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Timing Guru's Please Share Your Wisdom


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Hey guys. 86 ESI-R supposedly with 89 motor. (had small clutch...which was installed backwards... sigh)

 

Got the ol girl back on the road and am remembering I was tweaking on the timing before I put her away for the 2 year bushing/strut/clutch upgrade.

 

I put in a new vac advance and fixed all the leaks when I got the car, and everything seems to be working well. I put a helper spring on the wastegate to run 14psi, and am using NGK BP7ES at .044" stock gap.

 

So with the colder plugs (well i think 7 is factory for 89, but it had 6 in it...) I started to push timing and the butt dyno gave the thumbs up. I've heard 12 deg BTDC is the remommended max, but when I parked it I had set it to about 20... now i've pushed it a bit more without putting a light on it.

 

My question is if something might be wrong that is pulling timing allowing me run so much?

 

Is my vac advance (boost retard) overactive? Is it adjustable?

 

Is there a centrifugal advance that could be sticking or someone effed with?

 

Messed up Knock box?

 

I pushed the timing to a smidge from bottomed out, and it ran great on the highway with better top end, but did a bit of spitting and sputtering at idle after warmed up... so i backed off a hair and it seems like the sweet spot. I'm afraid to check it tho because the number will probably scare me.

 

Car feels great now... so you'll have to come drive it before calling me an idiot for running so much advance, lol.

 

Any advice appreciated.

 

-Tony

 

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Advanced timing feels great, right up to the point where it breaks. Not knowing the timing? Er, well, not a recommendation anyone would make. All motors are different, one exactly similar one may want more timing than another can tolerate, that is why tuners are paid. But tuners also know what the real timing is.
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I'd suggest getting a timing light and see what the timing is set at now. For a stock OEM G54B T engine It should be around 100 BTDC with the vacuum hose off of the vac advance and plugged.

 

If you run the G54B T with too much advance you will start burning exhaust valves and or get detination as has been documented here on SQC many times in the past. She may run great for a while with the advance really advanced - but it won't for long.

 

Don't forget that the Starquest OEM vacuum advance retards advance during turbo boost and the G54B T has a knock box. Why do you think that the Mitsu engineers designed it that way?

 

For What It's Worth.

 

KEN

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Let's try to keep this constructive ;-).

 

Scott was being constructive. ;) You need to know what the timing is set at with the G54B T engine.

 

I'd suggest getting a timing light and see what the timing is set at now. For a stock OEM G54B T engine It should be around 100 BTDC with the vacuum hose off of the vac advance and plugged.

 

If you run the G54B T with too much advance you will start burning exhaust valves and or get detination as has been documented here on SQC many times in the past. She may run great for a while with the advance really advanced - but it won't for long.

 

Don't forget that the Starquest OEM vacuum advance retards advance during turbo boost and the G54B T has a knock box. Why do you think that the Mitsu engineers designed it that way?

 

For What It's Worth.

 

KEN

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Timing lights are inexpensive and as Ken said the advance ( if it's the correct one) will retard the timing under boost. Also I suggest getting a wideband A/F Gauge if you plan on running anything over stock boost. Good luck.

 

Dad

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Not knowing your timing is destructive, very simple.

 

I'd go back to square one and rebuild the dizzy, I've seen them stuck solid with old grease so they were not advancing or retarding with rpm (centrifugal advance), if that is the case with yours then I can see where advancing the static timing would make it feel much more responsive. There are also different sets of centrifugal advance springs for intercooled and non-intercooled cars, intercooled cars get more advance. Boost retard is non-adjustable, you get a maximum of 7 degrees IF your vacuum advance is working correctly.

 

And then I'd build a piston stop you you can determine true TDC, I've seen those come out several degrees off. The crank pulley and timing cover marks should be at least verified.

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I realize the stupidity of running blind with the advance, which is why I brought it up. It makes me uncomfortable and I will address it soon.

 

The real problem is it seems there is something wrong with my timing sytem, because at 10 deg it is all boost no go. I had to run 20 deg before just to make it feel right and get ok mileage. (these numbers came from my timing light... w/ vac adv. plugged)

 

Ken,

Thanks for the feedback!

So, does the knock box pull timing if it feels detonation? Maybe mine is faulty? How can I test it?

 

Dad,

Glad to have your input.

I remember reading here somewhere that the stock fuel system is good for 15 psi, so I though 14 would be ok. I've thought of getting a wideband sensor/gauge, but how would I adjust the mixture if I didn't like what I saw? Need to install RRFPR?

 

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I use a Gm mass air flow and 1st gen translator, Scott on here could fix you up with a more modern system to control your fuel.

 

Dad

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It takes me about 1/2 hour to rebuild a distributor, there really isn't much to it as long as you don't loose any of the tiny bits. Go to http://www.starquestgarage.com and you'll find the FSM with exploded views on all the parts. The little clips holding the weights down come off with a small flat blade screwdriver, use the same on removing the springs, unbolt the top nut (you have to hold the bottom cam gear tightly) and slide off the stator. If it doesn't want to slide then you know it wasn't working. Clean all the old grease off the shaft and inside the stator, make sure the little wave washer is on the bottom of the shaft, re-grease the shaft and re-assemble. Don't forget to test the vacuum advance, it just needs to be able to hold a vacuum (and move the tip).

 

You can buy a fancy stop, I just made mine with an old plug and some steel tube welded to the plug, the steel tube extends 1 3/4" beyond the bottom of the plug.

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How do you get true TDC with a piston stop? go from both sides and average?

 

Are you degreeing a cam? If not, just drop a long wood peg down the plug hole. Whats wrong with your main pulley?

 

20deg adv base should be giving cranking issues IMO.

Edited by Funky Phil
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Take out the #1 plug, set the crank pulley to 20 degrees ATDC, put in the piston stop until it just touches the piston (either a real one or Mr. Funky's wood dowel that you'll have to secure) and then crank it around clockwise until you touch the stop again. If you're now at 20 BTDC its perfect, if not do the math and make a new mark.
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