I completed step 1 to finding my miss, ordered a RPM Performance data recorder kit from KillerRons, w/ (2) O2's, vac, oil, rpms x2 & batt. Other plans include: sending 7al & HVC-2 coil to Techwest for checkup, reterminate wiring (after comfirming wires are not broken), swap Moroso wheel for MSD. Thanks for all the opinions and recommendations I will be sure to post results in Springtime as they present themselves.

This message has been edited. Last edited by: Richie,

I keep checking back in here hoping you have resolved the issue.

5 pages and numerous months trying to figure out this miss.

Did you ever try to put a gas carb on, put some c14 or sunoco blue supreme in it and race it?

Answer is either a yes or no.

NO.

quote:

Originally posted by Strange Magic:
5 pages and numerous months trying to figure out this miss.

Did you ever try to put a gas carb on, put some c14 or sunoco blue supreme in it and race it?

Answer is either a yes or no.

I like this recommendation!!!

Easiest, and cheapest way to figure this out...pull the motor and put it on a Dyno!

Easiest, and cheapest way to figure this out...pull the motor and put it on a Dyno!

Not so much....I would have to BUY or borrow a carb, 3 to $400 for dyno time, All THAT for a TEST, I am NOT interested in going back to gasoline...
and this MISS happens on about 90% of my runs, could take 5 or more ? pulls before it will show up, IF it shows up at all. I would rather drop my spare 601 in & track test.

Already talked w/ Techwest, I'm sending my 7AL2 & HVC2 coil for checkup.

Its not really about going back to gas its about finding the issue....I asked about gas on the first page because ive seen a really similar combo not work on alcohol. You may have to change camshaft to make alcohol work. Another buddy has a sr20 deal that wouldnt run on alcohol carb either. We both believe it work with injection but its pretty deadly on gas.

This message has been edited. Last edited by: BLIND MULE 2217,

quote:

Originally posted by Richie:
Easiest, and cheapest way to figure this out...pull the motor and put it on a Dyno!

Not so much....I would have to BUY or borrow a carb, 3 to $400 for dyno time, All THAT for a TEST, I am NOT interested in going back to gasoline...
and this MISS happens on about 90% of my runs, could take 5 or more ? pulls before it will show up, IF it shows up at all. I would rather drop my spare 601 in & track test.

Already talked w/ Techwest, I'm sending my 7AL2 & HVC2 coil for checkup.

Or you can keep chasing your A $$ and not fix it. Dyno would of saved you money at this point..

Good morning Forum

The issue Richie is a common story we see alot at TechWest Racing servicing customers MSD 7al2's. The problem can be the box itself or the ignition coil not wanting to play along. The boxes usually have one or more of the main amps that start to fade. ( getting weak) This usually pops up as driver complains car feels like it has an anchor tied to ass end of the car. Or some version of Richies problems with flat or poor performance from half track on. These boxes should be able to with 12vdc applied be able to climb from 0 to 12,500 rpm flawlessly pulling the right amount of current. And have an arc of Hot white/ light blue only. Any colors like reds,oranges or yellows is just showing the box is weak and needs some attention. The MSD HVCII 8261 has an issue we have seen pop up over the last 4 years. The coil develops a short internally which over time beats up on the main amps of the MSD box. Not all the HVC II coils have this issue but we usually see 70 to 90 HVC II coils a year for testing and about 45% have the problem. The coil will cause similar issues as mentioned above. Plus it could be just a high rpm miss that is randon and can not seem to be traced down. Like Richie you could have a flawless weekend or a pass or two and then the problem comes back. To check your MSD HVC II we have found if you use a infared temp gun and sweep the whole coil case. Your looking for a dime size hot spot that is 70 to 90 degrees hotter than the rest of the case. We recommend to all our customers that run a MSD HVC II coil to add the sweep test to the car checkout sheet. It will help head off a possible issue down the road. A box causing these kind of issues on the bench load test we do. Will go through about 3800 rpm to 4700 rpm and start drawing more current than it should. Then once above 5800 rpm it will at some point be drawing way to much and refuse to climb any further. ( Usually around 7200 to 9400 rpm)
I hope this can help the forum members out, these are some of our favorite boxes. When hooked up right they are are like rocks. If I have created any questions please feel free to contact me. Have a great day all!

