centerline
Regular Contributor
I have asked the questions and gotten some answers, but there is some conflicting information concerning the answers....
so im looking for some clarification from someone who knows everything about these 4cylinder engines.... this has been an ongoing problem since I aquired the boat, so please allow me a minute to describe what Ive done with it so far...
I have a GM 181ci engine and cant get the timing right for some reason.... I bought and tried an EST system, and had numerous problems getting it to set properly, so I have removed it and going back to the conventional distributor, but this time with a pertronix module....
I acquired this boat as a project at an estate sale, and have the back story on in from the wife of the guy who owned it.... the boat/engine is a factory rebuild with no hours of actual usage due to it never being able to get it to run properly....
the Delco distributor that was installed at the time I got the boat had an initial timing of 8BTDC (which is correct) and seemed to run fine on the muffs... but the test run on the water showed a problem. when accelerating and while running on plane, it had a serious ping.... when retarding the timing while it was at speed on the water, I could get the ping to go away and run great with lots of power, but when it was returned to an idle, it was extremely rough and wanted to die, which is because the timing was too far retarded now for the idle.... the flyweights are free and work fine, which is seen with the timing light as it runs....
so instead of trying to fix the old distributor, I bought an EST ignition and tried it.... I had the same issues and could NOT get it to set right after many attempts and too much money spent on trying to fix it....
so im NOW back to the conventional distributor.
I took the distributor into the local speed shop to have it turned to see what the curve is, and even though it seemed to follow the curve chart reasonably close without any modifications, the guy that turned it said this was cam specs and not crank specs.... he said the crank specs will be double what is shown on his paperwork.... without opening my mouth and saying something that may insult him, I had to wonder if he knew what he was doing, but I took the distributor and installed it to see what happens now....
its the same as it was before on the muffs, but I didnt take the boat to the lake just to see it ping again.
the initial timing is set at 8BTDC, and at 3000rpm, the all in timing shown is about 31BTDC..... according to the charts I see, the "all in" advance should be 24-26BTDC, which the guy at the speed shop said this seemed a bit low... and that base timing needs to be added to the chart to give the actual "all in" timing.....
so what I need clarification on is, how does one read the "ALL IN" number?... with a conventional distributor, what should I see at the balancer/timing mark when the engine is running at 3500-4000rpm?....
should the distributor curve be set to the chart, and the initial added to it for "all in".... 8btdc base and 24 degrees advance from the distributor would equal 32BTDC "ALL IN".....
with all the confusion that I have in my head, im asking someone to figure the numbers out and tell me how many degrees NEEDS to be built into the distributor to get the proper "ALL IN" advance, when I set the initial timing to 8BTDC..... without showing me or instructing me how to decipher the chart.... i need a number to give the guy at the shop so he can set the distributor up to get what the 181 engine needs to run like it should...
and should the total all in advance show 24-26 degrees at the crank timing mark, or 32 degrees at the crank timing mark?... thank you
so im looking for some clarification from someone who knows everything about these 4cylinder engines.... this has been an ongoing problem since I aquired the boat, so please allow me a minute to describe what Ive done with it so far...
I have a GM 181ci engine and cant get the timing right for some reason.... I bought and tried an EST system, and had numerous problems getting it to set properly, so I have removed it and going back to the conventional distributor, but this time with a pertronix module....
I acquired this boat as a project at an estate sale, and have the back story on in from the wife of the guy who owned it.... the boat/engine is a factory rebuild with no hours of actual usage due to it never being able to get it to run properly....
the Delco distributor that was installed at the time I got the boat had an initial timing of 8BTDC (which is correct) and seemed to run fine on the muffs... but the test run on the water showed a problem. when accelerating and while running on plane, it had a serious ping.... when retarding the timing while it was at speed on the water, I could get the ping to go away and run great with lots of power, but when it was returned to an idle, it was extremely rough and wanted to die, which is because the timing was too far retarded now for the idle.... the flyweights are free and work fine, which is seen with the timing light as it runs....
so instead of trying to fix the old distributor, I bought an EST ignition and tried it.... I had the same issues and could NOT get it to set right after many attempts and too much money spent on trying to fix it....
so im NOW back to the conventional distributor.
I took the distributor into the local speed shop to have it turned to see what the curve is, and even though it seemed to follow the curve chart reasonably close without any modifications, the guy that turned it said this was cam specs and not crank specs.... he said the crank specs will be double what is shown on his paperwork.... without opening my mouth and saying something that may insult him, I had to wonder if he knew what he was doing, but I took the distributor and installed it to see what happens now....
its the same as it was before on the muffs, but I didnt take the boat to the lake just to see it ping again.
the initial timing is set at 8BTDC, and at 3000rpm, the all in timing shown is about 31BTDC..... according to the charts I see, the "all in" advance should be 24-26BTDC, which the guy at the speed shop said this seemed a bit low... and that base timing needs to be added to the chart to give the actual "all in" timing.....
so what I need clarification on is, how does one read the "ALL IN" number?... with a conventional distributor, what should I see at the balancer/timing mark when the engine is running at 3500-4000rpm?....
should the distributor curve be set to the chart, and the initial added to it for "all in".... 8btdc base and 24 degrees advance from the distributor would equal 32BTDC "ALL IN".....
with all the confusion that I have in my head, im asking someone to figure the numbers out and tell me how many degrees NEEDS to be built into the distributor to get the proper "ALL IN" advance, when I set the initial timing to 8BTDC..... without showing me or instructing me how to decipher the chart.... i need a number to give the guy at the shop so he can set the distributor up to get what the 181 engine needs to run like it should...
and should the total all in advance show 24-26 degrees at the crank timing mark, or 32 degrees at the crank timing mark?... thank you