Head gasket replacement?

dtwallace84

Seaman Apprentice
Joined
Jun 27, 2007
Messages
39
Im going to change my head gasket due to a leak in it. I was wanting to know after taking the distributer cap off and other stuff like this to take the head off, what all electrical things will need to done when its all put back together, like the timing needing to be shot again and stuff like this.

Thanks for any replies.
 

a70eliminator

Captain
Joined
Sep 9, 2007
Messages
3,688
Re: Head gasket replacement?

Scribe little line up marks on the distributor base for referenceing then you can get it back in the same spot, thats all you have to do.
 

mkast

Lieutenant Commander
Joined
Nov 6, 2002
Messages
1,934
Re: Head gasket replacement?

If you acquire the correct factory maintenance manual, your trip into the maintenance world will not have too many bumps.
 

littlebookworm

Chief Petty Officer
Joined
Nov 30, 2007
Messages
574
Re: Head gasket replacement?

We could use some more information, such as: What engine? What year? How do you know it's the head gasket? Do you have experience replacing head gaskets? Do you have a torque wrench and know how to use it? Do you have a manual for your engine? If not, you'll need to get one to follow the sequence. In general, after you pull the distributor, intake manifold, exhaust manifold (maybe), you need to loosen all the rocker arms and remove the push rods, keeping them in order. You then need to remove the head, check it for warp and cracks, check the block for damage, and clean everything. Then, assuming all is well, you need to set #1 piston on TDC, replace the head gasket, torque the head properly, in stages and in sequence, reinstall the pushrods, set the distributor to line up with #1 wire on the cap, set the oil pump gear to match, drop in the distributor and tighten tentatively. Then you need adust the valves as outlined in the manual. Finally, you need to reinstall everything you removed. You then need to start the engine and set the timing. That's a quick summary of the process. I strongly recommend that you get the manual before you start anything so you can check the specific details related to your engine. Good luck and safe boating, Hy
 

dtwallace84

Seaman Apprentice
Joined
Jun 27, 2007
Messages
39
Re: Head gasket replacement?

Its an 85 searay seville w\140hp mercruiser 3.0. I do have a manual and torque wrench. I am familiar with changing exhuast manifold gaskets and stuff like this, but I have never done a head gasket. The reason I know its the head gasket is that I took the exaust manifold off and noticed that the head gasket was leaking between the block and head. Im pretty good with fixing this type of stuff on my own but never got this deep into the engine.
I appreciate the replies.
 

a70eliminator

Captain
Joined
Sep 9, 2007
Messages
3,688
Re: Head gasket replacement?

It's a fairly easy job, the biggest battle is cleaning everything up, pay close attention to detail, keep each pushrod and rocker arm together and make sure the combo mates back with it's lifter too, an egg carton works to keep things organized. It is very important when assembling used parts that they match their original wear marks, if you mix them up the wear accelerates rapidly. I like to put every single nut and bolt back into it's original hole, especially the head bolts, if you have any trouble at all getting them out and they look all rusty then you'll be chasing the threads with a tap so mixing them up doesn't really matter at that point.
 
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