Another MGB GT V8, work in progress

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DaveEFI
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Post by DaveEFI »

Welshie wrote:Well as you can see, its definately a serpentine motor
:D The loom looks to be hotwire too. Trouble is with our engines so much swapping of bits is possible that's best not to assume anything. And my glass is half empty.


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Post by 3xpendable »

Popped home this weekend and did a bit to the car, but my time was predominantly taken up with stripping the cylinder head off an Aston DB7.

After that though I started with the scuttle shaping for the wings I am going to use. The drivers side wasnt too far off but the passenger side needs some more meat adding on to match the contour of the wing. I will be taking the beading off and replacing it with rupper T beading which will help prevent rust but also give a bit of flexibility of fitment.
I have decided not to incorporate the rubber bumper's GT pillar badges so began shaping over that area to make it standard as per chrome bumper cars, along with sealing the rear wing to valence seams. They look a bit notieceable at the moment but seam sealer has smoothed them out and once the rear valence is stonechipped it should blend in nicely.

Basically is the front scuttle shaping and some tidying up of the rear valence to do before the car can be painted, but I may leave the valence as I have to relocate the exhaust lip/s for the twin pipe layout anyway. I havent stripped the block anymore as I didn't get time, but want to find a way to clean it before I start stripping it more so that it can be cleaned as soon as its stripped.

Finally, I changed one of the flat tyres so that it can be wheeled around by one person.
1971 MGB GT (V8 project)

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Post by 3xpendable »

Ok here are some photos of the wing fitment issues. You can see that the wing is being held out slightly but I can't take much more off the scuttle material. Of course when the wings are bolted on they will be held tighter and i;m replacing the lead beading with rubber beading so that will give some more flexibility in fitment etc.

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As you can see, the nearside wing needs some scuttle profiling to fit....i'm sure each wing is different!!!

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The final bit of shaping work needed will be cleaning up this repair...but I need it out of the tunnel before I can grind that.

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Now onto the engine, the heads look in good order but need a clean up

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However, when i had my original 3.5 engine, I bought these off a friend as an upgrade. They are 3.9 heads but also have a hole plugged off by the exhaust ports which i was told was an air injection port? These heads have been cleaned and seem in excellent condition but i'm not sure if, given that plugged hole, will be as good as the original heads, ideas?

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Progress is slow due to the weather at the moment and other work being in the garage, plus my brother has found his shell again so has decided to do work on that instead of the MGB...you very much have to get him in the right mood ;)

Engine looked good though the big-end journals at the back of the engine have some scoring

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The accompanying bearings.

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Given that further forward you went, the better the bearings were, seems to indicate its been starved of oil a bit maybe at some point. It may be ok but to be sure i'm getting the crank checked and ground if needs be. The shells were the originals so I have oversize to work with.

Looking pretty clean

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Now its ready for cleaning before I buy new bits and put it back together. In the mean time I decided to measure up and look at the new front cover I will be fitting. This came off my 3.5 litre engine (see earlier) from a Rover P6 and had the short nose pulleys and covers that are required for the V8 MGB install. I've been told they bolt on but the engineer in me and my dad wanted to check everything first.

On the left is the cover removed from the 3.9 and on the right is the cover I want to fit.

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The main difference is on the later one the oil pump is internal and driven directly by the crank (its casing can be seen held by the cross head screws) and the earlier one has a completely different and external oil pump that has a long shaft thats driven by the distributor, which is turn is driven by a gear on the camshaft. Dimensionally the distributors are the same and have the same pitch on the teeth but the earlier one has the slot in the bottom for the oil pump drive shaft. This is removeable so I can fit it to the newer distributor if I choose to use it.

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Closer view of the older cover oil pump

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I need to clean this up and fit a new seal in before using it, along with driving out a snapped bolt which will be fun. Slow and steady will be the way me thinks.

