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I regapped my sparkplugs with good results by zkhennings
Started on: 05-17-2013 01:18 AM
Replies: 50 (1412 views)
Last post by: 84fiero123 on 10-13-2013 08:29 PM
carbon
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Report this Post05-22-2013 09:12 PM Click Here to See the Profile for carbonSend a Private Message to carbonEdit/Delete MessageReply w/QuoteDirect Link to This Post
That literature you linked to did not come from GM. From that same search Popular Science has it listed as 8.46:1 with 140HP and 170TQ... which is also wrong.

The L44 in 1985 used the same H.O. heads, flat topped pistons, connecting rods and head gaskets as the L44 in 1988. Part numbers exact. The only difference was the use of the balanced crank in 1988, which had the same rod journal and throw as the earlier unbalance crank. The 2.8 had two different heads one with small valves(1.6In/1.3Ex) and one with large valves(1.72In/1.42Ex). The small valve engine had a compression ratio of 8.5:1 and the large valve engine was 8.9:1.

Manufacturing tolerances don't net you a range of 0.4:1... and you can't change compression ratio without a different combustion chamber volume, piston pin height, piston dish or head gasket.

I'm glad that neither of us care and that is why we have dragged this out so far...

[This message has been edited by carbon (edited 05-22-2013).]

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Justinbart
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Report this Post05-22-2013 09:30 PM Click Here to See the Profile for JustinbartSend a Private Message to JustinbartEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by nosrac:


LOL...Don't take my word for it....Google it?

What plugs and gap for Formula's car?


http://www.ngksparkplugs.co...qpregap.asp?mode=nml
Another consideration that should be taken into account is the extent of any modifications that you may have made to the engine. As an example, when you raise compression or add forced induction (a turbo system, nitrous or supercharger kit) you must reduce the gap (about .004" for every 50 hp you add). However, when you add a high power ignition system (such as those offered by MSD, Crane, Nology) you can open the gap from .002-.005".


I actually can't remember. Either AR103 or 104's and .030-.035. The first think I did was a compression check since it ran like poop when I got it. Compression was good so I tossed new plugs in and took it all apart. I never touched the plugs again because it never had a spark problem.

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cmechmann
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Report this Post05-22-2013 11:04 PM Click Here to See the Profile for cmechmannClick Here to Email cmechmannSend a Private Message to cmechmannEdit/Delete MessageReply w/QuoteDirect Link to This Post
Just my two cents. Don't read if you don't want it.

Car manufactures went to higher output ignitions because of the EPA demands to clean up the exhaust.
Before that lower output coils and gap around .035 were normal. Just richen it up to stop the misfires. The more fuel molecules you can get into the gap, the easier it is to make it fire.
First EGR was introduced and even though the added gases are inert(not leaning) it caused less molecules of fuel to be in the gaps. All manufactures tried different ideas to combat that but it boiled down to increasing ignition output.
Than EPA required converters. This required more increases on ignition demands because fuels had to be better controlled(leaned) compared to older cars.
Gm ranges were not unheard of at .080. You also saw drastic changes to wires and caps to handle the load. Firing times also got longer. If you can get the plug to fire longer, you can burn a leaner mix. You also saw holes now burning through parts when, things were not right. Bad/open wires would caused holes burned through the cap grounding out on the coil in HEI. This continued until about early 80s when fuel controls and engine designs got better. With this for a short time, if you used those .080 gaps in the wrong engines, small burn marks were noticed on pistons.
Now with the better fuel controls, 3 way converters were introduced. We could now keep it closer to complete combustion. With that the gaps decreased a little..045-.060., but firing times still were getting longer, and ignition demands were still getting higher. This was also when you started seeing different tips on electrodes. Retapped many a 1990-1991 3.1 head due to spark plug thread heat. Don't get me started on late model Ford truck plugs.
Beyond that without going to 24volt systems DIS was the only alternative and then coil on plug. Taking the long plug wires out of the equation. Coils still break down. 24volt coils would only need half the windings to do the same job. But heat still takes it's toll.
There are too many variables to say that just opening the gap is better. Manufactures have to build a safe range into the design. And going .005-.010 may be OK.
By EPA rules they had to insure that the system could still keep the exhaust clean to around 50,000 miles of normal wear and upkeep. And plug wear was an area of concern. So .005-.010 of wear was built into the (Safe Operating Area)SOA. Beyond that you are pushing things and not just the ignition. The mid 80s were transformation ages and there was a lot more to work with. If you are going to go to .060 Keep pulling you plugs regularly and keep them there or under as they wear.
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Report this Post05-23-2013 10:45 AM Click Here to See the Profile for 2.5Send a Private Message to 2.5Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by cmechmann:

