MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGA - Replacing Valve Guides

Hi Guys,

I am putting an 1800 5 main bearing engine in my "A". It needs new valve guides in the haed, (1968 model head). My question is,...do I need to take the head to a machine shop for this, or is this something I can do from my home shop? Also, if I can do it from home, what is the procedure?

Thanks in advance,
DT
Danny T

They are installed/removed with a hydraulic or large mechanical press. If you don't have one it needs to be done by a machinest. After installation the valve seats need to be reground to maintain concentricity with the new guides. It would also be a good time to have them install hardend seats.
John H

You will also need to fabricate a mandrel to use with your press to install the guides. It will have to fit the ID with little clearance and have a shoulder for pressing the quides into the head. Not an easy task but can be done. Be sure you know how deep to press the guides into the head. Have a good day!

John
John Progess

Hi Danny

Further to the comments from John and John:

It can be done with a mandrel and hammer, but better done (with less of a risk of damage) with a press. The inserts are cast iron, and liable to crack if the mandrel is not an exact fit, and not struck squarely with the hammer. (Don't ask me how I know!)

THe guides need to be reamed after fitting to the correct size.

As pointed out, the seats need to be recut, so this will remove any lead retention that exists so having exhaust inserts installed is a good idea.(if not already there)

All in all - a job for an auto machine shop.

If you can make a mandrel and bash the old ones out yourself, this is a good time to clean up the inlet and outlet ports.

Cheers
Ian F
Ian Fraser

No problem installing the guides and valve seats with a hammer. The first rebuild of my engine, which I trusted to a local shop (Sports Car Haven in St. James, NY) apparently was done that way, and it lasted all of 55 miles :~)

Do it the right way - have it done by a reputable local machine shop!

- Ken
Ken Doris

This thread was discussed between 07/03/2006 and 08/03/2006

MG MGA index

This thread is from the archive. The Live MG MGA BBS is active now.