'48 C60 engine rebuild

[phill_mi]

My machinist did the work on my '48 Cub block, crank, valve guides and head. With other work and farm issues, and with the cold weather, the parts are sitting there begging me to get moving. I saw the "Hi I'm Pete" series that was recently posted to the Supper C board. Very informative. Thanks! I also saw another thread about an engine being rebuilt that was too tight. This brings up a couple of newby questions.

1) to start with assembly of the valve train first or the crank shaft first? Pete did the valve train first but it is a different engine with push rods. A responder to the tight engine thread suggested doing the crank first.
2) When Pete installed the crank he liberally greased and then put plasti-gauge on only the center main bearing with the grease. I was thinking it better to plasti-gauge without grease, and was planning to do everything, but that would be slower. Opinions?

Thanks; Phill

[tst]

myself I have done many cub engines
I prefer to start with the cam , then valves so can make sure they work correctly before putting in the crank, always use plasti gauge even if the crank is machined or not, grease is not good to use as it can plug a oil hole before or if it melts and cause bearing failures, use engine assembly lube

[Glen]

Hi,
They have said on here to use Plastigage on every crankshaft bearing pair, as you put them together.
The Cub service manual tells about using Plastigage.
The service manual says to wipe off all oil from the journals and bearings before using the Plastigage.
Also wipe off all oil from the bearing caps, and the places on the connecting rods, or block, where they touch together.

Below is the Cub and LoBoy service manual, it has lots of info.
I would read the engine section, section 1, before working on the engine.
There is a contents beginning on page 1 of most sections, that makes it easier to use online.

http://farmallcub.com/rudi_cub/www.clea ... index.html

This manual was made in the 1970's so it has newer, 12 volt electrical system info.

When replacing the valves or valve guides, the valve stem clearance in the guides needs checking before putting the keepers on the valves.
If the clearance is too small, the valves can stick in the guides when the engine warms up.
I remember someone on here in the past that had that problem after his engine was rebuilt.
If the clearance is too small, the guides need reaming to make the holes bigger.
I guess you had a shop do valve work to the engine, you didn't say if they checked the valve stem clearances in the new valve guides.
The head bolts need non hardening sealer put on the threads before installing them, the bolt holes go into the engine water jacket.
I use Permatex Aviation Form A Gasket liquid.

[phill_mi]

Thanks for the feedback. I have been looking at the service manual as well.
Tim when I said "grease" I meant "assembly lub". Sorry and thanks for the feedback.
Glen the machinist installed new guides, and checked the valve stem clearance and lapped the valves for me. I read the service manual a while back to see how to double check that work, but I will have to review it again. The machine shop came highly recommended by several sources including the folks at the local steam and gas tractor club, so I was glad to find someone familiar with the cub engine to do the work.

[tst]

I have many "rebuilt" engines come here after assembly with issues, most common is valves to tight in the guides so they hang up, get stuck and wrong oil pump gasket resulting in no oil pressure from cheap import gaskets

[Stoffregen Motorsports]

Doing a quick mock-up of the major components is always a good idea. Install the crank to make sure it turns. The cam too. I'll even put in one rod/piston combo without rings to check deck height, to make sure it's not too far above or below deck. You don't need to torque anything or have seals in place for a mock-up.

[john2189]

Doing a quick mock-up of the major components is always a good idea. Install the crank to make sure it turns. The cam too. I'll even put in one rod/piston combo without rings to check deck height, to make sure it's not too far above or below deck. You don't need to torque anything or have seals in place for a mock-up.

If you “install the crank to make sure it turns” you will have to torque it. I torque one journal at a time.

[phill_mi]

Tim (tst) said:

grease is not good to use as it can plug a oil hole before or if it melts and cause bearing failures, use engine assembly lube

I responded, maybe too quickly

Tim when I said "grease" I meant "assembly lub".

