Dwell

[Dunzvett81]

Gerry LP: if you got your ears on, this question is for you. I just want to make sure that I set my dwell right at 30 deg. However I have a dwell meter that is for 4, 6 & 8 cyl. engines. I know that Gerry always said use the 6 cyl. side but there was a switch for 6 and 8. There is no switch on mine. So do I use the 6 or 8 cyl. line? Here is a couple pics of the meter.
thanks in advance
Jay

 

[Hib Halverson]

If the engine to which you have the dwell meter connected has 6 cylinders, use the 6 line. If the engine has 8 cylinders, use the 8 line.

 

[Dunzvett81]

thanks

 

[GerryLP]

DunzVette81,

In page 6C4-7 of the 1981 Corvette Shop Manual says to use the 6-cylinder scale. I must admit that I could not tell you why the instructions say to use the 6-cylinder scale (but I have tried to research why that is); however, to verify the information (in case of a typo), I searched the L81 Rochester manual Delco 9D-5-1, and on page 17, paragraph 4 it says to use the 6-cylinder scale.

But to answer your question, on your Dwell meter use the 6-cylinder scale.

GerryLP:cool

 

[Dunzvett81]

Thanks Gerry

 

[Sensei]

If the engine to which you have the dwell meter connected has 6 cylinders, use the 6 line. If the engine has 8 cylinders, use the 8 line.

Whoa! We are not talking about setting points! This is an '81, you use the dwell meter for carb adjustment. USE THE 6 CYLINDER LINE!!! (Like Gerry said)

 

[Dunzvett81]

thanks Gerry & Sensei !!
Jay

 

[Hib Halverson]

DunzVette81,

In page 6C4-7 of the 1981 Corvette Shop Manual says to use the 6-cylinder scale. I must admit that I could not tell you why the instructions say to use the 6-cylinder scale (but I have tried to research why that is); however, to verify the information (in case of a typo), I searched the L81 Rochester manual Delco 9D-5-1, and on page 17, paragraph 4 it says to use the 6-cylinder scale.

But to answer your question, on your Dwell meter use the 6-cylinder scale.

GerryLP:cool

I'm sorry. I was confused by the original question asking about a 30 deg dwell angle which would have been right for a point type dist. in a V8. That confusion had me thinking we were talking about setting points. I don't remember the original post stating the car was an 81 or that it was the carb being worked on, but if that's the case, then, yes, to read the mixture solenoid's dwell time, you'd use the dwell meter on the 6 cyl setting.

Again, sorry for the confusion.

 

[Dunzvett81]

Okay, I took off the air cleaner cover to set the dwell. I turn the air valve adjust screw in very small increments until I hit 30 deg. on the 6 cyl scale. When I put the cover back on the dwell goes up to 40 deg on the 6 cyl scale which is about 30 deg on the 8 cyl scale. When I take the cover back off it goes back to 30 degs on the 6 cyl scale. I am a bit confused :confused. Any thoughts??
thanks
Jay

 

[GerryLP]

Jay,

The initial setting is as close to 30 degrees. Once the setting is done, the carburetor will adjust anywhere between 20 and 50 degrees. There are certain conditions and parameters playing to get the carburetor deliver the right mixture.

For example, you were in the garage or driveway when you did it, but once the car is on the road, it will encounter air and attempt to adjust the mixture accordingly. If for example, you are driving along and come across a column of air 15 degrees cooler, the carburetor will adjust and en richen the mixture to avoid getting too lean...

GerryLP:cool

 

[Dunzvett81]

okay, so I did nothing wrong then. I set it at 30 in the garage.
thanks Gerry

 

[GerryLP]

I'm sorry. I was confused by the original question asking about a 30 deg dwell angle which would have been right for a point type dist. in a V8. That confusion had me thinking we were talking about setting points. I don't remember the original post stating the car was an 81 or that it was the carb being worked on, but if that's the case, then, yes, to read the mixture solenoid's dwell time, you'd use the dwell meter on the 6 cyl setting.

Again, sorry for the confusion.

Hib,

it happens!

But you had me guessing for a moment (I mean, I really thought for a moment that the 6-cylinder scale thing could have been a typo or something), and I didn't realize you were thinking distributor-dwell...

I wonder if the use of the 6-cylinder scale has to do with the phasing of what it represents? But more and more I think that the engineers felt it provided the correct algorithm or even voltage, Que no?:confused

GerryLP:cool

 

[Peer81]

Thanks for this thread everyone.
I remembered I also needed a dwell meter, and with this explination I know what to do now
Just bought a dwell meter on the internet for a few bucks (or euro's) so that should be mine in no time

Groeten Peter

 

[LannyL81]

I put an O scope on the test connector to take a look at the pulse width, also had a dwell meter connected. The dwell meter was showing about 30 on the 6 cylinder scale..the O scope was showing about a 30 millisecond pulse width. Have to connect them both back up now that I have a varying dwell and see if the two really do correspond.