Pat Collins

Thanks Pat

Sooooo.......this car has ran forever with this ignition box and coil combo until you changed motors and now thats the problem?
Maybe it is your problem and this fixes it but I doubt it.

Blind, I know I'm reachin' but I 'think' that if the motor combo didn't like Alky, my issue wouldn't vary like it did...1st. pass was BRUTAL...then it lessened...DISAPPEARED...came back, If the motor wasn't happy it would of never ran good.

I have had 3 7AL-2 boxes go bad in last 4 years and Pat (TechWest) fixed them. One of them I originally got maybe 1986? Worked great for all those years then took a dump.

I thought the OP here said he changed the ignition box already? After what I have been through last few years ignition box is one of first things I check.

Anyway I do believe in checking the things that are quick, simple and easy before you assume the worst and start changing everything.
Trying a gas carb is a great idea even if it is too small for optimum performance you can quickly determine if it is a carb or fuel supply issue.
Ignition box only takes a few minutes to change and if you have a miss look at ignition....

One other thing here is OP said something about it almost dying like turning ignition switch off. That makes me think bad wire somewhere.

One other note, all three of my ignition boxes that went bad acted different.
One would run perfect one pass run a 5.09 next pass 5.49 banging and popping.
Another box was just real weak on top RPM and slight miss at peak rpm.
The last one would have like several dead cylinders from idle up.
Pat fixed all three of them.

I did change the box, BUT I bought it used (unknown health) acted exactly the same so I left it in the car, newer serial #. I did some welding on the car over Winter for T/S, shut off main power before welding as I've done a million times but? I started w/ the easy cheap fixes first of course. I run a Terminator.. changed from 01/2 to a 0 pump & pilled both ways.
The last time out it went: 7.900 clean, 7.920 2-3 misses, then 7.902 clean

This message has been edited. Last edited by: Richie,

Have you replaced the battery, disconnect switch, igntion switch, and or the alternator?

329L, Yes, Yes, Yes & Yes. Looking on the brighter side of things - I have enuff spare parts to build another car lol...

quote:

2018 bought & rebuilt a 632 w/ HH383, has a top end only miss

A terrible candidate for alky. That high speed miss you speak about, has been discussed numerous times, over and over again on this board. If you don't want to change over to gas, then dump some compression out, change the cam and it will run without a miss.

Strange, Not looking for an argument but How can you make a statement like that when you don't know what my cam or comp. is now??? WHY would it run Awesome on some passes???
I asked Killer about the H/S bypass, he didn't think it would work for my setup.

quote:

Originally posted by Richie:
I did change the box, BUT I bought it used (unknown health) acted exactly the same so I left it in the car, newer serial #. I did some welding on the car over Winter for T/S, shut off main power before welding as I've done a million times but? I started w/ the easy cheap fixes first of course. I run a Terminator.. changed from 01/2 to a 0 pump & pilled both ways.
The last time out it went: 7.900 clean, 7.920 2-3 misses, then 7.902 clean

It’s highly unlikely that two completely different ignition boxes did the exact same thing at the exact same times. Was the coil replaced as well or was the same coil ran with both?!? How do you have the cylinder heads grounded? And the block?

I know of several engines that didn’t like alky! I know of one that went on APDs dyno with their alky carbs and they couldn’t make that more run clean! Bolted on their gas carbs and not only did it run clean, but it made over 100hp more!

Other question...have you checked the polarity of the mag pick up? Check the timing..reverse the mag pick up polarity and check the timing again. Which ever way nets you the most retarded timing is the correct way for your box. Worth a try!