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Ram Air Causing Fouled Spark Plugs And Fast Idle

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First off how in the hell does one get better fuel economy AND gas fouled spark plugs at the same time?
Second how does one get more CFM from one's DIY ram air hood?
Especially after they claim it is fixed,
43e732dc69890764a54e07c3638456d2.jpg


Now I'm not an engineer by trade but as I remember it Ram air hoods weren't very effective on street cars not unlike useless headers with mufflers attached. I believe they do nothing but look good ;)

I DO KNOW choke blades are designed to stay open from air velocity so someone must have a bad choke coil or whatever he uses to open it.

Now for the fuel milage increase it sounds like someone un-restricted their air intake system by accident ☺

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Huh?
 

kpic

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After I modified my choke and used vacuum to pull it completely off my problem vanished. Yes, I would like my choke to remain on a little bit longer but my goal was to get it to work long enough to get my engine started in real cold weather.

And I'm running a #3310 with an electric choke.

Which is it?


I'm running the 286-H Competition Cams hydraulic flat tappet with a 236/236 duration and .556"/.556" lift (part #11-318-4). With the 3.08 gears my engine rpm was too low for adequate runner velocity so when I switched to the 3.70's the runner velocity and fuel mileage increased. And I'm running a #3310 with an electric choke.

As most know, a higher numeric axle ratio increases RPM at cruising speeds. This is why all the OEMs have added more ratios or gear planes to their transmissions to supply an OD which lowers engine RPM. Are you trying to say the 3.08 ratio was lugging the engine??

Additional gear planes also provide more steps which is a good thing also. However as an engineer, you know what steps accomplish in transmissions.

BTW, it is a 3.73 ratio. It has been a long time; however, I'm fairly certain your ring gear has 41T and the pinion has 11T.
So do the math: 41/11= 3.7272...72 or 3.73 when rounded off.
It is the same for any R&P no matter who cuts the gears.

 

Vettehead Mikey

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People are trying to point out that the volumetric efficiency has not changed with addition of the cold air hood. In other words, the engine is not pumping through more air than it used beyond the equivalent of what's gained with a 70 foot decrease in altitude. The air is not moving through the engine any faster than it used to- so the choke plate is neither being sucked not blown partially closed.

If you had constructed a duct that blows the air directly at the choke plate through a nozzle, possibly a one inch column of water at 60 mph would be sufficient to move the plate.

But you didn't.

Instead, the air is directed into a plenum, meaning that the pressure would be uniform throughout the chamber, and then flows through a conventional round pleated paper filter to the carb inlet. Any turbulence in the incoming air would be eliminated as it passes through the filter element.
 

dougelam

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[quote name="dougelam" post=1175818]No, nothing wrong<br />
It's just decades later then he talks to us like we never opened up a hood! <br />
<br />
THEN he doesn't know why someone would change the number of turns<br />
<br />
He then criticises someone's method and precedes to tell us his and never once referred to the factory service manual. His wiggle method is no better or any more accurate than the running one! <br />
<br />
Sent from my SM-N920P using Tapatalk[/QUOTE]<br />
I've read carefully through the posts on this thread. The only person who seems to be taking offence to the OP's comments is yourself and I'm not sure why. From my perspective, nothing toobroketoretire wrote appears as condescending or provocative as your responses.<br />
<br />
If you don't like what toobroketoretire says when he posts, perhaps you should forego reading those posts. The CAC's software allows members to "ignore" others who they find objectionable. If you don't wish to "ignore" then I'm going to suggest you regulate your replies with a bit more consideration. <br />
<br />
Life is too short for the drama, dude… <br />
<br />
Mac

You know,
I had this guy's number a while back and mac didn't like it.

I'm glad others are seeing it

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Antz81

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BTW, it is a 3.73 ratio. It has been a long time; however, I'm fairly certain your ring gear has 41T and the pinion has 11T.
So do the math: 41/11= 3.7272...72 or 3.73 when rounded off.
It is the same for any R&P no matter who cuts the gears.


There are 3.70 gears out there. They're based on a 10 tooth pinion.
 
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Prior to getting my degree in mechanical engineering I ran a full service engine building shop for 20 years that rebuilt everything from Briggs & Strattons to V-16 locomotive engines. So if you have some knowledge you'd like to share with me please do so because I love to learn new things.

