The Stovebolt Forums Forums The Shop Area The Engine Shop What next? Engine break in completed.

Hopefully the egg on your face will be a beacon to others. Compare new to old before installing and bag and tag everything as it comes apart to make future comparisons easier. Thanks for the update.

I had no “old” to bag up or compare. I started with this, and nothing else. No intake, a mismatched head and no carb or accessories. Nothing else.
If that one bolt hadn’t stripped out of the head then none of this would have happened.

Problem solved, doesn't matter how it gets done as long as its right in the end.

For those that may not know what a bad lifter looks like, here are some I have pulled from Pontiac engines. The one on the far left is from a '67 that was stored for 20+ years, the owner would start it every year and let it idle for a while till it got where it wouldn't start, the cam was totally trashed and would barely open a valve. The real short ones ran for about 12 minutes before shutting off, the owner left out the cam retainer plate so the cam walked forward. A couple ran about 200 miles before take lobes off, and the one on the far right is still good just so you can see how much has worn on the others.

As a matter of fact, yes I have- - - - -one of my trade school students decided he really didn't need air conditioning on his hotrod Monte Carlo, so he removed the compressor and all the associated brackets. That included one that was attached by two intake manifold bolts. When he reinstalled the bolts sans the bracket, one jammed the pushrod. In that case, the lifter operated ONCE- - - -bending the pushrod and holding the valve wide open. When the piston hit the valve, it bent it, along with breaking the rocker arm and putting a big gouge in the top of the piston. May I humbly suggest that you install a Heli-Coil thread repair in that stripped intake port thread and go back to a regular length bolt?

You're pretty lucky!
Jerry

Lugnutz,

Kudos on the arthroscopic surgery to get that lifter back in place.
Although pulling the intake manifold might have been quicker.

Glad you got it all sorted out. Your story may help others when building an engine.

I think it was THIS bolt that stripped out. What would be the benefits of doing the heli-coil repair over using a longer bolt in that position?

While you can engage part of the available thread depth with a longer bolt, you'll be sacrificing a good bit of clamping force by using only some of the thread. You're also threading into cast iron, not steel, which won't handle as much torque under ideal conditions. That bolt, and the next one in line straddle a coolant passage, not an intake port, so there will be more stress on the gasket when the cooling system pressurizes, possibly leading to a coolant/oil intermix if there's a leak into the valve valley. Lastly, the helicoil is a stainless steel thread, making it much less prone to strip than an equivalent diameter and pitch cast iron thread. If you choose, use a slightly longer bolt that will engage the entire thread depth.

Other than that, I guess there's not much advantage!
Jerry

With that enlarged pushrod hole, you might be wise to install a self-aligning rocker arm. The hole is all that keeps the rocker from rotating off the top of the valve stem.

https://www.ebay.com/itm/163801790888?epid=140199121&hash=item262358f9a8:g:xjUAAOSwBh9dRDGP

Jerry

I just got back in from the shop. I was able to use a borescope to confirm that there’s no obvious damage to the pistons or valves in cylinders #4 or #5.
I ordered the Heli coil kit today. I watched a video on how to install a Heli coil but it raises some questions in my mind.
Step one is to drill the hole to the correct size. I think the drillbit is included in the kit.
Step two is to tap new threads into the hole. I think the tap is also supplied in the kit. How difficult is it to tap threads in cast iron?
Step three is to put the heli coil into the newly threaded hole.
Step four is to install the 3/8-16 bolt. I have a fear that installing the bolt might push the Heli coil further into the head if the threads don’t mesh exactly right. Or is it a blind hole? See picture.

Cast iron threads like butter- - - - - -you probably won't even need any lubricant. Just turn the tap about 1/2-3/4 turn at time, and back it up a little to break the chips off. A helicoil thread insert is compressed as it is installed with the included tool, and it expands to grip the walls of the hole when the installation tool removed. Once the thread insert is fully engaged, use a punch to break off the drive tab at the bottom of the insert and fish it out if the hole doesn't go all the way through. Clean up all the chips you create, obviously. I've also used a tiny bit of red loctite on thread inserts, then waited a few hours for it to cure and run a tap into the insert to make sure the bolt doesn't also get locked into place. I believe that end hole is blind, which also makes it important to use all the available thread depth without risking bottoming out the longer bolt and getting a false torque reading while getting little or no clamping force.

I'm very reluctant to use a torque wrench on parts with a compressible gasket between them, but nothing beats decades of experience and a few screwups to develop a feel for how tight is "just right". Good luck!
Jerry