head gasket issue

I purchased a 2 piece wiseco head gasket cfm20 w4069. It says it fits 76-80 kz 1000th which is what I need the only issue are the 4 outer stud holes are larger than normal .20mm holes compared to my old ones were around 12.
Any ideas or tips would be great.

Hi Toad,
I find this interesting. If your talkin only .08mm I would not worry about it. The first thing that comes to mind is that most guys running larger displacement big blocks will use heavy duty cylinder studs (among other parts) that are larger in diameter and the holes may be slightly enlarged to address this. The thing that puzzles me is most guys running enlarged big blocks use one piece copper head/base gaskets and not graphite 2 piece ones. They do make one piece graphite head gaskets for big block applications. Although they are getting harder to source. I think you made a typo with your numbers posted, did you mean your new gaskets are 20mm and your originals are 12mm? If so that is a huge difference and may not be enough sealing surface to prevent the galleys from leaking, I'd call Wiseco and see what's up. It's ok to be slightly larger but never smaller as oil flow through this area is paramount as you already know. I only use copper head gaskets (sadly, lol) and don't have any stock graphite ones that I could measure for you for reference. The one piece Cometic copper head gaskets I use has oil galley holes that run @ 12.30 - 12.35mm in dia. I am running a 1200 kit, big cams, valves, bla bla bla.

Cheers,

Doug

All the gaskets that I have seen measure 12.30mm around those studs but this is a old style wiseco gasket but the only difference is the holes do measure 20mm.I would think the same probably leak.I will have to check with wiseco.thanks.

If the hole sizes are that different, are there any holes etc that do fit to dowels or anything that will locate the gasket in place? If there's sufficient material the gasket could still seal, but you don't want it to be floating around in there.

I suspect you have a gasket set for a J model. From what I understand they use O rings. What size dowel pins do you have?
Steve

All other holes and pins are correct and it did fit fine . The gasket set does state kz900 to 1000. 1976-1980.

Yup its for a J model. Someone must have swapped it out of the packaging.

That happend to me when I ordered pistons from Z1E. Somebody switched pistons. Had to wait two weeks for another one. Started looking elsewhere for things I needed. Not the only problem but it was the last.
Steve

I had an issue with a cometic 810 gasket and have been waiting for 6 weeks

In the end it was better to modify a Japanese made aluminium gasket from the engine kit. I had it wire cut out from 66mm to 69mm for $60au. It fits much better and I,Ve been told buy some hot rod builders that the alloy gaskets are better then what wiseco supply

Looks the goods and here come the head at last