B20 engine noise

[CliffHeaton]

Agree with Mike above take the drive belt off to eliminate non engine problem.
Check fan bearings too if noise disappears without belt on.

[tonydgray]

Originally Posted by turbotroll

Tony,

I have the same noise in my B20A (1972 145, which has done just over 100k). Valve clearances have been set to 15 thou with a warm engine, which has helped slightly. Timing gears have also been replaced with steel gears. This helped to quieten the noise initially however it returned after a few hundred miles. The feeling now is that it is a worn camshaft lobe and/or camshaft bearing.

Thanks for that that's good information and interesting regarding the timing gears. I don't know what yours is like but I still get the feeling that the noise is coming from under the manifolds. Does it sounds like that on yours?

Cheers

Tony

[tonydgray]

Oh, I also posted on the swedespeed forum if anyone is interested in this thread:

http://forums.swedespeed.com/showthr...32165&posted=1

Cheers

Tony

[Derek UK]

It is possible that this is a small leak in the exhaust, either at the manifold to head or the manifold to exhaust pipe joint. If it's noticeable when starting from cold you have a short while to feel around underneath for hot gas or use a rag around the joints underneath. It will quickly get too hot to make more checks but with the engine running fast, get someone to hold a ball of cloth tightly over the end of the exhaust. That will also show up any leaks.

[tonydgray]

Sorry for the delay in posting but I'm honestly at a bit of a loss at the moment with this one. I've done my best so far listening to the engine using the stethoscope and its just difficult to narrow down the where the noise is coming from. I think the noise is actually getting louder at the moment so as long as its not causing irreparable damage it may do a better job of letting me know where its coming from!! The one thing I'm pretty sure of now though is that its a definite knocking and I think we can rule out an exhaust leak as that was one of the things I managed to check out successfully...I thing :-)

I'll keep you posted, cheers Tony

[tonydgray]

Latest findings:
With the stethoscope, the worst noise seems to be when holding it on the alternator casing. I've taken the fan belt off and the noise still sounds the same so we can rule out the alternator and water pump.
The fuel pump is fairly new so should be ok.
It gets worse when the engine warms up.
There seems to be descent pressure from the oil pump as oil does get spat out of the rocker cover when the oil filler is removed.
I also tried eliminating individual cylinders by removing each spark plug in turn, this made no difference to the noise.
The paint does not seem burnt under the exhaust manifold and no leaking successfully found in that area.
Noise is worse when driving so I'll try and get a video of it while out on the road.

Cheers

Tony

[Derek UK]

Have you checked the valve clearance with a feeler gauge after using the clickadjust? I also have one of these and it does work but always check with a feeler after each adjustment. Do it again if needed. Having a stray noisy tappett is usually down to cam wear I think. The cam in a high mileage engine likely to have at least one cam lobe starting to flatten off. Bad ones can be spotted by watching how much the rockers depress the valve.
What oil are you using and when was it last changed?

[tonydgray]

Originally Posted by Derek UK

Have you checked the valve clearance with a feeler gauge after using the clickadjust? I also have one of these and it does work but always check with a feeler after each adjustment. Do it again if needed. Having a stray noisy tappett is usually down to cam wear I think. The cam in a high mileage engine likely to have at least one cam lobe starting to flatten off. Bad ones can be spotted by watching how much the rockers depress the valve.
What oil are you using and when was it last changed?

Hi Derek

That's a good point about rechecking the clearances. I have done three rounds i all, the first with the feelers, second and third with the click adjust. I did not follow up the last set of adjustments with the feelers gauges though so I'll give that a try.

I've also visually checked that all valves have opened by a fair amount, not measured in any way, and all appear to open ok. Hopefully this rules out cam lobe wear to an extent.

New oil a couple of weeks ago. Millers 20w/50 classic oil.

Cheers and thanks for your help

Tony

[tom-madbiker]

on mine when i took the camshaft out the shaft was running in the bearing shells as the babbit had all but dissaperred just a word of caution if you find it is camshaft bearings be very carful putting the new ones in they are very easy to damage i turned up a tool to do it