The only other question I have now is about the front pulley. Both the 3.5 and 3.9 cranks are the same shank length (70mm for pulleys, drives etc). Now, the stack-up of all the components on the 3.9 engine make 70mm considering the timing gear drive, a small spacer, the cover seal and oil pump drive and finally the pulley. Bearing in mind the older casing is about 25mm shallower given it just has a crank seal and no oil pump it means in theory that the older front pulley should too be about 25mm longer to take up this clearance but its not, its about 10mm short. Its been ages since I stripped the 3.5 and cannot remember if there is some sort of spacer to take this clearance up or if there is just a 10mm or so gap between the timing cover and the pulley? I will look through my old pictures tonight and also go through all the parts I saved from the 3.5 next time i'm home. But some food for thought for anyone who's done this before.
1971 MGB GT (V8 project)

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Post by 3xpendable »

The block is now cleaned, though i'm having trouble finding a machine shop locally (ish) that cn grind and balance the crank for me. For now it will be a job after christmas where I plan to rebuild the engine in the cold months, and then finish the bodywork when I can get out to the shed without a polar suit.

In the meantime, the car is now officially a V8 :) Got the logbook back recently with the updated details.

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Post by 3xpendable »

Just got back from a 3 week visit to America which was awesome. While i was there I did some research and found out the spare cylinder heads I have for my engine are no good as they are 14 bolt jobbies with 36cc combustion chambers and the engine has 10 bolt heads with 28c combustion chambers. This was done to facilitate the use of thicker composite gaskets to cure head gasket ailments though if you skim the earlier heads you can still use them on the later engines, and just nip up the outer row of 4 head bolts. But for now I will clean and re-use the later heads as they look tidy enough with some minor porting. I may exhange the spare heads with 10 bolt ones so I can make them trick later.

Also found a supplier of parts, and a local machining company so next week I will take the crank to be grinded and balanced (hopefully only needs 10 thou) and then will be rebuilding the bottom end later in January. I then intend to get a gearbox so I can bolt it all together and do a test lineup in the car. Once thats done the top end will be rebuilt and then hopefully it will be warm enough to paint the shell.
1971 MGB GT (V8 project)

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Post by chodjinn »

Welshie wrote:Just got back from a 3 week visit to America which was awesome. While i was there I did some research and found out the spare cylinder heads I have for my engine are no good as they are 14 bolt jobbies with 36cc combustion chambers and the engine has 10 bolt heads with 28c combustion chambers. This was done to facilitate the use of thicker composite gaskets to cure head gasket ailments though if you skim the earlier heads you can still use them on the later engines, and just nip up the outer row of 4 head bolts. But for now I will clean and re-use the later heads as they look tidy enough with some minor porting. I may exhange the spare heads with 10 bolt ones so I can make them trick later.

Also found a supplier of parts, and a local machining company so next week I will take the crank to be grinded and balanced (hopefully only needs 10 thou) and then will be rebuilding the bottom end later in January. I then intend to get a gearbox so I can bolt it all together and do a test lineup in the car. Once thats done the top end will be rebuilt and then hopefully it will be warm enough to paint the shell.
RV8 heads are interchangable depending on what compression ratio you require. The outter head bolts are not required at all, particularly if you use ARP head bolts which are a must in any rebuild. I assume you are building a n/a motor therefore the 28cc chamber heads with thinner copper headgaskets would give you the highest comp ratio. May as well port the heads a bit while you are at it, free power basically ;-)
RIP MGB V8 .... served me well as a learning curve.

R32 Skyline V8 .... this one is gonna be a monster!

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Post by 3xpendable »

Been spending a fair bit of money the last few weeks ordering all the bottom end engine parts, which are at home awaiting fitting. I finally got a flywheel that was decent and will be picking up the balanced and reground crank on Thursday. I also was lucky twice with a gearbox...I got a bargain picture less auction on eBay and it even included the release bearing, fork and gear lever, all for less than you usually pay for just the box!

Then TNT delivered it, and the driver was moaning about it spilling some oil in his van and had no-one been home, he would have sent it back as damaged goods. Luckily my dad had just popped home to feed the chickens when he arrived!

