Which Rover V8 should I use in my project. I have 3 choices

[James]

Hi all, nice forum

I will cut to the chase,

I am doing a ford 100e with Rover V8 engine

I have 3 engines , all good internally

They are

10.5-1 CR P6 engine (engine code is 4510xxxxx)

9.25-1 CR unknown engine (engine code is 45118710D) can't find this engine on the lists

9.35-1 CR SD1 engine (10Axxxxxx)

Intake wise I will be using Offenhauser 360 and holley 4 barrel
Exhaust wise, tubular headers and free flowing system
not sure on cam yet

Am I right in thinking the P6 engine with 10.5-1 would put out more power than the later SD1 engine due to the difference in CR, or would I be better off using the SD1 engine as its got the stiff block

Any info much appreciated

edit: I should add, I don't mind ripping all three apart to create the best combination if thats an option (ie SD1 block with P6 pistons if thats possible)


James

[katanaman]

The SD1 engine will make the most power because it has the better heads. It also has the better crank seal system and front cover/ oil pump and ignition system. You could put the high compression pistons in the SD1 engine but the compression could be a little high these days on unleaded, they were also supposed to be the weakest of all the piston. Your 9.25 engine will be one of the last P6 engines before they went onto the SD1 I think.

[katanaman]

Oh and welcome

[James]

Cheers, I think i'll do a freshen up on the SD1 lump and use that then.

[kiwicar]

I had 10.5 pistons and SD1 heads on a rangerover with tin gaskets, in a rangerover most of the rest of the spec was similar, worked fine, didn't pink.
Mike

[mgbv8]

My old engine is a pre SD1 low comp (about 8:1) lump which was the factory standard MGB V8 engine.
This ran 12'4's on the drag strip with a shed load of nitrous. But was a little sluggish on the road off gas.
Apart from the cam it runs all stock internals.

The new engine is a 4.6 from a Rangie and that runs 12 seconds dead on a lot less gas while I'm testing it.
But there is a world of difference on the road without gas. And believe it or not. It uses less petrol than the old 3.5 lump.

I've only ever melted pistons while testing the old pre SD1 engine. All the other original 33 year old internals have held up ok even with the nitrous abuse.

I would start off with the SD1 lump and take it from there.

You can change the rope seal to rubber on the old front cover in ten mins with no probs by the way if you need to.

[Nigel B]

I would use a combo of the above

the block and pistons from the 10.5:1
The heads from the SDI

With compossite gaskets the 10.5:1 will drop, can't remember how much but it will be fine 2Pink" wise

The timing assembly from the SDI (the 10.5 will prob have a rope seal)

and if so then have the rear crank main seal remachined to take a later seal vs rope type

HTH

Nige

[James]

food for thought, cheers guys

I always run on super anyway so doubt knock would be an issue at these levels

does anyone have bhp figures to hand of the 10.5-1 P6 engine? Nigel, what sort of gains would i expect using this engine with the sd1 heads on instead?

Regarding the rope seal, this is something i'll look into. doubt my local engine machinist will be keen on doing this work, he's more new-skool

As for nitrous, im quite a fan and will be running 150bhp through a wizards kit on a minimiser

[RoverP6B]

The 10.5 : 1 CR 3.5 litre V8 as it appeared in the P6B had a range of horsepower figures quoted.

They ranged from 152bhp to 186bhp @ 5200 rpm. Torque from 202 ft lbs to 226 ft lbs @ 2750rpm.

You can fit your SD1 timing cover onto the P6B engine, with the distributor from the SD1, else just have a wobbly drive fitted onto the distributor off the P6B and use that instead. As for the oil pump front cover, either one off either engine will do the job, provided the face where the oil pump gears run is unmarked. If it is scored, then you will need to acquire a new one.

Ron.

[katanaman]

I would use a combo of the above

the block and pistons from the 10.5:1
The heads from the SDI

With compossite gaskets the 10.5:1 will drop, can't remember how much but it will be fine 2Pink" wise

The timing assembly from the SDI (the 10.5 will prob have a rope seal)

and if so then have the rear crank main seal remachined to take a later seal vs rope type

HTH

Nige

I don't get why you would go this route? Using comp gaskets gets rid of any marginal advantage this engine has over the SD1. I agree all the disadvantages of the P6 engine are marginal if indeed they even are a problem but when a perfectly good SD1 engine is sitting there, its just stupid not to use it. If you want to use the higher compression fine use the P6 pistons but put them in the SD1 block and don't use comp gaskets or its pointless. Like i said before the compression is the only advantage the P6 engine has, just about every other part is inferior to the SD1. You have it so why not use it?

[sidecar]

I would use a combo of the above

the block and pistons from the 10.5:1
The heads from the SDI

With compossite gaskets the 10.5:1 will drop, can't remember how much but it will be fine 2Pink" wise

The timing assembly from the SDI (the 10.5 will prob have a rope seal)

and if so then have the rear crank main seal remachined to take a later seal vs rope type

HTH






Nige

I don't get why you would go this route? Using comp gaskets gets rid of any marginal advantage this engine has over the SD1. I agree all the disadvantages of the P6 engine are marginal if indeed they even are a problem but when a perfectly good SD1 engine is sitting there, its just stupid not to use it. If you want to use the higher compression fine use the P6 pistons but put them in the SD1 block and don't use comp gaskets or its pointless. Like i said before the compression is the only advantage the P6 engine has, just about every other part is inferior to the SD1. You have it so why not use it?

Don't forget that the P6 had a poor main bearing cap location system and that it was better but not by much on SD1. The SD1 block also has thicker ribs in the valley area. I can believe that Rover changed that part of the design without good resaon. (It must have cost thousands for that one modification).

I would check for the "black death" fretting of the any blocks that you are considering using on the location step of all of the main bearings (Especially the rear ones).

I would certainly use ARP studs in this area even if it does envolve the hassle of inline boring the mains.

It is pointless to build a motor round a block that shows signs of main bearing cap fretting.

To use a block just because the pistons have slightly more compression is not a good enough reason to choose that block. It should be made for other reasons and then if the chosen block does not have the desired compression either it or the heads should be skimmed.

Also I believe that the later pistons are stronger than the P6 ones.


Pete