1500 Midget head bolts

[GTsRFine]

Which end goes into the block? The end with the longer threads or the end with the shorter threads?
The block's holes aren't quite deep enough to accomodate all the threads of the long ends. And conversely, the short ends may not provide enough gripping hold.
Another question - what's the story on the slot cut through the short end threads of the head bolts. The Haynes book says some came that way. Doesn't that weaken the bolt?

Thanks in advance

 

[Matthew E. Herd]

The slot through the bolts would indeed weaken them slightly. How much is hard to say, but more than likely, the threads are the weak link as opposed to the shaft itself, regardless of whether or not it is slotted.

Also, the number of engaged threads (threads actually supporting the load) is comparatively small (likely to be no more than 3-4), so it probably irrelevant that the stud does not go all the way into the block. Consider too that a nut has no more than 5-6 threads on it and this is what holds the head onto the block, so that is the limit of the number of threads engaged at any time anyway.

Now to answer your question. You don't want the threads bottoming out lest they warp the block. On the other hand, I imagine that the short threaded end is to go on top so that there is a minimum of exposed stud once the head is installed. I don't remember in the case of my engine, but that seems to be the logical solution. Some thread can stick out past the block into the hole in the head, and some thread can stick up past the nut holding the thread down. Its not critical that the threads be completely screwed into the block, so as long as the studs get a good bite on both sides and fit correctly, they should be fine.

 

[RobSelina]

this is just a WAG, but based on the manuals I have, the short end with the groove should point up, the longer thread should go down into the block. I think this is logical too for two reasons:
1- you want the studs properly threaded into the bock, since you want the nut to turn, not the whole stud when you torque down on it or disassemble it for that matter.
2- the groove acts as a pressure release for the threads, helping you break the nuts loose, which also fits with the above...
Like I said, it's a WAG, but a reasonable one I think /ubbthreads/images/graemlins/grin.gif
Rob

 

[Dave Russell]

I don't know which end goes up (most of the time in fact)

Matthew is correct about the thread loading. The first two threads carry something like 59% of the entire load & the first four carry about 83%. If a stud bottoms out hard in a blind hole it will raise a thread around the hole which will prevent the head from pulling down evenly on the block. The studs do need to be bottomed or topped out firmly enough to prevent them from turning with the nut. I usually just set them lightly & use Green Loctite. Make sure to remove any previously raised threads/burrs around the holes before assembling things.
D

 

[GTsRFine]

I guess this stud thing goes along with the other counter-intuitive stuff on the 1500 engine (half thrust washers, no cam bearings, sealing blocks w/wood inserts, the P/S extra motor mount plate [the one that doesn't show up on any drawings]). By the way, any problem with notching that P/S motor mount plate to permit free access to the dipstick?
The block threads have been cleaned with a bottoming tap and the stud threads have all been cleaned with a die, so no problem there.

 

[Bugeye58]

I don't know about the slots, but the short threaded end of the stud goes into the block, and should be torqued to no more than 48 in. lbs.
Additionally, you may find it easier to lay the head gasket on the block, and then thread the studs through the holes in the gasket, and into the block, rather than trying to push the gasket over the studs.
Another thing is, you can fit cam bearings to a 1500 engine, if you use a small journal cam as was used in the earlier Spits. Just use the Spitfire bearings. If you are swapping cams to another profile, just have it ground on a small journal blank.
Jeff

 

[GTsRFine]

Thanks for the input everybody.
Bugeye - when you say earlier Spits - how early is early?

 

[Bugeye58]

[ QUOTE ]
Bugeye - when you say earlier Spits - how early is early?

[/ QUOTE ]
'72 and prior.
Jeff