8BA Basic Cam Issues That're Over My Head

L

leon bee

Well-known member
On my first flathead engine my machine shop guy, who I like and trust, got me a rebuild kit. It all seemed like pretty good stuff except the lifters, (the often discussed hollow adjustable offshore items), they seemed kinda cheap. Also included was an Isky Max One cam. That engine is a year or more done, runs great, only has about 70 miles on it. And not much idling time.

Now I've pulled that engine from my car, it's going in a pickup. I've freshened up a 53 Mercury engine and put it in the car. Looking ahead to engine #3, I decided to pull out that Max One cam and save it. This one in question is going to get some 8RT heads I collected........and also I've collected a really nice looking OEM used cam.

I measured the journal parts of both cams, right on so in the used one went. Now is where ignorance comes into play: I can't get enough clearance on the intake valves, adjuster won't screw down enough. These are those cheap hollow adjustables. I even put one in the vise and it seems like it'll break if I try any more.

I have some of the solid adjustables here, tried a couple of them- they would work alright. But I'd like some idea of what the hell is going on. I would have thought that, logically, I'd have been adjusting things the other way. I know this is wordy and not very clear, but I'm really curious. Why the trouble getting enough clearance? Any ideas, Thanks!
 
There are also lifters available with thinner adjusting screw heads to address the longer valve issues.
 
leon bee said:
On my first flathead engine my machine shop guy, who I like and trust, got me a rebuild kit. It all seemed like pretty good stuff except the lifters, (the often discussed hollow adjustable offshore items), they seemed kinda cheap. Also included was an Isky Max One cam. That engine is a year or more done, runs great, only has about 70 miles on it. And not much idling time.

Now I've pulled that engine from my car, it's going in a pickup. I've freshened up a 53 Mercury engine and put it in the car. Looking ahead to engine #3, I decided to pull out that Max One cam and save it. This one in question is going to get some 8RT heads I collected........and also I've collected a really nice looking OEM used cam.

I measured the journal parts of both cams, right on so in the used one went. Now is where ignorance comes into play: I can't get enough clearance on the intake valves, adjuster won't screw down enough. These are those cheap hollow adjustables. I even put one in the vise and it seems like it'll break if I try any more.

I have some of the solid adjustables here, tried a couple of them- they would work alright. But I'd like some idea of what the hell is going on. I would have thought that, logically, I'd have been adjusting things the other way. I know this is wordy and not very clear, but I'm really curious. Why the trouble getting enough clearance? Any ideas, Thanks!
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I'm curious, just how "thick" are your present adjusting nut heads?

Your issue does appear to be the valves are too long, for years we've recommended NOT to use the Chevy valves, they create more of a problem than they're worth. Like your situation now and also getting the desired installed spring hgts correct, it really becomes a headache when doing the final ***'y.

We have never come across any situation where there was a "need" for any longer valves than the OEM lengths, regardless of whether or not the cam base-circle has been reduced. If the adjusters are too "short" (due to the base-circle) simply use some (.060" thick) lash caps, we've been doing this for years now when some extra length is needed, which is rarely.

(Add) Over the last 40/45 years or so we've done a few units where the customer requested slightly larger (not longer) o'size valves, in this case we used the Ford 240"/300" 6 cylinder exhaust valves.

Thanks, Gary in N.Y.

P.S. The adjusting nut thickness on the Johnson's we use measures .125" thick. If it'll help, to use your lifters now you might be able to "shorten" the nut heights a bit, would only need a decent valve grinder capable of grinding the valve stem ends?
 

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The 8RT heads have the loest compression Ford makes.. As for the valves I only used them on the L-100 , 1.6 on the intakes and 1.5 on the ex. Never had a problem. Lazy I guess.
 
Thanks a lot guys. Ron: I have these nice 8RT heads and am using them since the engine is going in a truck. Using them is one of the reasons I decided to pull this Max One out and save it for the next engine.

I never thought about chevy valves. I think these said Sealed Power, maybe from Mac's. So it would be just a matter of that particular dimension on that Max One cam will accomodate the chevy valves, but the OEM cam won't? At least with these lifters? And I guess that kit included those valves cause they knew they would work with the Max One.

I'm a long time motorhead, but I sure don't know much about cams. I think I'll set these hollow adjustables aside and use the new solid ones I've picked up. It does look like the bolt head is pretty thick, didn't think to measure that.
 
The chevy valves can only be used with a cam with a small base circle like the L-100 which was very popular a few years ago, because it sounded like a rall hot engine. They worked pretty good when set up right. Back to the 8RT heads. I would suggest that you have them milled for .045" piston to head clearance. This simple modification will improve drivability and fuel mileage. Good luck
 
The reason for the issue with the lifters when going from a high lift cam to a stock cam is the change in the base circle diameter. The stock cam has a larger diameter base circle which decreases the distance to the valve. Think you would have been a lot better off leaving the Max-1 cam in there.
 
I'm sure I would have, but I want it for engine #3. And also, I'm an experimentalist on this stuff. I like to put stuff together and see how it works. "Do it once, do it right" often doesn't apply here. I AM in Arkansas. Like I said, I read this everyday and I value the posts by every one of you guys.

This particular issue is resolved by putting in one of my sets of new solid adjustable lifters. I was wanting to hoard them, but I got some more. Most interesting to me, I wouldn't even know about the chevy valve deal, and the base circle etc., without those cheap lifters.
 
Leon bee, before i had my engine rebuilt it had an 8cm cam & 8rt heads. Don't know if those heads were milled or not, but it ran REAL GOOD. It was just worn out & using oil.
I put Offy heads on the rebuild, but wonder how it would have run with the 8rt's .
Just my 2 cents, or maybe non sense....???? m
 
mfirth said:
Leon bee, before i had my engine rebuilt it had an 8cm cam & 8rt heads. Don't know if those heads were milled or not, but it ran REAL GOOD. It was just worn out & using oil.
I put Offy heads on the rebuild, but wonder how it would have run with the 8rt's .
Just my 2 cents, or maybe non sense....???? m
Click to expand...

Without checking the piston to head clearance there is no way to know what you had, so difficult to compare or draw conclusions.
 
Ol' Ron said:
The chevy valves can only be used with a cam with a small base circle like the L-100 which was very popular a few years ago, because it sounded like a rall hot engine. They worked pretty good when set up right. Back to the 8RT heads. I would suggest that you have them milled for .045" piston to head clearance. This simple modification will improve drivability and fuel mileage. Good luck
Click to expand...

The L100 is still a very popular cam , not sure how many flathead engines are built each week anywhere in the world these days but I ship 1 or 2 out somewhere in the world most weeks. I have shipped them to 17 countries in the last 4 years plus al over the great USA. Whether my KiWi-L100 or a Cam Technique L100 ( I own several of Dave’s) the base circle is typically .965 - 1.050 depending on thy donor cam as even genuine Ford varied. For a cam with.375 or so lift that’s a good sized base circle as I have many cams in my large collection by big name grinders with base circles much smaller with less lift. Not only do these cams sound like a real hot rod and as Ol Ron has stated many times, (along with many others) they run great also in almost any flathead powers vehicle.
Cheers
Tony
 
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