NOS 8RT camshaft

[GB SISSON]

Originally Posted by 38 coupe

Now we need to figure out what valve lash this cam is designed for.
The earliest 8BA cams used the same lobe design as the 38-48 cam.
The later (late 1949 and on) cams had a new design lobe with different "ramps"

The lash is different between the two cam designs:
early intake: 0.010-0.012
early exhaust: 0.014-0.016
later intake: 0.013-0.015
later exhaust: 0.017-0.019

Looking through the 49-51 Ford F-Series Truck Shop Manual it shows 8RT part number camshafts use the later lash settings. Anyone have any other information?

Wow, great detective work. I was well aware of the settings and how different they are. Now we add in the rotator style valve assemblies on top of that. I did receive a PM about a method of determining lash on an unknown cam, but with my limited knowledge on the subject of camshafts I was hoping I might find something in print, since we DO know what this cam is labled and it is clear that it hasn't been altered. Scary thing is I'm leaning towards Ford lifters and I can't adjust out the tapping if needed. Maybe this is a clear case for adjustablkes.... I have 2 sets of used hollow johnsons.

[rotorwrench]

This link has info but I didn't see anything about the 8RT.
https://www.fordbarn.com/forum/showt...9029&showall=1

Some of the parts with odd prefixes are follow on replacement parts. The 8RT cam may have been a replacement for trucks. A lot of trucks had 8BA cams but after the EAB and EAC part change in 1952, the 8BA and 8CM parts were likely obsoleted so the later cams were called out as replacements. Sometimes they just made a new prefix for them. The EAB cam was designed to give a bit more torque than the earlier 8BA cam.

[GB SISSON]

Originally Posted by rotorwrench

This link has info but I didn't see anything about the 8RT.
https://www.fordbarn.com/forum/showt...9029&showall=1

Some of the parts with odd prefixes are follow on replacement parts. The 8RT cam may have been a replacement for trucks. A lot of trucks had 8BA cams but after the EAB and EAC part change in 1952, the 8BA and 8CM parts were likely obsoleted so the later cams were called out as replacements. Sometimes they just made a new prefix for them. The EAB cam was designed to give a bit more torque than the earlier 8BA cam.

Thanks! Lots of good info here. .

[Ol' Ron]

Boring & stroking an engine also increases the compression ratio as well. This will add more torque than cam swap. also consider NO 239 ci engine makes more than 80 HP in stock cindition, and this is with out generator and fan, JWL proved that/
Gramps

[GB SISSON]

Originally Posted by Ol' Ron

Boring & stroking an engine also increases the compression ratio as well. This will add more torque than cam swap. also consider NO 239 ci engine makes more than 80 HP in stock cindition, and this is with out generator and fan, JWL proved that/
Gramps

I have never thought about that increased compression Ron. Longer stroke, larger bore but same combustion chamber. And it gets that right outa the chute! Or I guess you hot rodders say right off the line

[Bored&Stroked]

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You're going to have a great engine and you'll be surprised how much power it has down low . . . you'll soon be a dyed in the wool hot-rodder! LOL

[GB SISSON]

Originally Posted by Bored&Stroked

You're going to have a great engine and you'll be surprised how much power it has down low . . . you'll soon be a dyed in the wool hot-rodder! LOL

Oh great, a new can of worms opens up, or is it Pandora's box? Next thing ya know, I'll be installing dropped spindles on the woodie. I actually do envision dual exhausts though, but I only have one old swingset frame in my pile, so might have to go single.

[cas3]

Save the swing set frame for the hillbilly paint booth like I got. Hang lots of parts!

[GB SISSON]

Originally Posted by cas3

Save the swing set frame for the hillbilly paint booth like I got. Hang lots of parts!

Sounds like a good idea Skip. Truth be told, I wouldn't really want to skimp on the exhaust for this project. I have been enjoying working on this engine with the best parts I can come up with. So far I have found a lot of really good pieces here on shelves at the shop and online. I have NORS main bearings from The Barn's swap meet section, rod bearings from Van Pelt Sales, Gaskets from Olson's Gaskets,Cam bearings, reconditioned rods, and pistons and rings fitted by Wes at the machine shop. I have a friend here who runs a very well equipped auto repair shop which includes full custom exhaust service. Don't be too surprised if I have him bend something up for me. With all the help, direction and encouragement I have been getting here, I feel I'm really gonna have something that will stand the test of time. Thanks to all who have steered me in the direction of a high quality, if not all brand new, engine build. GB