Stop the PING! jet and plug choice etc..

[TulsaSpider]

I had another long post( http://fiatspider.com/f08/viewtopic.php ... &sk=t&sd=a ) that had kind of gotten away from the original issue so I thought I would start a new one. I have a 2L block with 4MM domes, 1800 head re done but stock except for port matching, Mark's street cams, Marelliplex distributor (electronic, no vacuum advance), Weber 32/36 DFEV
jet next to cam tower 140 jet next to fender 137.
I had tried an NGK plug in 1 colder range. NGK BP7ES. and the performance decreased very noticeably, but no pinging.
So I put the Champions back in. Set the timing to about 8degrees btdc There is definitely a performance difference!!! However upon listening closely I could hear the slightest pinging, but man it really screams! With the NGK's there was no pinging but definately less performance. So If I put in more advance with the NGK's I wonder would I get better results performance wise with them?

Champ RN9YC The pinging is very slight, under max load, but now I'm paranoid about it!
OK maybe I should begin another thread here..?. I was talking to my buddy Kent and I realized I really didn't explain myself before, when I wrote that switching the plugs caused a drop in power.
Specifically the change was not from low RPM or take off. That seemed about the same. In the upper RPM range about 4K RPMS with the NGK's it simple did nothing. With the Champions in when I rev it in gear about 4k I get a nice surge of power. Not so with the NGK's hold it to the floor at 4K nothing, no more RPM's no more power. With the Champions in it will continue to rev to 5K. I was just at the local cruise night and had her going at 4500 RPM and mashed the gas and it lurches forward I still had plenty of power.
Kent's a pretty good mechanic. He thinks that the spark from the coil may be weak, thus the hotter plug does better at high RPMs. With the performance changes I could try get a better coil and ditch the decades old module.
Sounds logical to me especially since it has been said that the should be no performance differences in the plugs according to consensus... Opinions?

[baltobernie]

I've heard of high compression motors "blowing out" the spark under load in older-style low-energy ignition systems such as ours, but I don't know if this is an urban myth or not. This phenomenon allegedly occurs under high load conditions, and that's what you're describing. Too bad no shops have Sun machines any more; you can visually see the spark amplitude and timing on the CRT screen.

[131]

I run my 131 on LPG, when I installed it I was told a better spark would improve performance. A Bosch MEC coil provides a huge spark when run with the stock Fiat module.

[lanciahf]

I would try a richer jet on the secondary circut, cam tower side. I have basically your engine and I put a msd master blaster coil 2 in my car. http://shop.advanceautoparts.com/webapp ... P2041_____

[TulsaSpider]

Ok thanks for the suggestions!

[lanciahf]

Any News?

[TulsaSpider]

No I was gone to Colorado for a week. My first vacation in 17 years or so. I get back and it's 108 degrees, yikes!

[Daniel]

I've heard of high compression motors "blowing out" the spark under load

This is more of a Turbo Engine under high boost issue ! not NA Engines

[TulsaSpider]

Well I got some jets in today. 1.45 and a 1.47. I tried the 1.45 in the secondary first and it liked that. Then I tried the 1.47. About the same. Then I tried the 140. in the primary and it liked that as well. I can't hear any pinging but I might hear a tiny bit of clatter. It's running really nicely, and I even got a second gear chirp! I think I may still upgrade ignition components.

[TulsaSpider]

Today I upgraded my ignition with the electronic Accel coil #8145 and a new ignition module. I found that I had a definite improvement on my top end power! Money well spent!

[Sunracer]

Your motor should rev hard to at least 6K. Is your tach accurate? a hotter spark will always help. Where is your timing set? Usually hot cams require more advance to be happy. Are you running premium?

[TulsaSpider]

Tach accurate- no idea lol Yes it pulls past 5k haven't run it that hard past that. I have it set about 8 degrees advanced at the moment- yes using 91 with octane boost. Not sure when I'll be able to play with it again. It was 109 here today! BRUTAL!!!!

[Sunracer]

Tach accurate- no idea lol Yes it pulls past 5k haven't run it that hard past that. I have it set about 8 degrees advanced at the moment- yes using 91 with octane boost. Not sure when I'll be able to play with it again. It was 109 here today! BRUTAL!!!!

Ouch 109! too hot for top down motoring : ) What distributor are you using, if you are running cams you may not have enough advance. PB

[TulsaSpider]

The Marelliplex. I plan to play more when the weather is less brutal...

[124ADDHE]

Sorry, did you post your total advance? That is the most important factor to the timing...total advance should be 34-38 deg with 36 being pretty common for the approc 10-1 compresssion and premium fuel (in canada it is usually 91 octane but chevron has 94 in some places). Whats your exhaust like? is it a good 2-2.25" with high flow muffler?