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10:1 compression and pinging

beater74

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I have a new 350 with 10:1 copression and it's pining at highway speeds. I only run on 93 octane and have my timing set at 4 degrees above top dead center should I keep retarding timing or do you guys have any other ideas.
 
Try running a cold air intake setup. The colder air will help eliminate detonation.

A cooler thermostat may help.

Another thing that helped my 99 GTP is running a different plug. It's been actually proven that a TR55 NGK plug (non platinum) had less knock retard than the stock AC plugs.

If the above doesn't help, you may try water injection.

Also read this:

www.speedomotive.com/Building Tips.htm

quench height has a big role in detonation.

Shawn
87 K5
few mods
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You still running that stock air cleaner with the ittity bitty little hole pulling all that hot under hood air?
Go find a air cleaner off a 79 up with the snorkle. The knock out should be in the core suport for it.
I was having the exact same issue on my 75 and a 85 cleaner and snorkle with a K&N cured it. Back up to 8 deg advance as it should be now. I went as low as 2 deg and it would not go away. Gears are not helping either if you still have the factory 3.08's

Diging it in the dirt with my K5's
Grim-Reaper
<A target="_blank" HREF=http://grimsk5s.coloradok5.com/>http://grimsk5s.coloradok5.com/</A>
 
great thanks for the info I'll try the snorkle(new housing) and I already have the K&N. but could you give me more info on those spark plus you recommend i don't understand TR55 NGK. had plans already for snorkel because an open element air fillter and offroads don't mix very well.
 
Model number just like the TX44 AC that is listed as replacements.
Thanks for the info Shawn. I have wanted to find a better heat range plug. I get a lot of high speed glaze on my plugs and this may cure it. Now if I could fix the deposites I get I would be a happy camper
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Diging it in the dirt with my K5's
Grim-Reaper
<A target="_blank" HREF=http://grimsk5s.coloradok5.com/>http://grimsk5s.coloradok5.com/</A>
 
Sorry, didn't mean to confuse you on the plugs but I was just using those plugs as an example but I would do what Grim said and cross-reference your stock plugs with the NGK's. We used OBDII software and hooked it up to our Supercharged Grand Prix's to prove the Knock Retard (KR) was lower with the NGK's. Everyone on the GP list uses those plugs but they might be different # for your engine.

Another plug thats famous for the Syclone/Typhoon crowd is the AC-CR42TS which is for the 4.3 engine (similar to a 350). The CR42TS plug is actually a commercial plug and has also proven to reduce detonation compared to other plugs.

Shawn
87 K5
few mods
smile.gif

<A target="_blank" HREF=http://www.off-road.com/chevy>http://www.off-road.com/chevy</A>
 
okay still a little confused what does NGK mean and who makes CR42TS's and better yet when i go to local parts store what should I ask for.
 
Sorry. NGK is a spark plug brand like Champion or Autolite. The CR42TS is a AC Delco plug but it was designed for commercial applications or Turbo use. The plugs I listed are for cast iron heads and will not work with alum heads. I'd try the cold air/snorkel thing first and see what happens.

Shawn
87 K5
few mods
smile.gif

<A target="_blank" HREF=http://www.off-road.com/chevy>http://www.off-road.com/chevy</A>
 
thanks but hey it's only money and when it comes to my blazer i don't mind spending it and neither does my wife (kinda)so should I try those CR42TS
 
I love NGK plugs... but probably the main reason for this finding is heat range... if you end up looking up different heat ranges of AC delco plus you find most NGK's cover 3 or even as many as 4 heat ranges. So you can always try running a cooler plug in ac delco if you are unsure of NGK... although I love them.

-Mikey
1987 Chevy K5 Blazer- 350 TBI
<A target="_blank" HREF=http://www.geocities.com/milnerlives_2000/blazer.htm>http://www.geocities.com/milnerlives_2000/blazer.htm</A>
 
Are you sure that the timing tab on your chain cover matches the balancer that you are using? On the older engines, the mark on the balancer is at about 2 o-clock when the engine is at TDC. On the newer engines, the mark on the balancer is straight up (12 o-clock) at TDC. You said you have a new engine, so depending on the vintage of the balancer and the timing cover or tab, there could be a mismatch.

Tim

70 Blazer CST 4X4 350 SM465 NP205
87 Burb 4X4 350
01 GMC 2500HD 4X4 Duramax/Allison
 
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