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Discussion Starter · #1 · (Edited)
spark plugs fouled ... 3964291 casting head . added pic..

Iam in need of some help again , Heres what the engine is as far as i know . 1973 454 block , 3964291 heads ( casting date b-71 ) . using r43xls plugs with the little ring on the plug . I have stock hei and plugs are gapped at 40 . The spark plug holes has at first no threads then the threads starts .

The car since i got it has fouled plugs out pretty quick , i had a 750 holley on it and thought power valve was bad or float level was wrong . I checked float levels , bought a new power valve ( stock size holley for 750 ) changed the needle and seat , jets where front 72 and rear 80 .
After about 2 or 3 mins ( even with rpms above 1500 to 2000 ) it burns you eyes . i pull plugs and tey are black and some are kinda wet , smelling like fuel . so i fiqure the carb is shot for now .

Well i put a new holley on it today , and tried r45xls plugs and for a min the smell was strong then seemed to clear up .. then after about 8 mins ( not just ideling ) it started smelling again and the plugs are just starting to get black ( very light).
Iam wondering if the xls plugs are wrong for the heads , or what else can i check . The motor thru all this doesn't skip , miss and revs quick , still idles also , so iam thinking valve adjustment is correct , carb is not dripping . But i don't know where or what else to look for , buddy of mine said fuel pump maybe .

Heres a link to where/how the spark plug hole is , i read that this head could use two different plug type , did i get the right ones ?

http://i118.photobucket.com/albums/o101/brevard454/sparkplugforhead.jpg

Thank you
 

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Tough to tell by the pic, but I think you need the tapered seat plugs instead of the gasket seat kind you have. Don't know if this would cause the fouling, but it probably doesn't seal right with the gasket plugs.
 

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I have an LS6 454 and ran accel # 276 plugs with good luck.
Plug temperature should be in the 500-800 C range or about 1500 or 1600 F. Below this they will foul. The jump from one plug range to another is about 75C or 125F per number.
 

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looks to me like you have the right plugs. that's not a tapered seat hole. see the non-threaded area and the flat place for the plug gasket to seat.

have you looked down into your carb while it's idling to see if it's dripping from the booster venturiis?

are you able to do a cylinder balance test? this involves pulling the plug wires out of the cap one at a time to see which cylinders are firing and which are dead. you'll get a noticeable RPM drop on the good cylinders, no change on the dead holes. start by pulling all 8 wires out of the cap (engine off) one at a time and re-install loosely. use insulated pliers or the plug wire pliers made of phenolic, then crank it up and lift the wires one at a time.

ever run a compression check or leakdown test on the engine?
 

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Discussion Starter · #6 ·
Thanks for the help guys ...

Compression check was 137 to 140 on each . No compressor so i can't do a leak down thou . This is in a 79 malibu , so the main hei wire was there but i will check it .
I pulled each wire from the cap one by one and replaced it back on one by one , each one i pulled dropped the rpms ,till i put it back on .

iam lost at this point , unless the cam is a solid and not a hyd like i was told , i think i may pull the intake as i can't seem to get the lifters to push down like a hyd i thought would . Don't know if that would be enough to make it run rich like that but not miss a beat .

Maybe drain all fuel and start with fresh fuel and see if its a solid or hyd cam to be sure .
 

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What cam are you runing & what are the specs?

I ask this because if you running an aftermarket perf cam (hyd or solid) with the initial timing too retarded set to stock gm cam timing specs like 0-6 deg btdc that can cause the idle vacuum to be considerably lower due to retartded timing. This in some cases can cause the power valve to prematurly open at idle esp with auto trans in gear lowering the idle which in turn lowers the idle vacuum. This can cause an over rich mixture that fouls plugs & the ex fumes can burn your eyes just like in your case.

If you runing an aftermarket cam make sure your running approx 16-18 deg btdc initial timing,anything less is to retartded for even a mild aftermarket perf cam. This is because aftermarket perf cams have more duration then stock gm cams do but watch out that the total timing doesnt go over 38 deg when adv the initial 16-18 deg. If that happens you will need to remove the dist to have the mech adv limited to 20 deg max to avoid detonation & poss engine damage.

