slatgrille Posted June 19, 2023 Report Share Posted June 19, 2023 My '48 P15 Special Deluxe Coupe has been a pretty trusty vehicle these past few years. It belonged to a good friend for 34 years until he died suddenly and his widow gave it to me. I've been familiar with car over those many years and much of the time it was in storage. (He was a Merchant Marine at sea.)The car is mostly original and the engine never taken apart. Unfortunately it developed a 'skip' while coming back from a car show. Besides burning a little oil, it purred like a kitten until yesterday. Long story short, I believe the head gasket blew between #5 and #6. No compression on #6 and under 15psi on #5. I've rebuilt many flathead jeep engines over the years and a more modern 258ci 6 cyl. jeep, but this is a first for the Chrysler Corp. flat 6. It looks like a simple job, but I'd like to know if there is anything 'quirky' about these engines before I tear into the 'top end'. I'll get the head planed and check the block for flatness. I thought about doing a ring job, but I've got a tractor to finish and a Model A that has bearing knock that demands my attention. Although I take 'Plymmy' to shows, it is a driver so I'm not ready to 'shelf' it to do a complete rebuild and paint. The head measures 23" long x 7" wide so I'm assuming it is a 218ci. The block indicates P15 then a 'star' with serial #. Thanks for any comments! Craig Quote Link to comment Share on other sites More sharing options...
slatgrille Posted June 19, 2023 Author Report Share Posted June 19, 2023 Forgot to ask....what's the best place to get a head gasket? I'd like the original style with both sides copper with the filler in between. I see several places have them, including RockAuto, but not sure of composition... Quote Link to comment Share on other sites More sharing options...
Sniper Posted June 20, 2023 Report Share Posted June 20, 2023 None of the head gaskets at RA have copper on both sides. I think Best Gasket is the only new maker that has what you want, Quote Link to comment Share on other sites More sharing options...
slatgrille Posted June 20, 2023 Author Report Share Posted June 20, 2023 Thanks Sniper, I'll search it out. Quote Link to comment Share on other sites More sharing options...
Neira Posted June 20, 2023 Report Share Posted June 20, 2023 In the Tech forum is a topic titled "Engine Rebuilding Gotchas". It might cover some info you're looking for. Quote Link to comment Share on other sites More sharing options...
Matt Wilson Posted June 23, 2023 Report Share Posted June 23, 2023 Be careful when removing the coolant temperature sending unit from the side of the head. Make sure the little tube that goes through the middle of the nut does not twist with the nut, or it will twist off into two pieces (believe me, I know). Your engine could be a 218, as you said, or could be a 230. Either way, the head gasket should be the same. Vintage Power Wagons self the Best Gasket brand (or used to, anyway). Quote Link to comment Share on other sites More sharing options...
slatgrille Posted June 24, 2023 Author Report Share Posted June 24, 2023 Thanks everyone, I've got one on order. While I wait, I'm having my overspray paint job I did a several years ago buffed out by a professional body man down the road. It is something I probably could have done, but didn't want to acquire all the materials or spend countless hours doing it. Craig Quote Link to comment Share on other sites More sharing options...
keithb7 Posted June 24, 2023 Report Share Posted June 24, 2023 I did a cylinder head replacement a couple years ago. I made a 3 part series. Part 1 is here: https://youtu.be/vlb2q9w0vGk?list=PLiWbTXH-Vdq71DBuggVl1_URZuov-2Rs9 Quote Link to comment Share on other sites More sharing options...
andyd Posted June 27, 2023 Report Share Posted June 27, 2023 When I started getting the bits for the 230 I planned to build using an edgy Finned Alloy head I didn't want a copper head gasket as I had been told many times copper & alloy are not a good mix.....at the time,around 2010, the Best Gasket brand company were the only place I could find that made head gaskets how I wanted...steel on both sides & were happy to accommodate my request however they would have made the gasket with copper on one or both sides if I had asked......I'd try them as Sniper says.......andyd Quote Link to comment Share on other sites More sharing options...
slatgrille Posted July 16, 2023 Author Report Share Posted July 16, 2023 An update on the head. Except for one head bolt 'hanging up', removal was flawless! Sending unit slid out smoothly and was very clean....as was the head gasket. The copper looked brand new except for the break between # 5 and 6 cylinder. I know that the head has not been off this engine at least for 40 years...if ever! The gasket's printed info on its facing has even 'embossed' itself onto the head surface and will not scrape off. Only resurfacing will get rid of that. I've since cleaned it up including the mounting holes and head bolts. All bolts are good except for one which I will replace. The block and cylinders look good, as there are very minimal ridges at the top of the bores. No pitting anywhere. Once resurfaced and painted, back on it goes! One question...when I put it back on, what is recommended as a sealer for the head bolt threads? With all the cleaning I did I don't want any coolant seepage. Craig Quote Link to comment Share on other sites More sharing options...
rallyace Posted July 17, 2023 Report Share Posted July 17, 2023 Just a couple of things to check while it is apart. Look carefully at the land between the cylinders. Make sure when the gasket failed that the exhaust gasses did not erode the metal. If it did you are looking at having the block decked. Second, Take a straight edge and check to see how flat the head and block are. Again, making sure the new gasket will seal properly. Now as far as a sealer, get a can of the copper gasket sealer. It comes in a spray can. I use plumbers pipe dope on the head bolts. Good old Rectorseal #5 works well as it is a non-hardening sealer that is designed for the temperatures that it will see. Probably the most critical step is torquing the head bolts. The sequence outlined in the service manual must be followed and torque them twice as the process indicates. Once done, bring the engine up to temperature and shut it off. Let it cool and re-torque the head. Again, a very critical step in the process. Good luck. Quote Link to comment Share on other sites More sharing options...
keithb7 Posted July 19, 2023 Report Share Posted July 19, 2023 Sealing threads: Permatex High Performance Thread Sealer. Its in a white toothpaste type tube. Make sure its the high performance stuff. 1 Quote Link to comment Share on other sites More sharing options...
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