P38A tapping/knocking noise

kermit_rr · Oct 4, 2020

Is there any trick to checking oil pressure, other than taking the pressure switch out?
Seemed like an easier job to change the cam and lifters and hope for the best!!

Henry_b · Oct 4, 2020

kermit_rr said:
Is there any trick to checking oil pressure, other than taking the pressure switch out?
Seemed like an easier job to change the cam and lifters and hope for the best!!

The only way it to pull the pressure switch and put a gauge in its place.

Cam wear is common on the V8 if it has had a hard life before your tenure!

kermit_rr · Oct 4, 2020

Henry_b said:
The only way it to pull the pressure switch and put a gauge in its place.

Cam wear is common on the V8 if it has had a hard life before your tenure!

Cheers, i couldn't get any purchase on the switch with a spanner and socket was no good!!
Yes the cam in the last engine went from good to bad in less than 100 miles!! Still got it as evidence¡! 2 of the libes are completely round

Henry_b · Oct 4, 2020

kermit_rr said:
Cheers, i couldn't get any purchase on the switch with a spanner and socket was no good!!
Yes the cam in the last engine went from good to bad in less than 100 miles!! Still got it as evidence¡! 2 of the libes are completely round

Common on the RV8 with the wrong oil, or lack or servicing..

Pulling a cam isn't too difficult, a great time to do the timing chain too!

kermit_rr · Oct 6, 2020

appreciate it is not a fix, but what about dumping some 'lifter treatment' into the engine? if that reduces/removes the noise then its a sure sign of the issue rather than stripping the lot down with fingers crossed.
I'm due an oil change before too long anyways and I don't see any kind of cleaner/additive can do much harm in the short term?
the only other thing it could possibly be is a worn rocker/shaft...

Henry_b · Oct 6, 2020

You could try

rob1miles · Oct 6, 2020

Ran some lifter cleaner in an old Merc, it freed off the stuck cam chain tensioner.

kermit_rr · Oct 6, 2020

Gotta be worth a try and can't do harm, unlike slick50 etc

Marshall8hp · Oct 6, 2020

This is exceptional stuff. Not sure if it is available in the UK, but you could do a search. Basically molybdenum di-sulphide. One tube in and it will sort things like dry lifters etc very quickly.

https://www.itwpf.com.au/molybond-lubricants/product-category/oil-supplements/

kermit_rr · Feb 25, 2022

Finally an update!!
The passenger side (odd numbers) cylinder head is in my living room, as is the remains of the rocket shaft assembly. The rest is some where in old oil!

There was evidence of a blow through the gasket to the outside, explains the leaky exhaust i couldn't find.

A couple of the rockers were badly worn, but all past their best. That's the source of the knocking I've been getting!! If course i will only know for sure once it's running again with a new rocker shaft.

The related lifter also was starting to show wear on the cam face.

Also wear in a couple of the lifter bores, but i don't think there is much you can practically do about that without huge expense.

Pics to follow shortly

kermit_rr · Feb 25, 2022

Rubberknees · Feb 25, 2022

kermit_rr said:
appreciate it is not a fix, but what about dumping some 'lifter treatment' into the engine? if that reduces/removes the noise then its a sure sign of the issue rather than stripping the lot down with fingers crossed.
I'm due an oil change before too long anyways and I don't see any kind of cleaner/additive can do much harm in the short term?
the only other thing it could possibly be is a worn rocker/shaft...

Have used the Lucas engine treatment on some older cars and found it helpful also on an old petrol lawn mower

P38A tapping/knocking noise

kermit_rr

Very

Henry_b

Think outside, no box required.

kermit_rr

Very

Henry_b

Think outside, no box required.

kermit_rr

Very

Henry_b

Think outside, no box required.

rob1miles

Well-Known Member

kermit_rr

Very

Marshall8hp

Well-Known Member

kermit_rr

Very

kermit_rr

Very

Rubberknees

Well-Known Member

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