Adjusting timing 240
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Fleet Mechanic
Joined: Sep 2012
Posts: 1,610
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Adjusting timing 240
I am trying to adjust the timing on my 66 240 with manual trans.
I am trying to keep the engine at about 750 rpm, while aiming for 6 before TDC.
I have read everywhere, and know, that i am supposed to remove the line on the distributor to set timing. Well, my distibuter has a metal line that ties into the Load O Matic carburetor. This is the only hose that comes out of the distributor. Do i disconnect this? If so, it make no difference in how the engine performs. What does this mean?
Thanks
I am trying to keep the engine at about 750 rpm, while aiming for 6 before TDC.
I have read everywhere, and know, that i am supposed to remove the line on the distributor to set timing. Well, my distibuter has a metal line that ties into the Load O Matic carburetor. This is the only hose that comes out of the distributor. Do i disconnect this? If so, it make no difference in how the engine performs. What does this mean?
Thanks
Post Fiend
Joined: Apr 2002
Posts: 19,311
Likes: 97
From: Waterloo, Iowa
The reasoning for disconnecting and plugging the vacuum advance line is for accuracy, we want to be sure that the 6° or 10° BTDC (or whatever) initial timing we are measuring is not being skewed by vacuum advance tipping in.
A loadomatic type distributor is a little different than what many people are used to. There are no mechanical or centrifugal weights internal. All of the ignition advance is via metered vacuum only from the carburetor ported from two separate locations. As such the OEM type carburetor must be used. Maybe you know this already.
A loadomatic type distributor is a little different than what many people are used to. There are no mechanical or centrifugal weights internal. All of the ignition advance is via metered vacuum only from the carburetor ported from two separate locations. As such the OEM type carburetor must be used. Maybe you know this already.
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Fleet Mechanic
Joined: Sep 2012
Posts: 1,610
Likes: 54
I understand all you said except the last sentence. I don't fully understand the workings of these components.
I am using the stock 1101 carb and the stock Load o Matic distributer. Are you saying that this set up will not have vacuum?. I know for sure what the vacuum is like on my 77 f100, it is a rubber hose i disconnect to set timing. The 66 is steel.
So, should there be a change in how the engine reacts etc, at idle, if i unscrew the line to the distributer?
Sorry for being thick.
I am using the stock 1101 carb and the stock Load o Matic distributer. Are you saying that this set up will not have vacuum?. I know for sure what the vacuum is like on my 77 f100, it is a rubber hose i disconnect to set timing. The 66 is steel.
So, should there be a change in how the engine reacts etc, at idle, if i unscrew the line to the distributer?
Sorry for being thick.
Post Fiend
Joined: Apr 2002
Posts: 19,311
Likes: 97
From: Waterloo, Iowa
The problem is when peeps install a different carburetor than factory issue. The loadomatic distributor will only work correctly with the correct metered vacuum applied. Manifold vacuum or conventional carburetor vacuum won't work right and will run poorly.
While not directly familiar with this type of arrangement I would not be surprised if disconnecting the vacuum line at typical idle RPM has little to no effect on base timing. It's more of a belt & suspenders thing in the checklist.
There shouldn't be any additional timing being pulled in (My opinion) disconnecting & plugging the line just makes sure. Some people set their idle up around 3000, gotta account for that just in case.
Now if you spool the RPM way up, then you should be able to observe the limits of the advance curve.
While not directly familiar with this type of arrangement I would not be surprised if disconnecting the vacuum line at typical idle RPM has little to no effect on base timing. It's more of a belt & suspenders thing in the checklist.
There shouldn't be any additional timing being pulled in (My opinion) disconnecting & plugging the line just makes sure. Some people set their idle up around 3000, gotta account for that just in case.
Now if you spool the RPM way up, then you should be able to observe the limits of the advance curve.
Thread Starter
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Fleet Mechanic
Joined: Sep 2012
Posts: 1,610
Likes: 54
Once again. Thanks for the help. This engine is running great.
I also bought an oil pressure gauge and checked the pressure just to be sure this engine is good.
Seems as though i have a good one.
Thanks again.
I also bought an oil pressure gauge and checked the pressure just to be sure this engine is good.
Seems as though i have a good one.
Thanks again.
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