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MG MGA - Main Bearing Cap/Piston Removal???

Final thing before I get my block to the machinist is removing the middle and rear main bearing caps.

Does anyone have any ideas on how to accomplish this?

I was able to remove the front cap with a hammer and blunt object in the drain grooves and slowly tap it out on either side. The middle and rear caps obviously have no such way of me using my caveman inginuity.

As I write, I am asking myself/you if there is an actual bearing cap pulling tool? I have a feeling there is something based on the fact that there are threaded holes in the bearing caps. If there is a tool, I'd appreciate knowing what it is commonly referred to as.

Finally, when I pull the pistons out from the top of the block, are the rings going to pop out from the ring grooves? I wasn't planning on putting in new rings (<500 miles on these) and don't want to have to cross hatch the cylinder walls, so I want to make sure they don't go flying out when I pull them out. I'd appreciate any knowledge that will assure me being able to take the pistons in and out easily, efficiently, and most importantly correctly.

Thanks for the help!
J DeRienzo

Do you have a Workshop Manual? My factory Workshop Manual (Twin Cam) shows special tool 18G284 and adaptor 18G284A for removing main bearing caps. You should be able to copy this by using a long bolt threaded into the cap and a sliding weight.
The piston rings will not come out of their grooves when the piston is removed.

Mick
Mick Anderson

An image of the puller and adaptor is attached.

Mick


Mick Anderson

You need a slide hammer - should cost less than thirty bucks. Also used for pulling wheel hubs and bearings
dominic clancy

Ahhh!!! You guys are awesome!!! I have to get this done in the early part of tomorrow or else have to pay someone else less knowledgeable to get everything prepped, but this is the exact info I needed!!!

Also, the service manual (which I didn't check to see if they had a listing of special tools) mentioned something about when reassembling the block, putting the main caps back on with some sort of sealant. What should I use for this?

Thanks again a bunch!
J DeRienzo

Important!
Check your Workshop Manual, if it is a factory version Manual, it may have a serious error. Early editions of the Manual told you to face the oil grooves of the thrust washers towards the center bearing.
DO NOT DO IT. The oil grooves in the thrust washers must face towards the crankshaft surface.
Incorrect fitting will wreck the crankshaft.

Service Memorandum attached.

Mick


Mick Anderson

Interesting how the article is listed as confidential...!!!

I wonder how they figured this error out!
J DeRienzo

There is a threaded hole in the top of each cap. With a short bolt screwed int the hole you can then use a roll bar and pry against the studs.
This picture will give you the idea. 2 changes from the picture. A shorter bolt or some washers would help. Leave the nuts on the end of the studs to protect the threads.


R J Brown

Regarding miss-assembled bearing caps. You should always mark bearing caps for location and orientation before removing them to make sure they are correctly re-assembled.
Cheers,
GTF
G T Foster

Main bearing caps for the 3-main engine cannot be physically interchanged. Orientation of the front and rear main caps is obvious. The center main cap has "FRONT" clearly marked on the bottom edge of the cap in raised letters.

Note that CSM MG-416 was issued well after MGA was out of production, and the workshop manuals were never "corrected" as that memo implies. Everyone should mark the appropriate page in their factory issue shop manual accordingly.
Barney Gaylord

Intersting,
my workshop manual (page A14, section A20) correctly states that the thrust washers are to be installed "with the oil grooves facing away from the bearing".
This is a "repro" manual but is labled "M.G 'MGA' Issue 9 40954".
Regards,
GTF
G T Foster

My reprinted Workshop Manual also shows the correct placement of the thrust washer. However the proper orientation does seem to me to be quite obvious.

I believe that the "issue 9" listed by GTF refers to the page revision and not the book. The "40954" numer refers to the ECO, memorandum or control document related to the release of the page change.

My book is AKD600. The Contents page (page 5) matches GTF's numbers: Issue 9 40954. The page for the orientation of the bearing is: page A.14; Issue 3 20290. I do not know when Issue 3 was released. Anybody with an original FWM with the loose pages have the date of release? I know I saw one such manual some 20 years ago. The owner had kept the cover page for each update and the superseded pages.

Chuck
C Schaefer

Chuck,

My Workshop Manual has page A.14 as issue 3 and 20290, which is the same as yours. But it has the thrust washer orientation incorrect with the oil grooves facing the bearing.

Mick
Mick Anderson

Mick,

This gets "curiouser and curiouser". It can't be one of those British / American translation things can it?
I didn't think so!

Is my understanding of the sheet revisions numbering system correct?

Chuck
C Schaefer

Chuck,
Yes, I think you are correct. My manual number is indeed "Part No. AKD600d". The notation at the bottom of various pages varies from Issue 1 to Issue 12 (as far as I've seen, at least). I never really noticed this till you mentioned it. I don't seem to find a "publication" date anywhere. This is indeed curious!

GTF
G T Foster

The way it seems to work is that the early Workshop Manuals and Service Parts Lists were loose pages in ring back folders. Both of mine (Twin Cam) were bought when the cars were still in production and are loose pages.
BMC then issued individual page changes that were sent to BMC Dealers. A MGA owner in the USA said some years ago that he had a lot of these loose pages of various issue numbers, that he bought from a bankrupt Dealer.

Some time after production ceased, when the decision was made to freeze the design and stop any more modifications, the books were issued as fully bound books.

Still puzzled why my page A.14 is the same issue number as Chuck's but has different wording.

Mick
Mick Anderson

I should have said that it is only my Twin Cam Manuals that are loose pages. My pushrod Manual which we have been discussing is a fully bound book.

The Twin Cam Manual also has the error.

Mick
Mick Anderson

This thread was discussed between 24/01/2008 and 26/01/2008

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