ignition and rev limiting question

DDS · 05-03-2002, 05:59 AM

I am considering the MDS6-AL unit and blaster (oooh scary!) coil with a new pertronix and bosch 050 distributor.

Is the rev-limiter worthwhile for $40 more?

What should I consider an appropriate 'redline' for a precision balanced 2056cc big valve engine with a cam similar to a Webcam 86a, dual webers, with FAT single HD valve springs? Shoulod a limiter (if worthwhile) be set at that redline?

Many TIA,

John Rogers · 05-03-2002, 06:31 AM

I'd say no to the rev limiter since most of the engines I have seen blow have happened at down shift time and the rev limiter will not help that. The amount of life is inverse proportional to the rev limit so if you wind it to 6500 all the time it will need overhaul much faster than if you shift at 6000 or even 5800. I found that for my big four that shoft shifting so the next gear came right in the middle of the torque peak gave me much better performance and this equates to about 5800 or so even though I have a very radical valve train and it is good for 8000 or so. Good luck

Joe Bob · Joe Bob's Garage

I'm NOT a fan of the Pertronix.....if you use it keep a spare set of points around for emergency roadside repairs. BTDT

The Crane/Allison optical units are my favorote for upgrades to pointless ignitions....as to where to get them, the best place is Summit racing....unfortunately PP is not competitive on pricing for these units.

JohnConnolly · 05-03-2002, 10:15 AM

You guys should really check out the new Mallory boxes. More features then the MSD and 30% less! They are fantastic.

John
Aircooled.Net Inc.

DDS · 05-03-2002, 10:33 AM

Many thanks guys. I won't bother paying for a rev-limiter. I do remember I made a related post awhile back and sparked a small pro/con pertronix debate.

Which (complete) setup do you guys run or recommend? I have learned that there are options WRT triggering (points, optical, magnetic), then electronic spark generation (ie stock, electonically controlled, multi-spark, rev limiting, etc, then coil choice as well. My initial thought had been points replacement, then some fast-talkin' salesmen got me thinking about the multi-spark setup, and well, I might as well look at the coil too. Purty wires would then be mandatory...

John Rogers · 05-03-2002, 12:23 PM

On my race car I use a 009 distributor with Compufire module, MSD ignition box and off road coil and Accel 8.5 mm wires that I make from a universal big block chevy kit (two sets that way) with all wires same length. I have about 15k volts at idle and 42k volts at 4500 RPM (I use a Snap-on secondary voltage tool) and has been completely trouble free for over 3 years. Good luck.

DSPTurtle · 05-03-2002, 02:21 PM

I went with the Rev limiter just for the times at autox when I don't look down. Every once in awhile you try to squeeze a few more RPM out of the motor and the MSD Pill politely lets you know that you are trying to go too far. It was worth the $40 in my opinion. Especially if you ever want to add it on at a later date...that is about $125 upgrade. I have the Pertronix, MSD 6AL, Blaster 2 coil (although the completely potted off road is probably better), and MSD 8.5mm wires. If you send them an email, MSD will send you a set of their special plug hole covers. On DD's recommendation I stepped down to copper bosch plugs. I always ran Platinum but these copper's seem to be doing okay...I think you could put AC Delco's in with an MSD and they would do okay.

DDS · 05-04-2002, 04:20 AM

Aircooled John has me thinking about that mallory dist - expensive, but not so bad when you consider that it has the optical triggering already installed. he has a good basic article on ignition options - which I needed - on Aircooled.net. (sorry the link is at work) I'm toying with the mallory multi-spark ignition as well.
Good tip on the plug hole covers JB. I was wondering how to make those
John Rogers - I thought the 009 was the devil's own handiwork for the type 4?? Apparently it can be made to work!
Thanks again guys. All clear but the budget.

maf 914 · 07:03 AM

Turtle,

With the MSD ignition wires, what is needed for the spark plug connector, assuming you have a four cylinder. Do you use the standard straight adjustable MSD plug connector with a shroud sealing grommet? Or do you have to cannibalize the long spark plug connectors from a 914 wire set (i.e. Bosch OEM)? I would like to get a universal 8-cylinder MSD wire set for my 2.0L but I am not sure which connector I should get.

Thanks,
Mike

The straight boots are called M/A, multi-angle, since they can be bent to various angles: http://www.msdignition.com/

DSPTurtle · 05-04-2002, 10:32 AM

I will go look at my box to be sure but the wires came with the plug end installed...it is just a long straight. You have to put the little tits back on the spark plugs though or the MSD won't stay on.

JohnConnolly · 05-04-2002, 02:13 PM

FWIW, Jake Raby has run the Mallory on a lot of engines, and last I checked, he had yet to have one yet that didn't pick up 10hp minimum when the Mallory was installed on the engine. 009/050, 010, 019, anything, with or without a pertronix, compufire, Magfire, etc.

John

John Rogers · 05-04-2002, 03:25 PM

The 009 works okay since I don't have an FI system to worry about and initial advance is not a big issure, total and what RPM it comes in on is. My main worry is starting, which the stroker motor does well since it has the MSD box and huge amounts of spark and what total advance is and we set it to 34 degrees with 100 octane U76 or 36 degrees with 110 VP like they sell in Las Vegas. I have worn one out in the fours years I have had the car and they are cheap to replace. The final issue is the vac advance diaphragm which gets in the way of my 911 fan system so I could not use a vac advance distributor anyways. The wires are 8.5mm for a big block Chevy, straight plug boots and I have lots of old rubber grommets from old type 4 wire sets to use. Good luck.