420 SEL engine help
 

Is the 420 SEL engine the same in 1986 through 1991 Models ?

AFAIK, yes.

M116 4.2 V8 engine, no changes (not in the UK anyway!)

Cheers, Martin

reviving this thread...
 

Did a search and found this; does anyone know the exact differences between the early, ('86-'89), and late, ('90-'91), M116 engine in the 420 SEL?

I have a '91 model that needs a heart transplant and have heard varying info on the differences and subsequently the PIA factor of using an earlier long block.

Obviously the ideal would be to locate a healthy late motor, but all I am finding is early ones. TIA for any help. :book:

You'll be fine w/ any 86-91 420 engine.

Jonathan

the differences are the sensors on the intake manifold and the fact that the later models had the small starters[which were interchangable]

So the intake manifolds would have to be swapped? No other differences? Someone told me that the later engines had an extra hole in one of the heads for a sensor or a tube(?) which would be missing on an early engine.

I really appreciate the help from shop owners who have actually done this swap/interchange.

The early engines used a warm up regulator and the later ones use a small computer. There are some sensor differences and with my '89, there are some differences WRT to the service manual.