New member with a few Rovers, mainly P6b

[Swede]

Hi
Cooling should not be too much of an issue, I think you should easily make 350 to 400 bhp but at such low revs that the friction losses will be low and therefore heating of components like wise will be low. The rad out of a 350 chevy or a 302 ford should be more than enough, the one for my chevy was only 24X13X 2.5 inches and that was to take 550 BHP
Your choice of cam may be tricky to get the best out of the combination but even there somthing close to standard but with extra exhaust duration and lift should be ok.
Good luck
Mike

Good news to me, after all i do not intend to race the car...The 425 now has the camshaft from the 500 that superseeded it in the original car, as before mentioned the previous owner ran this engine on E85 with EFI managed by MS, it then had the #3 camshaft from MTS
http://www.500cid.com/cams.htm
and produced some 270 hp according to calculations used by SAAB engineers, I reckon this is what i too will install in the future.
The 425 is the same engine as the 472 and the 500 but considerably less heavy which is my reason for choosing it...

[Swede]

I've had 2 P6B's - a Mk1 auto and a MkII 3500S, and neither had cooling problems. They do run very hot, though, which can cause fuel vapour lock.
But that's because there's a lot of engine in a confined space.

I can remember my father having starting problems due to vapour lock some seriously hot summer days on the brown car when I was a kid buy on my own cars I have not had the problem...space around the 425 will be furthher restricted and i will heat shield wrap the headers for sure. Rover engineers introduced the return fuel line in order to overcome the vapour lock problem...most likely a serious problem on US cars with A/C installed in states like Arizona...

[DaveEFI]

I've had 2 P6B's - a Mk1 auto and a MkII 3500S, and neither had cooling problems. They do run very hot, though, which can cause fuel vapour lock.
But that's because there's a lot of engine in a confined space.

I can remember my father having starting problems due to vapour lock some seriously hot summer days on the brown car when I was a kid buy on my own cars I have not had the problem...space around the 425 will be furthher restricted and i will heat shield wrap the headers for sure. Rover engineers introduced the return fuel line in order to overcome the vapour lock problem...most likely a serious problem on US cars with A/C installed in states like Arizona...

It got much worse here in the UK when leaded petrol was abolished - I was running the P6 3500S then. It's possible the petrol from UK refineries was worse than elsewhere in this respect. Although the return line helps to some extent with the engine running, it didn't do much when the engine was stopped after getting hot and the fuel vaporised. The mechanical engine mounted pump didn't help either - it's for a good reason the SD1 has an electric one in the tank. For that and a couple of other reasons - like the difficulty in getting some spares for the P6 in '88 - I changed to an SD1. Which I still have.

[sowen]

You should seriously consider the 2 door alternative...will look very nice with the look you are heading for. I pesonally find the chopped P6b Coupe that Graber built the best looking P6 of all times...It should be possible to use sections from BMW 2002 0r 635 for the rear pillar solution as well as for opening rear side windows. the other unchopped cars I have seen do not impress as much though...not sleek enough. Mercedes managed to convert their heavily designed 4 door saloons to the SL models...I wonder what a skilled artist can do with the P6 Saloon if he or she had the same goal...

The problem with p6 2 door conversions are that they seem to be sitting at the standard ride height and appear to have no other body mods unlike mine. I like the current stance and silhouette of mine, so a simple extension of the front doors and rear wings would probably do me fine. I will then have to carry out further work to send it through the UK's BIVA inspection, which means I will lose my tax exempt status and black & silver registration plates, but those are a small price to pay to get what I want.

[kiwicar]

Hi
I would think with cam #3 it will pull like a train, should be a good choice with the supercharger for cruising about. You will probably have an extra 250 to 500 revs at the top of the range to play with with the supercharger helping the breating so it should be very relaxed. Will you run E85? or normal petrol? If you can I would get the exhaust ports flowed but stick with standard valves. I probably not do more than a 3 angle valve job and a clean up of the casting marks on the inlet side though. I can easily believe 270 bhp from that engine on E85 normally aspirated, far more easily than 198 you should see the far side of 400 bhp when done.
Best regards
Mike

[Swede]

I've had 2 P6B's - a Mk1 auto and a MkII 3500S, and neither had cooling problems. They do run very hot, though, which can cause fuel vapour lock.
But that's because there's a lot of engine in a confined space.

I can remember my father having starting problems due to vapour lock some seriously hot summer days on the brown car when I was a kid buy on my own cars I have not had the problem...space around the 425 will be furthher restricted and i will heat shield wrap the headers for sure. Rover engineers introduced the return fuel line in order to overcome the vapour lock problem...most likely a serious problem on US cars with A/C installed in states like Arizona...

It got much worse here in the UK when leaded petrol was abolished - I was running the P6 3500S then. It's possible the petrol from UK refineries was worse than elsewhere in this respect. Although the return line helps to some extent with the engine running, it didn't do much when the engine was stopped after getting hot and the fuel vaporised. The mechanical engine mounted pump didn't help either - it's for a good reason the SD1 has an electric one in the tank. For that and a couple of other reasons - like the difficulty in getting some spares for the P6 in '88 - I changed to an SD1. Which I still have.

