The V8 Owners Forum -

I tried to install the crankshaft in my 4.6 RV8 engine today and with the crankshaft sitting on the bearings without the caps installed it feels quite tight to rotate. The crank spun fine when I took it out a couple of weeks ago.

I used graphogen on the bearings as that's what I had available. Once I'd put the caps on and tightened the top bolts the crank was solid.

I then took it out and cleaned all the graphogen off and used normal oil. It seems a bit better like this and I can spin it and it will continue for about 1/4 of a rotation. I haven't tried it with the caps on though.

Any ideas what could be wrong (if anything)?

Thanks

Did you fit the crossbolts too? In my experience, without those in and torqued up, your tests will be meaningless.

Chris.

So even if the rotation is tightish with without the bearing caps on it may loosen up when the crossbolts are in?

Just to clarify,
Are you fitting new bearings?
Was the crank reground
Have you checked the thrust bearing clearance?

Regards Denis

Definitely.

Wont work without the X-Bolts being in and tightened.

Ask me how I know!!!

Also as said, have you put new shells in? If so check clearance with Plastigauge. should be about 0.0015" to 0.0025".

Mark

Yes I'm fitting new standard bearings. The old ones we're pretty much perfect and had only been in a short while so I'm just replacing them because I can really.

The crank hasn't been reground to my knowledge.

I have had an engine that loosened off when I fitted the crossbolts as well.

Chris.

So I torqued everything up and it got smoother. I also installed new piston rings and put everything back together and got the engine in the car.

When turning the engine by hand it's a lot tighter than the old engine, the starter motor also turns a bit slower. Is this to be expected of a new engine vs a one with 160,000 miles?

When I started it it made a lot of noise and ran very very lumpy. It wouldn't idle and required quite a bit of throttle to keep the revs up. I didn't dare go above 2000 for fear of it going bang. I expected the tappets to be noisy but it seems a different noise to that. It did quieten down slightly but not much. I'm going to take the rocker covers off tomorrow and have a look whilst it's running. Hopefully I haven't screwed it up too much as I can't be bothered to take it back out.

A freshly rebuilt/reconditioned engine will be tighter than an old, tired one. The crank will be a little tighter as a function of reduced clearance between the crank and it's bearings, however small. Pistons with fresh rings in honed bores will be harder to move and 8 of them will be noticeable, so don't let that trouble you too much.

As for the noise on starting up, it depends what sort of noises it was. Was your ignition set up correctly or was it too advanced and pinking?
Are the carbs/efi correctly set up, is there possibly an air leak messing with the fuel ratio?
Did you leave something loose inside or something lying in the sump?
Check your exhaust manifold for tightness, it can make a weird noise.

It's fitted to a Range Rover P38 with the GEMS injection so I would have thought that would sort itself out wouldn't it? It used to have a 4.0 in so I'll try resetting the adaptive values in the ECU and changing it to be a 4.6 in the ECU.

As for the timing with the stock camshaft pulley I've got I've only got two choices in order to fit it; correctly or 180 degrees out. I think I've installed it correctly anyway. Piston 1 to TDC and cylinder 1 on compression.

Ok so here is a video of the noise: https://www.youtube.com/watch?v=mbNrDbrDu74

I think I also have a vacuum leak, it sounds like it's coming from the back around the intake manifold. I assume that wouldn't cause a knocking like that?

My first port of call would be an exhaust manifold leak.
My P6 sounds similar and it has a leak.

It's quite a slow noise.

Could be a lifter or valvetrain issue.

I took the cam, lifters, pushrods and rockers out of my old engine and put them all into this engine (in the same order they were in the old engine). They didn't make much noise when it was in the old engine.

It sounds to me more like a lifter/valve issue than the exhaust manifold as it's coming from the centre of the engine rather than one side. I'm lost as to what to try now though. It does run pretty well now with the only issue being the vacuum leak causing it to idle rough. I've driven it a few miles today and it's not bad apart from the noise.

stevieturbo wrote:It's quite a slow noise.

Could be a lifter or valvetrain issue.

I agree, that is at camshaft speed you sure a lifter is not refusing to pump up just because you have taken them from another engine is no guarantee the lifter internals are running the same pre-loads it may also be sticky or lacquered up internally