The V8 Owners Forum -

i all, i have a 3.9 block using an sd1 front cover. If i want to change to a 4.6 serp front cover (along with other associated anciliary items eg pas pump, alternator, alternator bracket, tensioner etc) is there anything else i need to change like oil pick up pipes?

Also i intend to use 3.9 serp anciliary parts, does anyone know if i can use my bottom pully/damper (sd1) but fitted with the serp belt pullies?

I think you are OK with the oil pick up.

I think you would need serp bottom pulley to match the rest of the serp gear, goes straight on to std 3.9 crank, as nose length on my 3.9(std journal crank) serp engine is the same as a 3.5 crack. The 4.6 crank is longer and a spacer is required to make up the difference

would a 4.6 cover fit a 3.9? I know the intermediate does but I thought the 4.6 needed the longer crank.

Hi,
I'm with Katanaman on this one, I doubt if it's possible.
The 4.6 cover needs the longer crank nose, and the oil pump pick up pipe is totally different from the 3.9 one. Your camshaft will also have to be changed to one without the dizzy drive. to fit inside the cover. You'll also need to run coil packs, as the 4.6 is a distributorless cover.
Intermediate 3.9 cover is straightforward, but the 4.6 one is a different ball game.
Jim

My cover is an intermediate type with integral oil pump, surely the only difference to the later serp is the deletion of the distributor location, Not 100% sure

As mentioned camshaft would be different

Maybe I'll shut up and leave it to the experts like Jim and Marki

So the 4.6 serp cover must be significantly different then

Anyone got pics for reference

Well heres the cover i'm getting. Its new so i though why not, might come in useful later on!



I didn't think that the pickup pipe made a difference? The latest 4.6 blocks can use the early style covers (in ref to the pick up pipes) so why not vice versa?

Oh I am no expert on 4.6 stuff by a long way. I just reasoned that they made the crank nose longer for a reason so doubted that it would fit on the shorter crank. That's why it was more a question than an answer. There are a lot of big changes between even your engine Roysten and the 4.6. Some you have found like the main caps.

Also the water pump rotation is reversed on the Serpentine front, compared with the 3.9.
But I assume if you change the front you will use the complete Serpentine set-up?

I know someone who did it. The longer nose crank has a longer woodruff key to drive the oil pump - so AFAIK he took a woodruff key from a long nose crank and filed it to fit the slot in his short nose crank. This meant the oil pump was driven by a bit of woodruff key that was effectively sitcking out. He didn't have any problems with it but I'm not sure it's something I would do. If your crank is out you could always machine the slot to take the later key properly.

Will you need to fit your own cam retainer?

Mike

Its looking like such a work up that i probably won't bother! I really want a serp set up so i can move my power steering pump up out of the way. Maybe i can fit a serp pump to it and make my own pulley system, back to the drawing board!

if all you want is serp then do what I did and make your own see pic in av.

Here is a pic of my intermediate front cover/engine block, unfortunately it is a little obscured may help though



It looks significantly different to the late 4.6 serp front cover now you can compare

Well its the serpentine pump that bolts to the n/s cylinder head that i'm specifically after so i though i may as well change the whole thing to a serp set up getting a better oil pump and doing away with the dizzy hole too as i have twin coil packs now plus obviously a better belt set up as i seem to forever have a squealing belt needing tightening every two minutes.

Thankyou for the picture royston, looks as though you have the front cover i'm after!

Unfortunately it is now installed in my Range Rover

If you need some additional pics of the serp set up, steering pump/alternator location let me know

I fell foul of this problem when i tried to upgrade my 3.9 to a serpentine front end. The end of the crank and the woodruff key are too short so the bottom pulley will not locate. in the end i changed the crank and ended up rebuilding the whole engine while i was at it., new bearings and composite gaskets etc. In the mean time i sold the car with no engine in so its been on an engine stand in my garage ever since ready to drop in something. is anybody looking for one?? comes complete with chipped hotwire injection system or motec ecu. all ancillaries etc...