Engine grumble

[dudload]

Hi, and a happy new year to you all!

After replacing the head ony 1098 (per other threads) I'm still getting the grumble fromy engine at specific revs and throttle. Can only really describe it as similar to a drill on hammer setting going through brick (although at a much lower loudness)

Have uploaded a couple of videos, hopefully demonstrating the noise I mean, first vid shows noise at top of revs before gear change and second is sitting with the noise (it's least unhappy between 40-50mph)

Oil pressure sits around 50 when driving and goes to around 20 on idle. When I had the head off, I pushed the pistons at tdc to see if there was any wear in bottom end, but no movement. Any thoughts on what could be causing it? Only thing I can think of is cam/bearing wear or timing (but it never pinks, just goes straight to that noise)


https://youtube.com/shorts/2P1E-trE9d4?feature=share

https://youtube.com/shorts/DAbwgaDPsp4?feature=share

[geoberni]

Your first link comes up as Unavailable because it's set to Private.....

[dudload]

Aha, sorry about that. Should be working now...

[serowman]

BOTTEM CAN NOT BE CHECKED BY PUSHING ON PISTONS.SUMP NEEDS TO BE REMOVED

[kennatt]

could be anything,take fan belt off and run it for a SHORT time to eliminate water pump and alternator bearings.

[liammonty]

You’ve been altering the timing, right, because you’ve put the correct 12G202 head on your 1098 engine which had a 948 head on it before? If I’ve got that right, and this issue/ noise has started SINCE changing the head, I’d put money on the grumbling noise you are hearing being the timing being set wrong. Do you have any idea roughly what it’s set at? If it’s in the ballpark of where the manual says it should be, I would try altering it slightly and road testing - a grumbling bottom end can be caused by incorrectly set timing just like pinking can.

[dudload]

Thanks all for replies. Correct that I've changed the head to be correct 1098 - the grumbling was still present on the 948 too unfortunately.

I've set the timing to a retarded enough level to remove the grumble, but it's so far back that the car struggles to start and performance is poor (compared to my other Morris). What's strange is that there's no pinking (it does do it if I advance any further) before the grumble kicks in. It does therefore seem timing related, but wondering if there's an issue in the bottom end that's coming to the fore when timing at a specific timing.

Probably nothing else for it bit to drop sump and check bearing shells. Is cam bearing wear a possibility that could cause that noise?

[philthehill]

Firstly I would remove the sump and examine the big end bearings and crankshaft big end journals for wear.
Secondly I would remove the centre main cap and see if there is any wear to the centre main bearings, crankshaft journal and thrust washers. You can wind out the top main bearing for examination.
Unfortunately you cannot examine the front and rear crankshaft main bearings without removing and stripping the engine.
Measure the big end journals to confirm wear if any.
Use a plasti-gauge strip to determine the wear/clearance of the centre main bearing.