My 1970 car had 2 electrical fuel pumps and a switch when I bought it...

Do you remember if the 3500S had the narrow or the wide transmission tunnel? I always wondered about that

[Swede]

Hi
I would think with cam #3 it will pull like a train, should be a good choice with the supercharger for cruising about. You will probably have an extra 250 to 500 revs at the top of the range to play with with the supercharger helping the breating so it should be very relaxed. Will you run E85? or normal petrol? If you can I would get the exhaust ports flowed but stick with standard valves. I probably not do more than a 3 angle valve job and a clean up of the casting marks on the inlet side though. I can easily believe 270 bhp from that engine on E85 normally aspirated, far more easily than 198 you should see the far side of 400 bhp when done.
Best regards
Mike

That sounds like music to me....E85 is my ambition but then I will probably have to dial the engine management on a dyno in order to avoid any leanouts...I will build 4-2-1 headers starting with 1 3/4" at the flanges because of the limited space available, then I might have to widen the transmission tunnel on the right side if i decide to install a dual exhaust...There are some very narrow areas to negotiate further back in the car as well if I want to build dual exhaust..

I think it is time for me to order those engine and transmission mounts and get this show on the road....

[al mackenzie]

Hello Swede. Interesting projects! The 'S' version of the P6 3500 has a narrower transmission tunnel than the automatic version. Easier to swap a manual box into an auto body shell, and the auto prop fits behind a 5 speed LT77 manual box without needing to be shortened.
Surely the cast iron block and heads mean the Caddy motor weighs a ton!? That ought to lower the front end of your project car without needing shorter front springs!
I'm intrigued by the idea of a Jag rear axle. I wonder though if narrowing the drive shafts would mean they then drop from diff to hub at too severe an angle, which would consume UJs frequently. When Sowen gets his mean machine on the road we'll find out!
The link to the P6 project where the guy is flaring his rear arch and door skin is also very interesting. Can't read a word of it though
Keep posting with your progress.
By the way, I don't suppose you have a tidy set of 14" P6 Rostyles for sale? I'm also looking for some other rare bits'n'bobs: Rover P6 headlamp wash&wipe was only offered in Norway, or perhaps all of Scandinavia ? Never seen it, only the exploded diagram in the parts book. Would look ace on my project car though... Got a set for sale?
Best regards from Berlin, where I'm ever-so-slowly completing my P6B resto.

[Swede]

Hello Swede. Interesting projects! The 'S' version of the P6 3500 has a narrower transmission tunnel than the automatic version. Easier to swap a manual box into an auto body shell, and the auto prop fits behind a 5 speed LT77 manual box without needing to be shortened.
Surely the cast iron block and heads mean the Caddy motor weighs a ton!? That ought to lower the front end of your project car without needing shorter front springs!
I'm intrigued by the idea of a Jag rear axle. I wonder though if narrowing the drive shafts would mean they then drop from diff to hub at too severe an angle, which would consume UJs frequently. When Sowen gets his mean machine on the road we'll find out!
The link to the P6 project where the guy is flaring his rear arch and door skin is also very interesting. Can't read a word of it though
Keep posting with your progress.
By the way, I don't suppose you have a tidy set of 14" P6 Rostyles for sale? I'm also looking for some other rare bits'n'bobs: Rover P6 headlamp wash&wipe was only offered in Norway, or perhaps all of Scandinavia ? Never seen it, only the exploded diagram in the parts book. Would look ace on my project car though... Got a set for sale?
Best regards from Berlin, where I'm ever-so-slowly completing my P6B resto.

Hello there,
Thank you for the information on the S building specs, this means that I need a 2000 manual body with the front section from a V8 car and the front end mountings from a V8 rear suspension if I want to recreate a correct S body...quite a build.
I spent a lot of time on researching american big block engines before deciding to use the 425, it will be installed with headers and aluminium intake manifold so I hope to restrict the weight gain on the front end to somewhere around 100 kg. I will return with total weight for both Rv8/BW35 and Cad425/TH350 as soon as I have recorded them. The front ride height of the wreck that now holds the 425/TH350 looks quite ok, but you never know with a car that has been idle for many years.
We certainly had the Headlamp wash/wipe laws in Sweden, not sure if Norway were using it...but this was only applied to the very last P6 imported...most wiper units were unserviceable after maybe 10 years so when the law was scrapped, many were taken out of the cars because they often seized and obstructed the headlights and you were not allowed to remove the wiper arm only, leaving the driveshaft protruding through the grille. I am deconstructing a 1975 P6B that I think had these....will check if there is anything left....
I have 4 14" Rostyles from the same 1975 car....they are not excellent but seem straight...center hubs are missing.

Cheers/Joakim

[al mackenzie]

Hi Joakim
Look forward to hearing if you do have the headlamp wash wipe set-up! Any chance of some photos of the 14" Rostyles?
I found some time to carry on reassembling my P6 restoration today. Got the intake manifold, carbs, valve covers, throttle linkage, alternator and bracket back on the engine this afternoon, all freshly repainted.