Also,whats your fuel pressure,it should not be over 8-9psi max with a holley so check that out,too high of fuel pressure can force fuel past the needles & seats in carb & cause flooding/rich mix.

A Vacuum leak within the carb due to crakced/warped carb body/metering block/s/bad gaskets or leaking or cracked intake manifold can all lower idle/low speed vacuume enough to prematurly activate the power valve resulting in rich mixture.

Poor/weak ign can aslo add to this problem but with the strong burning eye fumes you have i feel its a tuning/timing/carb setup issue . This is a common problem that happens when trying to dial in perf motors with perf cams.

Hang in there you will eventually get it squared away.

Scott
 

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Discussion Starter · #8 ·
Thanks everyone i think i found most of my issues , What helped alot was changing the vac advance on the distrib. ( i checked and it was like sucking on a straw in the open air ) that did help alot .

Messed with timing and carb alittle more it was better but not right still , but close .. int. timing was set at 15 degrees , overall timing i don't know for sure as that timing light isn't working . ( was set at 32 before thou ) . let it run for a bit and it did well .. turned if off . 20 min later , Went back out and noticed there was less fuel in the filter then when i first shut it off .. it wasn't empty , but over half of what it was .

Another thing i noticed was the spring assemly in the disturbutor was not right i don't think . i could move the rotor about 1 inch total and it seemed to lock when i let go of it . then go back into place , also had alot of play in it and the springs would go atop each other .

So i decided to pull off the intake and grab a lifter and see if it solid or hyd. , if i can't tell which it is or if its a solid , the cam is coming out to see if i can find some specs for it . The heads may too just to see what it looks like in there , since iam that far into it .

Guess this is what makes buying a car and not knowing what was done to the motor , even harder to tune it . After all i was told it was a ls6 replacement hyd. cam but who knows at this point .
 

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You say the total was 32 deg but you cant check it because your timing light ie broken then you say your timing (initial?) is set to 15?

How can you be sure the initial is set to 15 when your timing light is broken?

Get a timing light that works,the 32 deg total your running is too retarded ,you need approx 16-18 initial with an aftermarket perf cam and 36-38 total for most street setups.

Your initial timing will be very retarded with only 32 total. This is because for example if your dist has approx 25 deg mechanical then your left with 7 deg initial which is 9-11 deg reatarded from the 16-18 deg the initial should be with an aftermarket perf cam.

You loosing a lot of power running with the initial timing that retartded and it also wasts fuel, along with the motor running a little hotter too which are all not good.

This is very likely your problem because running with the timing way too retarded like youare lowers the idle & low speed vacuum a lot which can cause the power valve to prematurly open at idle & low rpms due to the lower vacuum .

This is very likely your problem so buy another timing light or borrow one.

Then idle the motor down low to 550-600 rpms to set initial timing to 16-18 deg & unhookd/plug the vac adv too when your doing this.

Then check the total to ensure it doesnt go over 38 deg,if it does have mech adv in disy recurved for 20 deg max (all in by 2,800-3krpms)so along with 16-18 initial gives you 36-38 total.

But i would still not run the real cold ac43's,too cold for street use esp in traffic,44's or maybe even 45's will wor kbest for you.

Scott
 

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are you able to do a cylinder balance test? this involves pulling the plug wires out of the cap one at a time to see which cylinders are firing and which are dead. you'll get a noticeable RPM drop on the good cylinders, no change on the dead holes. start by pulling all 8 wires out of the cap (engine off) one at a time and re-install loosely. use insulated pliers or the plug wire pliers made of phenolic, then crank it up and lift the wires one at a time.
Another way to accomplish the same thing: Use a test light with the ground lead connected to any convenient ground. Put a dab of silicone grease on the pointy tip, and slide the tip between the wire and the boot at the distributor end (or the plug end, whichever is easier for you.) The test light point will slide between boot and wire until the tip contacts the metal of the plug wire end, which will ground the spark, killing that cylinder. And because you're being careful, you don't injure the plug wire, either.
 
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