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MG MGB Technical - MGB engine - mystery specs

Hi folks, first time poster here. I have an interesting one for you (I think)...

A few years ago I bought a '70 MGB GT from a friend of mine, which had sat through a flood (to the door handles in water) After which he sat it in his barn for about 6 or 7 years, until I came across it.

Now, the reason I picked it up from him was mainly because the engine was supposedly very quick -- he said all he knew about it was that it was bored out .060 over, and had a 45DCOE Weber on it (which came with the car, thankfully).

Now my question -- I'll be pulling this motor out in the next few months to strip it down and rebuild it back up. My question is how do I know what's there? By that, I mean, how do I determine what cam is in it? How about if the head has been touched and to what degree? Should I take it to a machine shop and have them measure everything, then start comparing it to the parts on the market? Or is there a better way?

This engine is a total mystery to me, and I actually can't wait to start unraveling the mystery.

Thanks!

Jon
Jon

Jon, I don't think it will make any difference in the end. If the car was up to the door handles in water then the engine was probably full as well and I doubt if there is anything other than the block and head you might be able to salvage. Of course I hope that's not the case. As to the general dimensions such as bore, measurement with a micrometer will determine that. The pistons may be marked with a .060 on the top or similar marking also. As to the cam, unless there are some markings visable, the only way to see what's there is to take duration and lift measurements on both intake and exhaust lobes and compare those to cams on the market. Compression numbers are not easy to figure, but if the pistons have a flat top and are not dished then you at least have a high compression piston. Hard to tell if they are cast or forged unless you remove them from the rods and look under the crown around the pin boss area.
Bill Young

Jon, Welcome. I don't know how to try answering your question, you are concerned about what performance parts the engine may have. In my opinion your biggest problem is here. (A few years ago I bought a '70 MGB GT from a friend of mine, which had sat through a flood (to the door handles in water) After which he sat it in his barn for about 6 or 7 years, until I came across it.)

Any car that is flooded up to the door handles is probably going to get water in the gear box, engine and differential. The wiring has lots of connectors that have probably corroded and may not function. Most of the switches are probably ruined. If the fluids had been drained and some efforts made to dry the car out immediately after the flood, maybe it would have helped. I guess I'm trying to say you are going to be lucky if you can find any useful parts in a car that has been through what you describe. I wouldn't spend any money on it until it was completely dis-assembled and inspected to see what can be salvaged.

About your question on the engine. A .060' over bore should have the size on the pistons. I don't think it matters what type cam it has, it's probably junk now. Same with the DCOE 45. Most machine shops could tell very little about modifications to the head. Sean Brown at Flowspeed can look at the head and determine if it's been modified if you can get it off and cleaned, again I don't think it will be any good.
http://www.flowspeed.com/

Sorry, It was not my intention to discourage you but I think you should be aware of the obstacles you will probably encounter. Is this your fist car? What type automative experience do you have?

Good luck

Clifton
Clifton Gordon

Jon having restored more then a few flood cars,I have one very important????? Salt or Not? Fresh water cars can be brought back without as much trouble as you might think saltwater car are best left to parts unless it is a very rare item Ric
RIC LLOYD

Few things you can check on the head. Check the thickness from the top to the face. This can be checked against the factory specs to see if the head has been milled. You can also see if exhaust and intake ports have been polished or resized. If they are smooth and do not look at all rough, they may have been ported and polished.

If you are very very lucky, the water may not have gotten in to the engine or at least maybe all that much. Some may have got in from the oil dipstick opening, but it would have to have gotten up past the carbs to get in to the engine.

I have seen a number of cars, snowmobiles, 4 wheeler's and even a few tractors that go through the ice here in Wisconsin and run just fine after a full draining and oil change.
BEC Cunha

I've got most of a B that was submerged for a couple of weeks, nothing wrong with any of it. Far less devastating than leaving it under a plastic tarp for a few years! Assuming that the water was drained out, the only real problem is silt in the works, taken care of by full disassembly; if the water was clean, even that isn't necessary. Places where water could sit for long periods with exposure to oxygen might suffer, like wheel bearings, if they were not dried out quickly.

Sounds to me like your biggest problem is educating yourself on the basics of automotive mechanisms, then the specifics of this one.

FRM
FR Millmore

Hi everyone, thanks for all the replies.

A little more info for you --

I bought the '70 as a parts car, as I have a '71 B GT that will be the one the dollars are spent on. I'm not too concerned about the body and wiring, as anything I do with it (short of sell it) would probably involve pulling it all the way down to bare metal and replacing basically everything. If I do that, expect to see a '70 B GT race/rally car in the Portland area...

The water was fresh water, not salt, which is good. It only sat in water for about 2 or 3 days, and was dried out pretty well afterwards (no specifics, other than that an attempt was made to dry it out). Not sure if it makes a difference, but the water wasn't really stagnant -- it was a river that pushed it's banks.

There is a bit of dried mud on the floor panels and seats, but when pushing the car around it rolls better than the '71 that is the object of my affection. I guess that means the differential and wheel bearings are in okay shape, eh? And that also means I need to do some work on my '71...

I've never really torn into an engine before (pulled and reinstalled the head on my dad's 948cc from his 59 Bugeye, but that's about it).

I know the DCOE is in decent shape, as that was the first thing I pulled off to inspect. From peering through the intake ports on the engine, things look well inside there, at least at that point. The previous owner had borrowed some parts from it (water pump went into his '69 B GT, and ran fine there for many years, for example), so it's not "complete."

I plan on having to spend many dollars on this engine, although my hope is to spend less on this engine than it would take to bring my current engine to similar specs.

Thanks again for all your tips and points to ponder. I picked it up for $500, so even if the only salvageable part is the DCOE it's almost worth it.

Jon
Jon

This thread was discussed between 24/08/2007 and 27/08/2007

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