W126 V8 engine swap question

[mr_s]

I have a 1990 W126 420SEL with a fairly tired M116 V8 in it. It needs valve stem seals, timing chain and a few other bits and bobs doing to it.

I also have a much lower mileage, good condition 1990 M117 500SE V8 engine sat in my garage. I know that physically it is a straight swap, but in terms of the electronics, is it just 'plug and play' or are there many other differences?

Essentially, so long as it will start and run on the 420 electronics, I should be fine as I run the old lady on LPG which pretty much cuts the injection system out - although it is nice to have the ability to run on petrol as a backup!!

Any thoughts?

 

[grober]

Just make sure the electrics are exactly the same. If it fits/swaps I would swap the engine ECU and the EZL ignition unit = different advance curve???

 

[mr_s]

That's what I'm asking... I don't have the ECU/EZL for the 5.0 engine, I'm wondering if they'll work the same!

 

[grober]

That's what I'm asking... I don't have the ECU/EZL for the 5.0 engine, I'm wondering if they'll work the same!

Can't answer that sorry. Its a try it and see situation I guess.