Should I replace this cylinder head?

[EatPreyMow]

This is a 656cc Briggs 40 Intek V-Twin engine that I'm repairing for a friend. He's been running it for years loaded with mouse nests and they had chewed through the spark plug wire to cylinder #1. Mouse urine has dissolved a good portion of the topside cooling fins.

He really needs this soon and is hesitant to put money into it. If this were mine I would replace the cylinder head but he doesn't mow much area with it, maybe 1/3rd acre. Even if there’s enough cooling capacity I’m worried the aluminum has weakened too much.

Should I roll the dice or pony up the cash for a used head?

 

[ILENGINE]

My biggest concern would be valve guide locations and have they migrated due to heat. The corrosion on the surface may of caused some damaged, but nothing to loose in running it if the guides are fine.

 

[EatPreyMow]

My biggest concern would be valve guide locations and have they migrated due to heat. The corrosion on the surface may of caused some damaged, but nothing to loose in running it if the guides are fine.

Great, I'll check the valve guides tomorrow morning. Is it enough to just pull the valve covers and check for how proud the guide stands of the head surface?

 

[ILENGINE]

@EatPreyMow It is that easy. Make sure the guides haven't walked out. They should be the same height between both valves. No guarantee that they won't walk later but if they are fine now just run it.

 

[slomo]

If the fins are gone, I would replace. These are air cooled engines. They get to full steam in under 2 minutes. No need to measure valve guides. Keep running it and you will have guide issues, valve seats popping out and so on.

slomo

 

[reynoldston]

This is a 656cc Briggs 40 Intek V-Twin engine that I'm repairing for a friend. He's been running it for years loaded with mouse nests and they had chewed through the spark plug wire to cylinder #1. Mouse urine has dissolved a good portion of the topside cooling fins.

He really needs this soon and is hesitant to put money into it. If this were mine I would replace the cylinder head but he doesn't mow much area with it, maybe 1/3rd acre. Even if there’s enough cooling capacity I’m worried the aluminum has weakened too much.

Should I roll the dice or pony up the cash for a used head?

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If it was mine I would run it till it gives trouble, but seeing it is a customer it would be the owner's responsibility as to what to do.

 

[EatPreyMow]

I finally found a cheap used cylinder head to replace the bad one. I just fix these as a hobby and this was for a friend, so I didn't want him to have to haul it back over to my place. Total cost for the used head and a new gasket? $51 with tax and shipping. Tolerances on the new used head were better than on the original head.

He will now keep it in his garage rather than storing it in his horse barn.