But I have been re-thinking that answer. I used part of a tube of Lubricate #105 "assembly grease" when I reassembled the 560 oil pump a few months back, and had planed to use that on the cub engine, which I was calling "assembly lube". But I did notice white specs floating in the oil and on the oil filter when I did the first oil change after using it. Initially I thought tst's comment above was related to not using just plain old bearing grease for assembly, but I now realize there are differences between "assembly lube" and "assembly grease", so I bought some Federal Mogul Sealed Power, which is supposed to be a tacky oil, better for bearing surfaces. I have been reading articles that advise using the #105 be used on cam lobes but the Sealed Power on bearings, and other articles say to use either everywhere. So some confusion remains, but I now have both as I start to work on reassembly.

[tst]

coat it all with the "lube"

[Gary Dotson]

I have, for a long time, used Michigan then Clevite (after they acquired Michigan) engine assembly lube. Recently, I’ve been using Lucas engine assembly lube, both seem to be very good. A lot of companies make assembly lube, so take your pick but put the white grease away, engine builders dropped that habit long ago. I use assembly lube on cam and all valve train, all bearings and seals but for the piston rings, I use ordinary light weight motor oil.

[Stoffregen Motorsports]

Doing a quick mock-up of the major components is always a good idea. Install the crank to make sure it turns. The cam too. I'll even put in one rod/piston combo without rings to check deck height, to make sure it's not too far above or below deck. You don't need to torque anything or have seals in place for a mock-up.

If you “install the crank to make sure it turns” you will have to torque it. I torque one journal at a time.

Nonetheless, a mock-up is a good idea.

Yeah, don't use grease. I use Redline assembly lube, which gets dissolved into the oil once it comes up to temp.

[phill_mi]

Thanks for the advice, but looking for more.
I noticed when looking up the torque specs for the two bolts that hold the cam shaft to the front of the block, that the heads of the bolts are marked "Fc" without any grade marks, which I take to be Grade 2. I saw some other threads which indicate an early cub like mine, '48, would have "dot marked" bolts, then came the IH mark, and then the Wc mark. As far as I can tell this engine has not been opened up for service prior to this rebuild.
When I look at Messicks parts drawing:
https://www.messicks.com/commoncatalog?vendor=cas&modelId=147340

The first item listed, but not numbered in the drawing, are the two bolts which are 5/16 - 18 x 3/4" Grade 5.

Should I be concerned about using Grade 2 bolts and go get some Grade 5 bolts?
Any ideas on the Fc mark? I assume the mfg does not really matter.
Do these bolts need sealant? as I am not sure if they go into another liquid space.
Now back to valve stem keeper gymnastics with fat digits! (even so I am making good progress)
Thanks, Phill

[Bill V in Md]

The IH Parts Manual lists these fasteners below the part (camshaft thrust plate) with an all numerical part number and a standard fastener description. The bolts or Hex Head cap screws as they are correctly called have the part number 179816 and are 5/16" - 18NC x 3/4". The lock washers have the part number 103320 and are 5/16" medium. Since there is no IH Part No. with the Letter D, R or C, I believe these are non specific fasteners and are probably Grade 2. I am not sure what the Fc marking means, but pretty sure it is not a grade designation. I believe they should be snug, but nothing to get carried away with. Should not require any sealant, but a little thread locker would not hurt.

[ricky racer]

In my opinion, grade 2 bolts are only good for shear pins...

[phill_mi]

I made good progress today, in my view, but I have a few more questions. I installed the five plugs, the valves and cam shaft, and adjusted the tappets. I then installed the main bearings dry, and two of the pistons with dry rod bearings. I then used plasti-gauge on each of these bearings. My machinist had assembled the piston, rings, and rods as an assembly I lubricated the pistons and rings before inserting them. The spec for both the main and rod bearings is .002 - .003. My questions are:
For rod bearing #3 the plasti-gauge indicated almost .0015. Is this a significant deviation from spec?
For both the #1 and the #3 main bearing the plasti-gauge tappers from .002 at the front of the bearing to about .0015 at the back of the bearing. And the #2 main bearing is .003 across the center journal. Both the main and rod bearings .010 bearings. Is there a problem indicated by this data or am I good to proceed with plasti-gaugeing the other two rod bearings and proceeding?

Another concern that I am wondering, but have not researched yet, is how do I measure the run-out of the crank shaft? A feeler gauge on the side of the #2 main bearing? I understand that measuring this value is an important factor in avoiding a rear seal failure.
Thanks, Phill