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I have a 1500 cc engine in my mg midget it with a Weber 32 DVG carb. It has a 25d4 distributor in it that has the vaccum advance. I know this is not the one that came stock (the 25d4 was for a '70-'74 I believe. I was wondering if anybody has any comments on the performance of this type of distributor and/or recommendations of a different one since this is not the stock distributor.
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1500 midget & 25d4 dist change suggestions
- Thread starter recordsj
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Trevor Jessie
Yoda
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Check with Jeff of Advancedistributors
tosoutherncars
Jedi Knight
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My '78 1500 has a vacuum advance too...
aeronca65t
Great Pumpkin
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I'm running on in my 1500 race car.
With Pertronix and the vacuum unit gutted (so that only centrifugal is working).
Works fine. You can leave the vacuum unit on if you like...it won't make much difference.
With Pertronix and the vacuum unit gutted (so that only centrifugal is working).
Works fine. You can leave the vacuum unit on if you like...it won't make much difference.
aeronca65t
Great Pumpkin
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recordsj said:
Keep in mind that this 25D Lucas distributor has a combo of vacuum and centifugal advance. But the main (and total) advance come from the centrifugal system.
During lower speeds (say 1500 to 2500 RPM), the vacuum system kicks in a little extra timing advance to give the engine better torque at modest speeds. As the engine speed goes up past 3000, the vacumm advance has less and less available vacuum, so it backs off and no longer provides any advance....but the centrifugal system keeps advancing the spark timing all the way to about 5500 RPM or so.
If you drive these cars at lower speeds and chug around at 2500 RPM in 4th gear, the vacuum advance will make a modest difference. But many of us tend drive these little cars harder than that, so the advantage of the vacuum advance system is not really noticeable.
There are some non-centrifugal, fully vacuum distributors out there (mostly Bosch, I think) that work quite differently. They need the vacuum to be working since they have no centrifugal advance.
since the 25d was originally to go with the 1275 engine is there anything I need to do to make sure it works most effectively with the 1500 engine? Would this have anything to do in adjusting the curves for the distributor? Do you have any good reference info you can send me or websites to direct me to?