lower pressure in piston on one side . model d

I recently over ran engine . now have lower pressure on one side . removed head and checked valves . apparently passed leakage test ?? had to send out to special shop that could resurface the huge sweats . reinstalled . now have the lower pressure on one side . has anyone run a leak down test and compression check on model d ? how have you fitted into the 7/8 inch spark plug hole .. normal units are 12,14,18mm ..
 
Brazing a fitting onto a sacrificial 7/8 plug that has had the ceramic knocked out of it comes to mind as a method to connect a compression tester to it.

What did you do before the valve job to determine you had lower pressure?

Why are you doing a leak down test with a newly refreshed head? Mind that grins and giggles is a valid answer, time spent working on the old girls is never wasted time. But the logic part of continuing down this road fails unless it's a double check on valve job quality.

Have you included a session of several hours of very hard work in your toolbox? I'm speaking to taking her out for a date and working the living snot out of her before you make any other decisions along the lines of machinist category. Often 4 hours of this is all that is ever required to restore these engines - a simple long hard workout.

Doing anything before the workout is not smart at all, I fear you have already wasted good money in a valve job that was not really needed.
 
I over ran engine on startup . then ran it and continually back fired on one side . I was thinking valve burnt . so took head off and had resurfaced . valves fine . put back together and turned over and lower compression on one side . I readjusted valves this morning to match up lh exh open marks . now after that I have a stuck open exhaust valve . no matter how far I turn tappet nut it now stays open .. I now have that to deal with .. what might cause stuck valve .., maybe i'll ask another question . your thoughts on this one ???>
 
Well first an awfully bad valve job might have sticking valves especially so new. How qualified are they?

If you don't use a reamer on a new guide you will have sticking valves. If you are offering valve job services and not running a proper size reamer thru a new valve guide you should not be able to call yourself a proper machine shop.

You don't seem to understand that the LH exh mark is not a guide for valve adjustment, it's only there to verify proper cam to crank relationship so your use of it is just not right. How can it be that you jumped to this conclusion? Answer is you just don't know enough about which end is up. And I've already made the same call on the machine shop you are using.

"It stays open" ----- How far pray tell?

I suspect you are not doing it right and possibly now have some bent push rods by adjusting your valves far too tight. Adjusted barely loose, you can spin the rods with thumb and finger - they should spin like a top as in smooth and easy as mashed potatoes with no lumps or bumps. Any wobble detected requires removal and a test roll across a table top.

It sure sounds like the machine shop is lacking.
They did not remove the valves?
If they did (and they sure should have), they should have noticed the sticking valve that is causing the issue now. AND the popping in the first place. Did you even mention that part to them by any chance? Because you sure should have.
Any decent shop would know enough to check for a hanging valve issue if advised about the popping issue. Then they would have repaired the issue once and for all. Just in the general disassembly for refacing, a decent shop would have detected a valve that had hanging issues and yet they did not - that's inexcusable lousy work right there.

Is the oiler dripping oil onto the exhaust valves as it should? Hard to test that right now of course, but you can remove it and apply shop air to the inlet to blow any blockage out of it as a precaution for the next time it gets fired up. You will have to operate it without a valve cover on it to verify that you have oil dripping on both exhaust valves. This may be the single causal issue entirely. A decent mechanic MUST verify oiling here, a decent machine shop would take pains to be sure his customer is aware of the same rule especially when that customer is not a professional but instead a DIY hobbyist. Set your valves at TDC compression stroke only and at .022 cold for both intake and exhaust.

Odds are quite good you may get lucky by just applying oil to the sticking valve stem now and working it with some valve rotation thrown in. I certainly would try to work it oiled for maybe an hour or two before debating to pull the head again as they do tend to correct themselves and continue to function well if oiling is returned to them. And at that point, no harm, no foul. Not even close to the end of the world either, best of luck getting this sorted out.
 
i totally agree with your posts.i was confused soon as i read the first sentence, over ran engine??? a compression check was first on the list! then go from there.
 
I am not following your post.

Engine ran good before over-running?