I just bought a new Standard HEI distributor cap and rotor and added my cool air nipple and vent holes. I have a 1/2" hose running from my A/C evaporator to the right side of my cap so cool air is always circulating thru the cap to help keep the module cool. Something I started doing about 20 years ago on any HEI equipped engine. I found all 8 of the aluminum terminals in my old Proform cap had loosened a LOT (up and down as well as sideways) and 1/16" had worn from the tip of the rotor's brass blade. I also found a heavy buildup of aluminum oxide on the cap's inside terminals which certainly didn't help anything. The cap and rotor had at least 100,000 miles on it so it was in need of replacement. I still haven't identified the exact cause of my #2 cylinder misfiring and that bothers me.
 

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kpic

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There are 3.70 gears out there. They're based on a 10 tooth pinion.

37 tooth on the ring. Are they GM or aftermarket?

Toobroke...
"Corrosion is the chemical reaction of a metal, in this case aluminum, with its environment, which leads to the deterioration of the properties of metals, aluminum in this case. Aluminum is a very reactive metal, but it is also a passive metal. This contradictory nature is explainable because nascent aluminum reacts with oxygen or water and forms a coherent surface oxide which impedes further reaction of aluminum with the environment.

Corrosion is the chemical reaction of a metal, in this case aluminum, with its environment, which leads to the deterioration of the properties of metals, aluminum in this case. Aluminum is a very reactive metal, but it is also a passive metal. This contradictory nature is explainable because nascent aluminum reacts with oxygen or water and forms a coherent surface oxide which impedes further reaction of aluminum with the environment."

http://www.totalmateria.com/page.aspx?ID=CheckArticle&site=ktn&NM=187

Actually aluminum oxide protects the aluminum from further corrosion.

 

Antz81

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I just bought a new Standard HEI distributor cap and rotor and added my cool air nipple and vent holes. I have a 1/2" hose running from my A/C evaporator to the right side of my cap so cool air is always circulating thru the cap to help keep the module cool.

The cap and rotor had at least 100,000 miles on it so it was in need of replacement. I still haven't identified the exact cause of my #2 cylinder misfiring and that bothers me.

Won't the air in the tube warm up going past the engine? I can't see there being that much flow through it.

100000miles yes definitely time for a replacement.

37 tooth on the ring. Are they GM or aftermarket?

Actually aluminum oxide protects the aluminum from further corrosion.


They're aftermarket.

Aluminum is that reactive that it forms aluminum oxide very quickly. And it's still conductive.
 

kpic

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They're aftermarket.

Aluminum is that reactive that it forms aluminum oxide very quickly. And it's still conductive.

Most likely after my time of (crazed) interest also. ;) As the difference is to the right of the decimal; I doubt there is an advantage found in either. By advantage, the difference between the thickness between the fillet root of the ring gear's tooth space and the datum surface or mounting plane would be minor.

As usual you are correct and a simple test using an a ohm meter would confirm it. However, as it looks nasty, I see toobroke's concern/interest also.

Aluminum is weird in that (as the link said) it is both reactive and passive. Unlike rust its corrosion is to protect from further corrosion.
Although I've worked with them, I'm not a metallurgist, nor do I claim to be one and I didn't stay at the Holiday Inn Express lately. ;)





 

Mac

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You know,
I had this guy's number a while back and mac didn't like it.

I'm glad others are seeing it

Sent from my SM-N920P using Tapatalk

I'm glad you didn't decide to circle back and try to rub my nose in it or anything, dougelam... :chuckle

68807342.jpg


As I said at the time... and I stand by it... toobroketoretire wasn't being rude in offering his opinions & advice. Since you (and now several others) disagree or dismiss much of what toobroketoretire posted, feel free to redress his remarks politely. There's no need to kick virtual sand in his face. If you don't like what he says, set your account to ignore him. Is it too much to ask folks to be cordial?

If nothing else, toobroketoretire has started threads and initiated discussions. Since things around here are pretty quiet of late, I'm glad to see folks talking...

Mac
 
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More On My Ram Air Misfiring #2 Cylinder Problem

This evening I spent a lot of time CAREFULLY looking things over and am now certain the problem with my #2 cylinder misfiring was due to the air cleaner base being within 9/16" of the distributor terminals. To make matters even worse I had my spliced #2 wire (8" added to it) secured to the top/front of the distributor cap which put the core of that wire within about 3/8" of the air cleaner base. Because of the way the air cleaner base had been modified for my Ram Air I couldn't see how close the #2 wire really was until I got a good close-up side view of it. I am going to modify the base to allow at least 1" of clearance and that should take care of the problem once and for all.

