Rover V8 conversion in a '71 Marina

beniboyz · Post by **beniboyz** » Thu Jul 19, 2012 8:13 am

Hi All,

Long time lurker, first time poster.

I have searched the forum but I just need some pointers in the right direction.

I've been building what started out as a Historic Rally car replica of the 1974 UDT Marina V8 Coupe. It has evolved/devolved slightly but due to time and costs I've not yet done the rally car livery bit only the mechanical parts.

I started out using a Rover P6 engine and auto box (yes not very rally like!) but it was clear this engine was too tired and so I've now brought a 3.9 Discovery (interim) engine that I intend to fit to the P6 auto box

My first question is this: If I retro fit the front cover of the P6 to the 3.9 what kit will I need for the oil pump to match the discovery distributor? I have found two kits online that some posts have pointed towards, one with a spacer but I have also found another that doesn't include a spacer but states it will work with the later dizzy.

Without spacer:

http://www.simonbbc.com/ignition-spares ... emale-type

With spacer:

http://www.rimmerbros.co.uk/Item--i-RB7480

My second question is relating to the auto box: The discovery engine was from an auto but will my P6 flex plate, torque converter and started all swap around? Will my kick down cable mate up with the EFI manifold?

I would switch to a manual but finding everything needed for the conversion, i.e. flywheel, clutch, bearing, release arm and slave is quite a job in one package at a reasonable cost. Maybe next year?!

And my third and final question. For now anyway!: Will my P6 pulley bolt over to the 3.9 crank with or without a spacer for the bolt? I did read that these interim engines have the same crank but because of the difference in timing covers it may need a small 20mm spacer so the bolt can tighten up?

I really appreciate your time on this.

I've now got 6 weeks to finish the build and get an MOT!

Good job I've got some holiday owed! I will post a few pics up later, be warned it is rough and ready but strong. It has been built following the Special Tuning way of shoving a V8 into a Marina... i.e. cut the front out and brace it back up with new metal!

Regards,

Ben

DaveEFI · Post by **DaveEFI** » Thu Jul 19, 2012 9:20 am

The B-W 35 as fitted to the P6 isn't the strongest box in the world, and I'd be worried that the extra torque of the 3.9 will kill it in short order.
The 3.9 Rangie uses a ZF 4 speed auto, so it could be any of the 3 speed boxes fitted to the 3.5 will be marginal. My SD1 EFI has 220 ft.lb of torque and has the factory fit GM box - that has been rebuilt, so hasn't reserves of strength either.

The ZF box was used on Sherpa V8s, so is available for RWD. But these are quite rare, so expensive. The Rangie box can be modified to RWD by fitting parts from another RWD installation - like BMW, etc.

Note there are two versions of the ZF 4HP22 used on Rangies. The early one was cable controlled just like your 35 - the later ones electronic.

The ZF has a much deeper bell housing, so you'd need to check you have room for it.

It may also be possible to have a 3 speed box beefed up to accept the 3.9 engine.

As regards the control cable linkage and EFI, you'll need the Rangie version. The SDI GM only had a kickdown cable - the gearbox being controlled by engine vacuum.

beniboyz · Post by **beniboyz** » Thu Jul 19, 2012 2:18 pm

Thank you for this information Dave.

My box is the marginally better BW65, although I fear this will certainly not last long in my project.

I was conscious that the Rover box I have may be a little too "soft", but was unaware that the ZF unit could be adapted to suit non 4x4 cars. The discovery still has the g/box attached and is a cable operated kickdown. I will see what is available in our local scrap yard that could be made to fit the rear end of it.

The only problem with such a long bellhousing is that it will require some hefty work to fit the Marina tunnel. They have the steering rack running across the bulkhead and a very narrow tunnel.

Would this be suitable to mate up too the discovery bellhousing?

http://www.ebay.co.uk/itm/Bmw-4HP22-Swi ... 416736937c

Many thanks for your time.

Ben

DaveEFI · Post by **DaveEFI** » Thu Jul 19, 2012 3:26 pm

The Rangie auto is spaced a long way off the engine to suit the centres of the engine and transfer box mountings, IIRC. Sadly, this long bellhousing is the only one which fits the V-8 - unless anyone know different. It's why I've not fitted a 4 HP to my SDI - it fouls the bulkhead.

Because the V-8 / 4HP was never engineered for a car, BL simply used the parts they had for the van - where space wasn't a problem.

Unless you have good engineering facilities etc, the cheapest option would be to research strengthening your existing box. If you exceed to torque it was designed for it will fail in short order.

harvey · Post by **harvey** » Thu Jul 19, 2012 3:43 pm

BW65's can be uprated to 66 spec easily enough and they coped with the XK engine in XJ6's without too many problems. Plus they were used in Ashcroft conversions behind Rover V8's.

