79 Shoveldead
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2nd Gear
Joined: Jul 2008
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79 Shoveldead
Got a 79 FLH Shovelhead with a few issues. Just got done replacing head gasket, rocker box gasket and pushrod corks on cylinder one. Keeps blowing head gaskets, the most recent today. This will be the third gasket. Need help.
Road Master
Joined: Jun 2008
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From: NW Florida
I had that problem on a Panhead. First check your head bolt threads to make sure that the head bolt will go all the way down. When you tighten the bolts do it in a cross pattern a little at a time until you get the 65 ft pds of torqure. Pans and Shovels have a problem with the head bolt inserts pulling out of the head causing an uneven surface. If that is the case you will either have to counter bore the holes or lap the heads. They also make a copper head gasket that you can try first. I believe S&S has them also.
You can lap them by taping a piece of wet dry sandpaper to piece of glass or something else perfectly flat and moving the heads in a figure eight pattern until the gasket surface is level. It will only take a couple of passes to determine if the inserts are pulling out, they will get shiny before the gasket surface is touched. The exhaust port usually gets in the way though. If you have an old cylinder you can make a head gasket out of the wet dry and stick to the old cylinder and rotate the head on that to lap it. Use plenty of water to keep the paper from caking and clean everything real well after.
You can lap them by taping a piece of wet dry sandpaper to piece of glass or something else perfectly flat and moving the heads in a figure eight pattern until the gasket surface is level. It will only take a couple of passes to determine if the inserts are pulling out, they will get shiny before the gasket surface is touched. The exhaust port usually gets in the way though. If you have an old cylinder you can make a head gasket out of the wet dry and stick to the old cylinder and rotate the head on that to lap it. Use plenty of water to keep the paper from caking and clean everything real well after.
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2nd Gear
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Shoveldead
Yes I was kinda thinking along those lines a swell. I am hoping that I do not have to have the heads machined. If that is the case i will do it myself at work. The bike is also smoking very badly at low idle and when first taking off, but only on that cylinder. I think that the exhaust manifold gasket is leaking too.
Road Master
Joined: Jun 2008
Posts: 1,078
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From: NW Florida
On the cylinder that is smoking, pull the head bolt on the left side closest to the exhaust. If it has oil on it, the head gasket blew at the oil return and it is sucking oil and blowing it out the exhaust. It also could be letting oil by the valves guides if it is only at idle and at take off.
Stage I
Joined: Jun 2008
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Head gaskets
Dennis Kirk has Genuine James Firering head gaskets #H26725,I've ran these for the last 20 or so years with good results. Are you retightening your headbolts each time you run your engine for the first 5 or 6 times it gets hot and then cools down? I do this and I just pull them down in a criss-cross patern using just box end wrenches until they are tight. Good luck
Advanced
Joined: Sep 2007
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I had the same issue on my 78. I called Cometic Gaskets and they have copper gaskets at any size you want. I was sucking my gaskets IN to my jug at the oil **** hole everytime because of the 10.5 compression pistons I am running (every gasket I put on had a V from the oil return hole in toward the piston). If you are going to use copper coating on the gasket, 3-M makes a really good one. Also check the mating of the head and jug first by laying the head on the jug (no gasket) with a light on the inside to see if you have a bad mating surface and go from there.
ShovelheadGreg
ShovelheadGreg
Cruiser
Joined: May 2007
Posts: 207
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You have to retorq. the head bolts, also make sure that the head bolts are not too long and bottoming out (I have run into that one before) if you could post up a pic of the head gasket, I could give a little better idea.
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