So I replaced a bad con-rod bearing on my performance A14 (which had rotated in it's housing, blocked the oil galley and proceeded to wear itself out). The crank was okay thank god.

I started her up yesterday and apart from being out of tune she ran really well.

So I come back in today and started her and there is the knocking noise again. Off with the sump, oil pump etc.

I remove the spark plugs and crank her free to hear where the knocking is coming from. I am not convinced but it appears to be another con-rod bearing, it has some clearance either side (laterally) so when you give it a wiggle you can hear a knock.

I took that bearing off and it's looking rather worn. Not drastic but enough to raise the eyebrows.

Now I'm going to step back a bit and look at the bigger picture. Is my engine oiling properly?

Does anyone have a quick-check technique?

I checked the oil galleys when I first built the engine (20psi air) and if I remember correctly the crank is oiled first and the camshaft feeds off the crank feed.

I also have great oil pressure.

Does anyone have any advice or suggestions?

Revhead?

Without knowing exactly what has been done to the motor, the first thing that I would be checking is the conrod big end and crank for roundness. And a check for bearing clearance of various stages on the conrod bearing using flexi guage or something simular. As long as the crank oiling galleries are all clear oil feed should not be a problem.

I have seen simular problems before. Once it was because a mate had acid cleaned his block and had not washed it out properly afterwards (caustic ate the bearings pretty quickly) and on another occasion the conrods on a motor were not resized correctly causing the conrod to be out of round on the big end.

I'm just going through exactly the same scenario, spun a big end - replaced all big end bearings - went for a drive around the block and spun the same bearing (the night before a rally)

I spoke to the guy who does my bottom end machining and he says that 99% of the times you spin a big end bearing you distort the big end on the conrod and in most cases you bend the crankshaft.

So guess what I'm doing tomorrow.....pulling the motor out and checking everything, hopefully I haven't bent the crank.

Is that your knife edged crank Gary? Hell, you'd be pretty gutted is it is poked!

Don,

Cheers for the advice.

I have run it through, one thing stands out to me.

The engine hasn;t been under any load, she's been on a stand picture somewhere in here. She has only been spinning the flywheel so there wouldn;t be much to say the crank is bent.

I have also found something very, very interesting.....

The conrod bearings from stewart wilkins motorsport have much smaller oil holes than the NOS ones I found stashed here. SO i'm thinking there might just be a volume (lubricating) issue there.

I have taken pics of the bearings.

Anyhow the knock is still there. I am going to have to give in and call in the expert, my old man (which I absolutly hate doing!).

Yes mate, unfortunately it is the knife edge, hopefully will know the damage in the few days.

the hole in the big end bearing is to lube the bore/gudgen pin?
did u clean the oil gallery in the crank?
bearing material gets stuck in oil gallery in crank causing bearing to #### itself.
rod must have side clearance or oil will cook in bearing causing it to spin in the rod.
did u check the main bearing that supplys the spun rod?

Hmm no I didn't. I'm being lazy and trying to fix it on the stand, I know I shouldn't.

Just spent so much time on this project, I'm loosing the plot.

Anyhow I will take the engine apart tomorrow night and check the crank. I never actually checked it earlier, I did how ever check the feed from rocker to oil pump and to crank and cam (not the actual crank though).

Cheers Tommo, some good thinking there. I'll put an update on it in my project thread so you can see if you were right or not Be sure to have a look, the old B10 is looking mighty fine.

Okay well dad told me to f-off and fix it myself (in the nicest possible way).

I stripped the engine (process of elimination). As she came apart I kept cranking it and the knocking turned out to be several different knocks.

The bearings are sitting tight (well as tight as they ought to be). I put a size 27 spanner on the crank pulley (engine head off) nut and moved the crank back and forth, I placed a screwdriver (gently) on each piston and put my ear to the top of the screw-driver. As I rocked the crank the knocking was very audible through the screw-driver through all of the pistons. It seems the knocking is coming from the piston head and the pin securing the piston head to the conrod.

What is this pin called? Gudgeon pin comes to mind but I don't know what it really is.

The pistons are oversized with a '100' stamped on the tops. Is this apparent knocking normal?

The knock isn't huge but it is audible and in my mind it isn't right.

What shall I do?

my thinking is that you dont have an oiling problem but something is out of round. Bottom ends require accurate tolerances where thousandths of an inch can be critical so a margin of even half the width of a hair from your head out will cause you grief.

to do it properly you need to get your crank and rods machined and then get bearings to suit. thats my thinking anyway!