Thread: D1 V8 top end rattle. Ideas?

Does it change with revs?

Originally Posted by Pedro_The_Swift

Does it change with revs?

Pedro, it doesn't appear at all until 4krpm, then is constant until the red line. No change in the sound at all.

I know that sounds can be deceiving as to where they appear to be coming from, but this one sounds up high rather than low.

Do you regularly rev it over 4K to redline, seems like you have a heavy right foot, you may have a crook lifter thats running out of oil at these high revs and getting valve float, try keeping the revs down a bit, was the cam run in correctly, Regards Frank.

Originally Posted by Tank

Do you regularly rev it over 4K to redline, seems like you have a heavy right foot, you may have a crook lifter thats running out of oil at these high revs and getting valve float, try keeping the revs down a bit, was the cam run in correctly, Regards Frank.

Not regularly revving that hard at all Frank, but I should have written 3.5krpm+ rather than 4krpm+. It's just the occasional overtaking maneouver that I notice it.

Cam was run in according to the instructions I had - run at 2krpm for 20mins, not allowing to idle at all in that time.

I'm using 20w-50 Castrol GTX oil in it at the moment, was wondering if the combined brains trust thought that may be a problem?

The "under load" bit suggests that it isn't rocker etc related , although I guess it could be a sticking exhaust valve which is pretty common and mostly happens when they get hot under load .Otherwise the rockers etc have no idea whether the engine is under load or not.

The other area I would look is the exhaust gaskets and bolts from head to manifold and manifold to pipes. Many a person has been fooled by an exhaust leak.
Could be a tappet with a broken spring pumping up but that should happen under free rev.
Regards Philip A

Originally Posted by PhilipA

The "under load" bit suggests that it isn't rocker etc related , although I guess it could be a sticking exhaust valve which is pretty common and mostly happens when they get hot under load .Otherwise the rockers etc have no idea whether the engine is under load or not.

Ok, that may be something to look at, as I replaced all of the valves, and the exhaust valve was replaced with the D2 part number (LGH000040) as the supplier had given them as an alternative to the out-of-stock D1 part.

When I read up on it, the feeling around the interweb was that sometimes the valve guides needed reaming to fit the D2 part. However, they did seem like a very good fit at the time in my heads. I suppose it is very possible that they could stick when hot if they were a very good fit to start with.

Originally Posted by PhilipA

The other area I would look is the exhaust gaskets and bolts from head to manifold and manifold to pipes. Many a person has been fooled by an exhaust leak.
Could be a tappet with a broken spring pumping up but that should happen under free rev.
Regards Philip A

I'm pretty confident on the exhaust gaskets and fit - I had my father-in-law underneath it whilst I was revving it last night. He came out as deaf as a post

If I find nothing else, I may end up re-replacing the cam and followers.

Just to add a bit more info to this, and an extra thought, I was out on the GCLRO DARE today and the D1 got a fair old workout - absolutely howling up and down some fairly big hills.

During the whole day, not even a single sign of a rattle. But on the way home, pulling out to use an overtaking lane, there the rattle was again.

However, during the day (and as these things go - in the most awkward place possible) the fuel pump died, and was only restarted by grover69 banging hell out of the bottom of the tank with a rock.

So the fuel pump is dying. Connected to the above symptoms perhaps? Can't think how, but someone more knowledgeable than me might be able to confirm or deny.

Hi

I tried 20w/50 before and it was to thick for me, I got tappet noise from the engine (At least that what I guess it was). Changed to 10w/30 and now it's all silent. I should point out that I live in a more tempered climate (Sweden) so we might need a little less viscosity in the oil. The fuel consumption was higher with the thicker oil too. I think 20w/50 is for towing in hot climate or if you push the engine hard. Try a lighter oil and see if the problem remains.

Johan