Thread: New 4.6 or 5L engine project about to kick off

The coscast sounds like the go to me.
I was looking at their 4.8L versions the other night.
It would be nice to have a new engine on standby in the shed.

If you are doing a rebuild i dont think i would bother with a top hat job.
Nor would i do a rebuild without a new cam timing chain, heads etc this would be false economy if you are looking at keeping it for 10 years.

Just a little more power would be nice, but i think the std 4.6 is working pretty hard pulling the P38.

Just wondering why you haven't put new short motor and top hatted short motor as an option?

I had this similar "10- year car" decision a couple of years ago... but mine was cooked and sitting... if yours is driveable can't you find a river or a wall to drive it into?!? Anyway back to reality, at that time I opted to go a new short motor (from LR installed by backyarder LR mechanic relo of a mate) but knowing more now I would probably have gone for top hatted short motor. I'm sure I have read here they can be bought out of the UK for $5K or around that.

If I was in this position now, I think I'd move to a diesel L322 - especially if the car is running and able to be sold as is. L322s have dropped a lot in price in the past couple of years.

What is stopping me going to an L322 is that I went through the full engine rebuild and performance upgrade when I top-hatted my engine a year or so ago. I now have too much money tied up in the P38A.

I'd say that the P38 is well worth hanging on to, if it were my money i'd do it right straight up.

Go the 5 litre and get something you know you'll be happy with. It leaves you with the satisfaction that your driving a solid 4x4 with a reliable donk. Provided the rest of the car is in good order you should have a trouble free 5-10yr run!

Cheers
Keithy

I would look at getting a towing cam, get as much bottom end torque out of it as you can.
And if you get an exchange trans you will really be set up for another 10 years, by which time you will be driving a vintage car.

Ok my two cents worth - we did a complete rebuild and top hat liner job on our 4lt D2 a couple of years ago now. Other than the $1200 for a set of top hats and the machining the rest of it is just simple engine reconditioning that any one of a number of reputable companies can do. Think outside the green oval and get quotes from a few well known engine reconditioners making sure you ask them to include the top hat liner work.
The standard 4.6 in fresh form is a very adequate performer. Unless you also want to have the added expense of then having to get the fuel system programmed to allow for the additional fuel required by the stroker - forget it! The standard P38 engine manegement is not up to serious performance upgrades - it is a low compression engine after all! When the engine is reconditioned a performance upgrade cam is of little cost and the best way to go - the other performance consideration would be a good triple cut valve seat job - do both those and the P38 will pull like a bull and be reliable.
We have managed to extract about 300hp out of the 4 lt but the result has really been due to huge effort and the fact we race cars and have access to dyno's etc made it possible. My advice - keep it as standard as possible or you will make a money pit for yourself!
I hope this helps,
cheers,
Deano

Mine had tophat liners, HC pistons, full crank balance, flowed heads, ports matched, towing cam, injected LPG, Haltech Interceptor aftermarket engine management. It goes quite nicely but, even with all that, it still accelerated more slowly than PaulP38a's car - at least it did the last time we checked. Maybe it's time for some more comparison runs.

I guessed this was going to be a tricky one

I think the issues raised about maintaining reliability are really important. i really don't want to overwork this into a money pit.

I like the idea of an L322 but, from what I've seen on carsales etc, i'm looking at a minimum $40k. With the engine as is, i'm guessing $14k for mine would be as good as I'll get. if I spend $10k on it, I'm in a better position. Better for resale as well since it has all the trimmings and in very good condition (aside from a few small off road battle scars word with pride

I like the economy of diesel but to be honest, one of my loves for the P38 is the V8 sound. If i'm burning that much fuel, I want to hear it. (I know Ron has a particular distaste for loud P38's - sorry Ron

So, I'm looking for a solution with a focus on reliability as well as getting as much power out of it as possible. (aren't we all!) I'm ok with spending the money to achieve these goals - within limits...