[Sabre 200 Gxi]

How do you identify detonation, what what are the symptoms and the cure?

 

[nizzan4u2nv]

Didnt search did you? Kinda sounds like shaking beads in a can or something. Check you plugs. Symptoms can be from really lean a/f ratios, cheap gas, hot plugs etc. You probably wanna search.

btw - nobody gets flamed around here anymore for not searching. Thats a good thing, I guess we are all nice.

 

[Sabre 200 Gxi]

Well I only have 60megs a month so time is of the essence. Don't always have time to search. Thanks. I have no noises or anything, but did have a guy advance my timing and I'm not sure he did it right. Don't wanna bend the little sensor thingy....

 

[IXLR8se-r]

go up hill in a high gear, you'll hear it if you have it.. sounds like pinging

 

[Sabre 200 Gxi]

I'll try that tonight. Generally detonation will be caused by the timing that's to advanced right?

I had mine set to 17btdc but not sure if that's where it is now. Our pump gas is 93octane and I'm at 1550m about 1mile above sea level.

 

[Storm88000]

It's usually caused by using low-octane gas with advanced timing.

 

[Slartibartfast]

btw - nobody gets flamed around here anymore for not searching. Thats a good thing, I guess we are all nice.

No, I've been busy elsewhere. Duck and cover, guys.

Detonation sounds like rattling from under the hood/bonnet/engine cover. It gets louder as you open throttle at low rpm and gets quieter as you close the throttle or rev higher.

Sabre's 93 octane (Süd Afrika, nicht wahr?) is not the same as ours; they use Research method only, so it's more like our 89 pump octane. 17 ºBTDC should be fine if his engine has less than 10:1 compression ratio. Lots of miles (possible carbon build-up) or less than advertised octane grade would cause problems. Also, you have to follow the factory service manual procedure for setting timing, otherwise you have no real clue as to actual base timing.

 

[Salvisol82]

Oh wow. I'm happy this topic was discussed. I'm having a similar issue. I get a crazy rattly sound when I lug the engine around in a gear that is too high for the actual speed the car is traveling. I"ve heard it around 1500 rpm to about 3k rpm. It fades away as i go agressive with the throttle. Best way i can think of describing it is as if when your shaking up a spray paint can. If you can picture the sound the paint ball makes but with a frequency thats about 20 times faster.

Maybe i am getting detonation.

 

[spdracerUT]

Very good possibility. The fact that it goes away at higher rpms is another indicator. Denotation occurs more easily at lower rpms. Pull you spark plugs and have a look; you can often tell by checking the plugs. Also, either back off the timing and/or put in higher octane gas to see if the problem goes away.

 

[UK-SRi]

Also fitting the 300TT radiator cap MAY help, only if you have some hot spots in the head. It is available from Nissan at the same price as the std 0.9Bar rad cap, but it is 1.2 Bar, the Nismo is 1.3 Bar for reference.

Mike

 

[Sabre 200 Gxi]

Also running a different heat rated spark plug could help. I think colder like a BCP7ES or so...

 

[Salvisol82]

I think i fixed my problem. I adjusted the timing a couple of weeks ago. Problem was that I used the timing gun the wrong way. I'm thinking my timing was at 30 degrees at idle. So today i took the timing down to 15 degrees at idle. Hopefully this solved my detonation. Funny when you think of detonation you think of pinging. I thought it would sound metallic. The sound the car made was not like that at all.

I'll post up again in a week when my gas tank gets refilled. I put in some 91 octane just to be cautious. Hopefully it was just a advanced timing problem..

 

[webninja]

Just make sure you got your car in timing mode before setting the timing.