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Cylinder head gasket?


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Scotty Boy
06-23-2003, 12:08 AM
I have a 1972 b-gt that has been smoking and discharging oil out of the exhaust. I have pulled the cylinder head expecting to have replace the rings (minimum). But now I'm thinking it may just be a bad gasket. There is a trail of oil from the valves to the pistons on both the head and the gasket. Anyone have any advise or suggestions? Thanks

02Denali
07-05-2003, 01:46 AM
Did oyu do a compression test before tearing the engine down? and if so what were the readings? How many miles are on the engine?
you said that oil is running from the valves to the pistons? Could you explain a little better

Scotty Boy
07-05-2003, 08:38 PM
Unfortunatly I did not do a compression test, I just dove in. The motor has 100,000+ on it so the more I thought about it, the more logical a full rebuild sounded. It will be my first experience with internal engine work, so I will be posting here begging for help on many occasions to come. Thanks for the post, I will post my progress as i go(w/ questions attached I'm sure).

02Denali
07-05-2003, 10:08 PM
Well the MG engine is an easy one to work on. Paty attention to the little details and you will have no problems. gGet a manual I have found the Haynes series to be one of the best. Another thing is parts. Most of what you need can still be purchased through your favorite parts store. but for speciality items I highly recomend Moss Motors. Get a catalog they use actual diagraqms of the assembly you are working on and alot of hints through out their catalog. I would not buy everything through them but a good reference. Another source is John Twist. He has a web site and is a great place for help hints and even email tech help. Also if this is your first tear down or even if it is not. I also recomend taking pictures of the assembly before teardown. Alot of time can go buy before reassembly and these will be a good memory jog.
Sorry for the long post
One other thing re-tap ALL threaded holes before reassembly
( specially the holes for the head studs and make sure there are no raised areas around the stud holes in the block..a great place for head gasket leaks and FLUSH out the block after it returns from the machine shop. along with making sure all oil passages are clear.

Scotty Boy
07-06-2003, 07:24 PM
Thanks for the tips. I have been a picture taking fool of all I've done so far. A quick question; I have a very shallow ridge at the top of the cylinders about half an inch long, is this an indication that the block needs to be bored? or is it just normal wear? Also is there anything wrong with buying a complete rebuild kit, say from the proper MG, Or is it better to buy them individually through moss or another company?
Thanks. (Long posts are fine)

02Denali
07-07-2003, 11:20 PM
This ridge you are talking about If it is at the top of the cylinder( inside rim) then it is what is called cylinder ridge. This is caused by two things.. if it is a black crusty like material it is carbon build up cause by oil in the combustion chamber. This you can scrape away BEFORE you try to remove the pistons. if it is wear in the steel itself then it is caused by the piston rings as they slide along the cylinder wall, this type of wear if it really severe you need to remove it using what is called a ridge reamer.( specialty tool you can get at sears if they have a good tool department). BUT be careful READ the instructions first You can cause damage if you cut to deep. Wear in the cylinder is determined a couple of ways First by taking diameter measurments along the cylinder length both parallel to the crankshaft axis and at right angles to it at three points such as 3/4 " from top mid point and bottom of piston travel. then see what the taper is should be no more than .025 MAX This I would leave to a competent machine shop. As for rebuild kit.. I would wait until you know what is worn such as crank bearing journals and cylinder wear before buying parts... ( main and rod bearings rings and even piston or valves and guides if needed) These are determined by the wear. So let your machine shop recomend what is needed. As for gaskets...freeze plugs and so forth go ahead and buy them ( you need both a lower end gasket set and what is called a conversion set which has the head items ). I would strongly recomend having hardened valve seats inserted in the head due to the non lead gas that you now have to run.
Well hope this helps oh I would not have a problem buying those parts from your favorite jobber if they have them. save Moss for items that you really need them for and as always take your time.

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