Any time you deviate from stock you run the risk of creating problems and sometimes it takes some serious troubleshooting to find the cause of those problems. I have logged about 35,000 miles since I installed the Ram Air and I'm surprised it took this long for a problem to show up. Had I driven it real hard it would have shown up a lot sooner but as I drive like an old man it stayed hidden all these past months.

Here's a picture of what I'm dealing with and I'll post another picture tomorrow morning after I get my air cleaner base modified.
 

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Antz81

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This evening I spent a lot of time CAREFULLY looking things over and am now certain the problem with my #2 cylinder misfiring was due to the air cleaner base being within 9/16" of the distributor terminals. To make matters even worse I had my spliced #2 wire (8" added to it) secured to the top/front of the distributor cap which put the core of that wire within about 3/8" of the air cleaner base.

I thougjt you had a new set of leads coming? So why is there a splice there to make one longer. That will be whats causing the issues. As long as the wires going on to the distributor are properly booted they should be fine.
But that splice:ugh
 

dougelam

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I'm glad you didn't decide to circle back and try to rub my nose in it or anything, dougelam... :chuckle

Nope, no rubbing needed
I take your advice into consideration when posting after that ☺

What drives my less than positive responses is from being a master tech for 28 years and I take my profession very seriously. When someone works on their own car and THINKS no one else is as smart and posts their version of reality appears to be insulting to me.



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Hib Halverson

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Earlier, I posted to this thread:

I have the same hood with the same mod, ie: cut the back of the hood so the fresh air induction is functional. I have the same kind of carb, Holley 4150 with an automatic choke. Like yourself, I have the choke to make starting in cold weather easy. I pump the throttle once or twice then turn the key and it starts and runs at a fast idle until the choke comes off.

I've never had the air flow coming in from the back of the hood cause the choke plate to partially close.

That makes no sense that you'd have to go to the extent that you did to get the choke to work.

There's got to be some other problem.

How much clearance do you have between the bottom of your air cleaner top and the choke horn? Also, what are you running for an air filter?

After reading more of this thread posted after I posted the above, I realize I was way wrong. The set up I have on my 71 is completely different than that "toobroketoretire" has. What confused me was his saying it was an L88 hood. I also made a bad assumption that if he had an L88 hood it would also take air in from the high pressure area at the base of the windshield and have the correct L88 air filter assembly, rather than the odd set-up I see in the photos which, apparently, takes cold air from the front...which no L88 ever did.

Plus the engine in question has a manifold with the top cut off, an air filter which looks restrictive has hell and then there is this outstanding question...

First off, how in the hell does one get better fuel economy AND gas fouled spark plugs at the same time?
Boom.

I'm actually enjoying the pissing contest going on here, but I would suggest to "toobroketoretire" some of the "Big-Block from Hell" articles elsewhere in the CAC. They might offer some insight to building a street high-performance BBC C3 which actually works well.
 

Mac

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Nope, no rubbing needed
I take your advice into consideration when posting after that ☺

What drives my less than positive responses is from being a master tech for 28 years and I take my profession very seriously. When someone works on their own car and THINKS no one else is as smart and posts their version of reality appears to be insulting to me.



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Thank you for the explanation. That brings your remarks into context for me. I've about the same vintage in my profession (+27 years as a peace officer) so if someone waded in and started offering advice on policing that I didn't agree with, I would feel compelled to speak up as well.

Mac
 
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Earlier, I posted to this thread:



After reading more of this thread posted after I posted the above, I realize I was way wrong. The set up I have on my 71 is completely different than that "toobroketoretire" has. What confused me was his saying it was an L88 hood. I also made a bad assumption that if he had an L88 hood it would also take air in from the high pressure area at the base of the windshield and have the correct L88 air filter assembly, rather than the odd set-up I see in the photos which, apparently, takes cold air from the front...which no L88 ever did.

Plus the engine in question has a manifold with the top cut off, an air filter which looks restrictive has hell and then there is this outstanding question...

Boom.

I'm actually enjoying the pissing contest going on here, but I would suggest to "toobroketoretire" some of the "Big-Block from Hell" articles elsewhere in the CAC. They might offer some insight to building a street high-performance BBC C3 which actually works well.


My hood is an L-88 "style" hood that has the L-88 type of additional 2" dome and that's all. Just LOOKS like an L-88 hood from the outside. Knowing my taller Air Gap intake would require a taller hood I bought this one but ran into trouble when I tried to run the common 14" X 3" open dropped-base air filter. I managed to reduce the height of the dropped-base by about 5/8" and had to remove 1/4" from the Air Gap's surface and finally ended up with about 1/16" hood clearance. Using my water manometer I found there is a vacuum at the base of the windshield when running an L-88 hood because the additional 2" dome pushes the air upward like an airplane wing. The manometer revealed there was no pressure until about 1/2 way up the windshield so I decided to use a frontal intake for my Ram Air. The original L-88 hoods may have had "cold air" but not "ram" air because of their additional 2" dome.

