Hey Guys, I have done a search for this but nothing comes with my paticular problem. New engine is detonating only very slightly (can only be heard with chasis ear) at around 5000 rpm at only 15 psi at around 10 deg adv. Current setup is..... GT 35/40 with GT66 internals. 1.06 rear Boost6 manifold, HPC coated with Turbosmart 48mm gate 3" exhaust 600x300x100 cooler JD custom plenum/65mm G.M. T.B. Crow 650 L/C 119 cam / springs 550cc inj / 2xbosh m/sport pumps/surge tank Malpassi fuel reg. 60psi base pressure. Standard fuel rail/lines Wiseco 0.020" forged pistons 6.8:1 with HPC coated skirts (ring lands and piston crown de burred) Spool-Hbeam rods Copper Head Gasket 1.6mm Standard Valves/4 angle grind Standard squish area Wolf 3d plugin MSD Ignition Running BCPR8ES-11 gapped to .8 5/8 breather fittings out of rocker cover to catch can Running BP ultimate with 30% touene Air fuel is 11.8:1 Engine has been run in. (About 1000k old) Minimal blowby Have 5 speed with standard final ratio Cam has been dialed to .050" lift on intake lobe cyl 1 at T.D.C Everythig is match ported Rotor phaseing on wolf is correct Pinging is only very slight and very "untimed". can only be heard through "knock box" ear muffs. Should I be running a colder plug? is my cam timing incorrect? All injectors have been checked and flowed. The rear three cylinder seem to be running a little more fat than the front three. Still respectable colour and no lean out on any cylinders. Can have engine at 12-14deg with no audible pinging from cabin. I knows it's dodgey but i had to try to see if it got worse. Any help would be great as i have run out of ideas and would like to see what this engine capable off. Thanks, Sean

who is tuning it?

what fuel are you using ? Premium ?

What is your piston to bore clearance? If it does it regardless of where your timing is set,it may not actually be in the tune itself.

wilko - he is using premium and tol , which gives quite a fair high octane mix. fuel shouldnt be a prob. wiseco's have a rather large p to b clearance dont they , 8 thou or something. indeed could be a prob. too low of a compression can be just as bad aswell get urself a set of ngk r5671a-8 plugs. has the car ever been run without the msd?

Could it be the inlet plenum design? Why'd you go so low with the comp ratio?

I'm doing the tune. Piston to bore is pretty close. Im not sure what it is but it doesn't rattle on cold start. Plenum design should be fine. plenty of guys useing them and making good power. Comp is low basicly to run higher boost on lower octane fuel, or run heaps off boost on hi octane Some original photos have not been recovered yet.

iv got same prob only just started

sometimes it is pretty hard to differentiate injector ticking , even gearbox noises from detonation when ur wearing chassis ears. look at ur timing first , if u have to degree the cam in again , setup timing right and make sure what the computer has its base timing at is the same as what ur crank timing marks are at

Has the harmonic balancer spun which is giving you the wrong timing on the timing light. Being a low compression engine,this may not be such a problem down low where your timing may be reading higher than the problem area but once the engine comes into its 'peak torque' range,the timing may be a little excessive. This is only a thought as i have seen this happen many a time... Also with those chassis ears,i have a set,but i hardly use them when i dyno tune as they are hard to sort which noise is pinking and what is just engine noises or knocks. We use a pair of earmuffs with someone listening over the engine on a power run. The earmuffs block out most of the engine noises and if the engine is detonating,can be heard where the naked ear cannot hear it... Are any of your exhaust manifold pipes etc glowing? do you have an egt connected whilst tuning as this will help tell you if the problem is from your tune... Hope this helps... Some original photos have not been recovered yet.

mine was running very rich and pinging badly when we backed the fuel off it stopped.

so your runing 6.8-1 comp pistons and a 1.6 gasket. bjezuz u would have a low comp ratio and at 11.8-1 af ratios it shuldnt be pinging with low timing cos thats a bit rich. id expect to c 12-12.8 or so but thats just me. i sugest runing away and geting another tuner

LOL, I am the tuner. re checked cam timing, used lobe overlap and came up with same position. Rotor phasing is correct and balancer is almost perfect to TDC. Going to pull cat out and see if that helps. Could be melting in center and creating exhaust restriction. Dont have EGT but definatly another avenue to look at. Have used two different types of chassis ear and had same results. Running leaner mixture doesnt seem to change it at all. its there at 10:1 or 13:1. I'll keep trying things, checking the plugs as i go.and let you guys know how i go Some original photos have not been recovered yet.

Boy that compression is low, to me its sounds like a piston squish problem or EGT are going through the roof increasing combustion temps, what sort of power are you pushing through this thing before it pings

well its only making 200rwkw and then detonation sets in. Its not a lot but very rendom and untimed detonation.

OK, up'ed the boost to see if it got worse, could only just hear pinging from cabin at 18 psi at 12 deg adv. wound it back to 17 pinging almost gone. Put one range colder plugs in no pinging. Listen through knock box and slight detonation, wound down to 15 exactly the same same detonation. still at 12deg adv. I'll pull cat out tomorrow and maybe try one more colder plug. Has any one else got wiseco forged and ACL 1.6mm copper gasket? Starting to think its squish aera problem.

man, it must be annoying having these problems? considering ur setup, u should be making heaps of power and having a ball still what do u mean by "u r the tuner" ? u have a dyno and everything? : O Some original photos have not been recovered yet.

dude if you have a 1.6mm gasket and pistons with a deck height of zero or less, then you have no effective squish area. that gap is too large to be of any use. another problem is that the RB30 head doesn't really have effective squish areas in the first place, the chamber is basically a dome. at zero deck height i couldn't identify any areas of the combustion chamber which would work as a squish/quench area. maybe with a positive deck height, but nobody does that. compare it to an RB25 head which has laterally opposed quench areas, you'll see what i mean. after all that, i don't think the lack of squish is your problem. lots of people make big power out of the buggers so there's no reason you shouldn't.

RB30ET is a no-squish zone basically, open chambers like the Rb30's mean its not really an issue, (I run the pistons hanging out of the block by the way) are there any timing compensations in the ECU that you are not taking into account? my timing dips at 9.0 degrees around 4500-5000 (pk trq) and then climbs to 20 by 7500, im using avgas and my CR is 8.0:1, heat range 10 race plugs. those timing figures are at 1.3bar btw, 1.8bar is a bit less again. we were monitoring detonation all the time and did around 45 power runs and tweaked timing .5 of a degree at every point till we were just under detonation point. post up your timing map if possible? Cheers Brent

Funny you say that about the timming compensation, No there are none. Only stight retard under cold start. However if i try to change the overall trim it makes no difference. On the wolf or on the timing light. Does not seem to matter what the ignition timing is, It only like 1 or 3 pings over a power run and like i said if you are not listening through chassis ear you cant hear them. Have to get off my lazy back side and do some more testing.