Loss of power for a split second on off (72 Vette 454) Help please

[JohnZ]

you can still eliminate the vacuum advance and buy the centrifical advance kit w/ heavier weights and lighter springs f/ about $4.00 and get more advance at lower RPMs, and they work really well.

Why would you want to eliminate the vacuum advance?

 

[Rodney Gold]

I would only eliminate vac advance on a race only motor that spends all its time above 3000 rpm.

 

[1972corvette]

Can you send me the details please, who sells them, what percentage of power increase? lot better for the engine? Thanks
vadelsohn@cogeco.ca

 

[Vettehead Mikey]

Can you send me the details please, who sells them, what percentage of power increase? lot better for the engine? Thanks
vadelsohn@cogeco.ca

Save your time and money. Changing ignition curves willy-nilly rarely improves anything and frequently brings on a host of new problems.

 

[Jimmy C]

Save your time and money. Changing ignition curves willy-nilly rarely improves anything and frequently brings on a host of new problems.

Vettehead,
Since you seem not to know crap and either are too young or have just been "out of touch" w/ engines all your life, this is an old trick that EVERYONE who knew ANYTHING did to their Chevy V8 when points were the only thing around. What "know nothing" said that this kit was f/ race cars only??? More advance at lower rpm is "race car only" stuff??? And brings on a host of new problems. See me in twenty years. Then again, maybe the time won't do anything f/ you. I know you kids aren't representative of a majority of people on this site.

I'm stating this very much "to the point" as two guys who know crap on here decided to run their mouths in a smart-ass fashion before having a clue.

Better to be thought a fool than to speak and remove all doubt.

 

[73shark]

SHARK, Condensor/reschmencer-the guy fixed his problem which is what is important.

You're right, solving the problem was the important thing but just wanted to let him (and anyone else who might read the thread) know that it wasn't a ballast resistor that fixed it.

 

[Rodney Gold]

Gains can be from 0-25% depending on the state of the ignition system. Inherently electronic systems are more reliable over the long term in that performance doesnt drift and they can generally allow higher revs than points (which bounce and burn). Adding a MSD6al will ensure against fouled plugs (often from sporadic starting or starting , moving the car a few ft to shuffle others in and then cutting the engine)
The distributors that allow curve modification also often have adjustable vacuum advance too.
This enables you to set the total centrifugal advance , how quickly the curve comes in and fine tune the amount of both centrifugal and vacuum advance . This translates to more responsivity and often better gas mileage. The advance curve you choose depends on your engine. I have built and run many 454's and find em particularily sensitive to the "right" curve. I have picked up time on the 1/4 mile by using the optimal curves , as much as .3 of a second on a 12 second car.
Most stock dizzys are curved way too conservative , often finding they are still advancing at 4500 rpm+
You can manually recurve stock distributors by lightening weights , changing weight springs and relocating or adjusting the stops that determine total centrifugal advance - most stock distributors will not have adjustable vaccum.
You can buy aftermarket distributors etc from most V8 performance places. BE carefull!!!... Recently brand name "billet" distributors seem to have sourced manufacturing offshore and some components are compromised. I find MSD to be the best of the bunch with respect to quality assembly and components used.
As an aside , 99% of the time , the best bang for the buck re engines , especially a 454 , is a decent seat of headers .

 

[Jimmy C]

