Ford 8n Cam Bearings

I recently started to rebuild my 1952 ford 8n, starting with the engine. This is my first rebuild of any kind but i pick up on mechanicals very fast. I know that these engines did not come from the factory with cam bearings inside but mine does have them so it must have been line bored at on time. The bearins they used are solid steel, which i have pulled from the motor for inspection. I have a brand new cam going into this motor and don"t want to ruin it, nor do i want to have low oil pressure because i did not put new cam bearings in when i rebuilt the motor. I am replacing just about everything in the motor so it would be a shame not to replace these as well. I believe the specification for the maximum clearence is .005" and i have more than that if i was to reuse the old steel bearings. They measure roughly .008 to .01 over the cam journals. If anyone has any knowledge of what to do or where to acquire cam bearings for these motors it would be greatly appreciated! Any information would be helpful!

If you can't find them why not have them made machine shop?

Machine shops have parts reference catalogs, Sealed Power, for example, that list many of their products by dimension.

I'm NOT sure about cam bearings, though, I'll look at some catalogs later, if I remember.

What somebody probably did was to look at such a catalog and found some bearings the correct dimension to fit the cam, then bored the block to accept them. That's what you are going to have to do... search by dimension.

BTW, measuring the ID of the bearings when the are pressed out of the block is nearly meaningless, as their ID's will "shrink" when pressed into place.

Check with the Ford tractor dealer. Even though they don"t have them, they may know what to use.

You have stated that just about everything is going to be new in the engine, but you did not specify exactly what was being replaced, that brings up the following questions;

1) was the engine taken out of the chassis and to a machine shop for inspection

2) did you have a machine shop check or perform any mill work on the block, cylinders, valves, crankshaft etc.

3) if no, then are you certain that neither the head nor block needs milling

4) did you have the block and head boiled out and magnafluxed

5) are you going to replace the complete valve train

6) are you going to replace the rod and main bearings

All of the above requires machine shop work and is necessary if you want everything to be installed correctly according to the manufacturers specifications, as well as certifying that there are no cracks nor other problems anywhere in either the block, head, valve train, camshaft and crankshaft.

Since there is evidence that the camshaft previously had oversize bearings installed, then it would be only sensible to assume that the crankshaft and/or rod bearings may well have been also replaced at the same time.

It would also be likely that the crankshaft may have been turned/milled as well.



Scott

(quoted from post at 10:15:01 01/03/11) I recently started to rebuild my 1952 ford 8n, starting with the engine. This is my first rebuild of any kind but i pick up on mechanicals very fast. I know that these engines did not come from the factory with cam bearings inside but mine does have them so it must have been line bored at on time. The bearins they used are solid steel, which i have pulled from the motor for inspection. I have a brand new cam going into this motor and don"t want to ruin it, nor do i want to have low oil pressure because i did not put new cam bearings in when i rebuilt the motor. I am replacing just about everything in the motor so it would be a shame not to replace these as well. I believe the specification for the maximum clearence is .005" and i have more than that if i was to reuse the old steel bearings. They measure roughly .008 to .01 over the cam journals. If anyone has any knowledge of what to do or where to acquire cam bearings for these motors it would be greatly appreciated! Any information would be helpful!

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Measure the OD - you know what the ID is supposed to be. You say they are solid steel - are you sure about that. Camshaft bearings are often one piece lined steel inserts. Check the inside of the bearings for evidence of a coating. One alternative would be to install bronze sleeve bearings in place of the old steel ones. If you are near to me (Frederick, MD) I can help you out.

TOH
301.655.0631

I can only say that .8 to 1 tho is a issue,,, I spec you will suffer with low OP numbers,,, it will run along time like that but you will never be satisfied knowing that you loss of OP was rite their in your hands and you did not take care of it...

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I've read someplace that the flathead ford camshafts have the same journal size at the 8n camshaft thus allowing you to use the bearings for a v8 flathead.

