EDM holes in solid flat tappet

I have a buddy who has been in the EDM game for ages and some of the stuff he does with a drill "bit" about it the size of a hair is absolutely mind boggling. I know solid flats are available with about a .015 hole and my spring pressures are reasonable but a hole seems like a really sound idea. Any opinions/experience here? I know he would do my existing lifters for peanuts. Kinda sorry I didn't pursue this while I had the motor out this winter but wasn't planning to pull the intake. It's coming off next winter though. Hopefully no sooner,fingers crossed.

I always use the EDM with a flat tappet lifter.

Cool if you can do it yourself

I should have had him do it when I first purchased the cam/lifters but it never even crossed my mind until I was at his place recently and it dawned on me. Everything looked good when I had the pan off this winter but when I pull the intake next year I'm going to get them done regardless. Is .015 the rule of thumb or should I get creative? I'm running a Melling standard volume oil pump,will it cover the additional leakage? Thanks.

Is this what we are talking about when we discuss EDM ?

https://www.waykenrm.com/edm-machining-for-aerospace-industry.html

https://hotrodenginetech.com/edm-flat-tappet-lifters-johnson/

the tree man wrote:I have a buddy who has been in the EDM game for ages and some of the stuff he does with a drill "bit" about it the size of a hair is absolutely mind boggling. I know solid flats are available with about a .015 hole and my spring pressures are reasonable but a hole seems like a really sound idea. Any opinions/experience here? I know he would do my existing lifters for peanuts. Kinda sorry I didn't pursue this while I had the motor out this winter but wasn't planning to pull the intake. It's coming off next winter though. Hopefully no sooner,fingers crossed.

EDM holes are burned into lifter faces BEFORE they are assembled because the trash from burning the hole can now be cleaned inside before it is assembled.

If you don't mind trash being inside a lifter and hoping it never comes out; do the EDM work on otherwise finished lifters.

On a finished lifter, you would be better off surface grinding a .003"/.004" flat on the out side diameter from the oil annulus ending just before the lifter face. You can do that on hydraulic lifters as well.

OR, you can buy the tool and put a small scratch groove in the lifter bore.

I'll talk to my EDM guy. Never thought about a debris field problem. Everything I've seen him do was squeaky clean but that's an interesting alternative coming from the side. This direct oiling approach has me interested mostly because it seems to solve the problem of the lack of splash oiling on a street engine,like mine,that sees a lot of idling and plodding along. Thanks.

After some more reading it looks like doing holes in my existing lifters is not such a hot idea after all but I'm still curious about direct oiling. I've had a few SFT cams way back when and never had a lifter failure so this may all be a snipe hunt anyhow. Thanks for the input.

the tree man wrote:After some more reading it looks like doing holes in my existing lifters is not such a hot idea after all but I'm still curious about direct oiling. I've had a few SFT cams way back when and never had a lifter failure so this may all be a snipe hunt anyhow. Thanks for the input.

If the cam is broke-in with soft springs, the direct oiling will usually be helpful or even needed if the open valve spring pressure gets around 400 pounds or more.

My pressure is about 325lbs and like I mentioned both cam and lifters had a nice wear pattern. I should have measured my valve lift while the engine was out to check if I lost any or at least check my lash before pulling the rockers to see how much it widened. Motor was quiet and I did not relash for the whole summer. Well,technically until the trans suffered a RUD. I know what my lift was with the brand new cam/lifters so next time a valve cover is off I'm curious what a lift check will show.

Putting a groove in the lifted bore doesn't seem like it is going to do anything but leak oil onto the crank case. Isn't the cam lobe narrower than the lifter face?

stanger68 wrote:Putting a groove in the lifted bore doesn't seem like it is going to do anything but leak oil onto the crank case. Isn't the cam lobe narrower than the lifter face?

Scratch grooving vertically the bottom half of a lifter bore in the horizontal center of its diameter will put oil directly onto the lobe of the camshaft.

Too bad it's not something that can be done after assembly but it's a great idea if you're getting a bare block ready for assembly. Shoots the oil right on the leading edge of the lifter/cam contact area and gets drawn in. Might be even better than the hole and no expensive lifters. Between this and my over crushed rear seal I'll be a wise guy next time.

Whats involved in taking apart a solid lifter?

Tore wrote:Whats involved in taking apart a solid lifter?

Just time and ability ...

After reading this promo article,no doubt biased somewhat,(http://toplineauto.com/wp-content/uploads/2019/04/Lifter-Application-Catalog.pdf)cleaning out the lifter is only part of the trouble. There's some ugly sputtering around the hole when it's burned in a finished lifter. Maybe it matters,maybe it doesn't and cleans up just fine. These guys machine the lifter face after punching the hole which makes sense to me. I won't be the one to burn a hole in my serviceable lifters and find out the byproduct splashing around the orifice compromises the lifter face in some fashion and failure ensues shortly thereafter. Oh well. Interesting stuff none the less.

I work in a edm shop.
I ordered comp edm drilled lifters when I was swapping a cam to another block just cuz I liked the idea of direct oiling.
I checked them with a drill rod and found that 6 didnt even go thru the body. So I took them apart and finished the job. I found when I took them apart that it was obvious they where drilled after they where
assembled cuz the lifters where full of edm grit. I dont see that helping a cam break in.
So I disassembled them all and cleaned them. I also ran the lifter across a fine stone to break the deposit on the face where the drill entered.
Ive ran the lifters multiple seasons and they look great.

Interesting. Since I'm still in an "ain't broke,don't fix it" situation this direct oiling idea has been put on the back burner for now but it's definitely something I'd put into practice in the future. Judging from that lifter story I guess like a lot of aftermarket parts,as well as OE for that matter,it's always best to trust but verify. I've had a nice refresher on that lesson in the last decade since getting back into the hot rod hobby. Had my share of goods bad outta the box.

I have a Ford blue print to Johnson Lifter Co to add the hole in the face to a lifter and the date is '69. Seems Ford developed it LONG before the aftermarket began offering the concept.