Thread: glowing pipes 3.9 V8

Definatly no air leaks in the exhaust system?

Originally Posted by Lucus

Definatly no air leaks in the exhaust system?

not that i can see,
the narrowband is in 1 bank where the only joins before it are head>manifold and manifold>downpipes and they all are sealed pretty well.

wideband it just after a flange after the 2 pipes from each bank meet, and also looks to be sealed quite well. Have done the rags blocking the exhaust trick and cant hear any leaks.

Both sensors correspond with what the other is showing too.

Ok had a bit of a play,
advanced the timing to 12deg. noticed bit of a drop in temps with my el cheapo laser thermometer, took it for a drive, had to retune it a little as it was now a little lean. No pinging heard.
Bumped it up again and now its on around 16deg BTDC. drove it and no signs of pinging heard. Will have to wait till tonight for my 'glow test'.
Also should i keep advancing it? i'm on 16deg atm which i though is fairly well advanced! i guess if it will take more give it to it?

Thermometer now shows roughly 200deg at each port on the exhaust manifold and around 235 at the collector on the exhaust manifold. This is at idle after a 30 min drive.
ambient temp 24deg.

on a side note, grand final day in Vic is an awesome time for tunning test runs on the road, next to no traffic!!

Will see how i go tonight.

not a bad time in qld either, she is watching the footy too, and i am able to do whatever, can't mow as it is too loud
and back to the tuning,
checking the glow in the dark is probably more of a scare than you need, it probably always glowed in the dark.

Originally Posted by PSI250

Ok had a bit of a play,
advanced the timing to 12deg. noticed bit of a drop in temps with my el cheapo laser thermometer, took it for a drive, had to retune it a little as it was now a little lean. No pinging heard.
Bumped it up again and now its on around 16deg BTDC. drove it and no signs of pinging heard. Will have to wait till tonight for my 'glow test'.
Also should i keep advancing it? i'm on 16deg atm which i though is fairly well advanced! i guess if it will take more give it to it?

Thermometer now shows roughly 200deg at each port on the exhaust manifold and around 235 at the collector on the exhaust manifold. This is at idle after a 30 min drive.
ambient temp 24deg.

on a side note, grand final day in Vic is an awesome time for tunning test runs on the road, next to no traffic!!

Will see how i go tonight.

Ummmmmm, I may be wrong as Im not all that much of a petrol head, Im more comfy with Diesels but if your running 16 deg advance then it should really be pinging........are your timing marks correct?

Even if it is 5 deg out this may be the cause of your problem.

If you havnt already done it I would pull the plug on No.1 and check the timing mark is spot on or pop the rocker cover off the bank on No.1's side and get the rockers rocking on 1 and then check the mark would be even better.

Ive seen it on more than 1 occasion when a harmonic balancer is changed that the timing marks are out, I cant explain why but Ive seen it on a couple of 4clys in Datto's, at least 1 holden 6 and and a couple of 308's but Im not sure about Rovers, the only ones Ive played with have all been fine.

If the mixture is leaning out as you advance it then your obviously getting more burn in the combustion chamber rather than in the exaust ports/manifold so your getting closer to where you want to be.

I'd keep advancing it until it started pinging and then back it off and see where you are, it may give you a clue as to whats going on.

Originally Posted by mcrover

Ummmmmm, I may be wrong as Im not all that much of a petrol head, Im more comfy with Diesels but if your running 16 deg advance then it should really be pinging........are your timing marks correct?

Even if it is 5 deg out this may be the cause of your problem.

If you havnt already done it I would pull the plug on No.1 and check the timing mark is spot on or pop the rocker cover off the bank on No.1's side and get the rockers rocking on 1 and then check the mark would be even better.

Ive seen it on more than 1 occasion when a harmonic balancer is changed that the timing marks are out, I cant explain why but Ive seen it on a couple of 4clys in Datto's, at least 1 holden 6 and and a couple of 308's but Im not sure about Rovers, the only ones Ive played with have all been fine.

If the mixture is leaning out as you advance it then your obviously getting more burn in the combustion chamber rather than in the exaust ports/manifold so your getting closer to where you want to be.

I'd keep advancing it until it started pinging and then back it off and see where you are, it may give you a clue as to whats going on.

yeah i thought 16deg advance would be close to pinging but cant hear any signs even when loaded up in 5th gear. has anyone else had to advance this far?

did the screwdriver trick and got it to TDC and the marks seem to correspond fairly well, so wouldn;t have thought the harmonic balancer could have slipped.


i'll see how i go tonight. will see how it goes as is then maybe advance it till it pings so then i know where i stand in that area.

took it for a run last night, no pinging or glowing on 16deg advance. Still can feel a fair bit of heat throwing out but no glowing even when giving it a bit of a hard time, so starting to look better.

Will replace the vacuum advance unit this week and then advance it some more and take it out and see how it goes.
i shouldn;t be able to get too much more advance out of it before it pings, but we'll see.

thanks to everyone who replied in this thread. i'll keep you updated on how it goes.

Cheers,
Cal.

Originally Posted by PSI250

Ok had a bit of a play,

Bumped it up again and now its on around 16deg BTDC.


.

I think that you are running at 16 degrees.... because you don't have the vac advance operating .... You are advancing to compensate for no vac advance

When you install a new vacuum advance unit ... you will find that you will have to go back to the original settings
I am unsure of your 3.9 motor ... but my "factory setup" for 3.9 EFI is 3 degrees ...so check what degrees you are suppose to set for