Gains can be from 0-25% depending on the state of the ignition system. Inherently electronic systems are more reliable over the long term in that performance doesnt drift and they can generally allow higher revs than points (which bounce and burn). Adding a MSD6al will ensure against fouled plugs (often from sporadic starting or starting , moving the car a few ft to shuffle others in and then cutting the engine)
The distributors that allow curve modification also often have adjustable vacuum advance too.
This enables you to set the total centrifugal advance , how quickly the curve comes in and fine tune the amount of both centrifugal and vacuum advance . This translates to more responsivity and often better gas mileage. The advance curve you choose depends on your engine. I have built and run many 454's and find em particularily sensitive to the "right" curve. I have picked up time on the 1/4 mile by using the optimal curves , as much as .3 of a second on a 12 second car.
Most stock dizzys are curved way too conservative , often finding they are still advancing at 4500 rpm+
You can manually recurve stock distributors by lightening weights , changing weight springs and relocating or adjusting the stops that determine total centrifugal advance - most stock distributors will not have adjustable vaccum.
You can buy aftermarket distributors etc from most V8 performance places. BE carefull!!!... Recently brand name "billet" distributors seem to have sourced manufacturing offshore and some components are compromised. I find MSD to be the best of the bunch with respect to quality assembly and components used.
As an aside , 99% of the time , the best bang for the buck re engines , especially a 454 , is a decent seat of headers .

Rodney,
So true. Electronic ignitions are far superior to the old breaker points models. I remember the Mallory dual point distributors which were "the thing" back then. I even had one on my '65 VW Bug, along w/ a Holley 2 bbl., on a 1600 transporter engine, made a BIG difference.
Seems that so many companies are farming components out to overseas places being void of quality control. I've used Mallory f/ years and currently have Mallory fuel pumps and regulators on two different rides. Does Mallory farm out work that you know of?
My point about the centrifical advance kit, is that f/ just afew dollars and a half hour's time, you get alot f/ the price, and it works very well.

 

[Vettehead Mikey]

Better to be thought a fool than to speak and remove all doubt.

Well, you've done a good job of doing just that.

I made no mention of race applications only. That was someone else talking about removing the vacuum advance. If you're going to rant at somebody, get it right. :eyerole

Here's is my original post in it's entirety:

"Save your time and money. Changing ignition curves willy-nilly rarely improves anything and frequently brings on a host of new problems."

The key is changing things willy-nilly. The OP most likely has no idea how his distributor is presently set up, either the centrifugal or vacuum advance. It might be dead stock or (most likely) someone has already been in there. Assuming that no one has played with the distributor over the last 37 years and that there's no wear to contend with is foolish.

Throwing a generic kit at an unknown dizzy might just undo some good that's already there, or bring on a new set of problems with an over aggressive mechanical advance coupled with an incompatible vacuum can. The most sensible advice is get the distribitor curve mapped as-is, then decide what should be changed if anything. Older, more experienced engine people would know these things. I learned this when I started playing with engines in the late 60s.


By the way- you were asked a direct question by JohnZ which has gone unanswered: "Why would you want to eliminate the vacuum advance?"

Care to share some wisdom on that?

 

[Rodney Gold]

I recon if your USA made stuff is 2-3 yrs old , you have a good chance of it lasting a long time , if it is like my last Milodon whose waterpump was stamped "made in china" and was probably made by 7 yr old kids in Poontang , out of latvian scrap iron...I dunno I have 2 "old" Holley FPs still going strong , I have 3 "new" holleys in my discarded [arts bin.
PS im not American so not being all jingoistic and such...

 

[72VETTE454]

Jimmy C,
Since there are so many people on this site that are intellectually inferior to you, maybe the site is not for you .
72corvette,
Glad to see your problem is fixed .

 

[Jimmy C]

Well, you've done a good job of doing just that.

I made no mention of race applications only. That was someone else talking about removing the vacuum advance. If you're going to rant at somebody, get it right. :eyerole

Here's is my original post in it's entirety:

"Save your time and money. Changing ignition curves willy-nilly rarely improves anything and frequently brings on a host of new problems."

The key is changing things willy-nilly. The OP most likely has no idea how his distributor is presently set up, either the centrifugal or vacuum advance. It might be dead stock or (most likely) someone has already been in there. Assuming that no one has played with the distributor over the last 37 years and that there's no wear to contend with is foolish.

Throwing a generic kit at an unknown dizzy might just undo some good that's already there, or bring on a new set of problems with an over aggressive mechanical advance coupled with an incompatible vacuum can. The most sensible advice is get the distribitor curve mapped as-is, then decide what should be changed if anything. Older, more experienced engine people would know these things. I learned this when I started playing with engines in the late 60s.


