Head alignment
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- G-Private First Class
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Head alignment
Still have a compression leak and I have I think found the culprit. I used some permetex spray copper sealant when I mounted the head, still no more than 25psi. I pulled the head and see that the head is not correctly sealing to the cylinder. See picture...
disregard the sealant as it will be cleaned off, but do you see where it actual looks like there isn’t contact when it is mated. I used the soap bottle and it was bubbling right in the same spot when doing the compression test. Have any of y’all seen this crap before? I guess the only thing that was helping before was the copper ring which wasn’t supposed to be there to begin with. I guess I should go with all new top end? It has been a year really since I messed with this because I’m crazy busy at work. Any recommendations on this beside all new piston, cylinder and heads? Thanks for the help-
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Re: Head alignment
put the copper spacer back in.
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- G-Private First Class
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Re: Head alignment
It does have the genset heads with the short valve stems.
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- G-Sergeant First Class
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Re: Head alignment
Chuck, I'm installing my genset head right now. I'm waiting in new lifters.
I'm curious why you would say to leave copper spacer in when using the genset heads.
Everything i read says you pull it.
Let me know before I have to tear this down a third time
Thanks
Dave
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Re: Head alignment
Please review my POST AO42 Mule vs 2AO42 Power Plant Engine Differences
viewtopic.php?f=148&t=262382
If you are using Genset Heads do not use the copper spacer. The spacer is ONLY used with the longer valves found on the AO42 Mule engine.
Yes the Genset heads can be used when rebuilding the AO42 mule engine but must be mounted without the spacer.
Torque the head nuts evenly to ensure proper alignment to cylinder lip.
The genset engines either the 2AO42 or the 4AO84 did not use the copper spacer and sealed directly to the cylinders.
The AO42 heads produced a 6.5 to 1 compression about 125psi and the 2AO42 heads produced 6.9 to compression about 145psi.
Years ago I contacted an engineer working on the Mule engine project and he said they dropped the compression to produce better low end torque because it was in a vehicle.
Review Lance's POST My first Mule M274A5 1968 SN 10797 REG #325091
viewtopic.php?f=79&t=267953&start=105
Starting with page 8 to see the damage to an engine when using the copper spacers with Genset heads.
viewtopic.php?f=148&t=262382
If you are using Genset Heads do not use the copper spacer. The spacer is ONLY used with the longer valves found on the AO42 Mule engine.
Yes the Genset heads can be used when rebuilding the AO42 mule engine but must be mounted without the spacer.
Torque the head nuts evenly to ensure proper alignment to cylinder lip.
The genset engines either the 2AO42 or the 4AO84 did not use the copper spacer and sealed directly to the cylinders.
The AO42 heads produced a 6.5 to 1 compression about 125psi and the 2AO42 heads produced 6.9 to compression about 145psi.
Years ago I contacted an engineer working on the Mule engine project and he said they dropped the compression to produce better low end torque because it was in a vehicle.
Review Lance's POST My first Mule M274A5 1968 SN 10797 REG #325091
viewtopic.php?f=79&t=267953&start=105
Starting with page 8 to see the damage to an engine when using the copper spacers with Genset heads.
Mules are my passion
www.m274armymules.com
www.m274armymules.com
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- G-Lieutenant General
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Re: Head alignment
I'll defer to Charles on this, he has much more AO-42 engine experience than I do. If he says leave it out, then leave it out.'m curious why you would say to leave copper spacer in when using the genset heads.
Everything i read says you pull it.
Let me know before I have to tear this down a third time
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