What symptoms occurred after over running?

I think it had lower compression on one side after event, did it have lower before, is same cylinder still low?
 
After you do your leak down, CYL at TDC both valves closed set your air at 100 lbs, You are either leaking on the exhaust valve,intake valve or piston rings. Head gasket unlikely Put your ear to the exhaust pipe, to the air cleaner pipe or the crankcase oil fill.It will tell you which is leaking compression.
 
Remove both sparkplugs. Take a Old spark plug knock center out, braze in air hose coupling. Then use pressure reg on your air hose. Set it at 50lbs. first and slowly increase to 100 lbs. Locking Brakes ? Tie it to a bigger tractor. Tractor in high gear.
 
The engine normally is limited to 900 rpm .. I started it up and rpm went way above .. I ran it around and the right#2 cylinder sounded like a shot gun blast each time .. so after a while I shut it down and figured that the exhaust valve must have bent , burnt or something . so I pulled head and took to machine shop and valves themselves were okay , so had the surface refaced and leak tested .. put it back together . now lower pressure on right side .. I set the clearance with valves all closed . I now have the exh 31 does not open until when the piston is bdc . that is about 20 degrees ( as measured by rotation angle of flywheel ( 360 degrees total ) I read that to correct must rotate the cam .. that's a lot of work and I could not believe that engine would have run with it being that far out .. so 2 problems .. one lower pressure on #2 and exh valve opening 20 degrees late .. It opens when piston bdc .. if opens at bdc then that means the power cycle fires after tdc .. know that won't work . 20 degrees prior firing okay and that is the spec ( exh valve open on mark) . so I rotated flywheel to mark and adjusted the #1 to open .. without further adjusting the other valves .. with this the exh valve remained open all rotation . returned it back to opening at bdc .. now my question is can I set #1 exh to open on mark and then adjust the other valves to open at their respecting open or close on mark or opposite side ( 180 degrees ) . instead of rotating the cam ??
 
The low pressure on #2 cylinder would indicate valve or rings .. since I resurfaced valve seats , that would leave rings .. so before I do this I will run a leak down to determine if valves or rings ( maybe the shop did not do a good job and just said it passed the leak test ..
 
The engine normally is limited to 900 rpm .. I started it up and rpm went way above .. I ran it around and the right#2 cylinder sounded like a shot gun blast each time .. so after a while I shut it down and figured that the exhaust valve must have bent , burnt or something . so I pulled head and took to machine shop and valves themselves were okay , so had the surface refaced and leak tested .. put it back together . now lower pressure on right side .. I set the clearance with valves all closed . I now have the exh 31 does not open until when the piston is bdc . that is about 20 degrees ( as measured by rotation angle of flywheel ( 360 degrees total ) I read that to correct must rotate the cam .. that's a lot of work and I could not believe that engine would have run with it being that far out .. so 2 problems .. one lower pressure on #2 and exh valve opening 20 degrees late .. It opens when piston bdc .. if opens at bdc then that means the power cycle fires after tdc .. know that won't work . 20 degrees prior firing okay and that is the spec ( exh valve open on mark) . so I rotated flywheel to mark and adjusted the #1 to open .. without further adjusting the other valves .. with this the exh valve remained open all rotation . returned it back to opening at bdc .. now my question is can I set #1 exh to open on mark and then adjust the other valves to open at their respecting open or close on mark or opposite side ( 180 degrees ) . instead of rotating the cam ??
 
