Wanting to convert 69 stock 340 to electronic ignition. Is there a problem with using a stock distributor from a 71 or 72 360? I have a couple of distributors I pulled, cleaned up and seem to be ok although I haven't checked vacuum advance to see if it's working. I thought these would be better than some of the later junk that's out there. Am I wrong?
Early 70's electronic distributor
- Thread starter etngeorge
- Start date
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@halifaxhops can make you one if you can't... He has a Sun distributor machine and can cater the curve to your application...
Check the curve specs might be close enough to work. Even if you buy a new junk one they do not list the curves on them that I have seen.
yellow rose
Overnight Sensation
And the junk new ones don’t all have the same curves even with the same part number.
Not many engines got the transistorized ignition and magnetic pickup distributors before the '72 model year. (see 1972 MTSC here)
A '69 340 would be the higher compresion engine with four barrel.
I don't know what a 71 or 72 360 would have but my guess is a low compression and a 2 bbl and intended for a truck. So the ignition curves would probably be different.
A '69 340 would be the higher compresion engine with four barrel.
I don't know what a 71 or 72 360 would have but my guess is a low compression and a 2 bbl and intended for a truck. So the ignition curves would probably be different.
cudamark
Well-Known Member
Maybe, maybe not. It will depend on the specs of each distributor. I'd get one setup for a 340 with your engine/transmission,rear axle specs.
I could have taken these distributors from 73 or 74 but they were two barrel engines. Was the direct connection (MP) distributor a stock recurved unit or was it a different animal entirely? Apparently the USA made units are no longer available. This is for a cruiser so reliability is important without breaking the bank. Thanks, everyone
There have been several versions.
A. Race/Drag Race with no vacuum advance but has provision to mechanical tach drive. I'm sure these are not what you are looking for.
B. With Vacuum advance.
- 1 Versions made by Chrysler. The one I have, has an advance curve similar to a 340 except somewhat less in the initial advance. This will make more sense on a diagram. Basically its more a pre-emmissions advance curve like used on the 273 Hi-performance engines.
- 2 Versions made by Mallory (same part number as the later Chrysler built versions). Quick advance that is not particularly good as delivered. Also not so good with control at the high rpms. In its favor was more easily changed springs etc.
I would suggest a Chrysler made one (Halifaxhops may have) or the current copy that Rick Ehrenberg sells on ebay
Does your car have 4 speed or torqueflite?
From that I can show you roughly how the advances differ and you can see how that effects the initial timing.
Honestly, for a cruiser not driven alot, the points distributor is probably just as reliable. You could halifaxhops check it out and he could also supply some good quality points and condensor. The biggest advantage to the electronic will be the reduced maintanance. But if the yearly milage is low enough, then that advantage goes away.
If you do go for the Chrysler ECU, get some 'piggyback' terminals. That way there's no need to splice into the existing wires.
That is a valid point. My car is a torqueflite and I doubt it will see 1k miles a year. So I think I will contact Halifaxhops for some quality points. I thought it would be dual points(not) but it may not be original distributor.
If I change it later I have a better idea how to proceed. Thanks
The advantage of the dual point is mostly at the drag strip. They provide more time for the coil to saturate at engine rpms where the time between cylinders firing is less than half the time available at idle.
Here's the range of timing expected with an original '69 340 distributor for automatic transmission.
It's based on the specs in the Dodge Service Manual.
According to Dodge (sometimes Plymouth was different) base timing should be set at 5 *BTC
And here's the comparison with the advance of a Chrysler built MP distributor using 7.5 *BTC for the initial.
That 5 degree initial was spec'd to reduce CO and HC emissions. With advance curves like the ones above, it would be worth setting initial a few degrees higher.
If it doesn't cause any ping or detonation, it should prodiuce better milage, throttle response and slightly cooler engine temperatures. For a comparison, the initial timing in the 1967 Plymouth manual for the 273 -4 bbl engine was 10 *BTC (non-emissions versions)
The vacuum advances of the original 340 may come in earlier. I know the '68 version does. But the MP vacuum advance can be adjusted to come in earlier as well. So as far as advance curves go with magnetic pickup distributors, these look like reasonable options.
Here's the range of timing expected with an original '69 340 distributor for automatic transmission.
It's based on the specs in the Dodge Service Manual.
According to Dodge (sometimes Plymouth was different) base timing should be set at 5 *BTC
And here's the comparison with the advance of a Chrysler built MP distributor using 7.5 *BTC for the initial.
That 5 degree initial was spec'd to reduce CO and HC emissions. With advance curves like the ones above, it would be worth setting initial a few degrees higher.
If it doesn't cause any ping or detonation, it should prodiuce better milage, throttle response and slightly cooler engine temperatures. For a comparison, the initial timing in the 1967 Plymouth manual for the 273 -4 bbl engine was 10 *BTC (non-emissions versions)
The vacuum advances of the original 340 may come in earlier. I know the '68 version does. But the MP vacuum advance can be adjusted to come in earlier as well. So as far as advance curves go with magnetic pickup distributors, these look like reasonable options.
BillGrissom
Well-Known Member
Easiest is the "ready-to-run" HEI distributor by Ningbo, ~$45 plus you need an e-core coil. See Skip White Performance (ebay) or others. I don't know the curve, but won't matter for me since using a Holley Commander 950 for spark control. Easiest wiring and best spark with a Mopar e-distributor is to use the GM 8-pin HEI and coil from a 1985-95 V-8 truck. The Mopar pickup will trigger it, but get the polarity right (spin in air, view pickup teeth w/ timing light, assure it sparks when they align). The GM cable connects the HEI and coil, so all you need is 12 V IGN power. Also has a tach wire out. You can use the Mopar ECU, but will be much more wiring effort (ballast or dual ballast), all for a weaker spark and less reliable.
Easiest what? To have the wrong timing and distributor almost guarenteed to fail?
Read this thread before wasting any time or money.
Carbon button in distributor cap broken off, melted
Read this thread before wasting any time or money.
Carbon button in distributor cap broken off, melted
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