I used a dowel pin extractor to remove the main cap dowels in my block. They were very tight, I was able to get all but one out, I tried to drill it out and no drill would even mark a mark on it, very hard heat treated steel. I got the oxy acetylene torch out and got the pin cherry hot put some penetrating fluid on it and then was able to pull it out with the extractor. For our discussion the dowel pin's primary purpose is to locate the cap and the bolts/studs apply the clamping force to oppose the extreme forces, but the pins also help stabilize the cap and a good tight fit of the pins is key. When there is not enough engagement of the pin into the cap the hole in the cap can become elongated and this demonstrates that the pin does more than locate. Putting in a longer pin further into the cap does provide more stability.
There are various grades of dowel pins used for a variety of uses. I needed to put longer dowel pins in the back of the block for aligning the trans because with the mid plate there just wasn't enough engagement into the trans. I had to remove the existing pins and I tried every trick in the book and could not remove them, so I drilled them out. These pins are much softer than the pins that locate the main caps as a HSS drill bit did the job.
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Tim Corcoran
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