Engine knock

smoker · Post by **smoker** » Mon Oct 12, 2009 11:33 pm

Did you manage to stop the tapping noise Kevin?

I'm about to fit another new cam (im changing fom a piper to the standard cam this time) and followers hoping this effects a cure

kstrutt1 · Post by **kstrutt1** » Tue Oct 13, 2009 2:04 pm

Iv'e fitted a new cam (3.9 one) but hav not quite finished the re-assebly yet, I will let you know when I get it running.

evin

kstrutt1 · Post by **kstrutt1** » Sat Oct 17, 2009 7:45 pm

I finished puting the new cam in today, Now I have another problem, The oil pressure seems to have dropped, at first I got around 20psi at around 1500 rpm but as the engine rpm increased this dropped away, after a few minutes I now only seem to have a few psi, it's a mecahnical gauge so I don't think that is the problem, I primed with a drill on the distributor drive before starting it and had oil coming out of the followers,I obviuosly removed the front cover which allowed the oil to drain out of the pump and I also removed and re-fitted the relief valve to gain access to one of the bolts.
My thought is to take the oil pump apart inspect it and if OK re-assemble with vaseline. any other thoughts?

I also think it's still knocking but won't be sure until it has warmed up properly (and has decent oil pressure)

Kevin

johnm · Post by **johnm** » Tue Oct 27, 2009 11:58 pm

Kevin,

Did you make any further progress on the knocking noise? I only ask as I have what seems to be a similar problem and coincidentally also a TR7 V8 with SD1 engine. Engine was fine but recently developed a tappet rattle/knock when hot and at idle. Seems to improve/go as the revs rise.
Naturally, like you my first thought was lifters or valve gear but pulling the oil filler on one bank and the PCV valve on the other doesn't make the sound more noticeable. There don't seem to be untoward noises coming from the rocker cover area.
My feeling is that the noise is coming from the timing cover/water pump/distributor drive area but you know it isn't easy to pin down an exact location.
So just thought I would check to see if you had got to the bottom of it.

John

kstrutt1 · Post by **kstrutt1** » Wed Oct 28, 2009 9:55 pm

John,
I changed the cam and followers, on strip down one follower had a pitting pattern as if it had been bouncing and another lobe was missing 2-3mm.
I also could not pin the noise down, but it did seem to be from the centre of the engine which is where I believe you would hear a cam/ follower most.

The problem is now I can't get a decent oil pressure (see other thread), Hopefully I can sort this out over the weekend, I'm suspecting a leak on the pick up pipe somewhere, and am even wondering if this could be related to the knock (air in the oil).

kevin.

kstrutt1 · Post by **kstrutt1** » Sun Nov 08, 2009 12:14 am

The new gasket fixed the oil pressure but it still knocks when hot, its more loud tap not a heavy knock like big ends to sumarize, originaly it knocked and could be made to quieten by removing the plug lead from no 2 cyl, I removed the head, and con rod/ piston which had a slight twist, fitted new rod/piston, this did not work so I changed the cam followers and chain/ gears (cam was worn on one lobe) still no effect, I also changed the rocker shafts and set the cam preloads.
It has 20/50 oil and 15psi hot idle / 40psi over 2000rpm. The plugs are all clean and a nice light brown colour so it does not seem to be suffering from a damged piston/ rings. listening with a screwdriver, the noise seems to be most audible around the front of the block My thoughts are :

Piston slap
Little end
rods somehow touching each other
piston or rods touching something in crankcase
Something in combustion chamber.

I need to get my Landrover ready for the winter so for the moment I will just drive the TR (hopefully it will go away or get so bad it happens when the engine is cold) but eventually I will carry out a compression test, remove the sump, remove and check all the mains / big ends, look for any fouls etc, if this does not work I will remove the heads and all pistons / rods and check for wear.

Any other ideas ?

RoverP6B · Post by **RoverP6B** » Sun Nov 08, 2009 4:33 am

Main bearing caps on 2 bolt blocks can and do come loose resulting in a knocking sound audible at idle when the engine is hot.

If the caps are retained by studs and nuts, then that is not likely though.

It may well pay to pop the sump off and check all bolts for correct torque.

Ron.

