Guide pins

tinkirk

tinkirk

Senior Member
any one ever install head guide pins in the block so the head does not move around after setting it on??
Seems to me that it just moves around to much tell torqued in place,which makes me wonder that it can also move a little after being torqued


Tinkirk/Terry
 
Some flathead V8 engine builders drill the head and block for dowel pins. I do not think it would benefit the Model A unless you had a racing engine with valves and pistons close to the chambers.

John
 
J Franklin said:
The head constantly moves during heating and cooling cycles. No guide pins necessary.
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that to me is a problem the head moving all the time
mpo is that is why the gaskets seem to seep on the left side between the head and the block

T-T
 
If you do this, after figuring out where best position is you need to make some sort of permanent jig for the actual drilling so if you replace gasket, head, or block you can carry on without going mad. I don't think there are any places on deck that could take a concentric dowel around a stud.
 
Hi terry,

FWIW on head movement:

Ever since Model T days, vintage mechanics in the know, (from vast experiences), applied "Permatex No. 2", (non-hardening gasket sealer), on both sides of head gaskets to seal same.

When torquing a head and when squeezing a gasket, head gasket can move sideways; also, when engine is warm while running vs. when cold, cast iron head and block expands and contracts, (moves), but, differently from the expansion & contraction of a different metal like a copper lined head gasket also moving sideways.

Non-moving hardened gasket sealer provided in moving joints can crack when used with metals having differential expansion and contraction.

New silicon gaskets manufacturers recommend no gasket sealer ...... Do they want to sell lots of failed gaskets? Have no idea.

I still used "Permatex No. 2" on my new silicone gasket with no re-torquing, and no leaks in 10 years.
 
T T, I have found most gasket seepage is due to a warped head. Have you checked head and block for flat? I usually have the head checked and skimmed when it is removed.

John
 
john in illinois said:
T T, I have found most gasket seepage is due to a warped head. Have you checked head and block for flat? I usually have the head checked and skimmed when it is removed.

John
Click to expand...

on my 30 and my sons 29 head and block were both machined and installed new style gasket and both of us have gone over the torque numerous times and they both seem to seep just enough to notice and only when they cool off

on the 29 i'm playing with now i went with bigger int.valves and i have a couple that are a little close,I don't believe it's enough to matter but was wondering about guide pins to hopefully maybe to stop the head from moving the little bit that it does move!

always thinking of different ways to make thing better if possible

T/T
 
tinkirk said:
on my 30 and my sons 29 head and block were both machined and installed new style gasket and both of us have gone over the torque numerous times and they both seem to seep just enough to notice and only when they cool off

on the 29 i'm playing with now i went with bigger int.valves and i have a couple that are a little close,I don't believe it's enough to matter but was wondering about guide pins to hopefully maybe to stop the head from moving the little bit that it does move!

always thinking of different ways to make thing better if possible

T/T
Click to expand...

If you use guid pins, you better hope the block and head expand and contract at the same rate. It would also depend on where you put them. I do not see the need.
 
Per reply #9, if anyone wants to try a few Model A guide pins, a guide pin located in a thin cast iron part of a Model A water jacket in either the head or the block ? ...... just guess at "The Rest of the Story."
 
I drill the head holes slightly oversize, to facilitate gasket & head installation. On the 2 holes in opposing corners, I don't drill them clear through, to help locate the gasket & head properly.
Bill Questionable
 
I would think unless everything was disassembled the cost would far outweigh any benefit. No locating pins for 80+ years.
Also do a search on the silicone gasket. FWIW
Paul in CT
 
i do understand what you all are saying,

there is a reason why all motors from what the mid 40's all have alignment pins installed
in the block of some sort
are they needed? probably not
would they help? probably so
sooo i think i will flip a coin and see which way i go

i do thank you all for your thoughts

T/T
 
Let us take a somewhat common sense look at this.

In the early years of V8s the heads were a lot lighter and were easier to reach with a 5lb head and were mostly using studs, which held the gasket in place until the head could be slipped down over the studs, so really, no need for any sort of alignment pins.

Now, bring in the Over Head Valve train and the head weight more than tripled and it took a miracle to hold the gasket in place and get that boat anchor head onto the block over the high square fenders without a chain fall. Seems to me that to put locator pins was a MUST just to hold the gasket in place while you and three of your pals muscled the head over the fender and onto the block, and without the locator pins, you would never have that gasket in the right place.

So, the natural progression was while using studs, you didn't need locators, and then came the cast iron boat anchors and locators were a must, and then came aluminum because everyone was tired of paying the raising price of chiropractor visits and not enough beer to quiet the complaining pals with back aches.
 
RawhideKid said:
Let us take a somewhat common sense look at this.

So, the natural progression was while using studs, you didn't need locators, and then came the cast iron boat anchors and locators were a must, and then came aluminum because everyone was tired of paying the raising price of chiropractor visits and not enough beer to quiet the complaining pals with back aches.
Click to expand...

I agree fully.
 
so this is what i did
not sure if you all will be able to see these or not
laid the head on last night and there is no movement what so ever




picture.php
picture.php
 
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