Author Topic: compression question  (Read 5047 times)

Jim B PEI

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Re: compression question
« Reply #15 on: August 15, 2010, 07:42:23 PM »
I take it you have an earlier style car? If so, the starter is a sore point on them, because it doesn't have a proper follow through whatever the technical term is. The later starters are much better. The earlier cars tend to disengage. It almost sounds like you are getting too much fuel as you said. There could be something going on with the carburator or needle and seat, so just for the purposes of getting it started and running if it is flooding (and it isn't not starting because of bad old gas,) maybe disconnect/divert the gas supply until after you have got it started however briefly. If it is choked properly, try getting to run with a bit of starting fluid and followup a second time with a bit of gas in the carb. I try to work the linkage to get it to accelerate on the existing fuel in the carb. Every bit of running will make it hotter in the cylinders and more likely to fire the next times even with low compression. If you get it to the point where it will run a bit, then reconnect the gas line, and keep it running as long as possible, and pour a prepared mixture of 50/50 new gas and Marvel mystery oil bit by bit into the carb as it is running. Keep the revs above idle, and goose it a bit. The heat and pressure might ungum things a bit to raise the compression a bit--every bit helps the next time. If you get it to the stage where it heats up to operating temperature, and can idle, then I would adjust it to a fast unchoked idle. The oil in the gas will make it smoky, so if you can do this outdoors...

After this sort of treatment, I like to change the oil after a good half hour or so of running time while it is still hot, and put in fresh, and start it up again to repeat. With my Studebakers, they are sometimes reluctant to start if they have been sitting for a month of more (they all have un-rebuilt engines, but the Kaiser was rebuilt some years ago) and smoke and drip oil, but the more they are run the better they get.
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Lisa P

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Re: compression question
« Reply #16 on: August 16, 2010, 11:08:49 AM »
Jim, the car is a '48.  My mechanic friend, older fellow, came over and said that the timing was wrong and it was kicking back against the starter.  We adjusted it, put more ether in the spark plug holes and a little bit of gas and still nothing.  He said that it probably needs more oil dumped in to try and loosen the rings and new plugs as the ones I bought were el-cheapos from the farm store and once they get fouled aren't worth a dime.  They were sparking a nice blue flame outside the engine but he was thinking that mayber they weren't firing in the engine.  I have the fuel coming from a glass jar on the floor as I don't have the gas tank cleaned out yet.  The fuel is new and the carb is getting plenty to the engine however, I did notice that one of the carb gaskets has shrunk and is visible as you look down into the carb.  The choke does seem to be fully closed when I try starting it.  I did get fresh oil for her and will put that in tonight along with the new plugs, we'll see what happens then.  If I can get it running I will give it the Marvel Mystery oil treatment.  Thanks again for all your advice!

boatingbill

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Re: compression question
« Reply #17 on: August 16, 2010, 01:56:21 PM »
LisaP: I think the starting fluid is stripping any oil on the cylinder walls. I recommended before that you use Marine fogging oil to coat the cylinder walls and raise compression. I think your spark is fine as you have a low compression readings anyway. Did you verify the timing manually as I said earlier? Your engine may be running on only two or three cylinders. I recommend on a cold engine that you hold a 1/8 drill bit in the carb neck (don't drop it!) and adjust the choke enough to touch the drill bit against the carb neck wall. This setting always worked for me even in the coldest Minnesota Winters (below zero) with my '51 sitting outside and a 6v system. I still suspect your problem may be timing above other issues mentioned. Do not run this engine more than a minute or two without cooling fluid in the engine!

Lisa P

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Re: compression question
« Reply #18 on: August 16, 2010, 02:49:07 PM »
Boating Bill, you are probably correct about the starting fluid.  The night before I had put some motor oil in each cylinder as best I could since the cylinders are not directly below the spark plug hole.  I have Sea Foam (only thing I could find but says it will work) for fogging the engine and will try that tonight if it still refuses to start.  We did verify the timing as you suggested, this was how my mechanic friend noticed that the rotor was already past the #1 cylinder when it was at the top of the compression stroke.  I had taken the oil pump off to drop the oil pan not realizing that it didn't need to be removed and when I reinstalled it, I had it lined up wrong.  I will use the drill bit spacing method to adjust the choke tonight as well.  It is great to know that these started so well even in the cold, I can't wait to drive it and it may be winter before it happens!  Thanks again for all the advice, I really appreciate it.

mahin10

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Re: compression question
« Reply #19 on: August 17, 2010, 05:03:45 PM »
This is just from what I've heard, but supposedly rings etc can bind up and won't do their job with compression after an engine has been sitting for a while. Pouring just a bit of oil--Marvel Mystery oil gets mentioned sometimes, sometimes a bit of transmission oil to loosen it up, but regular oil would work--down the plug hole could raise the compression a bit. If you can then get it running with a bit of starting fluid etc so that the engine warms up, these problems sometimes sort themselves out with the heat and pressure enough that it gets progressively easier to start.



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Logan

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Re: compression question
« Reply #20 on: August 19, 2010, 08:38:22 PM »
This last post (by mahin10) is spam.  He has copied and pasted an earlier reply with a spam link.  Webmaster, can you remove him?