The V8 Owners Forum -

I'm confused.

I'm looking at the possibility of fitting one of these gearboxes to my car.
Now, the T-35 is used with the B series which makes about 90bhp
However, I would want to fit this behind a 3.5 Rover V8 making about 200bhp.

I guess this leaves me with two questions:

1) With the B series engine, no trans cooler is used.
However, given the greater power and torque that the new V8 engine will produce, will this neccesitate the fitment of a trans cooler?

2)Will I be able to bolt the V8 straight to the T-35 from the B series application? Or, will it need to be overhauled and beefed up to take the extra power? I know that this gearbox was also used in the Rover 3500 SD1. However, I am unsure if the components are the same or not.
The only visual difference is the tailshaft and bell housing. Although, I know these are interchangable.


Thanks in advance,

JC.

JC

I think you mean a BW35 which I think was also used in the SD1 with the v8.

The bellhousings will vary depending on which engine the box was attached to.

Another consideration would be the ZF 4HP22 four speed auto box which is a much nicer and more modern box, it was also used with the RV8 so mating it is not a problem. Bellhousing from a Range Rover and box from BMW, Jaguar and probably others.

I think there were two styles off bellhousing, one being less bulky than the other and thats the one you would want.

For information contact Ashcroft Transmissions.

Is this for an MGBV8 ?

Kevin.

Hi Kevin,

Yes, this is for an MGB V8 conversion.
I'm torn between a factory V8 4 speed and the Borg warner auto as both will fit in the tunnel without any modifications to the body.
Eventually it'll make way for a Chevy 700R4 which will definately need body mods. However, that's a problem for the future.

JC

Forget the standard 4 speed manual with o/d as these were marginal with the 137 BHP standard MGBV8 engine. The LT77 5 speed is a much better manual option

One of the modern overdrive Auto boxes would work nicely with a relatively soft cam making a nice torquey engine. The 200R4 is another option

There are issues with the later boxes as they have some form of electronic control, but this can be dealt with relatively simply.

Quite a few of the US V8 conversions have auto boxes and worth trawling through them for information and ideas.

http://www.britishv8.org/Photos-MG-Conversions.htm

You could also look at TCI for autoboxes and there is another company but I can't recall the name at the moment, I'll do a search for it.

Here you are, and they have a page with all the different box dimensions and a section dealing with the o/d lock up.

http://www.bowtieoverdrives.com/index.s ... Qwod1CQD2Q


Kevin.

CastleMGBV8 wrote:JC

I think you mean a BW35 which I think was also used in the SD1 with the v8.

Kevin.

The BW35 was used behind the V8 in the P5B & P6B but never in the SD1 with any engine, Sd1's had BW65/66 and GM180.

The 35box is more than a bit marginal when it come to taking the power of even a standard V8, although upgrades are available. Having said that it is easy to get any 35 box, whatever car it is fitted into as standard, to mate up to the Rover V8, and to add a cooler if required.

Kevin,

I'm not remotely interested in using an LT77 box. I put one in my last GTV8. It was a newly reconditioned box and was awful IMHO. Not least, fitting an LT77 involves modifying the roof of the tunnel - a mod which is unnecesary for the gearbox that will eventually go into the car permenently.

My aim is to do a V8 conversion over this winter with either an MG 4 speed or a BW35 auto and run the car in this configuration for 12 months and get some miles on it. Cost will be aprox £3k as I have a lot of parts already.

Once I am at this point, I know that to get the 700r4 in there will be another £3k. £1500 for the box and the same again for shifter kit, converter etc... and then I can look at making the engine better with bigger valve heads etc...

Thank you for the link to the Chevy box specialists. That'll certainly be useful in the future.

harvey wrote:The 35box is more than a bit marginal when it come to taking the power of even a standard V8, although upgrades are available.

How interchangable is the 35 with the later 65? Will the selector linkage bolt up, for example?

Cheers,

JC.