So, hopefully over Easter the bottom end will be built up and trial fitted to the car as the gearbox mount needs re-working. Pictures to follow.
1971 MGB GT (V8 project)

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Post by 3xpendable »

Well, had 6 days at home to play on the B over Easter. Of course there were other distractions so it wasn’t all spent on the car but I got a bit done. I got home to boxes of bits 

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And an LT77 gearbox, complete with the release bearing, arm and gear lever, all for the price you usually just pay for the box! I also lined it up to the engine to check the bellhousing, fits perfectly.

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Engine first, here it is with the crank in

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This engine came with a crank driven oil pump, and therefore had a thicker timing cover so when my dad and I measured the SD1 cover & pulley with the new crank we expected there to be a gap between the pulley and timing gear. So we fitted everything up and it all marries perfectly, which is a relief 

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Metal Cloyes adjustable timing gear fitted. There are 3 slots on the crank gear allowing you to use standard or advance/retarded timing. Seeing as the standard 3.9 cam is being used I stuck with standard.

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And here it is, the short motor almost fully built up 

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I have 2 distributors. One from my old 3.5 from a P6, the other from this circa 1993 3.9 and has electronic ignition. Can I use this system on my non fuel injected B or shall I just fit electronic ignition to the older distributor?

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The sump and oil pickup are being cleaned and will be fitted next, once the gearbox is cleaned up I will fit them together and to a trial fit in the car. Dad thinks it might be easier to install the engine with no heads but I have one question: Can you install the cylinder heads with block hugger exhausts attached to the engine in situ?

Onto the body. The donor car was put back together and made rolling ready for sale or scrapping (Edit: Since this time I had a complete timewaster on eBay who after bidding £300 expected the car to be a brand new shell, so I may just weigh it in to avoid the eBay Codbags)

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The car has good wheels, and nearly new tyres when I parked it up, so I fitted them to the shell. Its amazing how good a set of wheels cam make a project look isn’t it?!

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Fitted the brake drums which I’d painted some time ago

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Got the car out for some grinding, as the welds had failed on this part under the rear light

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Ground it down and covered it in weld-thru primer ready for dad to weld it

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I’ve not done much bodywork before, as my brother and dad are the experts at it. BUT in a bid to get confident with it I had a go on a simple part of the car first, so here is the rear quarter after some spot welding

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I painted it to protect it a few months ago

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Then I grinded it down.

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Onto the shaping! First layer

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I then sanded this with 80 grit to get the basic level and shaping, flattened it back again then added a bit more filler to take out any dips

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Measuring it with a straight edge after the 3rd levelling off showed two tiny indents which I have put a slim of filler over. Dad tells me filler sinks sometimes so I ran out of time yesterday to finish it off but left this final layer on to harden before I go back in a few weeks to put the skim coat on and flatten it back with wet and dry, for my first attempt I’m very pleased so far:

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I also got the floor painted with underseal in the corner that had to be left bare for the above welding, so now I’m just awaiting some padding material then I can paint and fit the fuel tank.

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Cleaned some interior parts too. This is the washer pump casing before

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And after, along with a few other parts

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I was annoyed with the heater knobs though, I washed them in warm soapy water with a soft spongle and not only has the lettering started to fade, but also the plastic has gone sorted of faded, like its degrading. Is this repairable or shall I just get replacement knobs?

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Painted up some engine brackets too

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Finally, the new calipers have been painted red, and look nice.

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On an interesting note, mum told me on the weekend that my brother (with the above mint Hillman) thinks I'm "rushing" the rebuild and will regret it...! That’s all for now folks, I’ll be off for the summer soon, so should make more progress!
1971 MGB GT (V8 project)

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Post by 3xpendable »

Cylinder head cleaning is coming on well, using copious amounts of Mr Muscle oven cleaner after the cleaning tank failed to clean much off. Here is a chamber before:

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And one after

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Exhaust ports are mostly cleaned save for the intricate bits

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Here is a before and after rocker, again Mr Muscle works great!

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I had to take the steering rack off today to fit the nut to the engine mount that side, thank you BL engineers.

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1971 MGB GT (V8 project)

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