1GGTE pinging after engine rebuild. UPDATE - no more pinging!

[Pube]

After rebuilding my 1GGTE im having issues with it pinging when I screw some more boost into her. When using around 8psi, It doesnt ping but when I turn the boost to around 14-15psi she pings. Im using Vorted 98 fuel and I have set my base timing initially to 10 deg (where it pinged) and have gone back down to 8 deg and it still pings. Before the build I didnt notice any pinging when running 15psi boost.

Should I back the timing to 6-7 deg base? The maintenance manual says 12-8 deg. I have also noticed in the maintenance manual that you can adjust the canm gears by moving the dowls to one of the other holes (3 in total) I put the dowl in the centre hole which im pretty sure is the factory position?

[Munki]

Do the 1g's distributor run off the camshaft? if so i would double check the cam timing and then recheck the base timing.

[Pube]

The distributor runs off the exhaust cam. It only pings when the revs are right up there, say about 5000rpm

[stradlater]

Factory ECU?

I'd be checking ALL your timing again..

I have pulled apart 1g's where the cam's weren't located on the middle dowel, so perhaps that is wrong.

[amon]

Hey Pube,have you touched your AFM(the tension spring tighten trick)mine likes normal tension for high boost (14psi) or 2 notches tighter for lower boost (9psi)a little leaner perhaps and on a hot day only pings fractionally up in the high RPM.

cheers Guy

[IN 05 NT]

try pushing more out of teh timing, 12-15dg (i havent played with the timing on my 1gs yet) but did have to advance the cressy a bit more then usuall to get it to stop pinging,

so far all the cams ive pulled out of 1gs have had there cam gear locater in the middle dowel.

[worldwalker]

I just found out my 3s has been pinging bad (hard to hear in my car with the whistle and exhaust) got my afm rebuilt and its perfect.

[J0RD0]

ah dude i feel for ya, rebuilt engines are supposed to get rid of all those problems. doesnt sound like your having a good run

[thechuckster]

did you set the timing with the Te pin in the diagnostic port grounded? timing should have been rock steady regardless of rpm.

[abently]

did you set the timing with the Te pin in the diagnostic port grounded? timing should have been rock steady regardless of rpm.

Do this and double check all the cam timing is perfect. Set the base Timing @ Factory specs. Retarding the Base timing it is only a band-aid fix at best......

How "worn out" was the old Engine ? As leaky valves and piston rings will always result in less Peak Cylinder Pressures and therefore not ping where a fresh Engine would. Also using over-sized pistons would have bump'd up the static CR a little as well.

[Joshstix]

Have you checked that the timing mark on the crank pulley is correct?

You could be running more timing than you thought if the outer of the pulley has shifted.

[jeffro ra28]

Another side to abently's point is that if the old engine was flogged out and the piston rings heavily worn there could have been oil getting up there which contaminates the air/fuel mixture octane rating having the reverse affect.

Rebuilt engine? how much where the head and block decked? I doubt its a problem due to the rebuild. unless its running ridiculous compression ratio due to any major fuck up.

[Pube]

wow so much feedback, this is great!

Im using factory ECU and im sure the dowls on the cam gears were installed in the centre hole. Before the rebuild, I had good compression and then engine made 180rwkw just fine and I never touched the distributor or the AFM. I spun a bearing and the engine was built back to standard specs. However, I had the head shaved a little more than usual because a shop damaged it when I sent it for cleaning. I had to take it to another place and he took a little more than just decking the head. I have ended up with a tiny more compression maybe? I dont know if this could effect anything.

When timing, I put the ecu into diagnostic mode and set the base timing from there. Ill try 12 deg and see if anything changes. I will be getting a fresh tank of premium tomorrow, maybe the last petrol station the fuel was crap or was labeled incorrectly which is a possibility with these greedy petrol companies.

[jeffro ra28]

You should find out how much was decked from the head. That would be a start.
Id be a bit suspect if it was decked over .010" (1/4 of a mm).
And if the chambers were properly debured etc etc.

[The Real Roadrunner]

try pushing more out of teh timing, 12-15dg (i havent played with the timing on my 1gs yet) but did have to advance the cressy a bit more then usuall to get it to stop pinging,

so far all the cams ive pulled out of 1gs have had there cam gear locater in the middle dowel.

do not do this on a turbocharged engine. it will shit itself in about 5 mins.

all other info seems to be reasonable.