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1979 35hp how to check for warpage

N

northrivergeek

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"I removed the head due to str

"I removed the head due to stripped out bolt, outside bolt edges look flat using metal ruler, but piston areas can get a 10 - 11 gauge feeler under the ruler is this normal ? and should I clean the head with solvents carb cleaner ? before reinstalling new gasket ?"
 
You need to find a piece of gl

You need to find a piece of glass and some emery paper to resurface the head to within 0.003".No point sticking a warped head back on.Some of the torque will be wasted in straightening the warped head instead of squeezing the gasket.
 
that didnt really answer the q

that didnt really answer the question.. should the head be 100% flat all the way across all surfaces ?

or do you have a picture or diagram that shows what surfaces to check.

Also should I clean the spark plug area and water passages to remove carbon ? and what should I use to do that ?
 
It goes without saying --- THE

It goes without saying --- THESE SURFACES SHOULD BE FLAT AND CLEAN BEFORE ASSEMBLY.
 
"Here is a picture of the head

"Here is a picture of the head, the lowest places are in red the middle is the biggest gap about .007 in the middle where two pistons meet and tapers out to edges to less than .002.

London Marine mention glass and Emory paper .. I have both .. do you mean using this like a sanding block, paper wrapped over edges of glass ?
And what is the deal with glass ? why glass over so many other things that could be used ?

http://i29.photobucket.com/albums/c296/northrivergeek/johnson35head002.jpg""
 
Hey it is recommended in the m

Hey it is recommended in the manuals and it is readily available and cheap--- GLASS IS GENERALLY FLAT so that you can use it to make / and check your head for flatness to within ------ 0.003" -------
 
"isn't recommended in my m

"isn't recommended in my manual lol, I just looked never tells you how to fix the warp, just says use straight edge, I used a metal ruler, and feeler gauge, So I guess Ill get Emory cloth and a long sanding block and start workin it flat"
 
Sorry mate----- Just looked in

Sorry mate----- Just looked in a 71 50hp manual ( factory of course ) and it mentions using 120 emery cloth and glass. It has been in every manual since then.You say you are not using a factory manual???
 
"I taped down a sheet of 120 e

"I taped down a sheet of 120 emery and moved the head in a figure 8 motion until the surface had a uniformed polish to it,then finished off with 180.I don't think a sanding block will get you completely FLAT.An 18"x18" piece of polished granite or marble may suffice.FLAT is important.I believe machine shops use a steel table made for this."
 
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