What pissing contest? I have never said a single derogatory word against any of you even though many of you have been bashing me all along. I have simply stated what I was doing and why I was doing it in my troubleshooting process to find out why I suddenly had a dead #2 cylinder. Although not absolutely verified it appears my #2 spliced wire that was secured to the top/front of the cap was flashing to the air cleaner base during my coast trip and that's why I got less fuel mileage. As that #2 cylinder hadn't been firing for about 300 miles debris got stuck on the valve face and seat which gave low compression readings until it dislodged at which time the compression returned to normal.
 
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Got The #2 Misfiring Cylinder Problem Solved

Okay, after finding my HEI terminals were within 9/16" of my air cleaner base I modified the base last night to achieve a full 1" of clearance. As the larger diameter Ram Air base completely covered the front terminals of my HEI I didn't know how little clearance there was until my #2 cylinder began misfiring on my coast trip. So with the additional clearance I shouldn't have that problem again.

I was determine to find the cause of my #2 cylinder suddenly misfiring when it had run perfectly for the last 30,000 miles. What was it about my coast trip that was different? Why would that longer higher-speed trip cause my #2 cylinder to misfire. It was the higher LOAD my engine was seeing during that trip and that load was causing my spliced #2 wire to flash to ground..............killing the #2 cylinder and causing the spark plug to turn black.
 

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kpic

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Columbus, NC/NE Georgia
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1997 boosted silver coupe
This evening I spent a lot of time CAREFULLY looking things over and am now certain the problem with my #2 cylinder misfiring was due to the air cleaner base being within 9/16" of the distributor terminals. To make matters even worse I had my spliced #2 wire (8" added to it) secured to the top/front of the distributor cap which put the core of that wire within about 3/8" of the air cleaner base. Because of the way the air cleaner base had been modified for my Ram Air I couldn't see how close the #2 wire really was until I got a good close-up side view of it. I am going to modify the base to allow at least 1" of clearance and that should take care of the problem once and for all.

Any time you deviate from stock you run the risk of creating problems and sometimes it takes some serious troubleshooting to find the cause of those problems. I have logged about 35,000 miles since I installed the Ram Air and I'm surprised it took this long for a problem to show up. Had I driven it real hard it would have shown up a lot sooner but as I drive like an old man it stayed hidden all these past months.

Here's a picture of what I'm dealing with and I'll post another picture tomorrow morning after I get my air cleaner base modified.

As a GM HEI has ~40kV (Pertronix claims 70ish and MSD claims 60kV; as you know now, you can't splice it.

A spark plug cable has an inner conductor, insulator, RFI shield and insulator so we don't get zapped.

As you spliced it, no wonder your plug fouled.

I drive like an old man also. At least until someone wants to pick on an older man in a base model coupe. :chuckle

 
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Splicing Spark Plug Wires

There is nothing wrong with splicing a spark plug wire as long as that splice isn't close to a ground. In my case my large-diameter Ram Air filter base was hanging over the top of the front two HEI terminals and I wasn't aware of how close those terminals were to the base. The terminals now have a full inch of clearance (actually about 1-1/8") so there shouldn't be any more problems with flashing to ground. I had created the problem and once my #2 cylinder suddenly began misfiring on my coast trip I was determined to find the cause.

There is no direct correlation between high gears and fuel mileage. An Air Gap combined with a long duration cam and high gears is a disaster because runner velocity is so slow fuel drops out of suspension. When I was running the stock 3.08's my fuel mileage was a dismal 8 mpg but it shot up to 10-1/2 mpg with the lower 3.70's because the runner velocity increased. That is why the CrossFires and Tuned Ports had small diameter LONG runners to keep runner velocity high to go with the tall 2.87 gears. My Magnum cam is rated for 2200 to 6200 rpm and so I geared it to achieve 2250 rpm at 65 mph. With a near-perfect match between the torque band and the final gearing my 454" gets pretty good fuel mileage at cruising speeds. It started off at 8 mpg and it's now getting 14 mpg..................a 75% increase with about 75 more horsepower; proof that I am doing something right. And with my engine now hitting on all 8 cylinders it'll probably get 16 mpg at freeway speeds.
 

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