cylinder heads

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malone748

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I am rebuilding a 4.3 the intake valves are all chipped. I need to know if a marine engine should have a diffrent valve than a car engine or was this caused by overheating. Thanks
 
Bt Doctur

Bt Doctur

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Re: cylinder heads

post a pic, seen V notches burned in them but never nicks or chips"
 
solar7647

solar7647

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Re: cylinder heads

Could have had something bouncing around in the cylinder, are there any marks on the piston or walls? But to answer the question it will depend there are like thirty different versions of that engine, so I am sure there are several different sizes of valve, pull the valve take it measurements and hit google for some research.
 
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38special

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Re: cylinder heads

Bt Doctur said:
post a pic, seen V notches burned in them but never nicks or chips"
Click to expand...

I seen that on the valves in my 3.0 also. I bought a replacement head and it came with new springs and stainless valves.
 
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malone748

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Re: cylinder heads

thanks for asking but I cannot get my camera to work. The spots are about as thick as a quarter and maybe a 16th deep on the edge of the valves. I will try to post pics if this will help. Do I need to use stainless steel valves?
 
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malone748

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Re: cylinder heads

There are no marks on the pistons or walls. I thinks when it was rebuilt the first time the valves were changed. The valves they used were not a high quality valve. It looks like a flat tip of a screwdriver blade took out part of the edge of the valve.
 
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38special

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Re: cylinder heads

malone748 said:
I am rebuilding a 4.3 the intake valves are all chipped. I need to know if a marine engine should have a diffrent valve than a car engine or was this caused by overheating. Thanks
Click to expand...

I'm going through the same process right now. Plans are to install 2.02's and 1.60's in stainless. If i have a choice and i do stainless valves are my first choice unless the engine is going to run at 1,500 rpm's all day. I'm not saying stock steel valves won't work, obviously they will and do but often don't hold up to the same exstream's that a stainless valve will.
 
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38special

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Re: cylinder heads

malone 748 said:
There are no marks on the pistons or walls. I thinks when it was rebuilt the first time the valves were changed. The valves they used were not a high quality valve. It looks like a flat tip of a screwdriver blade took out part of the edge of the valve.
Click to expand...

You might do an online search of defective valves and compare yours with the the pic's you find and the causes. Weather it was running hot, lean or out of time or they were just fatigued you know you want it right when you get it running again.
 
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malone748

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Re: cylinder heads

Took the heads to a machine shop. I was told that it was run lean, had low octane gas run through it or that the timing was not right. Thought you might like to know. Thanks for the help.
 
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