knock issue strocker gen 6 bbc 7400 vortec

[yanick]

hi, everyone
I built a strocker 7400 vortec (gen6 454) => 8L (489ci)
12cc dome piston
4.25 stroke
4.28 bore
0.027 cometic head gasket
comp cam xr264hr-13 (212 int 218 exh 113 lsa) @0.050 int open -5 BTDC close 37 ABDC @0.050 exh open 44 BBDC close -6 ATDC
stock 7400 vortec got compression ratio of (9.0-9.1:1) => now the statique compression ratio is 10.9:1
I built this engine to get good low end torque and use as tow rig

it idle good and AFR look good but a soon I load the engine it start to knock.
I don't have any knock detection device excepted 2 OEM knock sensor. I was thinking to buy a "link knock block" any recommendation?
I try 10-15 and 25 degree at load for low RPM but no luck it knock no matter what I do.
Did I when too crazy with this built and it need 93 only?
15 timing at cruise.hpt15 timing at cruise.hpl
10 timing 50-75 kpa.hpt10 timing 50-75kpa.hpl
normal timing table.hptnormal timing table.hpl

[edcmat-l1]

If that has 100 cc heads on it and the deck clearance is zero the compression is 11.6:1.

Why such a thin head gasket? Standard for quench is normally around .040. Best think you can do is pull the heads and put thicker gaskets in it. If the compression is really that high it might rattle on 93 especially when towing.

If I'm right on the chamber cc and the deck clearance you'll need a .100 head gasket to get to 10:1. That's what I'd shoot for in a towing motor. 10:1 MAX. Preferably 9.8-9.9:1

[yanick]

deck height is 9.800
head volume 102cc maybe 103cc now because I checked my cc and after when I built the engine the pointe of the heart was hitting the piston dome. until I grind the point
piston compression height 1.270
rod length 6.385
stroke 4.250 (1/2) stroke= 2.125
piston height at TDC= 1.270 + 6.385 + 2.125 = 9.780
when I built this engine piston height was 0.018 down + 0.027 head gasket = 0.045 quench

[yanick]

for now do you think I could tune this engine on 93 with 10.9 cr. I need to move this truck like 3h away and don't feel like paying a towing...

[5FDP]

You can't command a stoich ratio of 13.3 if the fuel you are running is not that. The stoich ratio must be correct for the fuel in the tank, there is no fudging numbers with that. Return the open loop EQ ratio to 1.00 for operating temps.

If you did any fuel tuning with a wideband with the open loop like that, the data you got would be all wrong. Also I'm not sure that those size injectors will support the power that this new engine can make.

[edcmat-l1]

deck height is 9.800
head volume 102cc maybe 103cc now because I checked my cc and after when I built the engine the pointe of the heart was hitting the piston dome. until I grind the point
piston compression height 1.270
rod length 6.385
stroke 4.250 (1/2) stroke= 2.125
piston height at TDC= 1.270 + 6.385 + 2.125 = 9.780
when I built this engine piston height was 0.018 down + 0.027 head gasket = 0.045 quench

That makes more sense now. looks like it's right at 11:1

Put high octane in it and see if the ping goes away.

[yanick]

sorry 5FDP I forgot to specify that. I did my MAF cal at low RPM at 14.7 (1.00). when I started to get some knock I played with timing 10-15-20-25. but no luck, until I tried to add some fuel see if I could get away from knock...

[yanick]

thank for the injector info, I will check my duty cycle. make sur I keep them under 85-90%