Valves sticking on new rebuild

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Re: Valves sticking on new rebuild

Postby geibes » Sun Sep 16, 2012 6:16 pm

6 out of 8 are now functioning properly!! I ended up taking the valve out and working the tappet up and down with vise grips on the wrench flats while spraying it with PB Blaster, Brake cleaner, and 3-in-1 oil. Note to self, assembly lube is not good for these parts.

beaconlight, I don't have a valve spring rate tester. They all measure slightly under the 1-31/32 free length spec so either I measured them wrong before or I overcompressed them when installing them. I have a new set on order from TM. I'm going to keep working on the two stuck tappets and install the new springs when they arrive. There's hope!
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Re: Valves sticking on new rebuild

Postby Boss Hog » Sun Sep 16, 2012 6:24 pm

the springs are not the problem, I expect there was rust or dirt on the lifter or in the bore. Assy lube would not cause them to stick that tight
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Re: Valves sticking on new rebuild

Postby Paul Wells » Sat Sep 22, 2012 8:03 am

[quote="geibes"] They put hardened exhaust seats and new guides in but I did the reassembly.

Do you know if the new valve guides were reamed? I am pretty sure new guides need to be reamed even if you use the old valves.
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Re: Valves sticking on new rebuild

Postby Boss Hog » Sat Sep 22, 2012 8:07 am

wellsknob wrote:
geibes wrote: They put hardened exhaust seats and new guides in but I did the reassembly.

Do you know if the new valve guides were reamed? I am pretty sure new guides need to be reamed even if you use the old valves.



The lifters are sticking not the valves from the info he has posted
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Re: Valves sticking on new rebuild

Postby Paul Wells » Sat Sep 22, 2012 8:31 am

The lifters are sticking not the valves from the info he has posted[/quote]

I agree there must be something (rust or deposit build up) in the tappet guides that will need to be cleaned out.
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Re: Valves sticking on new rebuild

Postby geibes » Mon Sep 24, 2012 9:00 pm

Can't understand why there would be rust or other buildup on the tappets since the engine was completely disassembled and everything was cleaned. Perhaps there was condensation from the season changes from when it was rebuilt to now but that's all I can think of. I would think the assembly lube would have kept that to a minimum also. I can't honestly remember if the tappets moved freely when I first installed them.

Anyway, I gave up trying to free up the last two (6th from the front and 8th from the front, I believe it's exhaust on cyl 3 and intake on cyl 4, sheesh I'm only 41 and I have CRS already!) after continuing to work on them for another week. I got the new springs from TM and installed them but no difference. I decided tonight to put everything back together and hope for the best. The parade is this Friday! I got the head back on, re-primed the oil pump to be sure, hooked the carb and pony tank up and polarized the generator. Guess what - it started up on the second try!!! I can tell it's running on 2 cylinders but it was a sweet sound nonetheless. It ran for about 30 seconds or so and then shut down - enough for my daughter to hear it and come running out to the barn with a huge smile on her face! I noted that oil pressure was good and it seemed to be charging. The 6th valve is not sticking open as far and I don't think the 8th one is either so hopefully with more engine heat and oil pressure they will free up completely.

I was unable to get it restarted though. The starter engages for a few revolutions but then just spins. It was rebuilt by Deputy Jailer/Podge a few years ago when I started the rebuild and he knows what he's doing so I don't think it's a starter issue but we'll see. Time to search this awesome forum for some clues on that issue. Thanks to everyone for the help and encouragement on the tappet issue.
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