The 'E' Type Forum

The 3.8l engine damper is like a dinner plate-almost the diameter of a 45 single.

The 4.2l damper has a much smaller diameter.

Anyone know if a 4.2l crank damper will fit a 3.8 engine? This is so I can attach a normal size trigger wheel.

Or will this mess up the harmonics?

James

I believe a later XJ6 damper will fit. Later design.

It'll fit OK. Can't answer the question about harmonics.

The older it is, the harder and more brittle the rubber will have become, the less effective it will be …

I would be very wary of substituting the later large mass damper for the earlier dinner plate type one. You do not want a fractured crankshaft

I believe it to be a common substitute. Look at all the available High Performance balancers for these engines. None of them have a design like the early ones. Mass seems to be less or same with smaller diameter. Been running one for 25 years on my 3.8 installed by the Jag performance shop that built my engine.

Thanks for the input.
I think I will try a 4.2 balancer and see what happens.
The rest of the rotating assembly is off to be balanced next week anyway, so I will add this into the mix.
It is amazing what a difference having it all balanced prior to assembly makes to the smoothness of it all.

It’s possible to neatly shrink-fit a much bigger toothed wheel onto the back of the oft-supplied (by UK retailers) ProRace damper, which is actually Australian.

If you search in the Megajolt thread for rfs1957 you should find all the details from when I did it, I would send you the link but am fat-fingers-small-screen in an airport lounge so ………… not tonight.

Much, much neater and more elegant than fitting one on the crank nose.

Thankyou Rory, I will have a look.

Details are on Post #425 of the Megajolt thread.

rfs1957 wrote: ↑

Fri Feb 02, 2024 6:58 pm

Details are on Post #425 of the Megajolt thread.

viewtopic.php?f=9&t=437&hilit=megajolt& ... 20#p108615