If you are going to go to .060 Keep pulling you plugs regularly and keep them there or under as they wear.


Good info.
So you are saying the plug will wear faster at 60?
Or just saying when it does wear, you wont want to to get bigger than 60.
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zkhennings
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Report this Post05-23-2013 11:13 AM Click Here to See the Profile for zkhenningsSend a Private Message to zkhenningsEdit/Delete MessageReply w/QuoteDirect Link to This Post
I think the second one

And yea I pull my engine apart all the time literally have never had it in the car longer than 1500 miles at a time and I usually replace all the plugs
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lou_dias
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Report this Post05-23-2013 01:04 PM Click Here to See the Profile for lou_diasClick Here to Email lou_diasSend a Private Message to lou_diasEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by carbon:

That literature you linked to did not come from GM. From that same search Popular Science has it listed as 8.46:1 with 140HP and 170TQ... which is also wrong.

The L44 in 1985 used the same H.O. heads, flat topped pistons, connecting rods and head gaskets as the L44 in 1988. Part numbers exact. The only difference was the use of the balanced crank in 1988, which had the same rod journal and throw as the earlier unbalance crank. The 2.8 had two different heads one with small valves(1.6In/1.3Ex) and one with large valves(1.72In/1.42Ex). The small valve engine had a compression ratio of 8.5:1 and the large valve engine was 8.9:1.

Manufacturing tolerances don't net you a range of 0.4:1... and you can't change compression ratio without a different combustion chamber volume, piston pin height, piston dish or head gasket.

I'm glad that neither of us care and that is why we have dragged this out so far...

The valves changing the compression ration makes sense to me. I've always thought about this and always wondered why it wasn't mentioned more in all the 'horsepower' magazines I've read over the years.

The iron head combustion volume of head with HO valves is 52cc. I think stock flat top pistons are .010" below deck at TDC and based on the compressed gasket thickness, you can figure our your own compression ratio just by figuring out that volume and adding the displacement volume then dividing by that original volume...

It also means I may be able to make a streetable compression motor with 3.4 TDC pistons by reverting to non-HO valves...and the thicker gasket...

[This message has been edited by lou_dias (edited 05-23-2013).]

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jon m
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Report this Post10-13-2013 10:13 AM Click Here to See the Profile for jon mSend a Private Message to jon mEdit/Delete MessageReply w/QuoteDirect Link to This Post
After reading this thread a while back - I'd thought I would try and see if adjusting the gap setting was any better.

so as stated in the first post 0.40 - 0.45 is the standard setting and you increased this to 0.60 with you msd high output coil.

I have an accell high output coil and all the ignition components are of low mileage use - so I increased the spark plug gaps to 0.50 which is in between 0.40 and 0.60 ( middle of the road ).

What I have found is that the car is a lot better at starting up - instead of a few turns of the engine before it fires up - it was almost straight away on turning the key - which in turn will lead to a slightly better mpg and slightly better performance.

so I am quite happy I did adjust the gap - however I dont fancy on setting the gap to 0.60 ( if it is working good dont try to fix it )

jon
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Report this Post10-13-2013 11:11 AM Click Here to See the Profile for hdryderClick Here to Email hdryderSend a Private Message to hdryderEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by zkhennings:

I have an MSD Blaster coil (2.8 v6) so I wanted to play with my sparkplug gap.



Are you using MSD GM Dual Connector Coil Part No. 8226?

