drilling the pass horizontle gallery (360). massive lifter clearance/leakage. I have the 5/8 long bit & the MP (2) piece copper tubing pieces/peen tool. Is dead on drilling critical? Your thoughts please. Thank you for your time.

What making you want to do this?

Possibly this?

" massive lifter clearance/leakage"

If we had all the money in the world we'd get the lifter bores sleeved, kill two birds with one stone.

Knowing you, Blazin' Bob, I would say you could do it. I suggest drilling vertically. Chrysler people have been doing this since the Stone Age. I swiped Coronet 500's post from FABO. Here it is:

"Far more time than I thought. Had some +1/64" bigger than hole drills which was not to difficult but caught each time I went through a lifter bore, but with the right speed and the right touch didn't break anything. Then went to a 39/64" drill which is normal length and found being hand held the entry diameter increased after drilling which troubled me for the final 5/8", 12" long drill so I made a jig. A steel tube welded to a plate at 90 degrees bolted to the block to get it going in straight and on center for the first 4-5" then removed it and drilled the remainder with LOTS of spray lube.

The hole from the back was bang on center the whole 10", the one from the front tailed of slightly maybe .050" off of center.

Would I do it again, Yes, knowing what I know now. Any guy who can take a 12" long 5/8" drill into that block one time, one pass is a better man than me!

I did this for the oil improvements but for protection if a pushrod failed won't lose all oil pressure.. Engine is starting of solid flat tappet the possibly solid roller next year."

Another part of the thread suggested using rigid copper tubing. As I have never done this, I don't have a comment.

R.

massive lifter clearance/leakage

I understand that, Im just wondering how he cam to that conclusion. Ive used alot of ragged out blocks before and always found options vs the tube.

Dog good info which I will read thru. Bird I preoiled with the cam/lifters/pushrods everything together & it gushed way too much.

Bird I preoiled with the cam/lifters/pushrods everything together & it gushed way too much.

Id think thats not a accurate way to gauge it since your dead heading pressure in alot of areas running the pump without much movement.

Id do some measuring if it were me, you could always bump up the pump pressure as well.

Myself I dont mind a little leakage as long as its close to spec simply because it end up on the cam.

But whatever the case im sure you will get it sorted out.

Yeah bro I would sure like NOT to do it!

Done it a few times - somewhat meticulous work. Easy to ruin a block if you are not careful. Forget to drill the right passages and you'll smoke the crank - don't laugh, saw it happen to a few guys. Forget to plug the right passages and no oil pressure - common even on stock rebuilds. Bit of relieving work required too to eliminate the super snugness the lifters will have in the lifter bores even after you peen the tube over - hand fitting each one. Not a 1 hour job or one to do with buddies hanging around or after a few cold ones. Kind of nerve wracking using a drill bit that size too if all you have is a hand held drill. Go slow as the bit will want to snag on the open spaces it breaks thru on the lifter bores.

the hardware store has a 5/8 by 17" bit for ~ $20 & that is enough length so I can make some kind of support so it drills straight. thanks for the heads up on the extra fitment needed & I read one time a guy was peening it with the same type MP tool I have & he broke the lifter wall so yes its gonna take some patience (I have that) & after 4 head gasket failures immediately upon fireup on THIS particular eng its gotta be right this time!

RR, make sure your fixturing is as ridged as you can make it, because any flex induced by it will be compounded by the length of the drill, which will flex some, even though it is 5/8", and you wouldn't think it would. if it were me, i would drill with a 39/64 [.609] drill, then ream with a 5/8" reamer, which would guarantee you a 5/8" hole top to bottom. it's very likely just using a drill of that size will result in a tapered hole just because of drill flex due to the extended length. but that would increase your tooling cost to approximately $50-60.00.[just a guess]

I admit that sometimes I am cheap. I cut a drill bit, and welded tube in-between to make a long bit extension. It worked for me, but a proper reamer is the correct way to size the oil passage.

Yeah the more I think about it the more I lean toward NOT doing it. I'll likely have to see what my psi is during breakin & noted on the reamer as I cant afford anymore issues with this eng.