Rover P6 3500 1976 engine - any way to upgrade performance?

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and any posts regarding swaps help.

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Coops Insurance
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Rover P6 3500 1976 engine - any way to upgrade performance?

Post by Coops Insurance »

Hi. I have acquired a 1976 Rover 3500 v8 engine and Auto box - I know 😱 auto box!! It is going in my 1991 Volvo 240 Estate which is on air ride suspension. The theme of the car is a low rider muscle wagon/estate complete with muscle car burble. The engine is being stripped down naked, cleaned and new shells, bearings, seals honing the bores etc.
Are there any good performance upgrades that i could add to it to increase the power? I work 5 minutes away so mpg isn't a major concern. Ta Ian


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Post by katanaman »

Change the heads for newer heads (they all fit) after that cam, inlet and carb. Not much point going any further with that engine and you might not even want to go that far. You want power start with one of the newer engines. 3.9 4.0 or 4.6. If you are wanting cheap change the heads and leave it at that. By the way measure your crank, if it needs new shells it might need ground.

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Post by katanaman »

I should add check if it doesn't already have the newer heads. There is a sticky on how to identify them.

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Post by Coops Insurance »

Thanks. When you say newer heads do you mean heads from an sd1 3500 v8? So the phasing of the cams are still the same and it's a straight swap.
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Post by Darkspeed »

Best advice would have to be to bin it. It's such and old design with so many flaws its a false economy to spend any money on it unless required for originality in a P6.

If you want old school looks get a pre serp 3.9 - and dress it with the P6 ancillaries.

With the later engines with the better crank seals larger oil pumps better heads you have a chance of not leaving oil smeared all over the road when you drop it, and have a chance of a little more performance than the original Volvo 4 pot. It's just not worth the effort to go less than a 3.9.
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Post by DaveEFI »

A late P6 is perhaps the worst car version to start with - it has a low CR. CR is set mainly by the pistons. The Vitesse unit used 9.75 pistons - about as high as you can go with 95 octane on this engine. Injection heads are also the best standard version. Later heads don't cost much used. Having then cleaned up to St1 is also good value for money.
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Post by Blown v8 »

SDi heads are a straight swap,valves are a lot bigger,castings (internal) are vastly improved.You will notice an improved performance !

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Post by Darkspeed »

DaveEFI wrote:A late P6 is perhaps the worst car version to start with - it has a low CR. CR is set mainly by the pistons. The Vitesse unit used 9.75 pistons - about as high as you can go with 95 octane on this engine. Injection heads are also the best standard version. Later heads don't cost much used. Having then cleaned up to St1 is also good value for money.
Not quite true - the P6 actually had the highest compression at 10.5:1 and laterly 9.25:1

P6 - has

Weak oil pump
Poor crank rope seals
Poor heads
Weak pistons
Clockwork dizzy
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Post by katanaman »

Coops Insurance wrote:Thanks. When you say newer heads do you mean heads from an sd1 3500 v8? So the phasing of the cams are still the same and it's a straight swap.
All rover heads fit all rover engines but valves and flow are the same from the SD1 on. The 4.0 and 4.6 heads have a row of bolts missing but that doesn't matter as its a bad idea to fully tighten the outer bolts on the older heads anyway.

It has all been done and documented in the forum before so have a good read around all the past projects ans stickies.

As your probably gathering anyway your engine isn't worth doing much with but the good news is if you fit it and you like it and want to go further all the rover V8 engines fit exactly the same barring sumps. You can go from the ancient P6 engine up to whatever the latest 5.£££ monster is.

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Post by Coops Insurance »

I haven't got another engine. The P6 3500 v8 with auto box is the one i have. Wish i had a SDI engine..but i don't unfortunately 😢 so this is the one i am putting in the Volvo 240 Estate. Thanks for the great help and advice. I am making notes as i go along especially about the weak points of the engine.
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Post by Coops Insurance »

Would these fit? Might be someone on here selling them hahha
http://www.ebay.co.uk/itm/122057510476? ... EBIDX%3AIT
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Post by unstable load »

Darkspeed wrote: Weak oil pump
Poor crank rope seals
Poor heads
Weak pistons
Clockwork dizzy
Oil pump can be fixed by either buying the upgrade kit or a front cover off the GM/Opel V6 engine. It's a bolt-on fit, AND it will give you a regular front seal instead of the rope seal.
I believe the rear seal can be modified to standard type, too.
Get your distributor sorted with new bits internally, go for an electronic module for better tuning control.
Cheers,
John

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Post by DaveEFI »

Darkspeed wrote:
DaveEFI wrote:A late P6 is perhaps the worst car version to start with - it has a low CR. CR is set mainly by the pistons. The Vitesse unit used 9.75 pistons - about as high as you can go with 95 octane on this engine. Injection heads are also the best standard version. Later heads don't cost much used. Having then cleaned up to St1 is also good value for money.
Not quite true - the P6 actually had the highest compression at 10.5:1 and laterly 9.25:1
Ah. My memory said a late P6 - like this one - was 8.5:1
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Post by unstable load »

ccording to this, the engine's CR changed with the introduction of the SD1 and went from 10,25/10,5 to 9,35:1. Range Rovers from that era were 8,15:1, though.
The following information is the sole property of Abbey SportCars Ltd and is not to be copied for use elsewhere without prior permission or reference. The pages are written for guidance only, the information contained therein is the view of the writer and should not be taken as the definitive recommendation.

Can you shed some light on the historyof the Rover V8?

Rovers 215 ci 3528cc V8 engine was first introduced into the UK in 1967 in P5B guise, a cubic capacity that was to be used extensively by the factory until 1989. During that period the engine was revamped periodically to meet more stringent emission levels. The first engines benefited from a 10.25 or 10.5 : 1 compression ratio in the rover saloons , or lower compression 8.15:1 when installed in the Range Rover.

In 1975 the engine underwent detail changes which coincided with the introduction of the SD1. The v8 engine now featured, revised compression ratio (9.35: 1), neoprene rear oil seal, revised cylinder head porting and valve gear. Lowering of the compression ratio was to enable burning the lower octane fuels that were becoming increasingly more popular.

All engines i.e., pre and post 1976 can be identified externally. The engine numbers on post 1975 units were stamped on the RHS block casting flange whereas earlier blocks were stamped on a pad to the rear of the cylinder block near the bell-housing mtg. flange. The engines comp. ratio is also stamped on this face and is a useful way of positive engine model specification. However, it is now unusual to find engines from the P6 era which have not been rebuilt and or feature later type cylinder heads as well as camshafts and induction systems.

Over the years there were several other detail changes to the v8 engine but from a performance point of view the V8 differed only in compression ratio. Post 1982 engines however, came with a revised cylinder block and optional induction systems. SU or Stromberg Carburetors were continued alongside Efi (Lucas LE flapper type injection) derivatives in the form of Vanden Plas and Vittese models. The Efi equipped vehicles also featured revised camshafts, valve gear and a compression ratio of 9.75:1 or 9.85: 1.
http://www.v8tuner.co.uk/faqs.php
Cheers,
John

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Post by DaveEFI »

I had several P6 in the day. After 5 star petrol stopped being available, they dropped the CR drastically, from the original 10.5:1. With a dramatic change in performance - commented on by mags of the day, and borne out by what I found too.

The SD1 unit was an attempt to recover that lost performance.

It would be interesting to see some dyno runs of all the variants in perfect standard condition.
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