Guest Len Sholes Posted March 9, 2013 Share Posted March 9, 2013 I am trying to help a friend get the engine started on his 1948 Cadillac. A bit of history is that approximately 6 weeks ago he took the car for a a 10 mile run and parked it in undercover storage. Now he tried to start it and it will not fire up. He asked if I could give him a hand and «i have done the following - checked points, cleaned and adjusted, checked spark at the plugs and have spark, madek sure that gas was getting to the clylinders by pouring gas down the carb and all it will do is fire up for a couple of seconds and then no sign of even trying to start. Let is sit for approsomately 5 minutes and try again and it is the sme thing over again. When I stuck my finger over the plug holes and had him crank it over I had hardly any compression. Checking it with a compression gauge I had readings of any where from 30 to 40 psi. I pumped some oil into a cylinder and now I had 100 psi. So it is appears to me the rings are the problem. I have squirted WD40 into each cylinder as well as engine oil to see if I can get them to free up so the compression will increase but to no avail.I am wondering if anyone has had this problem and come up with a cure other than pulling the engine apart. This car has been running fine up to this time. Link to comment Share on other sites More sharing options...
keiser31 Posted March 9, 2013 Share Posted March 9, 2013 It DOES sound like you are lacking compression, but before tearing into it, I would blow air backwards through the fuel line. Sounds like it will run if getting fuel, so maybe a flake of rust flips up and blocks the fuel line. How long before he last drove it (prior to the 6 weeks you mentioned)? Link to comment Share on other sites More sharing options...
PONTIAC1953 Posted March 9, 2013 Share Posted March 9, 2013 i remember back in the 1970's, my 53 pontiac was my everyday driver, then one monday morning, it would turn over, but not start. did a compression test, and found low numbers, number 8 was zero, turned out to be that the carbon build up was now enough to prevent valves from completely seating. so i decided it was time for a complete rebuild of the engine. charles coker, 1953 pontiac tech advisor. Link to comment Share on other sites More sharing options...
jdome Posted March 10, 2013 Share Posted March 10, 2013 It sounds to me that if it will run on fresh gas dumped down the carb but not on the fuel from your tank, either it is not getting fuel from the tank or the fuel has gone bad. Is the fuel pump working? How old is the gas in the tank? If you have 3 month old ethanol laced fuel in the tank it can spoil in 3 months, even if it ran OK 6 weeks ago. Take the cap off and smell the tank, if it has a paint or turpintine smell to it, it is bad. Gas can go bad before it smells bad too. Link to comment Share on other sites More sharing options...
oldcar Posted March 10, 2013 Share Posted March 10, 2013 It sounds to me like a fuel delivery problem Have you checked to see if the fuel pump is actually delivering fuel to the carb and that there is fuel in the float bowl? If you dump fuel straight into the carb and it runs but cuts out shortly after then there is probably no fuel in the actual carb (float bowl).Disconnect the main fuel delivery pipe from the carb and turn the motor over a couple of revolutions the pump should push fuel out of the pipe. If not you have either no gas in the tank or a faulty pump. Link to comment Share on other sites More sharing options...
trimacar Posted March 10, 2013 Share Posted March 10, 2013 This new ethanol gas attacks the old fuel pump diaphragms. I've had two fuel pump failures in the last year and a half, both with the same problem, and both older rebuilds on the fuel pump (20 years old). My bet is the fuel pump. There are two stations in my area that sell regular, no ethanol, gas, ten cents a gallon more expensive but worth it. Link to comment Share on other sites More sharing options...
Restorer32 Posted March 10, 2013 Share Posted March 10, 2013 Could be as simple as a stuck float in the carb. Link to comment Share on other sites More sharing options...
Friartuck Posted March 10, 2013 Share Posted March 10, 2013 Once the fuel delivery issue has been addressed, suggest using Seafoam motor treatment in both the fuel and crankcase oil. Its available at most auto part stores. This is a product that does free up carbon build up and frees sticky things like rings. It has a proven track record:Sea Foam Sales Company Link to comment Share on other sites More sharing options...
keiser31 Posted March 10, 2013 Share Posted March 10, 2013 Could be as simple as a stuck float in the carb.Seems to be running once fuel gets into the carb. Take the fuel line off at the carb and blow backwards into the line. Link to comment Share on other sites More sharing options...
D Yaros Posted March 10, 2013 Share Posted March 10, 2013 For whatever it is worth, I concur in the fuel delivery problem diagnosis. I would suggest filling the carb fuel bowl(s) via the carb fuel bowl vent tubes, firing her up and seeing if/how long she runs.After the engine dies, if you are able to repeat the results by refilling the carb fuel bowl you know you have a fuel delivery problem. Link to comment Share on other sites More sharing options...
Guest Len Sholes Posted March 10, 2013 Share Posted March 10, 2013 Thanks for the response to my question. No it is not a fuel delivery problem as I checked to see if the fuel pump was working and yes it was. I also have checked and find that gas is been sprayed into the intake when I pump the gas pedal. Even when I pour gas down the carb it will still not start. It is only after you let the engine sit for approximately 10 minutes and then you try to start it and it will fire right up but only stay runing for a few seconds. One thing that I did not mention is that there is no suction on your hand when you hold it over the carb and crank the engine over. To my way of thinking this is due to the low compression that the engine has. I have to think that the rings are stuck as the compression went up when I squirted oil into the cylinders. If it was due to bad valves then there should not have been an increase. I am going to try what Frairtuck suggested and that is try SeaFoam. I see that they have a spray avialable which I could spray into each cylinder. I have used this product by adding it to the gas tank and to the engine oil and have been amazed on how well it works. Link to comment Share on other sites More sharing options...
Owen_Dyneto Posted March 10, 2013 Share Posted March 10, 2013 If the compression really is as low as 30-40 in all cylinders the fact that it won't start comes as no surprise at all. And I'd also have a hard time believing that "This car has been running fine up to this time." Link to comment Share on other sites More sharing options...
Rusty_OToole Posted March 12, 2013 Share Posted March 12, 2013 Could be cylinder wash down from too much gas on the rings. Are the plugs fouled with black oily gassy residue? If they are, they will not fire right unless cleaned by sandblasting.You need to clean the plugs, oil the cylinders and get it started, once it warms up and burns off the excess gas and oil it will be OK.Either that or the carburetor needs to be rebuilt. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now