MGB restore and V8 conversion - some newbie questions please

[David_watt]

I currently have a 1978 MGB Roadster that a prior owner had converted to a 3.5l SD1 Rover V8, uprated brakes and axle etc.  It's lovely.

However, recently retired, I really want a project to build a V8 MGB from the ground up, to a really high spec, to drive for the next 20 years.

I've found a 1972 Roadster that had been stripped back to bare shell and the body work (welding etc) and epoxy primer already done.  The guys on the project had to stop for personal reasons.  So, I get a ready shell (albeit chrome bumper) and all the parts to build back up.

At the same time, I can buy on eBay a low mileage (60k), 3.9l 1988 Range Rover engine.  It's the serpentine pulley type, and has a Holley 390CFM carb, Mallory Ignition distributor with high performance HT leads, coil and X8 new spark plugs.  Small Block Chevy V8 rocker cover adapters with chrome Moroso covers fitted and Edelbrock oil cap/rocker cover breather.  It also comes with an LT77 gearbox with brand new 3 piece Valeo clutch kit including, Pressure plate, friction plate, release bearing and slave cylinder.

I plan to completely refresh the running gear with the Hoyle Engineering complete front (new cross member, suspension and brakes), and complete rear with Independent Rear Suspension, Ford Diff, propshaft and disc brakes.  Hoyle also provide a complete exhaust from RV8 style exhaust manifolds (through inner wing) pipe and silencer etc.  Ill put in a new Alloy radiator and dual electric fans.

Can you guys check my thinking on a few aspects?
For the engine, Clive Wheatley (mgv8parts.com) can supply:
•   V8 FRONT ENGINE COVER ( LARGER OIL PUMP GEARS )
•   FRONT COVER GASKET SET (COMPATIBLE WITH OUR FRONT COVERS)
•   RV8 WATER PUMP WITH FREE GASKET
•   V8 ALTERNATOR CRADLE
•   V8 OIL FILTER HOUSING BRACKET
•   RV8 ALTERNATOR
•   V8 ALTERNATOR ADJUSTING LINK
•   V8 OIL FILTER PREMIUM
•   V8 ENGINE STEADY BAR

Essentially, a new front cover as the Serpentine style is too long), remote oil filter, uprated alternator.  

Flywheel change to lighter?  What else am I missing?

I assume I also will need to swap the sump for the SD1 style rear-bowl to get clearance above the cross member?

I'll upgrade the cam to a sporty mid range.

I understand I will need to do some welding work on the shell to allow clearance on the transmission tunnel for the gearbox.

Can anyone point me to a guide as to exactly the cuts needed on the bulkhead, and on the inner shell for the RV8 manifold exhausts?  Also the exact position of the new engine mounting points?

What have I not thought about?
David

[Moderator]

Hi David! Welcome to BritishV8.

My first question is "Where are you located?"   If you're located in France, for example, it won't be helpful if someone on this board immediately starts telling you to discard your Rover engine and instead look for an iron Small Block Buick engine.  (Those are hard enough to find in U.S.A.!  I expect they're impossible to find in Europe.)  It also probably won't be helpful if someone tells you to forget about LT77 transmissions and to instead look for a T5 or Toyota transmission (either of which I'd personally prefer, and also either of which should fit easily without tunnel mods.)

[David_watt]

Apologies, I'm based in Winchester in England

[BlownMGB-V8]

The 3.9 should be a good choice, given your location, and your plan sounds solid. I would suggest you browse the 300 sticky thread to find the info and link to the thread about the new design side engine mounts. Far superior to any other mount design and eliminates any need of a steady bar. You will have to do some light fabrication but the templates are there. Several conversions have now used them with sterling results.

Jim

[MGBV8]

You may think that the serpentine belt Rover V8s are too long for an MGB engine bay, but.........it has been done.

https://www.britishv8.org/mg/JimStuart4.htm

[David_watt]

OK, so I have now acquired the shell that was a an incomplete project.  It's a 1972 Crome bumper roadster, and the shell has been mostly stripped, repaired and the outer has been epoxy primed.  the engine bay still needs shot blasting after we do the trial engine fit and modifications.

