Magnum 5.2 timing

[Slantsix64]

Hey guys wanted to know how much mechanical timing are you guys running along with initial timing on your guys magnum 5.2 . Stock cam compression only added an rpm air gap and a 600 cfm carb. The car is a stick four speed with 3.55s thanks!

 

[74 DART']

Anybody have an answer?

 

[Slantsix64]

Anybody have an answer?

Lol don’t think so

 

[Bobzilla]

You can treat this like any other decent engine, not 5.2 Magnum specific. Around 34-36 degrees mechanical at about 2500 rpm, and about 10 degrees initial.
Use a vacuum advance for best street mileage.
If using a swapped in factory LA distributor you use FBO limiter plate to get the mechanical limits you want.
How to limit mechanical advance in a mopar distributor, tuning for street, strip or all out racing, cure that rich stinky idle, win races

 

[66fyssh]

@Bobzilla the interesting thing about Don at FBO is he recommends full manifold vacuum.

I run my 5.9 Magnum at 20 initial and 36 total using an FBO limit plate. I've gone back and forth between ported and full vacuum. I feel full vacuum burns the idle fuel better.

 

[Slantsix64]

Yup i feel that my stock 318 magnum likes less mechanical and more initial timing. about 16 mechanical.

 

[Bobzilla]

Excessive initial timing just causes more turning resistance that makes the starter work more, potentially shortening it's life. Keeping the Initial timing around around 10-12 or so reduces that load on the starter. Then adjust the mechanical advance to give the total that engine wants at wide open throttle under load, like full throttle acceleration. This is where the FBO limiter plates come in handy on stock style distributors. Of course the springs and weights get adjusted for the curve from initial up to total, and at what RPM. Finally, the vacuum advance should be connected to manifold vacuum so that as soon as the engine starts the vacuum pulls in more idle and low RPM timing that the engine needs to run best and get good fuel economy.

 

[74 DART']

Excessive initial timing just causes more turning resistance that makes the starter work more, potentially shortening it's life. Keeping the Initial timing around around 10-12 or so reduces that load on the starter. Then adjust the mechanical advance to give the total that engine wants at wide open throttle under load, like full throttle acceleration. This is where the FBO limiter plates come in handy on stock style distributors. Of course the springs and weights get adjusted for the curve from initial up to total, and at what RPM. Finally, the vacuum advance should be connected to manifold vacuum so that as soon as the engine starts the vacuum pulls in more idle and low RPM timing that the engine needs to run best and get good fuel economy.

That’s some good info! Thanks. I have a question. I was thinking of buying a Mopar electronic conversion kit with the distributor. If so would you recommend the FBO plate also or just on a oem distributor? Mine will be a stock 5.2 with a carb swap also. Thanks

 

[Slantsix64]

That’s some good info! Thanks. I have a question. I was thinking of buying a Mopar electronic conversion kit with the distributor. If so would you recommend the FBO plate also or just on a oem distributor? Mine will be a stock 5.2 with a carb swap also. Thanks

The reman distributors came with all sorts combos bigger slots/smaller slots heavy springs, smog curves etc its always best to recurve for your application FBO plates are a great deal.

i just posted for sale a small block distributor that was recurved by ignition engineering in Orange county
[FOR SALE] - Small Block Distributor Recurved bolt in if your interested.

 

[Bobzilla]

That’s some good info! Thanks. I have a question. I was thinking of buying a Mopar electronic conversion kit with the distributor. If so would you recommend the FBO plate also or just on a oem distributor? Mine will be a stock 5.2 with a carb swap also. Thanks

I am running a Mopar conversion kit, distributor, and orange box. I never had any troubles with this setup yet, but I bought the kit new in the mid 90s. They have changed suppliers since then and I personally don’t know if the quality is still good or not.