Follower bleed down rate

[wokingwedger]

I think we should try and eliminate a few items from the equation in an attempt to find the cause of the noise.

Lets start with the dizzy.
Has anyone got the noise on a 500 engine that has been converted to crank trigger? If so then the dizzy is out of the equation and therefore forget the following.

Grasping at straws, my thoughts on the dizzy !!!!
Did TVR fit lighter advance springs in the 500 dizzy to give greater initial advance? Weights may rattle at 1200 -1400 rpm.
Slim argument I know but possible as the cam pulsing may chatter the dizzy drive at these revs.

Second thought, It it possible that TVR do not remove the oil pump drive toggle an the dizzy shaft when installing a dizzy in a serp engine.

Cheers Denis

All good possible things, but the noise only appears on 500s and the things you mention would also apply to the smaller engines TVR did.

I think the severe cam, piston slap and pin to piston fit possibilities are 500 specific.

[wokingwedger]

What cam followers does TVR use for the 500? Standard landrover ones or hi-rev/anti pump ones?

Do people still get the noise with different cam/followers?

Seems strange that this seems to mainly effect the 500's so you'd think it would be somethink unique to that engine other wise there would be loads more complaints from the thousands of landrover owners.

Tom.

Standard LR fitment I think

[SuperV8]

What cam followers does TVR use for the 500? Standard landrover ones or hi-rev/anti pump ones?

Do people still get the noise with different cam/followers?

Seems strange that this seems to mainly effect the 500's so you'd think it would be somethink unique to that engine other wise there would be loads more complaints from the thousands of landrover owners.

Tom.

[DEVONMAN]

What cam followers does TVR use for the 500? Standard landrover ones or hi-rev/anti pump ones?

Do people still get the noise with different cam/followers?

Seems strange that this seems to mainly effect the 500's so you'd think it would be somethink unique to that engine other wise there would be loads more complaints from the thousands of landrover owners.

Tom.

This is my list of unique items in the 500.

- Rover 4.2 pistons with the skirts shortened to clear the crank counterweights. This makes the piston less stable in the bore and loss of some of the skirt taper of the standard piston would result in more day one clearance in a standard block.

- short bespoke conrods

- Externally balanced crank with special weighted front pulley and flywheel. Not sure about later engines

-Agressive camshaft

-extensively ported heads with big valves.

-Different exhaust manifold.

-Possibly a metal cam wheel unlike the plastic ones fitted by Land Rover to give quiet running.

If you can add or correct the above please do.

Cheers Denis

[SuperV8]

Just thinking (which is always dangerous!) does the 500 have offset piston gudgeon pins?

Taken from http://www.gomog.com/allmorgan/40difference.htm
The 4.04.6 gudgeon (or wrist) pin diameters have been increased and they also have a gudgeon pin offset. The 4.2-litre engine was the first production Rover V8 to use this feature, but on the 4.0/4 6 litre engines it has been increased from the 0.55 mm of the 4.2-litre to 0.60 mm. The reason for this offset is to produce a slight side loading on the piston at TDC, thus eliminating piston slap all part of the infinite attention to design detail by the Rover engineers in their quest for refinement.

Tom.

[DEVONMAN]

Just thinking (which is always dangerous!) does the 500 have offset piston gudgeon pins?

Taken from http://www.gomog.com/allmorgan/40difference.htm
The 4.04.6 gudgeon (or wrist) pin diameters have been increased and they also have a gudgeon pin offset. The 4.2-litre engine was the first production Rover V8 to use this feature, but on the 4.0/4 6 litre engines it has been increased from the 0.55 mm of the 4.2-litre to 0.60 mm. The reason for this offset is to produce a slight side loading on the piston at TDC, thus eliminating piston slap all part of the infinite attention to design detail by the Rover engineers in their quest for refinement.

Tom.

Hi Tom,
Yes the pistons have offset pins as they are really just modified 4.2 items.

Denis