What Plugs for SE Stage 2 Heads?

nate, im sure i dont have the wire crossed, i check them all the time. im also only using a electric pump, no mechanical pump, and my guage says im getting 6 psi to the carb. ill check the mufflers to see if it feels like the pressure is even.

steve, when i did the upgrades i took the whole engine apart except for the pistons and crank. i doubt that the balancer sliped, its a brand new sfi certified and all that crap ta one. as far as mufflers go, im running through a pair of dynomax 3 " in 3" out. the ignition system is a msd 6a box, with a msd mechical advance billet distrubitor and a external coil.

it sounds like my next plan of attack is to check the cam to see if it is going flat. this sounds like the most logical plan.

 

I agree about the camshaft Dan, how many 13 second runs did you make? When you ran them did the car seem to laydown at a certain point or did it feel low on power overall? Was it slow to rev? You really have me really scratching my head now ..... like I said if there is anything I can help you with let me know. Im just down the road and I'd love to see your car.

 

Steve, i ran probably 5-6 13 second runs. the car feels great, i remember thinking to myself "but this was definitly a mid 11 run" only to discover it was a 13.4. I am currently in NY attending my grandfathers funeral, but i will be home tuesday. if you think you can make it to my house i will pm you my cell #. If you kknow how to dial in a cam, maybe i will pickup a new cam and have the engine torn apart by the time you get there. If you think that that is my problem.

 

Ill give you a ring on tuesday.

 

Any update?

 

yes actually, yesterday i pulled off the valve covers, had my wife crank the motor while i watched the rockers go up and down. They all seem to travel the same distance (about a half inch). but of course that is just eye-balling them. i rechecked the vacuum at operating temperature it is 11 inches at idle dropping to 9 in drive. i also took it out for a drive the other day, when i start it up when it is cold it backfires through the exhaust, then after it warms up, the backfiring goes away.

 

I think if it was bad enough to see by eyeballing the rockers it would run a lot worse than it 13s. Did you see metal in the oil? Pull the stick and hold it under a light or in the sun. If it looks like graphite (gray) worry. If it looks like oil stop worrying about the cam. Does the popping happen when you step on the gas to accelerate, or a certain RPM, all RPMs, or when you back off the gas?

I hate to complicate things with more theories but I want to help you get this thing fixed. I'm wondering if the basics were covered. Has the valve adjustment been checked? We have not talked about ignition other than you have to run a lot of timing. Have you pulled and inspected all the plugs? What are you running for an ignition system and is it right?

 

the backfiring only seems to be when it is cold, like on start-up. but i think that has to do with the new carb, it didnt do that with the 850 holley. i really need to find someone that can tune a carburator. I adjusted the rockers about a year ago, i did this by getting each piston to TDC, tightening the adjuster nut hand tight, then putting about a 1/4 turn into it with a allen key. I have pulled out each plug, they all looked like they were running lean. then i checked the gap and realized that they were gapped at .30, so i opened them up to .50. i know that this dosent seem right because the motor was running a little lean, but having a .30 gap can't be right, not with a MSD 6A, MSD distributor and external coil.

 

Stupid, I know, but could the dist. be off a tooth? or the cam gear off a tooth? I've seen similar weird issues when this happens, and it accounts for the need for alot of timing. We had one with a multi-position crank gear, but the guy had used the wrong mark to line up with on the crank gear. The engine ran ok, needed lots of timing, and backfired through the exhaust. Another had the dist off a tooth, backfired when cold, ran good warm. Guy had the distributor cranked enough to almost make up for the difference.

 

i think at this point, i am willing to believe anything, although past threads have tackled the issue of being "off a tooth" and i dont think that it would matter and/or there is no such thing?

also, i checked the oil, it seems fine, its black, not grey and i dont see and metal shavings/filings. :TU:

 

I know I said it before, but did you check all your valve springs seat pressures???? You may just be floating the valves with the "bigger" cam you say you are running...... what is the open spring pressure? How far from coil bind?

 

yea but whamo is away on business, hopefully when he gets back he will have some time.

i have a MSD mechanical advance distributor.

BUICK4SPEED I THINK YOU GOT IT!!! I did some research and found that i still am using the old valve springs from the Lunati cam (a much smaller cam). they are TA part # TA 1107 (O.D 1.360 / 100 lbs @ 1.9 / 250 lbs @ 1.4 and a coil bind of 1.06). santos over at TA says i should be using TA part # TA1125 springs (O.D 1.385 / 125 lbs @ 1.9 / 320 lbs @ 1.4 and a coil bind of 1.14). what do you guys think? im prety excited about this find...... could this be the elusive problem i have? could i have been floating the valves? are the TA1125 valves the ones i should be using or are there other ones? remember i am using the TA "Gibson" cam (110 version). Please let me know what you guys think!!!

 

Im away right now for the next 3 weeks. You said the plugs look lean. A lean mixture requires more advance. Maybe its just way to lean for some reason.

 

how can i tell if these are the right springs for the cam im running and TA isn't just trying to sell me a set of springs? inother words, i need a second opinion...