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1931 Chrysler CD8 Roadster Engine Compression

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Today I finished up the tweaking needed on 1931 Chrysler CD8 Roadster engine. This is an in-line 8 cyl 240CI unit, flathead, and engine was not run since the 1960's. The internals were previously checked out, and were fine except for the valves which needed refacing (2 replaced) and lapping in. Seats seemed fine. Anyway, new gaskets all around and torqued head to 60lbs. All accessories re-built. Engine started right up (I had it running briefly 4 months ago after re-doing the valves) with only noticeable noise a bit of valve tapping at #8, so I will check that clearance later (they were set at .009 and .007 if I recall). After it warmed up, fine tuned timing at distributor, then shut it off and re-torqued head bolts to 60lbs warm. I then checked compression and it varies from 77lbs to 86 lbs across 8 cylinders, with #5 highest and #2 lowest. Running new 10W30 oil, new 50/50 coolant (no leaks), temp got up to 140, oil pressure started cold at about 35-40 lbs, settled when warm around 15-20 lbs at idle. Ammeter charging 5-10amps at idle. Ran car thru the 5 speeds 4F +R (on jack stands) after topping up transmission with 600W oil and a rebuild of ball/trunnion drive joints. Still using the old oil filter, have a new one to put on eventually. Coolant running clear as glass in rad (I previously cleaned out and flushed block/head). I'm thinking I can sign off on this stage of restoration, what do the experts think? Is compression in decent range for a Sunday driver? Any other thoughts?

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These era engines are still running great at 60psi so your range, though slightly greater than 10%, should be fine I would think. Oil pressure also seems about right. I’m not sure about your engine but most valves were set .08 and .10. Your.09 and .07 sound tight to me. A little tick is better than a little or lot of valve burn.

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Chrysler manual suggests setting valve tappets at .011 intake and .012 exhaust when engine is cold and before setting timing. Then it suggests when engine has had timing set correctly, warm up engine and re-set valve tappets at .005(intake) and .007(exhaust) for "quiet valve operation". I was aiming for .007 and .009 respectively, and may have set one or two a bit slacker for cylinder 8. Not a big job to double check them now engine is running well. Without a body in the way, side covers are an easy removal. Next major step is the hydraulic breaks, new kits in wheel cylinders and master, new brake lines throughout, and new linings for some of the wheels (I have 6 good shoes/linings, need to re-line a pair). Oh the fun you're missing! 

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HI GUNSMOKE, I HAVE THE SAME CAR IN ROME, CHRYSLER CD8 ROADSTER OF THE END OF 1930. CAN I KNOW WHERE I CAN BUY THE ENGINE AND ENGINE GASKETS? YOU WOULD ALSO HAVE SITE ADDRESSES THAT PROVIDE RUBBER GASKETS AND SPARE PARTS. I'M ADVENTURING IN A VERY DIFFICULT RESTORATION. THANKS MANY FOR THE HELP

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13 hours ago, GianlucaCD8 said:

HI GUNSMOKE, I HAVE THE SAME CAR IN ROME, CHRYSLER CD8 ROADSTER OF THE END OF 1930. CAN I KNOW WHERE I CAN BUY THE ENGINE AND ENGINE GASKETS? YOU WOULD ALSO HAVE SITE ADDRESSES THAT PROVIDE RUBBER GASKETS AND SPARE PARTS. I'M ADVENTURING IN A VERY DIFFICULT RESTORATION. THANKS MANY FOR THE HELP

Try Olson's Gaskets....https://www.olsonsgaskets.com/

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I would just move forward and get your project on the road.  Adjust your valves and change your oil filter. 

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