PRV V6 into 504 BW35 auto?

frogs4ever

frogs4ever

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Fellow Frogger
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Hi Folks,

The XN1 motor in my 504 is getting tired in places. Valve guides are trashed, timing chain rattles, oil consumption is rising.

I'm toying in the idea of replacing it with a PRV V6, rather than rebuilding the existing motor. My gearbox is the 3 speed BW35 auto, which I intend keeping.

Do any gurus out there know what's involved in physically mating the V6 to the BW35 automatic, with regards to bellhousing, engines mounts etc.

The BW35 was also used in Rover 3500's and EA Falcons, so I'm guessing that it would have no trouble in handling the extra power. Also, mine was reconditoned about 12 months ago, with EA Falcon spec bands used in the process.

If I go for a V6, I may also want to fit a taller diff, but that's not really important right now, as most of my driving is on roads with 60/70/80/100 km/h speed limits.

Thank's in advance. :)
 
Hi frogs4ever
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replacing it with a PRV V6, rather than rebuilding the existing motor. My gearbox is the 3 speed BW35 auto, which I intend keeping
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I think the Volvo V6 auto mated to a BW65 - so you may be able to use some bits from a 264.

I am surprised you want to keep the BW35, I am told they only used them in Australian built 504s to boost the local content.

Can I suggest that the 504 to 604 v6 conversion is so much easier when you use the 604 gearbox as well (and especially so if you are thinking of using the 604 diff also!)

The 604 auto box is a german GM trimatic and the equal of the BW65 & better than the 35.

You can get these serviced/repaired extremely cheaply if you take them to a Trimatic specialist (not a Pug place). It should only cost as much as for a Holden & this also applies to the torque converter. (A few years ago I used to pay $325 to get a 604 gbox fully reco'd.)

You could probably get everything you need cheaply by buying a whole 604. The bonus would be the powersteering & brake setup. And 504s are very nice with power steering.
 
I wouldn't use the 35 either. They might have been used in some pretty powerful cars, but they were often marginal.
 
Borg-Warner's little 35 was designed for up to 2-litre engines... cars like the Cortina 1600, Hillman Hunter... that sort of thing.

BMC stretched the friendship fitting it to the Freeway, Ford went a step further with the Falcon XM or XP and their Pursuit 170 engine... then there was an upgraded version for Ford and Chrysler with their bigger sixes. But it's not the same at all...

The biggest engine that I know that was hooked up to the 35 was the C-series BMC in the last of the Wolseley 6/110s and Austin equivalents... and I once rang Borg-Warner to ask if this was the same gearbox as in the Freeway.

"Oh, you couldn't fit a 35 behind that engine, the static torque on stall would destroy the box..."

And it did.

The 35 is good behind a 2-litre, probably better than the ZF (ratios are better, I'm told), and cheap to repair. But the version in the Pug is very specific. I don't know if anything much interchanges.
 
Thanks for all the input guys.

The reasons I wanted to keep the BW35 are that:

a) less than 12 months ago, it was fully reconditioned;

b) as Ray Bell hinted, it does indead have a nice spread of ratios, and it's got a realy nice torque converter which actually gives quite a punchy take-off from the lights even with old XN1;

c) cheap servicing and repair - probably works out cheaper than a manual gearbox/clutch combo in the long run;

d) I was hoping to use a later, EFI version of the V6, which would be easier to track down in a wrecked Volvo than a rarer Renault or Pug. And I didn't want to have to go to the trouble of finding a suitable donor 604 for a gearbox in addition to a suitable donor Volvo for the V6. I don't have room where I live to have donor cars lying around everywhere.

Looks like I'll have to reconsider my options.

cheers!
 
I think I know where you'll find a Strasbourg GM box... without taking the car.

You might, by the way, get lucky with the 35. The C-series engine had a lot more torque than the Volvo/Peugeot V6 and was longer of stroke.

Maybe you could investigate a compromise with the modded 35 that was used in the Falcons and Valiants? Different outer housing, but if the mainshaft is the same you could make it work. That would help with the adaptation to the V6, too, as the Falcon bellhousing is pretty big.
 
I have a 604 bell housing, you may like to try and adapt this to the BW box

Graham Wallis
 
604 auto box is a german GM trimatic & ILINGA
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Ray Bell is correct on his point about Strasbourg being in France these days & I should have been a bit more particular in my description.

I will amend it to "604 auto box is a germanic GM trimatic".

If you use a 2.8 FI Volvo engine you may be putting too much grunt through the BW35 to make it last.
Do you know the the sad story of the ILINGA ? This was a pretty Australian-designed sports car project (1975) using the Leyland P76 V8 engine. Project went belly-up because the BW35 couldnt cope. I remember the workhop with all the dead BW35s in bits lined up against one wall, exposing their problems so the Ilinga & BW engineers could argue about them.
 
