Technical Flathead Ford Lifter Clearance problem

Guys

<O</OI'm building a 52' flathead Ford engine. The valve seats have not been replaced or ground excessively. Valves are basically flush with the deck when installed. Bought a new Isky 400 JR cam and adjustable lifters. I reinstalled the valve assemblies and there is no clearance when the lifter is adjusted all the way down and the cam in on the heel of the lobe.<O</O
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The stock (un-adjustable) lifter that was in there measures 1.7425 height. New Isky Lifter measures 1.8640 when screwed all the way down. It looks like the Isky lifter should be able to adjust down further but it won't. Feels like threads are bottoming out inside.
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Have the same problem with all 16 valves.<O</O

How do I get more clearance?

 

have you contacted Isky? you might want to disassemble a lifter and make sure it is fully threaded and there is no crud in the bore. a "bottoming tap" might be needed to get full thread travel.

 

What valves are you using?

 

Yep dissassembled the lifter, threads appear to go all the way down, no crud visible. Not sure aboout running a tap down it, that might mess up the locking function, then they would come loose.

I think they are stock ford valves, they are what was in there but no way to tell.

Talked to Speedway, they said Comp Cams lifter are shorter and they are sending me a set. They are going to credit me for the old set when I return them.

 

just talked to Isky. Isky says the valves are probably not stock length. They said use the comp cams tappet if the dimensions work. They also said don't mess with the internal threads of the tappet.

Thanks guys, new Tappets will be here Thursday, will keep you posted on results.

 

On '32-50 engines, 1.700 is the low limit for a resurfaced lifter, the only number I have handy here at work. Standard length not listed, but it wouldn't be far from that.
'51 or 2--53 used a different valve...memory is shaky but I think longer lifter, shorter valve, different retainers and spring. That stuff is rare as '49-50 parts as well as Chevy exhaust valves are the common replacements...very few people seem to keep the original '52 type setup. Something seems very odd about the Isky length. I put adjustables in a '52 engine once, back when you could get the good Johnsons, pretty sure they had to screw out to fit but had no problem reaching. Do not run a tap in...adjustment won't hold ever again.

 

Also, when I worked in an aftermarket parts store and the TRW catalog still listed adjustable lifters for flatheads, they showed two part numbers; one of them was .077 of an inch longer to compensate for reground camshafts.

 

Thanks all. New tappets should arrive tomorrow, let you know how it works out.

 

If your valve stems are as long as they sound .... I hope you&#8217;ve checked installed height of your springs.

 

Yep, planning to check spring height also. That's next.

Once valve are installed, I will also need to clay the valves to make sure the new Offy heads clear. They should since they are matched to the cam.

 

Also check to see if your plugs hit the valves. I used AC45 which is shorter.

 

Guys,

The problem is solved. I used the Comp Cams tappets which were shorter.

Plugs are good, they do not hit the valves.

Thanks