thessler

New User
Hi
I recently posted about my H with no compression.
Took it apart, rings all rusted to the pistons. Not a problem, ordered new rings. Upon disassembly I found the spacers on the bearing caps are not even.
What I mean is on cap #1 there is a significant thickness discrepancy from one cap bolt to the other . I don’t mean rod to rod I mean one side of the cap to the other. It seems to me if I was going to space out a cap I would do it evenly.
Is there a reason for this , or should I just shuffle the spacers around so the cap fits on more evenly ?
Thanks,Tom
 
I agree that the preferred method would be to space the caps evenly (or as evenly as possible) on both fasteners. While in that process, it might make sense to check the clearances, since things could have changed since it was last assembled.
 
Probably was adjusting the clearance on the rod and it was easier to add or remove the top set and not the bottom ones.
 
Thanks
I evened them out and now the crank binds. Figure it out this afternoon.
Tom
are you using plastigauge? That’s about the only way you’re going to get the clearance correct. Probably good to about .0035 which would be at the max spec for used. And yes u need the same number of shim thickness on top and bottom of the rod. Put 3 strips in the cap one in centre and one at the top and bottom then Torah the cap. Then remove the cap without any crank movement and read your results. Shim accordingly.
 
are you using plastigauge? That’s about the only way you’re going to get the clearance correct. Probably good to about .0035 which would be at the max spec for used. And yes u need the same number of shim thickness on top and bottom of the rod. Put 3 strips in the cap one in centre and one at the top and bottom then Torah the cap. Then remove the cap without any crank movement and read your results. Shim accordingly.
Plastic gauge doesn't work good on a John Deere crank as they tend to wear egg shaped. Best way is to remove shims until tight, then reinstall one on each rod bolt until it spins free.
 
As others have stated, there should always be an equal number (thickness) of shims on each side (or within 0.003”, one laminate thickness). The picture is an excerpt from an early Instruction and Parts Manual. Notice the wording “…should fit snugly, but not tight enough to bind.” I’m not a fan of using Plastigage on anything but brand new crankshafts because in an engine with some wear, it is very likely that the connecting rod journals have worn slightly egg-shaped. Thus, a Plastigage reading from one crankshaft position might be significantly different than another reading with the crankshaft rotated 90 degrees from the first reading. Also, notice the last paragraph describing the method to register the position of the cap to the rod. This will correct any possible misalignment of the cap, either up/down or in a twisted orientation, before the cap is tightened.
 

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Plastic gauge doesn't work good on a John Deere crank as they tend to wear egg shaped. Best way is to remove shims until tight, then reinstall one on each rod bolt until it spins free.
that is why i posted to use 3 strips of it in the cap. it will show 3 different thicknesses so go by the thinnest reading and go from that. cranks all wear egged shaped. i have done used stuff this way and it sure beats guessing.
 
Thanks for the replies.
I have put it all together, very happy with the crank shaft clearance .
And still no compression. I’m at a loss and don’t even want to look at it today.
Thanks,Tom
 
Thanks for the replies.
I have put it all together, very happy with the crank shaft clearance .
And still no compression. I’m at a loss and don’t even want to look at it today.
Thanks,Tom
Are your valves hanging open? Can you pressurize a cylinder and see if the air is going into the crankcase or out the exhausts or intake.
 
Thanks for the replies.
I have put it all together, very happy with the crank shaft clearance .
And still no compression. I’m at a loss and don’t even want to look at it today.
Thanks,Tom
dont know what to say s you said ur a pretty good mechanic. u give us no details on the job to go by. its either the valves are not set correctly . have you put a compression guage on it to actually check for pressure ? air just dont blow past new rings. loosen them valves off or remove the rockers to keep the valves closed. has the head had the valves done?
 
Thanks
Four new valves, cut seats. .020 rocker clearance on both intake and exhaust. I know that’s a lot but at this point more clearance Is better.
New rings, light hone on cylinder. Cam timing correct, checked dots on gear and confirmed with visual TDC and flywheel. Not enough compression to move the needle on the gauge. Yes the gauge works. I can easily hold my thumb over the plug hole during compression cycle. Charge cylinder with air on TDC and nothing blows out of intake or exhaust port, can hear some air escape into crank case. But I should still have some compression ! Ok what did I leave out?
Thanks,Tom
 
Well that would only leave the head gasket then. If those cylinders valves are closed on compression with a piston in the bore a bit before TDC and supply air to the cylinder it will push that piston back down pretty fast. Plus u are saying visual TDC. Well there is 2 TDC ‘s ,… one is compression and the other one is exhaust and if you are doing this with the rocking valves on the exhaust stroke you will have no compression. U did not specify compression stroke so I have to ask. Another question , are u a ticketed mechanic. ?
 
Yes compression stroke. Had head off three times. New gasket, and it’s the proper configuration, torqued down tight.
Yes air will push the piston down pretty fast, yet zero compression on the compression stroke. Only thing left is sleeve the cylinders and that seems to be a complete waste of time.
I might drag it around the yard today in gear and maybe everything just needs to settle in.
Don’t know what a “ticketed mechanic “ is.
went to mechanic trade school when I was young, built some pretty fast cars in the 70‘s . I don’t know new engines but know the old stuff, until now !
Thanks, Tom
 
Yes compression stroke. Had head off three times. New gasket, and it’s the proper configuration, torqued down tight.
Yes air will push the piston down pretty fast, yet zero compression on the compression stroke. Only thing left is sleeve the cylinders and that seems to be a complete waste of time.
I might drag it around the yard today in gear and maybe everything just needs to settle in.
Don’t know what a “ticketed mechanic “ is.
went to mechanic trade school when I was young, built some pretty fast cars in the 70‘s . I don’t know new engines but know the old stuff, until now !
Thanks, Tom
Did you put oil in the cylinder to see if it made pressure? No pressure on one cylinder or all? Should have said both.
 
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Do u have the correct ring end gap.the spec is .004 for every inch of bore. I have see it years ago on case 900 someone installed rings from a smaller bore. The guy had to pull it should the yard to get it started. But it still ran. I replaced the rings with the correct ones and it would then start east. I would drag it around and see what it goes. Just makes no sense at all to have 0 compression.
 

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