Engine rebuild 1949 Cub.

[bob in CT]

If the machine shop put in new guides and valve seats and lapped the valves, you should be all set. They would not install a guide and let it go with a sticking valve.

[BullDAWG]

If the machine shop put in new guides and valve seats and lapped the valves, you should be all set. They would not install a guide and let it go with a sticking valve.

Maybe I read his post wrong but it sounded like the machinist lapped the old valves and he just got the new valves . If they (the machinist) got the new valves then he should have checked all the clearances before he lets you have it. Though checking behind him is always a good idea as we are all human and have bad days or forget (did I torque only 3 or all 4 of the rods n main bolts)

[Flyboy]

Yep, I'm all set. Cylinders bored, valve seats in. New valves lapped. Time to start putting it all back together. Waiting for my 30 over Pistons to get here. I have no idea why my autocomplete likes to capitalize the Pistons. I was never a Detroit fan.

[Flyboy]

Block needs to be painted and then I can begin assembling the engine. Mulling this over in my head I was planning on the following sequence,

1. Drop in tappets
2. Install camshaft
3. Oil pump.
4 install crankshaft.
5. Install connecting rods/ pistons
6. Install valves and associated hardware
7. Install front cover on engine

Any warnings or recommendations with my proposed sequence?

[Eugene]

Before you start reassembly, check to see that the oil galleries are plugged. Specially the plug that goes under the cam shaft gear.

4, 2, 3, 1, 6, 5.

Idler gear, governor drive gear. 7.

[artc]

i'm coming in late to this thread. it sounds like you have new intake and exhaust seats and a rebore to .030. with new valve guides it is necessary to get adaquate clearance to the valves, and that means a little more than the machine shop would leave normally for a small block Chevy. in these slow turning engines a little more clearance is necessary. so when you install the valves make sure they rock a little in the guides, or ream them a bit.
you may also need to use the NewWay seat tool on the inserts, as they are not perfect from the factory. b e sure to lap the valves to see where the contact point is.

you are good on your assembly procedure, just be sure to use assembly lube for all the rotating parts and be mindful of wear on the front gears. when you get ready to put the head on, use some oil on the pistons to lube the rings.
oh and make sure all the oil plugs are installed, as Eugene said

[Flyboy]

Thanks for the advice.

[Charles (49) Mo]

Go to the top of this page and click on "PDF Manuals" and look around. Lots of service manuals and parts info in PDF format and its all free, thanks to a few members

[Flyboy]

I just got my .030 overbore aluminum Pistons/rings/pins from Steiner. It is item number IHS3238. No directions for the product. I figured out which are the oil control rings by the shape and number provided. I think that the thin rings go above and below the squiggly ring in the bottom slot if I recall correctly.

Then there are 4 rings that are aluminum colored, and 4 rings that look like black anodized finish. I don't see any markings that would indicate which side is supposed to be installed up on the black ones. On the aluminum finish rings, there is a segment about 3/8ths inch long that has a polished look to it (except one where the slot appears to be cut through most of that segment).

Next, looking into the bottom of each piston, there is a red ink mark on one side of the casting that holds the piston pin. Should that be toward the front of the engine?

Of course I waited until the evening to start working on these, so Steiner is closed for the day.

[Flyboy]

Pistons installed today. The crank journals came in at .006, .004, and .006 (plastigauge), and will have to wait a bit for new bearings. I need to get this thing together before the winter hits. I finally feel like I am going in the right direction. As I disassembled the tractor, I kept finding more things that needed to be done. There is still lots of work to do, but I am finally getting started reassembling. What a nice feeling.

Next, I have to find a valve spring compressor.

[Eugene]

Next, I have to find a valve spring compressor.

Sears has an inexpensive valve spring compressor with adjustable jaws and adjustable deck height. It takes a 2 x 4 block of wood on the head to work on the Cub engine

[Flyboy]

Thanks Eugene. I almost bought that one, but the local rent a tool had one for $10, so I picked it up. Valves went in fairly easily. I had my mechanic neighbor come look at them to see if there were any glaring errors. No errors, so camshaft goes in this afternoon after I return home from town.

[Flyboy]

The throwout bearing arrived Friday. The center does not rotate by hand. I see a grease zerk on it just like the original, so I figure it has to turn. Is it just a bearing material that does not rotate? If so, why the zerk?

[bob in CT]

It is a graphite bearing. it does not rotate but it is porous and that is what the grease is for. Use inexpensive grease, because you want it to bleed out if the graphite gets warm, so avoid high temperature and waterproof greases.

[Don McCombs]

In addition to Bob's comments, soak the entire throwout bearing in motor oil for a week or so prior to installing. Even if it looks oily out of the box. Then grease it according to Bob's suggestion.