The engine normally is limited to 900 rpm .. I started it up and rpm went way above .. I ran it around and the right#2 cylinder sounded like a shot gun blast each time .. so after a while I shut it down and figured that the exhaust valve must have bent , burnt or something . so I pulled head and took to machine shop and valves themselves were okay , so had the surface refaced and leak tested .. put it back together . now lower pressure on right side .. I set the clearance with valves all closed . I now have the exh 31 does not open until when the piston is bdc . that is about 20 degrees ( as measured by rotation angle of flywheel ( 360 degrees total ) I read that to correct must rotate the cam .. that's a lot of work and I could not believe that engine would have run with it being that far out .. so 2 problems .. one lower pressure on #2 and exh valve opening 20 degrees late .. It opens when piston bdc .. if opens at bdc then that means the power cycle fires after tdc .. know that won't work . 20 degrees prior firing okay and that is the spec ( exh valve open on mark) . so I rotated flywheel to mark and adjusted the #1 to open .. without further adjusting the other valves .. with this the exh valve remained open all rotation . returned it back to opening at bdc .. now my question is can I set #1 exh to open on mark and then adjust the other valves to open at their respecting open or close on mark or opposite side ( 180 degrees ) . instead of rotating the cam ??
 
The engine normally is limited to 900 rpm .. I started it up and rpm went way above .. I ran it around and the right#2 cylinder sounded like a shot gun blast each time .. so after a while I shut it down and figured that the exhaust valve must have bent , burnt or something . so I pulled head and took to machine shop and valves themselves were okay , so had the surface refaced and leak tested .. put it back together . now lower pressure on right side .. I set the clearance with valves all closed . I now have the exh 31 does not open until when the piston is bdc . that is about 20 degrees ( as measured by rotation angle of flywheel ( 360 degrees total ) I read that to correct must rotate the cam .. that's a lot of work and I could not believe that engine would have run with it being that far out .. so 2 problems .. one lower pressure on #2 and exh valve opening 20 degrees late .. It opens when piston bdc .. if opens at bdc then that means the power cycle fires after tdc .. know that won't work . 20 degrees prior firing okay and that is the spec ( exh valve open on mark) . so I rotated flywheel to mark and adjusted the #1 to open .. without further adjusting the other valves .. with this the exh valve remained open all rotation . returned it back to opening at bdc .. now my question is can I set #1 exh to open on mark and then adjust the other valves to open at their respecting open or close on mark or opposite side ( 180 degrees ) . instead of rotating the cam ??
 
it ran just fine .. then
The engine normally is limited to 900 rpm .. I started it up and rpm went way above .. I ran it around and the right#2 cylinder sounded like a shot gun blast each time .. so after a while I shut it down and figured that the exhaust valve must have bent , burnt or something . so I pulled head and took to machine shop and valves themselves were okay , so had the surface refaced and leak tested .. put it back together . now lower pressure on right side .. I set the clearance with valves all closed . I now have the exh 31 does not open until when the piston is bdc . that is about 20 degrees ( as measured by rotation angle of flywheel ( 360 degrees total ) I read that to correct must rotate the cam .. that's a lot of work and I could not believe that engine would have run with it being that far out .. so 2 problems .. one lower pressure on #2 and exh valve opening 20 degrees late .. It opens when piston bdc .. if opens at bdc then that means the power cycle fires after tdc .. know that won't work . 20 degrees prior firing okay and that is the spec ( exh valve open on mark) . so I rotated flywheel to mark and adjusted the #1 to open .. without further adjusting the other valves .. with this the exh valve remained open all rotation . returned it back to opening at bdc .. now my question is can I set #1 exh to open on mark and then adjust the other valves to open at their respecting open or close on mark or opposite side ( 180 degrees ) . instead of rotating the cam ??
 
with cylinder at bdc , the exhaust valve already open ( occurred when piston at the mark - which is before the piston reaches bdc .. with this setup the firing occurs at tdc . ( angle on flywheel is about 20 degrees offset not 180 degrees ) note the firing on #1 cylinder tdc occurs at the same time as #1 is at bdc .
 
Still working on it .. my two problems --
1. lower compression - brazing connection to old spark plug so can run leak down . will decide also if I can run with lower compression , but before that I must deal with #2.
2. the line up of #1 exhaust valve opening on mark .. discussed with old timer from Ia. his thinking was that usual way to get valve timed correctly ( on the mark) to lift the cam clear of crank and rotate back .. but.... there may be a larger problem .. that is the cam gear may have rotated on cam shaft .. it is bolted and woodruff keyed to the cam shaft .. so that's another issue ..
 

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