I'm purchasing the full Hoyle engineering front and rear suspension, brakes exhaust and diff package.  

The engine is a 3.9 rover and the seller is a mechanic who is doing the necessary modifiations using mostly Clive Wheatley parts.  The front cover with larger oil pump gears, water pump, remote oil filer setup, v8 alternator and bracket etc.

The shell is at the bodyworks guys and I will work with them to make the necessary v8 mods - new mounting brackets, moving the radiator as far forward as possible, holes in the inner wings for the RV8 manifolds, transmission tunnel mod, new bracket on  the gearbox crossmember.

Mark at Hoyle is providing a new CB crossmember as part of the front package.  

the one area I could do with some advice on is the bulkhead modifications needed to accommodate the engine heads at the rear, and ensuring the RHS steering manages to go below the manifolds and cover the crossmember at the right angle.

In Roger Williams book, he suggests a lot of CB conversions utilised dual universal joints to route the steering.  Mark is suggesting that's not needed.  he has provided a few photos of bulkhead cuts that appear to set the UJ back into the bulkhead slightly.

My question is this: if I'm adding whole new brakes, (Discs front and rear), should I also fit tandem master + new servo hydraulics rather than the earlier single circuit master and remote reservoir? That would then require a new post 1974 pedal box panels and bulkhead panels and that in turn would require post 1974 RB collapsible steering column and dashboard?  I'm happy to update the whole steering and braking mechanics to post 1974 to achieve better braking and to allow the steering to better fit with the V8.  (would that in turn also require a RB crossmember for the front steering bracket?)

Has anyone taken this approach to a Rover V8 in a chrome bumper MGB?  Anybody got any thoughts?

[BlownMGB-V8]

Stay with your CB crossmember, no reason to change it. Many CBs have been done but it is a little more work, mostly the steering pinion shaft mods. First the firewall. On that side of the car (your driver's side) there is a bulge in the end of the tunnel that has the plug on top that is removed to access the stock transmission dipstick. It's pretty easy to extend that bulge upwards until it meets the shelf with a simple one axis curve and a little flange bending along the top edge to match what is already there and the resulting job can be indistinguishable from stock. That gives all the room for the head you will ever need but you should look at what is done on RHD cars for the gas pedal. That could require a different plan.

On the steering, I like to use a 2 piece split collar around the aluminum casting of the rack, weld half of that to a cut down exhaust clamp saddle (double wall type), space that off the crossmember the required distance, position it for pinion clearance and weld to the crossmember. Then rack adjustment is as simple as loosening the collars, attaching the u-joint and clamping the collars down last. If needed a channel can be cut in the crossmember to move the rack downwards in which case the spindle arms need to be bent to match to avoid bump steer. Hot bending and slow cooling in dry sand is the recommended process to avoid any risk of cracks forming. At the firewall end the cup from a RB car may be used if needed but you may find that slight enlarging of the existing holes is sufficient. Small diameter replacement u-joints are available from several sources in polished stainless, some with replaceable bearings. There is a double unit also available if required due to length matching.

The CB pinion is shorter than the RB one and has a faster gear ratio which many prefer. Either can be made to work but you can only substitute the pinions if the ratio matches. Some do, I think the recent Moss CB rack uses the late ratio. It is possible to lengthen or shorten the pinion to meet your requirements, but you will need to find a shop that is willing to do that mod. Some simply won't touch it. The process involves drilling one part and turning a pilot on the other with a chamfer on both, truing it up between centers, welding, straightening, then reducing the weld to the original shaft diameter so it will pass through the bushing in the rack housing. Done competently the resulting part is perfectly reliable and can be made to the exact length needed, with the original splines and bolt notch.

Carl reports that using a dual diaphraghm brake booster gives a modern feel to the brake pedal and very effective braking.

Use of the Torrington roller thrust bearing mod under the king pin trunions reduces steering effort considerably.