I actually did alittle research and it does appear that if I am reading the catalog correctly that the cam journal size specified by Clevite does fit the little N's which specify the cam journals at 1.797. http://mahleclevite.com/publications/EB-10-07.pdf Take a look on page 305 tab 65 for the flat head ford info, looks the same to me. I'm not a machinist so don't take my word as absolute, but I would at least ask your machine shop about this and get their take on it.

(quoted from post at 00:07:06 01/05/11) I've read someplace that the flathead ford camshafts have the same journal size at the 8n camshaft thus allowing you to use the bearings for a v8 flathead.

I actually did alittle research and it does appear that if I am reading the catalog correctly that the cam journal size specified by Clevite does fit the little N's which specify the cam journals at 1.797. http://mahleclevite.com/publications/EB-10-07.pdf Take a look on page 305 tab 65 for the flat head ford info, looks the same to me. I'm not a machinist so don't take my word as absolute, but I would at least ask your machine shop about this and get their take on it.

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Good work - I scanned through the Clevite catalog for cam bearings that size the last time this topic came up but gave up pretty quickly. Never thought to check the flat head V8 specifically - Duh!!

I just checked an old cracked 1941 9N block I have in the shop and the journal widths appear to match as well. Looks like Clevite SH-21S is a winner - $40-50 for the set. While I was at it I measured the front journal diameter on that old block - a good .005 oversize. Little wonder we hear so many complaints about low oil pressure after major rebuilds.

TOH

Wow, this forum has an amazing amount of support and knowledge. Its good to know so many people are out there and are willing to help. I haven"t been on here for a few days but thanks everyone for your support. Here"s an update.

Just to answer some of the questions out there about what is being done to the motor.

I complete tore it down and i"m replacing the following:

Camshaft
Entire valve setup (auto-rotating)
Sleeves
Pistons
All bearings

I did take the motor to a local machine shop and had it dipped in the hot tank. I also took the crank in and had it turn down .01 under on the rods and mains.

I also agree that it seems foolish to rebuild the entire motor from the ground up and not replace the near impossible to find cam bearings. I will be checking up on the ones that were linked on this site by a couple of you guys. I believe that the set that was used in this block were made in a machine shop, as they have no markings of any kind on them! I also did learn that measuring the ID when they are out of the block in meaningless, which also someone stated on this forum, because when you drive them back into their repective homes they shrink. This also causes a problem because they will NOT fit my new camshaft when when are in the motor.

I now know that i must have new bearings when i put it back together. Either find and buy something that works, or have them made it will have to happen. It is what it is and i"m not getting to frustrated about it, although my dad (who i am rebuilding for as a gift) is getting a little discouraged.

I certainly will keep everyone posted on the situation. I also may have to take the block down to the machine shop again and have him check that the bore is good and straight and maybe have his help with these darn cam bearings.

Once again, thanks to everyone for the help!

(quoted from post at 00:16:52 01/08/11)

I also did learn that measuring the ID when they are out of the block in meaningless, which also someone stated on this forum, because when you drive them back into their repective homes they shrink. This also causes a problem because they will NOT fit my new camshaft when when are in the motor.

I now know that i must have new bearings when i put it back together. Either find and buy something that works, or have them made it will have to happen. It is what it is and i"m not getting to frustrated about it, although my dad (who i am rebuilding for as a gift) is getting a little discouraged.

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I would not be surprised to learn your old cam bearings were made undersize to fit a reground camshaft and that is why they do not fit your new stock cam. The OD on the OEM cam bearings for the Ford 239/255 CID flathead V8 (Clevite SH-21S) is 1.9275/1.9285. If that is the same or larger than the ones that you took out I would suggest you go with the OEM bearing. It's a standard bearing readily available for a modest price and should work perfectly in this application. If the ones in your block are smaller you will have to have it line bored for the OEM bearing. If the OEM bearings are too small there is no need to make new ones to replce what you already have - simply line bore the old ones to get them to fit the new cam. If you had new ones made you would still have to line bore them after installation. If you can use the OEM bearings next time it's just R&R the bearings :roll:

TOH

All of these replacement cam bearings for the old flat head ford engine have two opposing holes that would feed and remove the oil going to the camshaft. The 8n camshaft is only fed by one side. All your oil is transported down one small oil gally. If i did put these bearings in and made sure that one of the holes lined up with the oil gally and the other one would just have a piece of the block behind it would that hurt anything? I can't imagine that it would hurt anything but like i said this i my first rebuild. Suggestions?

