uh6077 Posted June 1, 2015 Share Posted June 1, 2015 My 41 Desoto flathead 6 has decided it is time to be rebuilt (see attached pics). Looks like two pistons broke apart a bit and the pieces got sucked up by the valves. The intake/exhaust valves in both those cylinders are bent. Engine isn't out yet but will be this weekend. This is my first flathead rebuild. Done a few motorcycles and a Toyota truck 6 cyl in the past. What should I look out for?Anything that should be replaced regardless of condition?Replace all six pistons and not just the 2 bad ones right? My quick list looks like this-Get the block and head hot dipped to clean everything6 pitons, rings and pinsRod and main bearingsCheck all valves, replaced bad onesReplaced all valve springsCheck and machine head and block as neededTiming chainWater pump (looks very old)Complete gasket setClutch plate likely unless it looks REALLY good Link to comment Share on other sites More sharing options...
jbbuick22 Posted June 1, 2015 Share Posted June 1, 2015 There is a 42 sedan with the hideaway headlights in a used car lot in Upton MA, rusty but complete. May have parts that fit 41. I don,t know if it for sale. It has been there for a long time 20+ years. JB Link to comment Share on other sites More sharing options...
ply33 Posted June 1, 2015 Share Posted June 1, 2015 Pull and inspect the water distribution tube (located behind the water pump. If it is brass it is probably still good but if it is steel (like most) it is probably badly corroded. You probably want to pull that before the block is put into the hot tank even if it is in good condition. Link to comment Share on other sites More sharing options...
uh6077 Posted June 1, 2015 Author Share Posted June 1, 2015 Will do, thanks. Link to comment Share on other sites More sharing options...
HarryJ Posted June 2, 2015 Share Posted June 2, 2015 (edited) Sounds like you've got a good plan to start....I would replace all the valves, valve springs, pistons, rings. Had it been bored and rebuilt in the past? Edited June 2, 2015 by HarryJ (see edit history) Link to comment Share on other sites More sharing options...
uh6077 Posted June 2, 2015 Author Share Posted June 2, 2015 I do not know the history of the engine. I got it last year and put about 700 miles on it. The last owner had it for around 5 years and did not rebuild. Not sure beyond that. I will measure the bore before I order any parts. If the walls look suspect I will have it taken down 10 thou to clean it up. If everything looks fine I will just give it a fresh hone. Link to comment Share on other sites More sharing options...
edhd58 Posted June 2, 2015 Share Posted June 2, 2015 from experience I speak. Find out what all you could possibly need. Then stat looking to make sure you can get all the pieces. My 42 Ford G series 6 cylinder has several parts that are not available. Had I known that before I took it to the machine shop I would have put in a V8 flathead. I can't get a fuel pump, every oil pan gasket I have gotten hasn't been an exact fit, and the oil pump internal gears aren't available. Just make sure before you spend the dollars to get some parts that you can get all the parts you need. Link to comment Share on other sites More sharing options...
keiser31 Posted June 2, 2015 Share Posted June 2, 2015 All of the parts to rebuild your DeSoto engine are currently available. Link to comment Share on other sites More sharing options...
mrpushbutton Posted June 2, 2015 Share Posted June 2, 2015 I would highly recommend the "Chem-Strip" method of block cleaning. A block that old has corrosion in the cooling passenges, and that is impeding the transfer of heat out of the engine. This method of stripping uses an alkline solution, though which an electrical current is passed. The block goes in filthy and rusty, comes out spotlessly clean, almost a bright silver color rather than a dull gray. One thing we did on all the engines we restored after this is to immediately coat all of the cast surfaces with DP-90 Epoxy primer and coat the inside of the cooling passenges with DP-90. Pour in an amount on the engine stand, tape off the openings and roll the block on the engine stand and pick it up by each end and make sure the primer gets everywhere inside. Drain the excess, and clean it off of any machined surfaces. These engines would go from overheating, temperamental things to running cool as a cucumber, no matter what. Go through the radiator core while the engine is out too--make sure it flows properly and is not coated with goo. BIG THING: Send the distributor out for re-bushing. It is as shot as the rest of the engine, and putting it back as-is is like taking a shower and putting dirty, sweaty clothes back on. 1 Link to comment Share on other sites More sharing options...
