Welcome to the next installment of the

Topic of the Week

This week, we're going to talk about ignition systems.

We want everything from points to electronic to capacitive discharge and everything between.

Good one! I have a question about the TPI that is about to go onto my SBC. I have a 1973 motor with 10.25:1 CR. I am putting TPI onto it and was wondering about the ignition. With the stock TPI distributor, what am I looking at in terms of capability to generate RPM's? Do I want more, and if so, how many and how do I get them? I hear all this stuff about voltage drop and stuff like that but everything having to do with electricity is greek to me.

J. J.

Multi- Batteries: What about having two batteries over just one better battery. If space alows go with two parell batteries, in parell configuration the internal thevinen resistance seen by the Heep's system will be halved, so there responce time will be faster. Parell configuration also enables double the current flow.

WIRES: Milti strand and solid wire have identical charicteristics But a 1000strand wire will be more reliable in a high flex and vibration environments like on our heeps.

Capacitance: you could put a Cap on your battery to keep a constant voltage, your deep cycle battery will provide alot of current but an added cap can help keep you voltage high for quick voltage drops. What size? (.5f-1f) could do the trick.

Thats my power_facts input

About 6 years ago I bought a Jacobs "energy team" package, consisting of computer, coil, and ignition wires. I'm on my third "brain". The first two self-destructed and were replaced and upgraded to "ultra team" under warranty (reluctantly on their part). The only improvement that I've noticed is that the engine starts quicker. I don't plan to buy anything from Jacobs again.

As for aftermarket ignition systems....I run an MSD Pro Billet distributor w/mechanical advance not vacuum advance, MSD 6AL (al=rev limiter) and an MSD Blaster coil...haven't had a problem in four years with this set up. Heep starts first click every time!!
IMHO---best set up made!!
As for factory set ups.....install a GM HEI into any 4.2l and ditch the Motorcraft crap...it's worthless.
One hot wire feed to the HEI....no brain to blow!...no broken or corroded connections to worry about!...no shitty black stuff runnin down your fender!....etc.

Originally posted by patooyee
Good one! I have a question about the TPI that is about to go onto my SBC. I have a 1973 motor with 10.25:1 CR. I am putting TPI onto it and was wondering about the ignition. With the stock TPI distributor, what am I looking at in terms of capability to generate RPM's? Do I want more, and if so, how many and how do I get them? I hear all this stuff about voltage drop and stuff like that but everything having to do with electricity is greek to me.

J. J.

J.J.,

The TPI on a stock 350 is only good to around 5000 rpm then your throttle body and runners become a restriction. What kind of RPM are you looking for?

You said you are running 10.25 CI, I have an bad ping at 9.8:1 that only gets worse the higher the RPM. Tried several advance maps and fuel maps and still get the ping. If you are trying to get big rpm's you might be asking more of your stock ECM than it is capable of. The compression ratio is also a concern for me if you are running steel heads, you can bleed off some cylinder pressure with a bigger cam, but that would require a good bit of trial and error with your PROM burn.

To get back to your first question, if you run the small cap distributor from a TPI car with the external coil you can buy a much hotter coil that will work with the stock setup and keep voltage loss to a min at high RPM's.

But all in all, I think the stock setup will be more than adequate to keep up with the RPM's the stock TPI plenum will support and an ignition upgrade will be worthless without, throttle body and runner upgrades..

Good Luck :p

TPI, I was hoping you'de chime in.

I guess I was hoping for around 5000 - 6000 rpm. If you say that what I've got is good for 5000, that's fine with me. I'de rather not spend any more money anyway.

The 10.25 CR is not anything that I can help right now. I got the engine almost brand-new with that ratio for $400. If I am having pinging problems, I will get some thicker head gaskets.

J. J.

I run HEI on my 360 from driveajeep.com I'm not sure if they are still selling them, but it runs great. Only problem is when setting the timing you only have a few degrees before the coil cap hits the power steering pump.


I'll probably be going to the TFI IV / Duraspark 2 setup because from what I've read about home brew TBI setup's, it looks easier to convert the motorcraft setup than HEI for use with TBI.

If you are a cheap bastid and have an ol' points ignition...advance the timing a little 5-10* and the idle up 2-300...you'll get a little throttle response and power.

Disclaimer-Probably will be detremental to engine longevity.

Originally posted by patooyee
TPI, I was hoping you'de chime in.

I guess I was hoping for around 5000 - 6000 rpm. If you say that what I've got is good for 5000, that's fine with me. I'de rather not spend any more money anyway.

The 10.25 CR is not anything that I can help right now. I got the engine almost brand-new with that ratio for $400. If I am having pinging problems, I will get some thicker head gaskets.

J. J.

J.J.,

I would consider getting a set of Brodix head gaskets, they are .078" thick and really helped me alot, I think they were about 100 bucks. Cheap insurance to save you pistons if you ask me!..

Good Luck

Come Awn people, I am sure there are a thousand questions on this topic lets have em!

I've kinda considered going the "Low tech" route as I've seen one too many (for me) GM HEI's fail after being even close to water. DISCLAIMER: I am referring to Mud trucks, so bear with/or ignore me:flipoff2: I am contemplating using a dual point chev distributor, using one set of points as the primary, and the other for a backup. dual coils, and (msd makes a 2 coil wires into 1 cap)
I am currently using a MSD 6AL, and it has been worth every penny for starting when hot, stalled, or wet. I like the rev limiter too:D

Points are ancient technology, but damn near anyone can fix/rig/repair them on the trail

Okay i have a question also. I will be running a carbed chevy 350 with a few performance mods (intake, cam, roller rockers, headders, etc) and I have a choice of 2 different ignitions to use. First is a mallory magnetic breakerless distrubiter and a mallory hy-fire 4 box. I dont mind running all the wires it will take. My second choice is a stock GM HEI with an accel super coil on it. This engine is going into a flat fender so clearence will be an issue on the firewall. I can probably pound it out or cut the firewall though. I would mostly be running on the rocks so which one would be the best setup? Thanks.

Brian,

I would go with the Accel coil on the stock HEI, the rest of that stuff is for high RPM race apps and not worth the money crawling..

Weps,

Boy oh boy, if your running mud, duct tape is your friend... I have never had a HEI fail me, nor ever seen one fail. just seal the crap out of it and let it bump....

All the mud racers look like they have a huge pile of tape on the top of the engines but it works well to keep the wet stuff out.

I have run points and they never fail to totally tick me off!

Of course this is just my opinion and I could be wrong.... :D

Originally posted by TPIJeep
Brian,

I would go with the Accel coil on the stock HEI, the rest of that stuff is for high RPM race apps and not worth the money crawling..
Thanks for the reply. I already have both so money isnt an issue between the two. The stock HEI unit is used and the mallory stuff is brand new except for the distributer, it has a fresh rebuild. I will use the HEI for now.

No prob TPI...I have heard the HEI's are OK, one I saw fail was in a truck some (idiot) actually tried to cross part of a lake, and the water was well above the hood. In reality, anything would probably fail here.I love the "Points never fail to piss me off" you are right there. Good topic though, anyone run a MAGNETO??:eek: I'm guessing the rock crawlers don't have much ignition problems, as the mud damage is pretty much self-inflicted:D

Can some post a diagram of a Battery, starter relay, starter, alternator and associated critical links?

Would be best if it was for a engine swap (5.0L Ford) ;)
I was informed the Ford 5.0 runs two starter relays and was told that removing one is suggested for starting better. Sure enough it has two relays.