Head alignment

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Wbdisco
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Head alignment

Post by Wbdisco » Sat Feb 08, 2020 12:57 pm

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...
117249B6-790E-443A-AEAE-E699ABD17CAF.jpeg
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

Chuck W.
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Re: Head alignment

Post by Chuck W. » Mon Feb 10, 2020 10:58 am

put the copper spacer back in.
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Wbdisco
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Re: Head alignment

Post by Wbdisco » Mon Feb 10, 2020 3:03 pm

It does have the genset heads with the short valve stems.

RAS1
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Re: Head alignment

Post by RAS1 » Sun May 17, 2020 9:28 pm

Chuck W. wrote:
Mon Feb 10, 2020 10:58 am
put the copper spacer back in.
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

muleman7
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Re: Head alignment

Post by muleman7 » Mon May 18, 2020 10:17 am

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.
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Chuck W.
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Re: Head alignment

Post by Chuck W. » Wed May 20, 2020 12:42 pm

'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
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.
North Alabama
Dixie Division Military Vehicles Club
former MVPA member

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