Allis B Cylinder head Questions

Thanks 

When you have bad valve guides it does not necessarily mean you need new valves. Valve guides are sleeves that are pressed into the head. They are not an expensive item and is something you change all at the same time. All the valves need to be inspected and in a lot of cases do not need replaced, just seats and valves ground. 

With an overhead valve engine with bad valve guides the oil (leaks) around the valve stem when the guide has became worn oversized and the oil sets on the valve head and enters the firing chamber with the fuel mixture which causes the smoke as it burns.

What happens when the valve guides are bad. 

Ne valve guides below. 

 

Thanks Doc! That's the way it was with my 8N. Rings were bad, low compression, and the edges of the valves were worn sharp. 

The B also has less oil pressure than it used to. The needle used to be on the O when hot, now it's in front of the N, borderline in the "Too low" zone. I think I'll pull the head and check things out.

Also, grandpa said he used to rebuild his 8N every year and as part of the rebuild, put in new bearings without getting the crankshaft polished/ground. He said he just bought new bearings that were the same size as what was in it and put them in. Is that an okay thing to do? It worked for him, but I've heard crankshafts get out of round and that could cause a problem. 

Thanks

So I'm thinking my only expense will be main, rod, and cam bearings, and an oil pump kit.

Anything I'm missing?

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If I must press them out, will I be able to press them back in afterwards and they still work? Or are they a "one-time fit" kind of thing?

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CrestonM wrote: Ok, here's my next question. I have two cylinder heads. I'd like to get the rebuilt head milled down to increase the compression. I understand the valves must be removed to accomplish this. Do I need to remove everything, or can I leave the guides in? Must I press them out first? If I must press them out, will I be able to press them back in afterwards and they still work? Or are they a "one-time fit" kind of thing? Thanks

Yes every thing will need to be removed from the head. The guides can be reused if they are good but they are not expensive to replace. I don't reuse them.

When I mill a head I first clamp the firing chamber down and take just enough off the rocker arm side to make sure it is true. I then turn it over to mill the firing chamber side.

Yep! He said he rebuilt his 8N every year. Got so good he could do it in 1 day, start to finish. New pistons, sleeves, rings, main and rod bearings (doesn't have cam bearings). He was so glad to get that 8N! He said that starting when the 8Ns came out, he prayed every night that he would get an 8N. His wish came true in 1952 when he bought a 1951 8N that had been bank repossessed. Drove it home 25 miles. It was grandma's favorite tractor because it was easy to operate. He said they ran that thing full throttle plowing several hundred acres every year, plus running what he called a POS All-Crop (He is a JD and Ford guy) He said if you just have 2 acres and want something to work on all the time, use your All-Crop. But if you're serious about farming, you'll get a JD 55. He said he thought he went to heaven when he got that thing. He went through 2 of those, and one is still in the bone yard at his place. The other one he sold to a fellow who was using it on a few acres of wheat a few miles from his farm as of a few years ago. Not sure if he still uses it or not. After the 55s, he got a 95 with cab and air conditioning. Used it until 1998 when he quit growing crops and focused on ranching.