engine assembly question

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Dave (69 lo-boy)
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engine assembly question

Postby Dave (69 lo-boy) » Sun May 03, 2015 7:04 pm

I am putting my engine back together, but it has been months since I tore it down.
So far I have installed the crank, after checking with plastigage for clearance and then putting assembly lube on the journals.
I have installed the lifters and camshaft (with assembly lube) and the timing gear (with the marks aligned).
So far so good.
I plan to lap the valves and then put in the springs and keepers and adjust for clearance.
What should be done next, and what is the best order to put everything on so that I don't have to undo anything?
New domed pistons and rings too.
I have built a lot of engines, but never a C-50 (or any tractor engine).
Any advice from people who have done this are quite welcome.
Thanks, Dave

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bob in CT
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Re: engine assembly question

Postby bob in CT » Sun May 03, 2015 7:15 pm

Sounds like you are doing fine, although I would lap the vales in a bare block and number them. That way you can clean out any lapping compound before you start assembly. Just be careful with your cleaning and you will be fine.

Assemble your oil pump and lap the pump body and both gears together until they are all flat and on the same plane. I use some adhesive-backed paper on a flat surface-an old window works in a pinch- and just stroke it back and forth until the gears are level with the housing. The gasket will provide the proper clearance.

Make sure the numbers on the bearing caps match and that they are all on the cam side of the block. Very important for the main bearing caps as they are align-bored as an assembly.

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Re: engine assembly question

Postby Jim Becker » Sun May 03, 2015 7:27 pm

bob in CT wrote:. . . just stroke it back and forth until the gears are level with the housing. . . .

Probably doesn't matter much, but moving in a figure eight pattern should be the best method.

Dave (69 lo-boy)
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Re: engine assembly question

Postby Dave (69 lo-boy) » Sun May 03, 2015 7:38 pm

Thanks Bob and Jim.
That is why I asked here.
You are right, it would have been better to lap first, I am not used to working on flatheads, I will be careful to wipe all of the lapping compound off.
It is on an engine stand so I can turn it upside down and rinse with wd-40 or carb cleaner when I am done.
I did put all of the valve train in 8 separate baggies containing the lifters, valve, spring and keepers from front to back numbered accordingly.
Should I put a dab of red loctite on the connecting rod bolts when I torque them, since it is only 16 lbs. of torque?
Keep those suggestions coming!
It will be a couple of days before I have time to work on it again.
Thanks again,
Dave

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Re: engine assembly question

Postby BigBill » Sun May 03, 2015 10:45 pm

I put the engine assembly lube(moly) on the valves/guides, burnish it into the cylinder walls and piston skirts, lifters, cam lobes. Gear teeth etc. I oil the valve seats. I oil the cylinders and pistons during assembly.
I'm technically misunderstood at times i guess its been this way my whole life so why should it change now.

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Re: engine assembly question

Postby lombard » Mon May 04, 2015 3:46 pm

PUT A SQUIRT OF OIL ON TOP OF EACH PISTON THEN TURN IT OVER BY HAND 2 OR 3 TIMES TO GET THE
WALLS OILED UP-----I DO THIS IF AN ENGINE HAS SET FOR 6 MO. OR MORE ------IT HELPS TO BUILD UP
COMPRESSION------I LEARNED THIS CRANKING THE OLD FORDSON-----


THANK YOU
LOMBARD

Dave (69 lo-boy)
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Re: engine assembly question

Postby Dave (69 lo-boy) » Mon May 04, 2015 6:24 pm

I lapped the valves today, my suction cup was too big so I used the method I found here about using twine wrapped around the valve stem.
I did not have a helper to push the valve against the seat (I did not want to use my nose!), so I used a stick of wood about 6 inches long and drilled a hole near each end and threaded the twine though the holes and knotted it. By pulling back on the stick and rocking my hand I was able to use only one hand to rotate the valve back and forth and used my other hand to push down with a small dowel. It worked just fine!
As to the oil pump, I checked with a straight edge and the gears and body of the pump were level, I suppose I could make it perfect but when I put the gasket on there will be a few thousands of clearance anyway.
Now I need to think about putting the pistons and rods together, and make sure the dome on the piston is turned the right way.
Thanks all.
Dave

Dave (69 lo-boy)
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Re: engine assembly question

Postby Dave (69 lo-boy) » Tue May 05, 2015 6:36 am

lapping valves with twine.
Image
Image

bythepond88
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Re: engine assembly question

Postby bythepond88 » Tue May 05, 2015 11:38 am

That's very clever, Dave. I think this should be a candidate for Tip of the Week.
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Mike in Louisiana
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Re: engine assembly question

Postby Mike in Louisiana » Wed May 06, 2015 9:26 am

You said new domed pistons. If you are changing from flat to dome MAKE SURE they do not hit the head.
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Dave (69 lo-boy)
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Re: engine assembly question

Postby Dave (69 lo-boy) » Wed May 06, 2015 10:08 am

"If you are changing from flat to dome MAKE SURE they do not hit the head."
Will do Mike!

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Re: engine assembly question

Postby Lee_Petrie » Wed May 06, 2015 10:54 am

Hi Dave , I realize that most of the members don't have , valve grinding and seat cutting equipment, to do it properly ! But at least take the project to someone ( or have them come over ) to have it done correctly , with all the time and monies you spent , so far ! I've done quite a few engines, the 3 angle seat cut , is the only way to go , how else would you get a "true" round seat match , valve to seat mating, with the correct width of contact , and not too wide , so carbon would not build up ( Cub is great for carbon to begin with), causing the valve failing to fully to close , in the future ? Without a good valve/seat surfaces to completely close the valve (tight), the domed pistons and new rings are just a "band-ade" attempt, to restore your good compression back ! Just a thought , it's you time and monies , and having to take it apart later ! Lee Petrie , Joliet, IL.

Dave (69 lo-boy)
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Re: engine assembly question

Postby Dave (69 lo-boy) » Wed May 06, 2015 12:22 pm

Lee,
The engine had good compression before the rebuild, as a matter of fact the machine shop checked the bores and said it did not need boring and there was almost no wear, and the cylinders are not tapered or out of round. The lapping shows the contact area to be very narrow and even and the seats look good. I am amazed at how clean the interior of the engine was after 45 years. I am rebuilding because of a spun bearing.
Thanks,
Dave

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Lee_Petrie
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Re: engine assembly question

Postby Lee_Petrie » Wed May 06, 2015 1:04 pm

Hi Dave,
Thanks for the fast reply, I only make suggestions , on what I've found in my other valve/seat restorations ! Just how wide is the "mating surface ? You said "narrow", is that the thickness of a (fairly new dime ) ? Is the same width , evenly on the valve and the seat ( all the way around ) , burnt & undercut areas are often seen, when doing the under-cutting ( seats) and the valve grinding restorations, that can't be seen , with the normal eye !
Good luck with your engine restoration . Lee Petrie, Joliet, IL.

Dave (69 lo-boy)
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Re: engine assembly question

Postby Dave (69 lo-boy) » Wed May 06, 2015 1:48 pm

Lee,
I am frankly amazed at how little wear there is on this engine, and the mating area is about 1/16" or less and even all the way around, and I see no pitting or burning.
Thank you for your excellent advice about valve seating, if I saw any indication that it was necessary to take it back to the machine shop I would not hesitate to do that.
Dave


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