By the way- you were asked a direct question by JohnZ which has gone unanswered: "Why would you want to eliminate the vacuum advance?"

Care to share some wisdom on that?

Already stated the answer to that. And if you were around in the late '60s, Y is it that you never heard of this centrifical kit??? These were widely used when factory Chevy muscle was EVERYWHERE!!!
Your talk of excess wear, etc. is "out of the ball park." If the distributor had all that wear on it, the engine wouldn't be running well, and it obviously is, at the very least well enough f/ a centrigfical advance kit. Your arguement is a pipe dream of "NOT" hands-on experience.

 

[Vettehead Mikey]

Jimmy C,
Since there are so many people on this site that are intellectually inferior to you, maybe the site is not for you .

At first I was going to agree with you but after reading JimmyC's latest gem, I think I would miss his off the wall rants. Hey- who else has been able to misread, misunderstand and misquote almost every post? On the other hand, it must be miserable to go through life being spring loaded to the pizzed-off position.

Sorry gotta run now, apparently vacuum advance is bad so I have run out to my cars and disconnect it before something unknown but obvious happens.

 

[Jimmy C]

Jimmy C,
Since there are so many people on this site that are intellectually inferior to you, maybe the site is not for you .
72corvette,
Glad to see your problem is fixed .

My statement (to Vettehead) was that surely YOU (Vettehead) were not representative of the great majority of people one this site, as you seem to be more of a magazine reader than a properly trained and experienced wrench turner.
(Also to my friend VetteheadYour running out to your car...is childish talk and another indication of your "NOT" hands-on experience, over all these years of your being into the automotive field. Good Luck w/ the shops you bring your 'Vette to when any mishaps occur.
My experience on this site, as I stated on a topic: My Sincere Thanks To All Who Reply, I started a week or so back, has been people who are quick to give very good help/info/replies and who are experienced and up to date. The post I'm referring to was to thank the members f/ the quick positive come-backs.

 

[Vettehead Mikey]

JimmyC,

I'm not going to get into a pi**ing match with you or debate who has more experience hands on, amateur, professional otherwise. Suffice to say that I maintain my own vehicles (I presently have 8, including my Corvette on which I did a complete frame off restoration) and have always done all maintenance short of machining tasks where I lack the equipment. I have recently retired from the aircraft engine manufacturing and overhaul business after a 31 year career in which I was responsible for a fleet of over 1,000 engines in active revenue service. Some of the maintenance techniques and processes I spearheaded are now considered standard practice throughout the industry having acquired Transport Canada and FAA approval. Think of me the next time you're flying somewhere.

Any statement or advice I choose to give on this forum is based on my own experience in directly related matters, or is based upon knowledge acquired in my professional career.

I think what 72VETTE454 was getting at (and he can correct me if I'm wrong) is that you have been rude to at least two other posters in this string, myself not included.

- JohnZ asked why you recommended removing the vacuum advance. As far as I can tell, you have not responded to this question with an explanation of why this is a good thing.

- You responded to 73shark with 'SHARK, Condensor/reschmencer' when he pointed out that the incorrect terminology was used by the OP to describe what was found to be faulty. Don't know about you, but that's pretty condescending.

Let's not go over your confused post where you accused me of making statements that were actually made by Rodney Gold. BTW- Rodney is correct and I agree with his recommendation about NOT removing the vacuum advance for a street driven car.

It's OK to disagree with someone opinion, (that's what these forums are here for) but it's not OK to go after someone at a personal attack level if they choose to disagree with your own opinion. Try to understand the difference and practice it. You'll probably be a lot happier here. If you do prefer to act like a troll, I'll be happy to send you a link for another forum where there are plenty of people that come out swinging at every opportunity.

For the record, I don't subscribe to any car magazines other than CE. Too many poorly researched 'technical articles' and not enough substance.

Have a nice day.