Jim

[BlownMGB-V8]

Here is the link for your engine mounts:

https://www.mgexp.com/forum/mg-engine-swaps-forum.40/buick-rover-engine-mounts.4267950/

Templates are on this page:

https://www.mgexp.com/forum/mg-engine-swaps-forum.40/buick-rover-engine-mounts.4267950/page-2

Jim

[waterbucket]

If you buy the "How to give your MGB V8 power " book all the details of bulkhead modifications are there as well as a huge amount of other information.

[David_watt]

Thanks. Yes, I've got the book; it's very useful. But clearly, words on a page (translating to visualising in my mind) as well as people's practical experience can sometimes be a bit different.

Anyway, the chrome bumper shell that I bought turned out to be not that good, so I've binned that and have bought a nice 1979 rubber bumper with very low levels of rust and in really good condition as the platform. I think it's certainly going to make conversion to V8 a whole lot easier.

The engine is nearly ready to drop in, and I'm going to be using these mounting brackets from Clive Wheatley. https://www.mgv8parts.com/product/v8-alloy-engine-mounts-pair/

Also have these for welding to the rails https://mgbhive.co.uk/product/15-mgb-v8-pair-engine-mounting-brackets-2-engine-rubber-mounts/
Exact position to be confirmed when we trial fit the engine.  Also have the rv8 gearbox crossmember from Clive Wheatley

The Hoyle front suspension system comes with a slightly modified crossmember, so I'll fit the steering before we do the trial engine fit and see where there's any clashes. I'm using the RV8 exhaust manifolds through the wings and having them ceramic-coated, which should help clearance-wise.

Hopefully the later rubber bumper engine bay won't require as much bulkhead cutting, but we'll see once we do the test fit. Anyone got experience with these late models and the Rover engine?

[David_watt]

A bit of an update. The Chrome Bumper project shell that I bought, although it had been media blasted and under primed, the quality of the work was not fantastic. Additionally, whilst I was told it was complete with all the parts taken off, it turns out that too much was missing. The cost to buy everything I was missing was going to be prohibitive, so I sold it for parts and found a much better rubber bumper 1979 project for about £5,000.

This starting point has proven to be much more acceptable, and the quality that the previous owners had kept it to has been fantastic. Hardly any rust whatsoever, and massively hard undercoated and well maintained.

I've now fully stripped it, had it sent to the blasters on a rotisserie and it's been epoxy primed. Apart from a small amount of pinhole rust on the sills and the rear valance, all of which is completely fixable, the shell is in immaculate condition. It's now gone off to my body shop guys to do the necessary V8 mods to the transmission tunnel, the inner wing holes and so on.

We'll then do a trial engine fit with the Hoyle front crossmember, steering, ceramic coated RV8 exhausts, etc. Strip it back and then bring it home for me to start the re-assembly process.

[BlownMGB-V8]

Good job. I've always felt that the best results come from the best start and using the best body you can lay your hands on.

Jim

[David_watt]

So the guys at the bodyshop have taken a lot longer to do their work than I had hoped, due to a backlog of classic cars in front of me, but their work was top quality.  Engine trial fitted, welding, and V8 mods and CB conversion mods all done. 

The quotes I received for a full respray have been exorbitant. but that's mainly been due to the huge amount of labour involved as opposed to materials cost.  So, with retirement time on my hands and keen to learn, my plan is to do all the priming, blocking and sanding and spraying myself.  Equipment purchased and spray booth set up in my garage.  Wish me luck!  It's going to be Aston Martin Silver Birch, with a Raptor bedliner underbody in a matched colour.  (plan is for a Mulberry leather interior)

All of the front and rear Hoyle suspension/brakes/quaife diff etc have arrived so keen to get those fitted as well.

Plan is a new custom wiring harness with relays rather than fuses, and wiring "tucked" as much as possible to get a really clean engine bay.  Reverting to a metal dashboard sprayed the same colour as the exterior, with chrome toggle switches.  Heater and radio deleted.  (All heater air inlets have been welded up)