Post by **katanaman** » Thu Jul 19, 2012 5:59 pm

Your oil pump question, one will be the standard smaller gear of the P6 the other will be the larger gear of the SD1 and on so it needs a spacer to space the end of the pump off. The better option would be the larger gear with the spacer. I take it you don't have any way to fit the interim front cover? its a much better setup than the old pumps.

beniboyz · Post by **beniboyz** » Thu Jul 19, 2012 7:08 pm

katanaman wrote:Your oil pump question, one will be the standard smaller gear of the P6 the other will be the larger gear of the SD1 and on so it needs a spacer to space the end of the pump off. The better option would be the larger gear with the spacer. I take it you don't have any way to fit the interim front cover? its a much better setup than the old pumps.

Excellent, thanks for that. So the longer gears will work with the discovery dizzy?

I would like to use the discovery cover but I think I will be pushed for space. Saying that tho I havnt tried it yet so I could modify the front some more ... I take it the pulley from the p6 would fit with a spacer if it called for it?

Could the discovery setup easily be converted to a v belt arrangement or not?

Ben

russell_ram · Post by **russell_ram** » Thu Jul 19, 2012 7:45 pm

"I've now brought a 3.9 Discovery (interim) engine that I intend to fit to the P6 auto box"

If you truly have a 3.9 INTERIM engine then your P6 front cover won't fit. The interim engines have the much better crank nose driven pump but retain the distributor ignition. You would be ill advised to try and go backwards.

If, however, you have an 'old' distributor driven oil pump type 3.9 engine then your cover will fit but realistically you'd be much better sourcing an SD1 cover/front pulley which already includes the oil pump upgrade in your links but also has a much better water pump.

Russ

russell_ram · Post by **russell_ram** » Thu Jul 19, 2012 7:48 pm

"Could the discovery setup easily be converted to a v belt arrangement or not? "

Sounds like you do have an interim engine, lucky you.

You can't convert it to v belt, the water pump on an interim engine runs off the back of the belt 'in reverse' compared to a v belt system - you can't get it to do that using a v belt (and you can't run it backwards).

Russ

beniboyz · Post by **beniboyz** » Thu Jul 19, 2012 8:03 pm

Thanks Russ,

Sounds like I will have to re think my plans for this engine. The reason I was wanting to have the P6 cover was so I could have the shortest distance between the crank / water pump c/member and radiator.. I guess the only way to tell will be to fit and find out.

Ben

russell_ram · Post by **russell_ram** » Fri Jul 20, 2012 7:46 am

Well I don't know about P6 specifically but one of the major advantages of the later belt drive engines is that, despite the fact that the crank nose is longer, they are actually shorter overall from front face of block to forward most part of the belt/ancillary drives than the old V belt SD1/RR types.

You'll probably need to relocate the alternator to a lower position on a custom mount (and dump the AC and PAS pumps) to fit under your bonnet line. Loads of info from people who have done this on line. TVR has the 'factory' version of this mod if you can find one.

Russ

beniboyz · Post by **beniboyz** » Fri Jul 20, 2012 9:49 am

Thanks Russ,

Yes I think you could be right. I have searched around a bit and it seems (not confirmed) that the interim RR/Discovery timing cover/pump measurement is around 175mm from face of block to furthest most point. This is the one with dizzy. The later 4.0 cover is about 20mm smaller still, but without the dizzy. I will confirm next week when I have the two engines side by side. This will make my life so much easier as the radiator will be able to be closer with it's two fans attached. It also means I will need less of a "bulge" in front of the custom valance and c/member.

Well that is a relief.. As for the alternator, I will see what to do once it is in the car. I do have good height clearance on the bonnet at the moment and it won't need altering for the EFI plenum. Figures crossed.

Ben

Post by **katanaman** » Fri Jul 20, 2012 3:54 pm

I believe you can use the older front covers in the interim engine. As mentioned you need a crank spacer to take up the extra length of the crank. These engines already have the distributor drive gear on the cam so no need to have to do anything with that.
I would definitely use the interim cover though. As Russell said they are actually pretty short already.

beniboyz · Post by **beniboyz** » Thu Aug 30, 2012 8:20 am

Well time for an update.

I got the car "together" for the bank holiday weekend but came up against a sticking point when the gearbox failed to go into drive.. It goes in reverse though..

A common failure on these ZF boxes, I am led to believe. So looks like it is all coming out again over the winter.. Still, it gives me time to sort out the engine bay and front end panel work... Don't you just love custom cars.

Here are a couple of pictures of the car.

It's still a work in progress but it is in.

Ben

JJMclure · Post by **JJMclure** » Thu Aug 30, 2012 8:41 am

looks like it went in there from the factory! Keep it up!