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MGB Gaskets and seals

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OntarioLes

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Under my 1977 MGB (100K miles) and along the drive train there is a coating of old oil with many bolts sweating drops of oil so I am assuming that all the gaskets between components need replacing. I anticipate that this will require pulling the engine as well as the transmission. Any tips on this would be appreciated.

Recently on a drive (on a hot day) it became hard to impossible to shift the transmission while driving. With the engine turned off, shifting through the gears was ok leading me to think that the clutch is needing service. Wise to do this while dealing with the gaskets. Naturally this will result in replacing all the fluids - engine oil, transmission and rear end gear oil.

What experience do members have with these jobs?
 
Sounds like you are in the right mind set for what's happening. Sounds like the clutch needs replacing, also replace the throw out bearing. Check the pressure plate and flywheel for defects, you do not want to go in there again! You don't HAVE to pull the transmission, but I always found it easier than just pulling engine alone and it gives you better access to do any transmission work if needed. I would pull the sump/pan and look inside and at the same time replace the front crank seal. Replacing the gaskets is just that, I always use a little High Tack spray on my gaskets, but that's just me. I would say that after 100,000 miles, a lot of little things will start popping up, just the nature of the beast! :thumbsup: PJ
 
PJ, you confirmed for me some of the steps that might be involved. Will check the hydraulics of the clutch while removing engine and transmission. Lots to look at with the components out of the chassis. It will be good to clean up the engine bay and drive tunnel. :encouragement:

Thanks for the quick reply! :cool-new: LH
 
The best method is what Paul suggests; pull engine and gearbox as a unit. Replace all seals, along with pan gaskets and the ones at the left side of the engine ("tappet covers"). R&R the T/O bearing, driven plate and pressure plate.

It's a fairly large job but doing it one time, all at once is smart. Find a "Bentley's" Shop Manual if you don't have one, gives you some good info and has tool illustrations that are helpful as well.


EDIT: The clutch slave is easily accessible with engine in situ, but "since you're there"with all out of the car, good practice to rebuild or replace it.
 
DrEntropy, thanks again for confirming what I originally thought. Good to know others have been faced with these maintenance projects. Next to the hoist to take things apart, order parts and get it all done. This forum obviously has a good and dedicated following.

Cheers,
LH
 
Will be going ahead with engine rebuild while replacing the gaskets and seals. AE Nural pistons are one choice - any thoughts on these? They are priced 35% more than another piston listed for use in the 18V engine.
 
AE pistons are what I've used for decades when doing British engines, whether a customer's car or one of my own. Only deviations are with German or Italian cars. Wiseco made us a set of twelve for a Ferrari overbore a while ago, had 'em in a couple weeks and were 20% of what factory ones cost. Ferrari told us it'd be several months before they could supply them. Used Mahle "Pro Series" for a Porsche 930 Turbo with no problem, as well. If you consider other than AE, I'd recommend checking with Wiseco.

Les, this seems to have gone from a "stop the leaks" job to a fairly significant undertaking! Some other recommendations for the task: Use Payen gasket sets. They've been consistent over the years. Vandervell for bearings, they are now part of the Mahle group but have been around just about as long as the internal combustion engine.

Keep us informed of your progress with this.
 
For sure this has become a major project. I definitely appreciate the tips on sourcing better quality parts - makes sense when planning for good long term driveability, enjoyment and future value. Back in the late 1970s I did some amateur racing with an MGB - used the best parts then.

Starting soon - will update.
 
I've put hundreds of thousands of miles on MGB's, Rebuilt the engines of my own and clients. The B is a stout, dependable little machine. This current example was my daily commuter for a 100 mile round trip for years. Engine rebuilt in '98, did a rebuild of the rest of the car in '05~'06.

Funny... in the late '70's I was part of an SCCA racing effort with a Formula-A car and another friend with a '67 MGB. The MG racer (a mechanical engineer) was the only guy I know who could downshift a 3-synchro gearbox into first cog while racing, without turning it into a giant aluminum maraca.


ICYMI: A bit of anecdotal background
 
Neat to hear the adventures of a fellow "have to go fast guy". A clean downshift to first, especially as the enginner in him would know the risk - awesome! Truly enjoyed your attached article.

Engine rebuild is underway - block off to machine shop, then order parts - meanwhile, de-gunk the engine bay of years of old oil and grit.

By the way, I see several posts about engine paint - my '77 B has a 18V motor, should be black, however as we cleaned it, it's orange, and not maroon. So a little mystery in the history. Apparently the undercoat used was orange so maybe this notor has been cleaned before, although absolutely so indication of black paint.
 
You are on track 100K good job so many of these cars get a glitch and get parked for years sad to say and see. I put a 1967 B back together this last year in shout time 3 months that had bad 1st Rev. gears it sat six years did not do motor but trans gears seals etc. also all new hoses clamps oil cooler lines clutch line slave cyl TO bearing with motor and trans out clean paint under hood engine stand made easy work. Paint flush all Rad. diff gas tank wheel bearing check brakes new tries seats, carpet, top. Paint had been done I sold as safe driver and made a new club member a plus. Madflyer Get ER done
 
hmmm... were the bearing shells oversize? Bore diameter? Sounds as if the mill has been gone through once before.
 
Next stage: Parts ordered for engine rebuild. Going to 0.030 over pistons, 0.010 bearings with new cam and lots of other new pieces. Hopefully all back together before Christmas.
 
:thumbsup:

I have a Crane cam in our personal MGB, along with a 40mm side-draft Weber. Good combo.
 
Sorry for the long silence, was out of the country for the winter and spring months. While away had the engine rebuild completed as well as the 2 SU carbs, new clutch slave, shims in rear end, a selection of bushings. It is running much better and leaks all gone - 350 miles on since rebuild, needs some fine tuning, tends to run on after some trips, idle is variable at times. Have a couple of electrical gremlins - horn no longer works, and dash light behind oil gauge is out. Installed new retractable seat belts. What is the trick to getting all four bolts back into the seat frame, front two are relatively easy, back two are a real chore being located under the seat frame rail.
 
Been so long since I've done seats there's a vague recollection that if you remove the stop at the forward end of the rails, you can get ~just~ enough room to go at the rear bolts vertically with a socket & ratchet.
 
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