Lifter Block Bolt Hole Repairs

[51Hog]

My rear lifter block was leaking oil at the base of the inside front screw head. You can see the soap bubbles in the pic.
I pressurized the oil system with 20 lbs air to find my leaks.

pressure.JPG

lifter block leak.JPG

After removing the block, I found that over the years, someone had broken a bolt in that hole, attempted to drill out the bolt with the cylinder in place, and missed by 1/4 bolt. In addition, the hole was about 2 degrees from being parallel to the original hole. They completely missed the bottom of the original bolt and drilled through the case and into the oil passage below.

lifterblockrep1 [800x600].JPG

I drilled out the mess (The hole already was too large to drill for a 1/4-20 helicoil) and tapped the hole with a 5/16-18 tap making sure to stop at the top of the oil galley. I made a threaded plug from aluminum bar stock using a die, put loctite on the threads and installed it into the newly tapped over-sized hole. The plug bottomed out in the hole and put pressure on the threads to help lock it in and seal up. I staked the edges of the hole after machining the plug even with the surface of the block.

lifterblockrep2.JPG

lifterblockrep3.JPG

I then made a 1/4-24 tap from an old lifter block bolt (I did not have one and did not want to wait for mail order)

.25-24 tap.JPG

After temporarily installing the lifter with 2 good holes and bolts, I marked the center of where the new hole should go, removed the block and drilled the new hole. The hole was then tapped with the home-made 1/4-20 tap.

lifterblockrep4.JPG

Then it was time to do the other inside hole on the rear lifter block----That one also had a broken bolt in it.

[mbskeam]

nice.......

[john HD]

nice work!

i got one i need to fix.

i debating on helicoil or not, now i have decided otherwise!

john

[51Hog]

Thanks gentlemen---
It is a very easy repair.

[FlatHeadSix]

Good job Dale!

now you can quit whining about that oil leak.

mike

[51Hog]

Yea--I really hope that cured it.

[hjans]

Very nice "i do not have a helicoil "solution.
Think i'm going to use it !!
Hans

[51Hog]

Good job Dale!

now you can quit whining about that oil leak.

mike

I wish----Just did 100 miles on the hwy 65 -75 mph.
oil came up the screw threads and out the space created by the star washers under the head of the base screws.
I pulled the two rear screws, removed the star washers and taped the hell out of the screws from half way up the threads to the edge of the screw head with teflon tape. It torqued down nicely. Lets see how well the Teflon holds back the oil.

[Moose]

great job now if we could only get you to make house calls

moose

[hjans]

maybe a problem in the gasket or a non-flat base ??
If still leaking, try some liquid gasket in stead of the lockring.

Hans

[hjans]

I remembered this post when assembling my lifterblocks, discovering one screwhole to have a worn thread.
Used the trick above.
Used a 3/8 - 24 bolt, drilled a hole in it on the lathe, tapped the 1/4-24 thread in it, corrected the length.
drilled the hole in the engine out, tapped in the 3/8-24 thread, assembled and there : OK !!

Thanks for the idea !!

Hans

[hjans]

The 1/4-24 tap though only costed me about $5,- , so no need to fabricate my own tap !!

[51Hog]

Glad it worked for you.
My repair is still working great.
Oil leak is stopped.
There is no oil at all that comes out of my engine---Normally----
She sumped once this summer and blew oil out the CC Vent.