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Discussion Topic:
head clearance
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sundog126 |
05-26-2018 @ 12:35 PM
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Member
Posts: 22
Joined: Mar 2018
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well all the tech personal are off for the weekend, so I ask the form this ques.,after buying a 4in stroke crank and some alum heads and recommened copper head gaskets for my flathead v8 , it looks like my pistons will hit the heads , the pistons pop up a 1/4 in above the block, my ques. is should I double gasket the head for clearance ?
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dandy32 |
05-26-2018 @ 1:58 PM
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New Member
Posts: 102
Joined: Oct 2017
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Iam just A newbee here but just check to make sure your pistons are for A 4" stroke crank and not A 3 3/4 " the wristpin location is different
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carcrazy |
05-26-2018 @ 2:50 PM
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Senior
Posts: 1675
Joined: Oct 2009
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Amen! You will need to get new pistons for a 1949 to 1953 Mercury to have the correct piston pin location for the 4" Mercury stroke. Such pistons are available from various vendors.
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TomO |
05-27-2018 @ 6:39 AM
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Senior
Posts: 7256
Joined: Oct 2009
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Double head gaskets double your chance for a head gasket leak. The edge of the piston should be flush with the block deck, if they are not, the piston pin is in the wrong location and you will have to get new pistons. If it is just the dome that is above the deck, use clay and a used head gasket to determine the clearance between the head and piston. It should be .050 or more. Put the clay at the top of the dome and add a thin film of oil to the head combustion chamber, so the clay will not stick to the head. Torque the head to 40 ft lbs.
Tom
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sundog126 |
05-28-2018 @ 9:34 AM
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Member
Posts: 22
Joined: Mar 2018
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Thanks, I was afraid of that, I guess I will be buying new pistons.
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TomO |
05-29-2018 @ 6:31 AM
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Senior
Posts: 7256
Joined: Oct 2009
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I don't know the condition of your engine, but if you are thinking about just replacing the crankshaft and pistons in a running engine, I would recommend that you rethink your decision and start thinking about a complete overhaul. The money spent now will save you lots of headaches and will be spent later to correct the problems introduced by putting new parts in an engine that has not been properly prepared for them.
Tom
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CharlieStephens |
05-29-2018 @ 9:56 AM
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Senior
Posts: 893
Joined: Oct 2009
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Do you mean the pistons are domed and pop up in the center or are you measuring at the edge of the piston? Photos are nice. Charlie Stephens
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