Topic: Compression in #3 Cylinder


Garrison202    -- 08-19-2021 @ 8:04 AM
  I have a ‘36 Phaeton that I’m putting back on the road after being parked for 25 years. I entrusted it first to an older gentleman, who gave it a once over, changed the fluids, got it started and left me lots of notes with his suggestions for getting it road ready.
We’ll, he got it running and passed away not long after. Now I’m trying to interpret the notes he left me. One of them is:

“No compression in #3 cylinder. Check compression.”

I don’t know if this was a note he left for me or a note he left himself! Is this something he might have fixed? If not… if it came back to me with no compression in cylinder #3, what effect would this have on it’s drivability? What does it even mean?

Thanks so much!
John


40 Coupe    -- 08-19-2021 @ 9:47 AM
  I suggest you do another compression test. With battery full charged, Remove a spark plugs, leave the ignition switch in the off position, step on the throttle all the way to the floor and pull the throttle knob all the way out, and choke pushed in all the way in. Connect compression tester to #1 cylinder (front passenger side) and then turn the engine over until the compression gauge stops climbing (about 20 sec) read the gauge and then remove and install in #2 (next cylinder rearward on the Pass side) repeat test #5 cyl is front drivers side. Write down all your readings. It often happens that a valve sticks open not allowing proper compression or no compression. Especially when the engine sits for a long time. Typically not a big deal adding MMO to the oil and slowly drizzle some in the Carb while running can sometimes fix this issue. Best to run the car .

This message was edited by 40 Coupe on 8-19-21 @ 9:51 AM


37RAGTOPMAN    -- 08-19-2021 @ 10:17 AM
  you can do this before doing a compression test
if you pull off the # 3 cylinder ign wire while runnig [ use insulated tool ], does it make a difference in the running ?
if you rev it up does the engine shake,?
take the air cleaner off, rev up the engine, do you hear a popping noise in the carb ?
try the same thing, listen to the exhuast and do you hear anything, popping
Like 40 coupe suggested try MARVEL MYSTERY OIL,
and drive the car, it might clears up,
if you have a vacuun gauge is the needle steady or does it shake alot ?
you might have to get a few tools to diagnose the problem correctly,
hope this helps 37Ragtopman Maine


Jacques1960    -- 09-08-2021 @ 8:09 AM
  Ragtopman, Fellow Mainer (MDI) here; what do you think is reasonable compression (warm engine) for a 36 flattie with aluminum heads ? Got 80 psi on all 8 cylinders which, while below 90 ish, is reassuring given consistency. Appreciate your thoughts. Thank you.


marko39    -- 09-08-2021 @ 11:17 AM
  80psi is not too bad the more important issue is that they were all even. You can enjoy for many more miles.


Jacques1960    -- 09-08-2021 @ 1:05 PM
  Thank you !


37RAGTOPMAN    -- 09-08-2021 @ 1:13 PM
  HI
each compression gauge might read a little different,
as long as they are close 10-15 lbs,
you can try a differnt gauge and see what it reads,
hope this helps, 37 Ragtopman, MAINE, SEARSPORT.
NICE 36 PHAETON ,,,, PHOTO looks like it was taken in FL ?



Jacques1960    -- 09-08-2021 @ 2:18 PM
  Thank you; previous owner purchased the car in California from “Checkered Flag” motors - no Palm Trees here on Mount Desert !


Jacques1960    -- 09-08-2021 @ 2:19 PM
  “Chequered” Flag


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