CastleMGBV8 · Post by **CastleMGBV8** » Sun Nov 08, 2009 9:59 am

Kevin,

One other possability is cam shunt, the earlier pre 4.0/4.6 engines did not have a plate to locate the camshaft and the cam can effectively move backwards and forwards and this does create a slight knocking sound against the front cover.

If this is the culprit it is nothing to really worry about, it can be fixed by fitting a cam button on the front of the cam.

If you can get your long screwdriver onto the face of the front cover you may be able to hear if it is where the noise is coming from.

The other advice re the mains caps is also relevent if the above is not the source.

Kevin J

kstrutt1 · Post by **kstrutt1** » Sun Nov 08, 2009 11:21 am

The mains are standard which I believe is bolts, so that does sound possible and easy to check (i even have a spare sump gasket), I'll also check for the cam shunt but you could feel it through the screwdriver more on the block than front cover so the first sounds more promising.

kstrutt1 · Post by **kstrutt1** » Sat Nov 14, 2009 11:26 pm

Took the sump off again today everything is very clean with no carbon build up etc, all the main caps seemed pretty tight with no sign of movement, though the front one did seem a little looser then the rest. The shells also looked good, Also removed all the big ends, the bearings are a little marked in the centre but not badly, no perceptable play in any little ends, all the cam bearings ar in place and look fine, the pick up pipe gasket had begun to split, but not right through.

Only problem was one of the windage tray bolts sheard off when I tightened it up and I could not get the broken bit out so it has gone back minus one centre bolt.

So I put it all back together with new gaskets, Haven't had a chance to drive it yet but at least I now know nothing looks like it is going to break and I can just use it and see what happens.

Kevin

kstrutt1 · Post by **kstrutt1** » Tue Nov 17, 2009 7:51 pm

I've used it for the last couple of days, feels much quicker and smoother with the new cam but still knocks the same, today I tried driving it with one plug lead removed to try and isolate which cylinder it is, the conclusion is it is the same one I replaced the twisted rod and piston on.
It comes and goes as the plug lead is removed, which leads me to believe it is either the piston in the bore (distorted bore?) or something to do with the valves / exhaust.
I will continue to use it for a while but may remove the ex manifold for a look when I get a chance.

kstrutt1 · Post by **kstrutt1** » Tue Nov 24, 2009 8:28 pm

I have now managed to isolate the problem, unfortunately it is the bore in cyl number 2 which is distorted being narrower top to bottom than across, my thoughts are that it has been allowed to freeze at some time damaging the bore.

So now I have a re-con engine with one damaged bore, so the plan is to get a servicable 9.25CR secondhand engine, fit my new cam and possibly crank, along with my heads and new piston rings if required.
Fortunately there seems to be plenty of engines going for little money (£50-£100)on ebay.

I have assumed I can use any 3.5 v8 from a range rover etc and fit my SD1 sump and front cover, can someone confirm this?

ChrisJC · Post by **ChrisJC** » Tue Nov 24, 2009 9:05 pm

kstrutt1 wrote: I have assumed I can use any 3.5 v8 from a range rover etc and fit my SD1 sump and front cover, can someone confirm this?

Yup. Blocks are the same.

Chris.

CastleMGBV8 · Post by **CastleMGBV8** » Wed Nov 25, 2009 11:46 pm

Also 3.9 and 4.2 engines.

kevin.

kstrutt1 · Post by **kstrutt1** » Tue Jan 26, 2010 10:54 pm

Well I finaly gave up on the original engine and bought another.

The second engine was a late SD1 engine running well with low oil consumption, as it was running well before I left the crank and pistons untouched (the bores looked fine), on strip down two of the cam lobes were badly worn but otherwise appart from some quite heavy black deposits in the valve area it was pretty clean and this time it actually was a 9.35:1 CR (the old one had 8.25 pistons fitted)

I built it up using the new cam and followers from form my old engine along with my existing cylinder heads. Used it for the first time today and now at last I have a knock free smooth and powerull engine.

The only problem now is the temperature rises a bit high but I am pretty sure this is the degas bleed in top of the inlet manifold blocked as it has happened before (usually a small slither of siloce sealer which has come off when the gaskets were removed)

When I get the time I will remove the piston and measure the bores but I suspect the liner could be moving somehow due to what ever trauma caused the rod to be twisted