The V8 Owners Forum -

Hi all.

I did do a quick search but didn't find a definitive answer.

Can I swap a 3.9 intermediate front cover for a later type (without dizzy) and then fit a sump and oil pickup from a later engine? Could I also swap the loom around and ecu to fuel the intermediate engine so to use the coil packs?

I'm guessing the answer is yes, but costly?

Ben

Ben

If you want to ditch the dizzy then you will need some form of ECU to generate the sparks etc, that will in turn need at very least a crank sensor with trigger wheel, it doesn't have to be too costly but I guess that depends on your budget.

Whats the reason for the change ?

The interim engine didn't run the ignition at all, so it can't drive the coil packs. You'll need something like MegaJolt Lite for that.

Also I think the camshaft will be too long to fit inside the cover as it will have the bits on the end to drive the distributor.

Chris.

Thanks all for the reply's.

My main reason for change is that I had heard that the later non dizzy front covers were about 40mm shallower than the one I have with the dizzy. I need all the space I can get up front as it's a bit of a squeeze in the engine bay.

My other issue is ground clearance and after looking at a Range Rover P38 or Discovery 2 sump, it "looks" shallower at the rear (inline with the flywheel) than the one I have on the interim block.

Maybe the easiest way if I want more clearance is to ditch the interim block and buy a GEMS engine complete with it's ECU, sensors and coil packs?

Ben

Buying a complete GEMS engine is almost certainly the cheapest. Just factor in that it probably has a cracked block and will need relinering!

Chris.

That's what I'm thinking.. Although, the engine I have is such low mileage and I've documentation to back it up I'm loathed to swap it out.

Am I correct that the interim engine's crank is the long type and therefor drives the oil pump? If so then I could change the cover, fit a trigger and wheel and then convert to aftermarket ECU? I know these engines are like lego and most things will go in some form or another..

Edit: By aftermarket I'm just thinking Megajolt and keep the 14CUX for fuel..

Ben

It certainly is possible to fit GEMS to an earlier block.

You will definitely need to change the camshaft though - this compares distributor vs non distributor cams:


I do believe your long-nose crank will be fine with the GEMS timing cover, although I seem to recall there are two versions, with varying keyway length?!?!

Chris.

You will need to fit a gems front crank pully to make the water pump and other pulleys line up. So, as the interim cranks nose is 20mm shorter than a Gems Crank you will need a longer crank pulley retaining bolt.
Be aware also that in the standard location the alternator is set very high and bonnet clearance may be a problem (Depending on the vehicle) and it's difficult to resite due to the loss of 40mm front to back space.
You will need to get a c shaped camshaft retaining plate to suit the Gems camshaft.

The gems crank pulley will need some lathe work to accept a trigger wheel.

Hope this helps
Denis

Thanks for the additional info. Duely noted.

All parts added to my shopping list.

For the Cam, am I right in saying I could just use the 4.0 GEMS cam (Land Rover)? I assume this is the same profile as my 3.9?

beniboyz wrote:Thanks for the additional info. Duely noted.

All parts added to my shopping list.

For the Cam, am I right in saying I could just use the 4.0 GEMS cam (Land Rover)? I assume this is the same profile as my 3.9?

The 4.0 is the same bore and stroke as a 3.9 so a 4.0 cam should behave in a similar manner.
Most guys are putting early dizzy type front covers on later engines. You are doing the opposite. The gems crank pulley will not have as much support as it would have on a long nose gems crank and it may tend to work loose. The 3.9 serp crank pulleys have been know to work loose due o the reduced support on the nose as a result of the oil pump thickness. I've not done what you are doing so I don't know all the pitfalls,

Regards Denis