This is the car that has inspired the questions...

http://www.britishv8.org/MG/HarveyLeichti.htm

If you are starting with a MGBGT BW35 box the selector on that bolts directly to the side of the transmission casing, so you won't be able to fit that to a BW65, which was never fitted to MGB's. Easiest way to get a selector to work is using a cable, such as the one used on the P6B with the 65box, and a selector lever of your choice. You would need the 65box/Rover V8 bellhousing as fitted to P6B or Sd1V8.

Harvey, I'll be honest, I don't know a lot about auto gearboxes.

I had seen this kit on eBay (it's been on there for about 6 months now!) that was taken from a 4 cylinder MGB. I figured that I might be able to remove the bell housing and mount it straight up to a V8.

http://cgi.ebay.co.uk/MGB-GT-COMPLETE-A ... dZViewItem


Eventually, I want to fit a B+M "mega shifter" to operate the 700R4. Would it be simpler to buy one of those sooner and get it to operate a BW65 via a cable instead of sticking with the BW35 kit?
My only concern is that surely the shifter must have to move the cable a certain distance to correspond with the various settings on the gearbox and I have no idea how you would get this to work.

Thanks again,

JC.

If you buy that MGB box you will then need the BW35/Rover V8 bellhousing and torque converter (and flexplate and spigot bush for a V8 auto) to get that box to fit the V8. I have all those parts (and of the later spec) should you decide to go ahead. You would also be advised to uprate the MGB box to Rover V8 spec.

Thank you, Harvey, that's really helpful.
A few more questions...

Am I right in thinking that all I would need to do this conversion is to purchase that kit, or one like it plus those V8 specific bits that you mentioned such as the bellhousing / converter and it would work? Have I interpreted this correctly?

Seccondly; Since the position of the gearbox is dictated by the positioning of my engine mounts (standard MGB V8 / late rubber bumper) if the position of the autobox was slightly different than it would have been if it were mounted behind a B series (an inch further forward or back for example) would it be a simple matter of adjusting the length of the linkage between the selector on the side of the box and the gear selector on the consol?

Thirdly; I believe the original MGB Auto's used a 3.3:1 axle.
The axle I am planning on using is an MGC 3.07:1 axle with a Quaif LSD. Will this be suitable?


Lastly; you mentioned that I should "get the box upgraded to V8 spec" is this as simple as purchasing an ex P5 / P6 box, changing the tailshaft and bolting on the MGB selector? Or, would it be better to send the original MGB box away for a rebuild and beefing up. How much is this likely to cost?


Thanks once again,

JC.

JC. wrote:Thank you, Harvey, that's really helpful.
A few more questions...

Am I right in thinking that all I would need to do this conversion is to purchase that kit, or one like it plus those V8 specific bits that you mentioned such as the bellhousing / converter and it would work? Have I interpreted this correctly?
JC.

That should be about it. I'd add a transmission cooler.

JC. wrote: Seccondly; Since the position of the gearbox is dictated by the positioning of my engine mounts (standard MGB V8 / late rubber bumper) if the position of the autobox was slightly different than it would have been if it were mounted behind a B series (an inch further forward or back for example) would it be a simple matter of adjusting the length of the linkage between the selector on the side of the box and the gear selector on the consol?

JC.

As the selector bolts to the box, then it will just move the lever forward or back inside the car. The link on the box that you showed doesn't look like it's an MGB part, as the lever bolts to the box direct IIRC.

JC. wrote: Thirdly; I believe the original MGB Auto's used a 3.3:1 axle.
The axle I am planning on using is an MGC 3.07:1 axle with a Quaif LSD. Will this be suitable?





Thanks once again,

JC.

P6B's use a 3.08:1 diff ratio so you're close enough.

JC. wrote:Lastly; you mentioned that I should "get the box upgraded to V8 spec" is this as simple as purchasing an ex P5 / P6 box, changing the tailshaft and bolting on the MGB selector? Or, would it be better to send the original MGB box away for a rebuild and beefing up. How much is this likely to cost?


Thanks once again,

JC.

That's about the strength of it, if you're capable of stripping the boxes. V8 boxes will more than likely have more clutch plates than in the MGB box.

I can't give you much of an idea of what other people charge, or what they do for the money, but if you care to PM me I can let you know what I can do, and for how much.