D17 center main girdle

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   I have a D17 block with broken center main cap.  I remember a post a while back with a machined center main.  Any help appreciated.  It is 6in stroke also. Thanks

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7080R62 Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 06 Apr 2025 Location: Indiana Points: 5	Post Options Post Reply Quote 7080R62 Report Post Thanks(0) Quote Reply Topic: D17 center main girdle Posted: 06 Apr 2025 at 8:07pm
	I have a D17 block with broken center main cap. I remember a post a while back with a machined center main. Any help appreciated. It is 6in stroke also. Thanks

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DrAllis Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 12 Sep 2009 Points: 21259	Post Options Post Reply Quote DrAllis Report Post Thanks(0) Quote Reply Posted: 06 Apr 2025 at 8:45pm
	Over the last almost 40 years, I have probably built a dozen large W and G-226 engines. From the very first one I have always made a simple girdle for the OEM center main cap. I always faced off the bottom of the main cap ever so slightly for the brace to rest against. The brace was just a 3/4" thick by 1 1/2" wide flat of mild steel. These numbers are from memory, but the width can only be so wide. Thicker would be better. Two homemade thick walled spacers from an old piston pin and two longer grade 8 bolts. The parts were assembled so I could just slide a sheet of paper between the brace and the flat spot on the bottom of the cap. The main cap ears aren't usually exactly the same height, so your spacers are made for each specific location. This set-up also helps keep things going when the block splits down the middle at the top of the deck. You've got your ignition timing retarded somewhat ??

7080R62 Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 06 Apr 2025 Location: Indiana Points: 5	Post Options Post Reply Quote 7080R62 Report Post Thanks(0) Quote Reply Posted: 06 Apr 2025 at 8:48pm
	Ok do you have any pictures of what you have made. And yes timing is retarded some.

DrAllis Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 12 Sep 2009 Points: 21259	Post Options Post Reply Quote DrAllis Report Post Thanks(0) Quote Reply Posted: 06 Apr 2025 at 8:54pm
	No pics. Longer grade 8 or 9 bolts. Two spacers. A plate of steel that I gave you the dimensions to. It's very simple and apparently works as I have never had a center main cap failure.

7080R62 Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 06 Apr 2025 Location: Indiana Points: 5	Post Options Post Reply Quote 7080R62 Report Post Thanks(0) Quote Reply Posted: 06 Apr 2025 at 8:59pm
	Ok sounds good will see what I can do there after getting back from machine shop. I am having block and crank checked.

DrAllis Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 12 Sep 2009 Points: 21259	Post Options Post Reply Quote DrAllis Report Post Thanks(0) Quote Reply Posted: 06 Apr 2025 at 9:09pm
	I've gotten out my decades old engine notes. The brace is 3/4" x 1 1/2" as I said. It is approx 6 inches long and will hit the oil pump tube if too long on that side. Other side not important. G-226 bolts are Grade 8 or 9 and are 5/8 NC x 4 1/2" long. If you make the brace thicker, which you can, then you have to get longer bolts of the correct length to use all the threads the block has to offer without bottoming out. Edited by DrAllis - 07 Apr 2025 at 5:34pm

7080R62 Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 06 Apr 2025 Location: Indiana Points: 5	Post Options Post Reply Quote 7080R62 Report Post Thanks(0) Quote Reply Posted: 06 Apr 2025 at 9:37pm
	Ok yes i am following you on that. One other question is there a oil pan that you know of made for rods to clear or just make it to fit?

DrAllis Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 12 Sep 2009 Points: 21259	Post Options Post Reply Quote DrAllis Report Post Thanks(0) Quote Reply Posted: 06 Apr 2025 at 9:49pm
	No special oil pan that I know of. The last engine I built with 5.800" stroke had D-19 Buda rods and I said I'd never do another oil pan. I had to remove the pan rail braces, heat, bend and grind the pan and refit the braces to get the rods to clear. My pan looks like a bomb went off inside it. If you had custom rods made with offset caps, that would surely help.