Pinging Problems

[B-Lazer]

Having pinging problems in the high load range of 1200-2400 rpm @ 60+ kpa.
I have found some issues but can't get it all to stop.
Pulled timing to the point it had no power these areas.

1993 Chevy Blazer
5800 lbs.
home elevation 2600 ft
short block GM crate L05
heads Summit Racing Aluminum 162108 62cc chambers
head gasket Felpro 1010 8.9cc .039in
cam GM performance 14097395 aka HT383 cam
bored throttle body and bored stock TBI intake
JBA small tube headers with their 2 into 1 pipe
flowmaster 3" cat and muffler

Tuning with TunerPro RT v5
Plan was to build a L31 vortec clone with aluminum heads.
Reading from the net lead me to believe this cam would work but in practice it holds dynamic compression close to static.
Looking up the specs on a stock L31 cam seems to be even more conservative...
Logic to me is says 9.25:1 in a heavy truck with these cams equals too much static compression.
I have played with 87,89, and 91 octane and lower timing to the point of no power.
It still pings even on Power Enrichment at 12.3:1 fuel
Suggestions are greatly appreciated

Here is the latest .bin and a log from today's drive home

[Keith74]

Hello Mate,
your timing table has all negative spark values. Unless i'm missing something why have you done this?

[Keith74]

Change your spark bias to 0
You will have to redo your idle and open spark tables and you may find that not having enough advance will cause pinging. Check your timing is set at 0 on the dizzy.

[Fast355]

Having pinging problems in the high load range of 1200-2400 rpm @ 60+ kpa.
I have found some issues but can't get it all to stop.
Pulled timing to the point it had no power these areas.

1993 Chevy Blazer
5800 lbs.
home elevation 2600 ft
short block GM crate L05
heads Summit Racing Aluminum 162108 62cc chambers
head gasket Felpro 1010 8.9cc .039in
cam GM performance 14097395 aka HT383 cam
bored throttle body and bored stock TBI intake
JBA small tube headers with their 2 into 1 pipe
flowmaster 3" cat and muffler

Tuning with TunerPro RT v5
Plan was to build a L31 vortec clone with aluminum heads.
Reading from the net lead me to believe this cam would work but in practice it holds dynamic compression close to static.
Looking up the specs on a stock L31 cam seems to be even more conservative...
Logic to me is says 9.25:1 in a heavy truck with these cams equals too much static compression.
I have played with 87,89, and 91 octane and lower timing to the point of no power.
It still pings even on Power Enrichment at 12.3:1 fuel
Suggestions are greatly appreciated

Here is the latest .bin and a log from today's drive home

Your biggest issue is your quench distance is too wide. 0.064" is far more than the generally accepted ideal range of 0.040-0.045". Running an aluminum head the only thing you can do is mill the deck of the block to fix the issue. If you were to get the block zero decked and run the .041" head gasket it would be perfect.

I had detonation sensitivity with that cam as well, but I was running it in a 9.6:1 cast iron Vortec head 350 in a 6,200 lbs Express van pulling a 6,000 lbs travel trailer. That being said on 93 octane I was still running 20* of timing from 1,800-2,400 and 26* of timing from 2,400-4,400 increasing to 29* by 5,600 rpm.

Marine cam and the stock L31 truck have almost the same exact DCR.

[B-Lazer]

Thanks!
You reset my thinking to what was stock and I found the original GM 10105117 head gasket is .028.
.053 isn't ideal either but it shows I went the in the wrong direction by searching for a gasket I knew to be compatible with these heads.

Any thoughts on CompCams 08-500-8 Xtreme Energy cam?
112 lobe separation over 109 should give it a little better idle
57 ABDC intake closing vs 24 would really help to bleed off some compression

[Fast355]

Thanks!
You reset my thinking to what was stock and I found the original GM 10105117 head gasket is .028.
.053 isn't ideal either but it shows I went the in the wrong direction by searching for a gasket I knew to be compatible with these heads.

Any thoughts on CompCams 08-500-8 Xtreme Energy cam?
112 lobe separation over 109 should give it a little better idle
57 ABDC intake closing vs 24 would really help to bleed off some compression

I went a little different approach to the cam I just had Comp grind for me. Basically the GM SPO 357 HP 350 cam with more aggressive lobes.

270/284° @ 0.006
215/223° @ 0.050
0.533/0.533 w 1.6 rocker
110 LSA + 4 advance

The 395' cam has a great idle IMO.

On the cheap you could bring your DCR down substantially just using a F/Y-car LT1 cam. ZZ4 cam would also be a nice runner.