads, matched manifolds, and put a Magnum cam, roller chain and lifters in it, smothered in cam lube.
After all that work and money starting it up and immediately holding 2500 revs for 20 mins was the scariest thing I'd ever done, but the instructions insisted on it.
It was a lovely motor and was fine for many years so it musta worked!
Last edited by 28Chevy; 05-07-2020 at 11:44.
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It is supposedly a lack of Zinc in later oils which are designed for catalytic converter engines .
The last spec oil with enough zinc to not add extra is SF ( from memory) .
I normally use a Classic oil, generally Halfords .
Playing devil's advocate...
How much actual metal off the cam lobe does the 3mm of lost movement at the rocker represent? What I am saying is I wouldn't think we are talking great jagged lumps of metal floating around the engine, more like the microscopic particles that would be in the oil of any engine, and would be caught by the filter or carried out with the oil when it's changed.
Disclaimer: I may be talking ********.
50 shades of grey primer....
It's a tricky one.
He's going to do 2 engine oil changes with some cheapo oil before we strip the sump off. We will check the mains and big ends and if they all look good then we may risk it. If they don't look good then it's a full rebuild.
Wayne, flat tappet cams have to be broken in properly so the cam & lifter wear into each other correctly, failure to do this will wear the cam in very short order.
His engine runs nicely - there is the small knock from the lifter on that lobe but the oil looks clean in the valve covers, oil pressure is extremely good still as well. It 'could' be a dodgy lifter??
When we pull the sump we will be able to see the cam so it will become obvious then.
As the engine has a magnet kit installed then 'hopefully' virtually all of the iron filings will be stuck to those rather than in the oil damaging anything else.
Cut the oil filter in half carefully, (as to not self contaminate) see whats in there.....that will tell you if you need to strip it or not.
the 2500 revs for 20 minutes thing is also due to the fact that most v8's lube the cam lobes by splashing oil on them from the spinning crankshaft. there is no designed in direct cam lobe lubrication and at low revs no oil to speak of gets to the cam lobes. until they 'work harden' to each other the cam lobes and lifter bases are quite 'fragile' relatively speaking.
need a job done on your project? i may be able to help.
Sounds like you are taking a sensible approach. Having only recently rebuilt a Ford Y-Block I use magnets to hopefully catch anything that shouldn't be there.
A while back, when I had a Y-Block Ford bored, I got the shop to make some modifications to the valley as per the picture below to help oiling to the cam. -
Like Kapri, For nearly 40 years I've used the same brand oil - Halfords 'Classic' 20/50 oil in my Y-Blocks. Never had any issue with it.
However, just recently I changed to Westway Oil.
More expensive - Says it 'Reduces Wear especially on Flat Tappet Cams'. Not actually put it in yet. Time will tell.
Here are the details. -
5L High Zinc SAE 20w50 Engine Oil
A quality Mineral oil blended for petrol and diesel engines of primarily pre 1980 vehicles.
A blend of carefully selected additives to help provide maximum engine protection.
Contains high levels of ZDDP (Zinc, Phosphorus & Sulfur)
Suitable for use in engines where a moderate amount of detergent is required.
This multi viscosity oil will help oil circulation at cold start but maintain excellent crank case pressure.
Reduces Wear especially on Flat Tappet Cams
Controls Sludge/Carbon Build up
Protects against rust and corrosion
Helps to reduce component heat
Halfords Classic oil apparently has about 800PPM of Zinc as opposed to Westways 1500ppm Zinc.
More info here -
Sorry to drift off topic a bit.
Last edited by Japchris; 06-07-2020 at 12:25.
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