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grivera · 07-30-2019, 06:07 PM

Quote:

Originally Posted by JLMounce

I have all M&H harnesses in my bird and they would not sell me an "HEI Ready" dash harness. Instead they provided information on how to jump the ignition line in parallel to achieve full voltage to the HEI. My dash harness is only about 2 years old. It's possible they will sell a harness that way if you really want them to, but that wasn't my experience. It's something that I would check all things considered. Put a voltage meter on the coil wire.

Jason - Interesting - In 2011 I ordered an M&H engine harness for HEI and they also sent one without the wire installed. I questionet it after install and they sent me the wire so I could add it. At the time, they said it was an issue with the order.

Joe - I would check the coil wire for 12V when engine is running. Likely not your issue but will make for a funky running engine.

JLMounce · 07-30-2019, 06:30 PM

Quote:

Originally Posted by grivera

Jason - Interesting - In 2011 I ordered an M&H engine harness for HEI and they also sent one without the wire installed. I questionet it after install and they sent me the wire so I could add it. At the time, they said it was an issue with the order.

Joe - I would check the coil wire for 12V when engine is running. Likely not your issue but will make for a funky running engine.

I should clarify here. I asked for an HEI ready harness and I wasn't told "no" I was just told that it adds significant cost to have it done. The rep without saying it couldn't or wouldn't be done, really pushed not to even go there. Since all you need to do is run a non-resistance wire in parallel, it's not hard to make the change yourself.

One other item to possibly look at while you're testing is the coil wire itself. I don't know how it is on the GTO, but in the birds, the resistance wire is in the dash harness and while the coil wire from the engine bulkhead is not a resistance wire, it is not large enough to really carry more than the 7-8 volts that it would be receiving with an unmodified dash harness.

What you would likely want to do is replace that wire with something more suitable for 12-14 volts.

Anyway, just something to check and mark off the list.

Sirrotica · 07-30-2019, 06:36 PM

They ran a jumper wire directly from the positive battery post directly to the distributor last weekend, it's in the posts from last weekends diagnostic efforts.

STEELCITYFIREBIRD · 07-31-2019, 06:53 PM

-Do you have idle speed, base timing / full advance specs from Paul /Jeff Korner?( carb builder) for this engine/dizzy/carb combo?

HWYSTAR mentioned he baselined the idle mixture screws @ 3/4T out.

-Where were they before adjustment?

Does the engine respond to adjustments, via the vacuum gauge reading?

We use Braswell custom carbs exclusively on all our race motors, the baseline on the gas motor is 1 1/4 to 1/1/2 turns out (4 corner idle). Purpose built, Custom carbs can vary greatly from an out of the box Holley.

A loss or drop in oil pressure is a big difference if it was at idle no load vs during a full pull at high RPM.

I'm disappointed and truly surprised Paul has drawn back from helping getting this figured out and remediated.

BTW:
I have no interest other than to help identify and repair this/these problems in a in a concise and logical way.

Va68goat · 07-31-2019, 08:21 PM

STEELCITYFIREBIRD,

Paul and Jeff did provide that information and it was done (Idle speed, timing etc). Next time we deal with the carb, we'll call Jeff though. Paul indicated that Jeff uses several different parts to build his custom carbs...I'm not sure what they are. I'm disappointed as well about Paul but for now...this part of the train is still moving. We are still driven to get it right. Jeff says he located a guy in my area that would be willing to take a look at the motor so I'm hoping that happens soon. The season will be over before you know it!

HWYSTR455 · 08-01-2019, 07:36 AM

I was going to dial the idle mix screws out to 1 1/4 each, remove/move the PCV, make sure only the batt/12v is on the coil and nothing else, and verify initial timing. Maybe bring a new coil to try, and check the dizzy cap for carbon tracking.

And yes, was going to bring a tach and vacuum gauge, just so there's no question there.

Was hoping to go there tonight, but not up to par the last couple days, will have to see how I feel later.

The note Paul included on the engine was for total timing of 34 degrees, so with the 18 degree bushing, would call for roughly 14 initial. Since you can't determine the advance curve or vacuum advance needs of an engine in actual driving conditions on the dyno, those recommendation were obviously omitted.

So mentally reviewing theory, the firing order is #1, then #8, and if due to the PCV being on the #1 runner, potentially running lean, possibility of advanced timing, and the 'noise' coming from roughly the passenger rear of the engine, it's possible #8 is experiencing pre-ignition, which certainly can cause a knock type sound. Might be a stretch, but feel its worth eliminating that factor/question.

Dial-back timing lights can be tricky, have seen folks have erroneous readings, and not even realizing it.

.

mgarblik · 08-01-2019, 09:18 AM

Quote:

Originally Posted by HWYSTR455

I was going to dial the idle mix screws out to 1 1/4 each, remove/move the PCV, make sure only the batt/12v is on the coil and nothing else, and verify initial timing. Maybe bring a new coil to try, and check the dizzy cap for carbon tracking.

And yes, was going to bring a tach and vacuum gauge, just so there's no question there.

Was hoping to go there tonight, but not up to par the last couple days, will have to see how I feel later.

The note Paul included on the engine was for total timing of 34 degrees, so with the 18 degree bushing, would call for roughly 14 initial. Since you can't determine the advance curve or vacuum advance needs of an engine in actual driving conditions on the dyno, those recommendation were obviously omitted.

So mentally reviewing theory, the firing order is #1, then #8, and if due to the PCV being on the #1 runner, potentially running lean, possibility of advanced timing, and the 'noise' coming from roughly the passenger rear of the engine, it's possible #8 is experiencing pre-ignition, which certainly can cause a knock type sound. Might be a stretch, but feel its worth eliminating that factor/question.

Dial-back timing lights can be tricky, have seen folks have erroneous readings, and not even realizing it.

.

It seems to me you will be dealing with two situations on this engine that may or may not be related. 1. very rough idling/running engine. 2. Engine noise.
Since the "engine noise" has been reported to have been there since day 1, it is probably safe to assume it isn't hurting anything immediately, given the many times it has been run in the car and on the dyno. So personally, I would concentrate on getting the engine to idle correctly and run right. Recently within the 1060 posts, it was mentioned that the engine now has a carburetor on it that is "new" to this engine and hasn't been run or tested on this engine? When you are dealing with problems, that's a bad thing to add to the mix. In our dyno cell, we have 1 carburetor we all refer to as the "go to" carb. It is a generic Holley 750 that was worked over by BLP in FL and donated to the school. Think of it as a "dyno carb". Whenever we have someone's engine on the dyno and it's doing weird things, just not putting up the numbers, whatever the reason, we take their carb off and just bolt this thing on. 9 out of 10 times, the "go to" carb fixes whatever the problem was and makes more power. It always "changes" the way the engine runs so it gets the thinking going the right direction no matter what.
I assume you guys have whatever carburetor was on this engine when it was idling smoothly and running correctly? I would strongly consider putting it back on to re-establish a base line for this engine. Once it's running and idling properly on 8 cylinders, you can turn your attention back to problem #2, engine noise, if it's still present. Good luck with the evaluation. This is the most bizarre sequence of events I have ever heard of on a Pontiac engine. Hope you can get it solved.