Flathead Adjustable Lifter question
 

Some folks grind down the top of the lifter bore to aid in getting a wrench on the lifter bolt to make the adjustment. How much is too much to grind off. I've seen some pictures of engines in some books that the lifter bore looked to be ground down a 1/4" or even more. Won't that affect how the lifter might ride in the bore?

Re: Flathead Adjustable Lifter question
 

I just now an hour ago drilled my 16 little holes in a block for that. I'm no expert, but I have done the holes twice before and it all works great. I'll be curious what others say, but I'd rather get in there with a long drill than a grinder.

Re: Flathead Adjustable Lifter question
 

Maybe I misunderstood. But I haven't had any trouble getting a thin wrench on the adjuster bolt.

Re: Flathead Adjustable Lifter question
 

drill the hole as low as you can, especially if you have a regrind cam. a lot easier to drill the hole than to grind down the top of the lifter bores

Re: Flathead Adjustable Lifter question
 

This all depends on the cam base circle. With the higher lift cams the you have a smaller base circle and the adjuster head is lower in the bore.

Re: Flathead Adjustable Lifter question
 

Re: Flathead Adjustable Lifter question
 

This is what I realized he may be talking about.

Re: Flathead Adjustable Lifter question
 

He's not talking about the holes that are used to insert a punch/rod to stop the lifter from turning, he's talking about the fact that with a high-lift cam (which means small base circle), the adjusting nut is not up high enough to get a wrench above the lifter boss to adjust the lifter. This makes it a REAL pain in the butt in that you now have to turn the crank to get the lifter up, adjust it with a guess, then turn the crank to get it on the back of the cam again . . . then measure and keep repeating this until you get it right. This can add HOURS to the job - and lots of chances to get it wrong.

If you grind the top of the lifter boss down a bit, then you can get your wrench in there.

So, to answer the original poster's question, the amount you need to grind is strictly dependent upon your block, your cam and your lifters. I would put the cam, and two lifters, two valves (one intake, one exhaust) and see how far down the adjuster is. Then you'll now how much to grind the lifter boss.

You need to go the right depth and then wide enough to be able to turn the wrench.

Also, grind the heck out of a 7/16 quality wrench to make it your special "tappet wrench". Make it about 1/8" thick and grind the sides to give you more turning radius in the lifter bore area.

On an engine that I'm currently building with a Potvin 3/8 cam (.375 lift), it takes about a 3/16 grind on the lifter bore - the width of the boss, to make it easy to adjust the lifters.

Once you've done, you should deburr the edges.

Also, you have to thoroughly clean the engine afterwards. This includes removing the cam bearings and doing a complete soap/wash, rifle brush, etc.. The last thing you need is the cast iron filings laying around somewhere in the block - just waiting to be picked up in oil so they can wipe out your bearings.

I usually do ALL the above work - before I bring the block to the machine shop for all the boring, valve, etc.. work.

Good luck!

Re: Flathead Adjustable Lifter question
 

I use a small piloted shell mill to re move about .075/.100" off the top of the lifter bore. Makes life much easier.
Gramps

Re: Flathead Adjustable Lifter question
 

I use carbide rotary files to do my relieving of the top of the lifter bores. Then I follow up with sand-paper rolls to smooth things out and remove any sharp edges. It takes an hour or two to do this work - bit it is well worth it if you are running adjustable lifters with a small base-circle cam.

Re: Flathead Adjustable Lifter question
 

Yep' nuthin' fancy.
https://www.fordbarn.com/forum/attac...6&d=1616074264

Re: Flathead Adjustable Lifter question
 

How long are the drill bits required to drill the lifter bores?

Re: Flathead Adjustable Lifter question
 

Standard length with appropriate drill motor.

Re: Flathead Adjustable Lifter question
 

I use extended bits that allow more clearance for the drill motor. I have some 12 inches long and some around 18 inches long.

Re: Flathead Adjustable Lifter question
 

I’ve got a question about the 1/8” hole I the lifter bore. Inserting a Allen wrench to hold the lifter does that work on the newer type lifter that isn’t hollow but has shallow depressions?


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Re: Flathead Adjustable Lifter question
 

Re: Flathead Adjustable Lifter question
 

To answer your question the 1/4 inch example may sound excessive causing a loss of lifter stability but it really has no ill effect. There's almost no side loading of the flathead Ford lifter.
As an example of how the lifter bore design is more than adequate for the example above. There's a far more extreme lifter application used on the flathead when you put a set of ARDUN overhead valve heads on the flathead block. The liters required for the ARDUN conversion as close to twice the length of the flathead lifter. This additional length is required so the push rod can pass threw the original guide holes to actuate the rockers. This taller lifter increase side loading substantially due to this push rod angle location.
My experience after many thousands of miles with this additional lifter side loading has shown no additional lifter bore wear. This is of course an extreme example of possible lifter bore wear but as I wrote the bores handles all of it perfectly.
Ronnieroadster

Re: Flathead Adjustable Lifter question
 

Yes it will

Re: Flathead Adjustable Lifter question
 

I drill the holes and use a tappet wrench. All us old guys have tappet wrenches.

Re: Flathead Adjustable Lifter question
 

Hey no problem - just trying to help out and hope you didn't take it as a "poke" at you. Was trying to leave in a hurry and didn't quite lead into my dissertation in a fluid manner! Hope you didn't take it as a step on your toes - it was not meant to be. :D