howardjnl Posted October 4, 2012 Share Posted October 4, 2012 Folks, My "new" (new to me) 1937 Buick Century has a serious ring problem, so I'll be doing an overhaul this winter. As part of this, I've been doing some online research to see how I may upgrade the pistons and connecting rods. I see that I can replace with connecting rods with the more modern "insert" type, a definite want-to-do, and I see references to using the 1949 domed type pistons with my current 1937 cylinder head, such as described in this issue of the Torque Tube http://1937and1938buicks.com/The-Torque-Tube/Volume%20XIV%20Number%203%20(January-February%201996)%20(From%20Dug%20Waggoner%E2%80%99s%20collection).pdf. Given that the 1937 was factory a flat topped piston, and it seems counter intuitive to use domed pistons, I'm pretty confused about the advisability of using these dome pistons in my '37 320 cu. in. engine. Has any one other than this one Torque Tube author actually done this to a 1937 using these pistons? John :confused: Link to comment Share on other sites More sharing options...
Guest Grant Magrath Posted October 4, 2012 Share Posted October 4, 2012 Hi John.The article also states that if you use a 41 head, and 41 pistons (the same as 49), you should be all good. Have you had the sump off the engine and checked the bearings? Our 39 coupe with a 47 engine was in need of a rebuild, but the bottom end was sound as a bell! It still has the poured white metal bearings. I've heard of guys who just removed a couple of shims to tighten up the bottom end with a good degree of success.At the end of the day, you have to ask yourself if the hassle involved in gaining an extra 5-10hp is going to benefit your 75 year old car!CheersGrant Link to comment Share on other sites More sharing options...
howardjnl Posted October 4, 2012 Author Share Posted October 4, 2012 Craig, Terrific! You are the first person, including me, to catch this reference to '41 head. That's a great help to me. Thank you! perhaps I'll work on my reading skills.A couple of the con rod bearing journals on the crank shaft have some minor striations, con rod bolts don't match, so I'll be giving the whole bottom end a very close look. The supposed ring job done before I got the car is still showing hone marks on the cylinder walls but still have lousy compression, burn oil, and are not seating any better despite driving it about a thousand miles since I bought it.Thanks again. Link to comment Share on other sites More sharing options...
jeff Posted October 4, 2012 Share Posted October 4, 2012 I did this upgrade with my '38 Special. In my case, I bought some 1950 rods and pistons. I ended up boring the cylinders .030 over to clean up some damage, so I bought new 1950 pistons to go with the rod update. On the bottom end, I ended up removing .010 on the crank, so oversized inserts were used. Went together very well.Don't think you will see any performance increase - just better life from the improved bearings.Of course, with a '37, you will need a newer head, as described above - this change may up the performance a bit, perhaps that's what Grant was referring to. You already realize that domed pistons with your old head will be an instant disaster.If you have nice clean journal surfaces on the crank, and babbit left on the rods and caps, then just remove shims until you satisfy the Plastigage. Should be good for another 30,000 miles or so! If you need to have the crank turned, then going to the newer rods may make sense.Jeff Link to comment Share on other sites More sharing options...
howardjnl Posted October 4, 2012 Author Share Posted October 4, 2012 Jeff, Thanks for the additional info. My current thinking is to go with new flat topped pistons, the so-called "improved design" that strengthens the top edge of the piston. I'll also go for the newer type of rods as I'd like to eliminate the striations on the crank shaft rod bearing journals and start fresh; I intend to keep this car quite a long while and use it as a daily driver. The top end is in excellent shape. It's already fitted with an HEI ignition system, '41 dual carb manifold set up and dual exhaust manifold. John Link to comment Share on other sites More sharing options...
jeff Posted October 8, 2012 Share Posted October 8, 2012 I have an old '38 248 cu. in. cylinder head, if you wanted to go the domed-piston route. Besides the usual machine shop work (mill the gasket surface, valve guides, valve seats, and magnaflux) it will need a repair on one of the bolt bosses. The top of the boss is broken off. It would need to be milled flat, then a steel rod welded to it, then drilled to accommodate the bolt. Or, just build up with weld, I guess.It's in Dayton, OH - let me know if you have an interest. I could bring it to Hershey on Wednesday of this week.Jeff Link to comment Share on other sites More sharing options...
jeff Posted October 8, 2012 Share Posted October 8, 2012 Oh yeah, I have a pair of '37 rear bumper brackets as well. I bought them thinking they were the same as '38's. They are slightly different, but could be used in a pinch I guess.Need them, by any chance? Link to comment Share on other sites More sharing options...
howardjnl Posted October 9, 2012 Author Share Posted October 9, 2012 Jeff, My engine is 320 with an excellent cylinder head, but thanks for the thought. Also, my bumper brackets are all refinished and powder coated, I'm in good shape there, too. John Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now