So I'm getting this 440 block ready for the machine shop, and I was thinking about removing the dowel pins that locate the cylinder heads. I noticed the diameter is 1/4 but there appears to be a larger hole in the deck. So that would mean the pin is stepped? Is there a tricky way to remove these pins? I did a 350 GM build last year and prior to decking that block, the machine shop simply drove the pins into the water jackets were they remain to this day. Kinda wanna make sure that doesnt happen with this project. thoughts? thanks
440 block dowel pins removal
- Thread starter Moespar
- Start date
70chall440
Well-Known Member
I am sure there is more than one method but I usually just use some vise grips. Get a hold of it as much as possible and twist and pull.
Thanks for the reply. I was able to get them out . And replacing them is not an issue for me being a machinist. I’m wondering how much material is at the bottom of the hole before it would break through ? I assume there is a portion of the water jacket below that. Any ideas ? Also, where could I find a schematic or blueprint with hole locations? Thank you
You're over thinking this. They are just locating pins. Nothing special just round stock. Grab them with a Vice grip and twist and pull like 70chal440 suggested. If you have a collet style puller then use that. If they are marred up from the VG jaws touch them up with a file or sand paper or cut some new ones the same dimensions and tap them back in after the machine shop is done.
I did that . And successfully removed three. Measured em at .2465. But one hole got a little wallowed. Measured that hole at .255. So I know I’ll have to make a step dowel that oversized by a few thou for the block. Just worried about how close they locate the heads. I don’t want a be chasin vacuum leaks after putting the heads on . Not sure how much tolerance the heads have to the block .
Adam
Well-Known Member
I’m sure you could even run without it. Remember there are head bolts that will also locate & secure the head. The corresponding hole in the cylinder head is probably several thousandths larger than the dowel and only aids assembly; I doubt the dowel has a large role in keeping the head in place on an assembled engine. Of course I would still replace it, but It’s not critical.
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You might be surprised (or disappointed) if you install the dowels and bolt on the head without the rotating assembly and look from the crankcase to see how perfectly the combustion chamber lines up with the bore. These old engines can be a ways off.
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