(quoted from post at 11:52:28 01/08/11) All of these replacement cam bearings for the old flat head ford engine have two opposing holes that would feed and remove the oil going to the camshaft. The 8n camshaft is only fed by one side. All your oil is transported down one small oil gally. If i did put these bearings in and made sure that one of the holes lined up with the oil gally and the other one would just have a piece of the block behind it would that hurt anything? I can't imagine that it would hurt anything but like i said this i my first rebuild. Suggestions?

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The holes allow oil in - not out. As long as one lines up with the oil galley in the 8N block you are good to go. If not drill a new one that does. I'd suggest letting the machine shop deal with this. You can mention the V8 bearings as a possible fix but it's conceivable they won't work for some reason The shop deals with this sort of thing all the time and can help you find the best solution. Bottom line is it's nothing that can't be solved with $$$$

TOH

Hokie,

Thanks for the heads up. I'm takin the top of the block back down to the machine shop this week and letting him figure this one out. He'll know alot better than me what to do. I will show him the bearings that you guys have suggested and maybe that could help him along the way to. Looks like this is going to cost some serious $$$ but i don't have a choice at this point.

(quoted from post at 17:05:18 01/09/11) Hokie,

Thanks for the heads up. I'm takin the top of the block back down to the machine shop this week and letting him figure this one out. He'll know alot better than me what to do. I will show him the bearings that you guys have suggested and maybe that could help him along the way to. Looks like this is going to cost some serious $$$ but i don't have a choice at this point.

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The cam journal has a V notch cut into it,,, make sure you round off the notch are it could cut into the bearing. I never gave this much thought till I read this, I brought a cam off ebay, a nice cam but the V notch's have all been brazed up real nice could it B that that engine was running bearings and this was their was to take the V notch out....

I posted this several years ago but no one had a answer for it... a pix in the archives and maybe I will get a better one for ya...



https://photos.yesterdaystractors.c...arameter=hobo,nc&mode=All&what=pieces

(quoted from post at 13:33:13 01/09/11)

(quoted from post at 17:05:18 01/09/11) Hokie,

Thanks for the heads up. I'm takin the top of the block back down to the machine shop this week and letting him figure this one out. He'll know alot better than me what to do. I will show him the bearings that you guys have suggested and maybe that could help him along the way to. Looks like this is going to cost some serious $$$ but i don't have a choice at this point.

Click to expand...

The cam journal has a V notch cut into it,,, make sure you round off the notch are it could cut into the bearing. I never gave this much thought till I read this, I brought a cam off ebay, a nice cam but the V notch's have all been brazed up real nice could it B that that engine was running bearings and this was their was to take the V notch out....

I posted this several years ago but no one had a answer for it... a pix in the archives and maybe I will get a better one for ya...



https://photos.yesterdaystractors.c...arameter=hobo,nc&mode=All&what=pieces

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I'm thinking someone had oil pressure problems and was grasping at straws trying to stop any pressure loss out those slots. I've seen similar notches in cam bearings themselves - never understood what it was supposed to accomplish - spread out the oil delivery over the face of the bearing maybe???

TOH

Round them with a small file or grinder?

Have you reassembled the engine ? What was your oil pressure ?
-- Mark

What was your oil pressure before?

-Mark

That notch helps cool the bearing by incrementally moving oil. I wouldn't round it or fill it. I'd recommend polishing it's edge by lapping or crocus.