uh6077 Posted June 3, 2015 Author Share Posted June 3, 2015 Any suggestions for someone to rebuild the distributor? I didn't think about that but it only makes since. There is a local guy who does a good job on starters and alt/generators so i think I will have those gone over as well. While crawling under the car I did notice the radiator has been leaking a little (tell tale blue/green deposits left behind). Might need to have it recored or find a good used one. Link to comment Share on other sites More sharing options...
Rusty_OToole Posted June 3, 2015 Share Posted June 3, 2015 For parts, try Vintage Power Wagons. They have plenty of parts, and Power Wagons used the same motor as your car. To be technical, in those days Chrysler made 2 different flathead sixes. A smaller one for Plymouth, Dodge, and Dodge light trucks and a larger one used in DeSoto, Chrysler, and heavy Dodge trucks. The smaller engine measures 23 1/4" long at the head, the large engine is 25" long. The large engine, used in your car, was also used in trucks and Power Wagons in the fifties. Andy Bernbaum you probably already know about. And of course, most parts are available from your local NAPA store or other good parts store, if the counterman is smart enough to find them. If you don't have a factory repair manual you definitely need one now. You will need to check the cylinders and crankshaft for wear, and rebore or regrind as necessary. If pistons are broken, it is time to replace the whole set. Timing chain, oil pump, all the usual parts should be inspected and if necessary replaced. One thing you can reuse, that you can't on modern cars, is the head bolts. Valve guides, valves, and valve springs must be checked and replaced if necessary. How many miles on the car? If it has over 50000 miles you should err on the side of caution when it comes to replacing moving parts or parts that wear out. There is no point in reboring, grinding crankshaft, installing new pistons and bearings then using iffy valves. Camshaft and lifters can be reground but they have an easy life in a flathead and often show little or no wear. You might get a kick out of this description of a rebuild of a DeSoto engine like yours http://www.allpar.com/cars/desoto/suburban-1951.html Link to comment Share on other sites More sharing options...
uh6077 Posted June 3, 2015 Author Share Posted June 3, 2015 I was thinking "How does that guy remember all the details from an engine rebuild in 1971". Then I saw that the article is from 1976. Good read Link to comment Share on other sites More sharing options...
Jon37 Posted June 3, 2015 Share Posted June 3, 2015 When you ask about rebuilding your engine in a "general" forum like this one, you will get a lot of expert advice from people who have worked on a number of different makes of cars over the years. But often, engines for different years of particular makes will have their own particular quirks, and it would be good to also get the advice from those who have specialized in DeSotos or other Chrysler Corp. cars. So you might also want to ask the same questions in a dedicated DeSoto forum (I believe they have one over at the National DeSoto Club, and they definitely have one here at the AACA Forums). It might be, for example, that others have encountered the same problem of the disintegrating pistons in DeSotos and could offer advise on how to prevent this from happening in the future. Or, someone sees your posting and then posts a message that he has NOS parts for your car in his basement, cheap. Or knows of a low-mileage engine for sale cheap, that was removed from a DeSoto that's being street-rodded. You never know what you'll find, til you ask! 1 Link to comment Share on other sites More sharing options...
Rusty_OToole Posted June 3, 2015 Share Posted June 3, 2015 Broken pistons are a typical failure point for Chrysler built flathead sixes and have been for years. So common that any time you overhaul a high mile motor you can expect to find 1 or 2 broken pistons. Mind you it only happens when the engine has a lot of miles on it. And the engine will continue to run, and make less noise and fuss than other brands of engines. But still, broken pistons. I can't account for it. Link to comment Share on other sites More sharing options...
mrpushbutton Posted June 4, 2015 Share Posted June 4, 2015 I knew a '38 Buick Special with pistons that were braking apart, the metail from the top ring groove to the top of the piston would break off, dance around on top of the piston and bend the spark plug gaps shut. Complete engine rebuild fixed that. Link to comment Share on other sites More sharing options...
