I decided I couldn't live without a set of Nickel Plated Engine Dress Up Cylinder Head Bolts for my 26 T engine. They look nice but today when I was torquing them for the final time one stripped. What a sick feeling. Fortunately it was the Nickel Plated Engine Dress Up Cylinder Head Bolt that went. I installed a Henry original and it is fine. These Nickel Plated Engine Dress Up Cylinder Head Bolts are 1/8 inch shorter than Henry's so when you use one where the coil box bolts to the head you have lost a lot of thread. Maybe no one will notice that I am missing one Nickel Plated Engine Dress Up Cylinder Head Bolt. I probably ought to replace the other two as well.

Jim

Same thing happened with me, those nice dome head nickel bolts are a tad short...most work fine, 'cept when you least expect it, where the block hole has some worn threads in the upper end.
Compounded maybe since this is a 'Z' head and a washer has to be used on the alum head surface under the bolts.


Made a long length bottom tap so I could re thread that bugged hole, with the head still on, used a longer bolt in place of that shiny nickel bolt.

I would replace them with studs and nuts, to get max purchase in the block. You might be able to find nickel acorn nuts, even.

rdr
T-hacha-P / Mojave

I haven't been able to torque the new ones to 50 ft lbs. they seem to start pulling about 45 lbs. the old originals will take it.

Jim,
Perhaps there are some quality issues with the nickel plated cylinder head bolts. I just re-used mine after changing the head gasket on my '14 Touring (I like the looks of them even though they are not right for the year). They seemed to be just fine after 15 years of use. So far, I've torqued them to 45 ft-lbs with no problems. I did use anti-sieze on them both times...on the threads and under the head of the bolt.
Verne

Jim,

thanks for the update, but at the same time, if the nickle bolt let go, and Henry's snugged, the only conclusion is that the compression on the block in that area is spread on but that 1/8" of threads. BE CAREFUL.

Not necessarily Henry specification, but the suggested conventional wisdom practice where possible for proper torque across area is that steel into cast iron should be at least 1.5 times diameter of bolt.

Yeah, I know, there are lots of ways to 'cheat', often Henry boys already used a bunch of that 'cheat'... but...based on a standard grade bolt, and the holding power designed to be spread over so many threads, having all of that load pulled into but a few threads is the recipe for block tear out.

At some point in life, I think you'd be wise to think about adding a helicoil.

Jim,
I just replaced the nickel plated dome shaped head bolts with grade 8 bolts. The nickel bolts were a hair too short and I was using hardned washers too so they were way too short. I stripped out 2 head bolt holes in the block. The grade 8 bolts were longer, actually too long, had to grind off a little of the ends and used a double layer of hardend washers except for the coil box brackets that got single hardened washers.

Ralph always recommends studs but he does not have a 26-27 firewall which prohibits installing the head straight up and down over studs, but to each his own.

Not to steal the thread, but what is the length of thread of the holes on the deck of the block supposed to be? My nickel bolts on my 26 barely make it to torque before bottoming. I bought them 5-10 years ago and don't remember who supplied them. I have one that still appears to be too long and am debating whether to remove one thread.

And Yes, I used a twist drill to clean out any junk at the bottom of each hole and then chased the threads with a tap before I installed the bolts. I am starting to wonder if this block has been decked so many times that the threads got too short.

Then if you want to be fancy and not polish nickel, you can get these caps at a hot rod shop and use the original bolts.

Tom,

The cylinder head on your car could have been milled a whole lot by now, as well.

Seth

Studs won't work on a 26 unless you either slide the engine forward or raise the body. The offset in the firewall prevents pulling the head in the car if you use studs. The bolts need to be neither too long nor too short.
Norm

Good point Seth. I'll have to compare it with others laying around my shop to see what's coming up short.

When I threaded the bolts in, it seemed like the threads seemed short. I didn't measure anything, it just seemed funny at the time.

AGAIN! You don't have to install the studs before you lay the head in place. They just get snugged down into the block with a nut and jam nut. Remove the jam nut/nut and put on a regular or acorn nut, and mebbe a washer.

Next?

rdr

Some folks don't know how to deal with studs, Ralph. Or listen either, obviously.

The fancy bolts were going good until tried to step up to 50 ft lb.