I've noticed that the PRV 6 cyl is a pretty popular conversion for 504s and 505s, but despite its decent power output, its a fairly average engine in terms of reliability. Without strict maintenance for its entire life, they have a penchant for eating cams don't they? Shouldn't be difficult to find one, as any self-respecting, intelligent Brick driver who had a 760 with one in it, wants to swap it for the B230! :D :D :D

They are reasonably refined though. And I suppose its the only engine you can stick in that keeps the original character of the car - to some extent.

Nick
 
Ray Bell:
And then there's the timing chain issue...
Click to expand...
and yet still have never seen one drop one
good idea to change them every 100-150km but that's fairly normal for any chain of it's length to be changed
still i have never seen a chain come apart in a PRV
i was actually having a bit of a chat to robert cherry on the weekend about this and he doesn't seem to think the chain is a problem either and he pushes his PRV's a bit further than most people
we also had a chat about the odd and even fire cranks as well
i'm looking forward to hearing more about his even fire engines but i still like the odd fire units plus the exhaust notes on the odd fire is a nice sounding thing
i was hoping to have a closer look at the 404 there on the weekend with the triple webers on it but i'm sure there will be other times
the thing about the PRV is that they are so understressed which i have stated so many times before and there is so much to gain from little mods to these engines and they are very strong
in regards to the cam issue i have onlt ever seen one engine with a stuffed cam but that was before peugeot brought out the modification to remedy this
PRV's seemed to get a lot of bad press mainly because it was in the 604 and the 604 was never as bad as people made out
 
maybe.. but it is an easy swap.. "shurgs"
 
Originally posted by pugrambo
<strong>and yet still have never seen one drop one
good idea to change them every 100-150km but that's fairly normal for any chain of it's length to be changed
still i have never seen a chain come apart in a PRV
Click to expand...
As you know, Owen has done in two... the guides fatigue and drop into the sprocket or something like that. One at 140,000kms, from memory, the other one he wasn't going to drive that far and didn't... it went 15,000kms sooner.

He attributes it to the change characterics in the auto box, one was a harsher change than the other, maybe a manual doesn't have a problem?

.....the thing about the PRV is that they are so understressed which i have stated so many times before and there is so much to gain from little mods to these engines and they are very strong
in regards to the cam issue i have onlt ever seen one engine with a stuffed cam but that was before peugeot brought out the modification to remedy this
PRV's seemed to get a lot of bad press mainly because it was in the 604 and the 604 was never as bad as people made out
Click to expand...
I'd agree with all of that... very strong engine, as mentioned before, the WMs had different heads, pistons and twin turbos on the standard block, crank and rods... and they did 240mph like that.

The 604 suffered because it had the wrong carburetion and simply too many things running on vacuum, which upset the carburetion... and it was a bit heavy for that engine, which was in turn hobbled by the auto transmission. Oh, and it was assembled by JRA, wasn't it?
 
wrong carb set up is the main thing
they starve with the solex crap
auto was not a good option
with FI and a few little mods even in auto form with the right torque convertor you can make a 604 burn rubber if you want to
but as far as the engines go they are pretty much bullet proof
 
Timing chain issue,cam issue!!!

I've owned my 604 for 17 yrs,245,000kms. Its on LPG for the last 6 yrs.

Still has original timing chains (no rattles),original cams,good oil pressure. As cheap as a diesel to run on LPG (@ 35c to 40c/ltre)

The cams may go because oil pressure drops due to bearings wearing out and starves the cams of oil. If they are looked after they last. Change the oil every 5k kms,change the oil & air filter when due. Use good quality coolant. If not looked after the V6 can cost big bucks to fix.
Love the exhaust note.
 
Mine has 318,000 on the clock, and it was totally rebuilt 40,000 ago. The cams needed doing as they were scrap. It got new chains and a few other bits too. The bloke I got it off was the second owner, and he changed the oil llike clockwork, but the first owner didn't hence the worn out cams.
Mine is a grey engine bay, so is imported.

I heard somewhere that the 505 V6 used the HP422 gearbox. I thought that was not the best with a 4 cylinder.
 
I heard somewhere that the 505 V6 used the HP422 gearbox.

Yes - I think you are right. I have not seen one myself, but the ZF name is actually 4HP22 (in case you want to do a www search on the reputation of the 4HP22 box). Also, I thought I had better get in first before that crusty old Ray Bell yells at you!

On the US Pug & BMW sites you will fing some frightening stuff on these as it seems they only last about 80,000 miles; & thats about the same as the ZF autos in the FWD Citroens (BX Alpha's & such
 
Me yell at him?

Never... I don't know much about automatics anyway, and I think I've heard enough about four-speed autos to stay away from them for a frugal lifetime...

Oh, and about the crusty? Where did that come from?
 
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