Rusty_OToole Posted June 4, 2015 Share Posted June 4, 2015 Auto electric shops used to rebuild distributors. If there is an old time shop near you with a Sun distributor machine they should be able to help. I would also try Andy Bernbaum and VPW and see if they sell rebuilt distributors. Link to comment Share on other sites More sharing options...
Guest pehernan Posted January 6, 2016 Share Posted January 6, 2016 If you still looking for somebody to rebuild your distributor let me know because I know the right person. He own a business that specialize in rebuilding electrical parts and they did an amazing job with my starter and just gave them my generator to be service.The only issue may be the location, but I don't think will be that much for shipping. Link to comment Share on other sites More sharing options...
c49er Posted January 6, 2016 Share Posted January 6, 2016 Inquiring minds would like to know who this person is ^^^^^^ ! Link to comment Share on other sites More sharing options...
Owen_Dyneto Posted January 6, 2016 Share Posted January 6, 2016 Even if you have only basic skills rebuilding a distributor is really a very simple job but if you're not up for it yourself, I can confidently recommend Jason Smith at AER - we advertises widely in the hobby. I don't recall if it was mentioned before or not, but in doing your engine rebuild check the valve guides and replace as needed. Otherwise your nice ground and finished valve faces and seats will have a shortened lifespan. Link to comment Share on other sites More sharing options...
Larry Schramm Posted January 7, 2016 Share Posted January 7, 2016 (edited) Even if you have only basic skills rebuilding a distributor is really a very simple job but if you're not up for it yourself, I can confidently recommend Jason Smith at AER - we advertises widely in the hobby. I second the endorsement Edited January 8, 2016 by Larry Schramm (see edit history) Link to comment Share on other sites More sharing options...
jcmiller Posted January 7, 2016 Share Posted January 7, 2016 The article available at this link should be helpful for you: http://p15-d24.com/files/file/70-flathead-6-engine-rebuildpdf/ Link to comment Share on other sites More sharing options...
Guest pehernan Posted January 7, 2016 Share Posted January 7, 2016 I agree with Larry,a distributor is not hard to rebuild. Either way the person who I mentioned before is Rogelio and own L& R Electronic in Elizabeth, NJ. 9083519384 They rebuild my starter and was an amazing job. Very quick, professional and even was kind enough to take pictures of the whole process. Link to comment Share on other sites More sharing options...
barry22 Posted January 9, 2016 Share Posted January 9, 2016 I realize this topic was started last year and most of the comments are months old, but the suggestion was made that after an engine is Chem-Stripped, DP-90 epoxy primer should be poured in the cooling passages and the engine rolled in order to spread the paint everywhere. Is painting the cooling passages of an engine something that people should be doing? It's tough enough to make paint adhere to the body of a car. With extreme thermal cycling of an engine going from cold to operating temperatures over a period of years, and the potential for antifreeze chemicals to affect the primer, isn't this a recipe for disaster when it delaminates and ends up clogging the radiator and the rest of the cooling system and overheats the engine? A person can go on and on preaching that as long as the surface is perfectly clean, DP-90 and Glyptal can be applied to internal engine surfaces, but there always remains the risk the paint will not stick and result in very negative consequences. Link to comment Share on other sites More sharing options...
knobless Posted January 19, 2020 Share Posted January 19, 2020 On 6/2/2015 at 1:41 PM, keiser31 said: All of the parts to rebuild your DeSoto engine are currently available. Thinking about rebuilding my 34 Dodge Dr engine , what’s the best place to get everything needed to rebuild and what am I looking at for parts price, no machine work...? Thanks Link to comment Share on other sites More sharing options...
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