Has anyone here tried the MSD Digital 6AL Ignition Control Part No. 6425?

http://www.msdperformance.c...roduct.aspx?id=16013
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84fiero123
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Report this Post10-13-2013 12:54 PM Click Here to See the Profile for 84fiero123Click Here to Email 84fiero123Send a Private Message to 84fiero123Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by zkhennings:

I have an MSD Blaster coil (2.8 v6) so I wanted to play with my sparkplug gap. The gaps were all around 0.045 - .0040 inches, and I changed them to 0.060".

I had a very noticeable difference in low end torque. I have yet to compare the top end but I think it will be a little better. Big difference at low rpms though. I have no idea what will happen to longevity, but performance wise it feels good.


College boys,

Col3. Gapping

Since the gap size has a direct affect on the spark plug's tip temperature
and on the voltage necessary to ionize (light) the air/fuel mixture, careful attention is required. While it is a popular misconception that plugs are pre-gapped from the factory, the fact remains that the gap must be adjusted for the vehicle that the spark plug is intended for. Those with modified engines must remember that a modified engine with higher compression or forced induction will typically require a smaller gap settings (to ensure ignitability
in these denser air/fuel mixtures). As a rule, the more power you are making, the smaller the gap you will need.

A spark plug's voltage requirement is directly proportionate to the gap size. The larger the gap, the more voltage is needed to bridge the gap. Most experienced tuners know that opening gaps up to present a larger spark to the air/fuel mixture maximizes burn efficiency. It is for this reason that most racers add high power ignition systems. The added power allows them to open the gap yet still provide a strong spark.

With this mind, many think the larger the gap the better. In fact, some aftermarket ignition systems boast that their systems can tolerate gaps that are extreme. Be wary of such claims. In most cases, the largest gap you can run may still be smaller than you think.

http://www.ngksparkplugs.co..._plugs/installation/

Sometimes I think I am right about,

"For every year you spend in College you lose a year of common sense."

Now before you go off the wall and get all sorts of pissed off at me and do just like every other college educated idiot does when proven wrong but can't accept it why don't you read a few articles by plug manufacturers about just what changing the spark plug gap does, because it does a lot more than what you are talking about.


Did you ever do any Dyno testing of before and after you changed you plug gap?
Because that is the only true way to find out if you are actually getting anything out of what you are doing, you are also changing many other things when you open the gap up on a plug, changing the heat range of the plug you are using would also be a good idea in this case.

just what did you go to college for?

Steve

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and one big pain in the ass when it doesn't



Detroit iron rules all the rest are just toys.

[This message has been edited by 84fiero123 (edited 10-13-2013).]

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lateFormula
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Report this Post10-13-2013 01:13 PM Click Here to See the Profile for lateFormulaSend a Private Message to lateFormulaEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by 84fiero123:

Be wary of such claims. In most cases, the largest gap you can run may still be smaller than you think.

http://www.ngksparkplugs.co..._plugs/installation/

Steve


Just because it's on the internet and was published by a major company, does not make it absolutely factual. I just read that page that you linked to, and the author makes a false statement in the second paragraph under item 6. Using "Racing" Spark Plugs. Anyone else recognize the error?
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84fiero123
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Report this Post10-13-2013 08:29 PM Click Here to See the Profile for 84fiero123Click Here to Email 84fiero123Send a Private Message to 84fiero123Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by lateFormula:


Just because it's on the internet and was published by a major company, does not make it absolutely factual. I just read that page that you linked to, and the author makes a false statement in the second paragraph under item 6. Using "Racing" Spark Plugs. Anyone else recognize the error?


But its on the net, it has to be true, they can't put anything on the net that isn't true.

isn't that what the kids say? that said, every manual I have ever read has wrong info in it, somewhere. But they generally have better info than some kid still in college trying to be a DIY engineer. reading and trying new things with tests to back those things up is how we learn, not everything is on You Tube, and not everything on you tube is right ether. But I do trust a manufacturers info more than a college students experimenting with no real proof, like Dyno tests before and after, that he doesn't have.

Steve

------------------
Technology is great when it works,
and one big pain in the ass when it doesn't



Detroit iron rules all the rest are just toys.

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