8BA tooling.
- Thread starter Tod
- Start date
I will chamfer the valve seats during machining like I do on my Model A iron blocks and the builder will have to seat the valves. I do not know what the cost to seat valves is. I will bore the cam and crank during machining and they will have to be line honed. I will ream the end journals (cam and crank) to within .01 and then bore the center journals to within .01. The cylinders will be bored to within .01 of stock. If someone wants larger than stock their builder will have to do it. Lifter bores will be reamed to size and shouldn't need touched. The valve guide bores will be reamed to size. Obviously, I will bore the lifter holes before reaming to make sure they are in the right spots. Same with the valve guide holes. Decks will be left a little high (say .01 or.02) like I do with all blocks I have ever made.
Tod
Ol' Ron
Well-known member
I'm glad to see this, it will make it easier for a shop to finish the block for the average builder. Will you make provisions for the 21 stud heads. Any changes to the water jackets around the intake ports for racers?. These kind of mods will increase sales. I have a fellow interested in getting one, I hope//
tubman
Well-known member
Ron,
Isn't this just what you were advising against about a page back? Maybe the changes to the intake water jackets, but provisions for 21 studs? I would think that would be a bridge to far.
I went past the intake question by accident. I have increased the intake ports and softened the turn from intake to deck surfaces. The jacket has been changed to allow more porting to my design and with little chance of break-through.
Tod
rotorwrench
Well-known member
Thanks for this info. This is all good to know. It will just be a matter of finishing and that is generally just an align hone to fit with the centers already correct. The decks wouldn't be bad either as long as the machine shop has good machinery for finishing.
Many of the later 1951 & on blocks had no valve seat inserts at all. If someone wants them, it's just a matter of counter boring for them and installing as needed. I think I would go without. The cast iron technology and composition is likely a lot better for durability that is was in the early 50s. In any case, they would likely only need the exhausts done like Ford did them for trucks in the later part of the 8BA era. It would be kind of neat cutting or grinding in seats on a block that has not yet had any. Most of the ones I've found over the years had a lot of wear on them.
Many of the later 1951 & on blocks had no valve seat inserts at all. If someone wants them, it's just a matter of counter boring for them and installing as needed. I think I would go without. The cast iron technology and composition is likely a lot better for durability that is was in the early 50s. In any case, they would likely only need the exhausts done like Ford did them for trucks in the later part of the 8BA era. It would be kind of neat cutting or grinding in seats on a block that has not yet had any. Most of the ones I've found over the years had a lot of wear on them.
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Let's hope so. My first inclination was to bash a build shop that can't finish machine one of these, but in my experience most shops aren't really engine machine shops, so I will try to help out on my end. I know 2 local shops that can't do extensive machining but they can still do quite a bit of finish work. If someone wants me to use local shops for a ready-to-assemble block that is a possibility. I have at least 4 shops to choose from.
Tod
Frank Miller
Well-known member
Ol' Ron
Well-known member
To allow a casting to offer either 21 or 24 studs, is relatively simple, Just place a bung where the 21 stud heads go. then they can be drilled and tapped. all the rest of the holes are in the same place. I used a 24 stud head gasket on the 21 stud build for the larger bore.,
Right. I just haven't done it yet. I probably will put in the bosses so it is accounted for from the start.
Tod
Bored&Stroked
Well-known member
I like the idea of the extra 21 Stud bosses - will be something that a few guys that want a "21 stud looking engine" will utilize. Obviously if one really knows how to look at an early block (starting with the integral bell housing), they'll know an engine built with this new block is not original.
Ol' Ron
Well-known member
Just think, Now the 21 stud guys can have a 258 cR 8:1 Cr engine with all stock bolt on stuff. With 8BA crank and rods. I remember putting an 8BA crank in Paul Howard's 37 21 stud engine. We were then going to do that with a Merc crank, but never got around to it. Sure miss him, RIP
Yoyodyne
Well-known member
I think the 21 stud pattern will limit the bore to about 3-3/16". That's .125 over stock 21 stud bore and the wall gets real close to the studs at the bottom of the cylinder
Bored&Stroked
Well-known member
That is probably true, but only if using the block in a 21 stud application and they are drilled out. In the case of the typical 24 stud usage, the cast bosses would be below the deck, but not used. Therefore, we can "hopefully" bore all the way to 3 7/16 and still have decent cylinder wall thickness. I'd love to go to 3 1/2", but this starts to make head gasket sealing an issue.
Hmmmm . . . maybe I'll think about high quality 3/8" 'step studs' and go to 3 1/2". I'll have to look into that!