Valve guides

Kscha41

Member
Hello, I'm on the process in rebuilding my 58 841 diesel and right now I'm trying to get the motor back together. I'm rebuilding it all. A complete rebuild kit, new crank, bearing and gaskets. Anyway, on to my question, the head was messed up so I bought a good used one and was in the process of taking the valves out to replace them and that's when I noticed that all the valve guides where the same. Now according to what I read and parts I received, it looks like on diesel models the intake and exhaust valve guides are different vs gas motors used the same guide for both intake and exhaust . What was the reason they used different guides for a diesel motor? Can I just leave the guides in there or is it necessary to change out the intake guides to the proper ones? Thanks.
 
depends on what you mean by different. have you got both guides out to see the difference?? are you doing the valve grinding yourself also?? then there is seats to look at and grind if ok, or replace.
 
(quoted from post at 20:07:07 02/23/19) depends on what you mean by different. have you got both guides out to see the difference?? are you doing the valve grinding yourself also?? then there is seats to look at and grind if ok, or replace.
Thanks for the response. By different I mean the actual guides. On a gas model the intake and exhaust guides are the same. On a diesel models the intake valve guide is different than the exhaust. The exhaust has a big chamfer on it along with I think the intake are little longer. My original head is set up this way but my replacement head looks like the Intake and exhaust guides are the same like it would be in a gas model. Also the replacement guides that I received in my rebuild kit match my original head. So I was wondering if I have to go threw all the work to remove the intake guides and replace with the proper ones or can I just leave the other ones in there as it seemed to work for the previous owner of this head?
 
so I take it both guides take the same bore. as I am not familiar with the ford engine. but do know about head work. do u know that changing guides requires the valves to be reground also.? where is this chamfer the top or bottom? and yes I know guides. its unclear what all you are doing to this head.
 
Yes both guides take the same bore. The chamfer is at the top. The whole reason I discovered the guides was because I'm rebuilding the whole engine and the rebuild kit comes with new valves so I am installing them in the used head I bought.
 
mvphoto31912.jpg


mvphoto31913.jpg

Hopefully my pictures will show up. The first pic is my original head and guides. The second pic shows my replacement head and the guides I'm talking about.
 
Years ago the Perfect Circle Company thought they had a "better idea". They built a special valve guide seal that fit tight around the guide and had a Teflon inner seal against the valve, that require machining of the out side of the guide to except the special seal. Especially on the intake valves. That sure looks like the situation.
 
(quoted from post at 11:16:32 02/24/19) Years ago the Perfect Circle Company thought they had a "better idea". They built a special valve guide seal that fit tight around the guide and had a Teflon inner seal against the valve, that require machining of the out side of the guide to except the special seal. Especially on the intake valves. That sure looks like the situation.
Thanks for the response. From what I've read in the manual and from what you say, it looks like my original head does have the perfect circle guides. But my replacement head the intake and exhaust guides look identical. The manual calls for two different guides to be installed and even the replacement guides I received are two different. I'll try to attach another picture of the guides I have received.
mvphoto31922.jpg
 
I am not in the business anymore , but never really thought they were that much better in a Ford tractor engine. Haven't seen any for a long time. Are they still in use?
 
So do you think I'm ok with leaving those valve guides in the head or do I have to change out to the correct ones?
 

1) they do not break up and get in the oil pump...

2) it is a positive seal not a umbrella..

3) I doubt you would ever know the difference on a sound engine...

4) If the positive seal valve seals are not sized correctly for the valve it will use oil and a bunch of it...
 
(quoted from post at 19:11:44 02/24/19) If the guides are internally within tolerance, I would see no reason to change them
The current guides in the new used head are within tolerance. I guess I'm just confused because both the book and parts I received say that two different guides are to be used on a diesel engine. And in my new used head it only has one type of guide it in. I figured I would change them out now if I needed to that way I dont have to tear the engine back apart to put the proper ones in.
 

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