AdmiralYoda

Well I figured I'd share my experience. I've read all over here that the best timing for my 87 4Runner w/22RE is the factory timing, which is 5 degrees with T and E1 jumped.

I did that when I first got it back on the road. It was a dramatic improvement from where it already was, at around zero. Ran great. But I'm the type of guy who likes to see what it can do. In the past with other cars I advance the timing as much as possible until it begins to ping then I back it off just a bit.

That happens to be at 12 degrees with my 22RE. Runs great and pulls harder on the highway. I'm able to stay in 5th gear most of the time on the highway with zero pinging. I could probably go up to 14 without pinging but I'll run a few tanks at 12 degrees advanced first. This is on regular 87 octane gas.

So to all those nervous nellies out there....advance it. Advance it alot. It likes it.

snobdds

Your probably off a tooth and your just compensating for that. The best I've ever seen one run at was 8* advanced with the jumpers jumped. I am at altitude so that makes a difference to.

Call me crazy, but a 22re would run horrible at true 12* advanced.

AdmiralYoda

As far as I know the distributor has never been out. If I was off a tooth wouldn't it run its best with the timing more or less maxed out? It ran fine at 0 degrees and ran even better at 5. At 12 it runs even a bit better. Not night/day but enough to tell the difference. Throttle response seems to be improved mostly. The engine sounds a bit more throaty.

I'm near sea level and there is about a 1/4 tank of 93 octane left in there. Its 100% stock with a huge muffler leak and a (maybe) malfunctioning 02 sensor. It has new OEM plugs and an OEM PCV valve as the original was broken.

The CEL turned on twice on the 50 mile maiden voyage home after its 15 year sleep. It has run for another couple hundred after that without a code. It was code 5 for a malfunctioning 02 sensor. I'll be replacing it with a Denso this weekend. If I had to guess I'd say it was running rich judging by the smell of the exhaust. Don't know if that has anything to do with it running great at 12 degrees..

snobdds

Without knowing what the base timing was set at, it's speculation at best.

Remember there are two types of timing; cam and ignition. Each one is set at a different setting for a 22re...

AdmiralYoda

And as far as I know the timing chain has never been off.....so I think the cam timing should be stock. The engine only has about 100k on it. Its an 85 but was installed in 99 when the original blew a head gasket and grenaded the motor at about 70k. The truck only has 88k on it now after sitting for the past 15 years.

AdmiralYoda

Well the truck has been sitting all week since I have a coolant leak and a caliper hanging up. I've taken it for a few short trips around town and it seems to be running great.

Tonight I'll be taking it on a 50 mile trip to my parents place so I can work on it in my fathers shop tomorrow. We'll see how it likes 12 degrees of timing on the highway. There is 3/4 tank of 87 octane and a 1/4 tank of 93 octane gas in it which should average out to be about an 89 octane. I'll keep an ear out for pinging, even though I didn't hear any on the back roads in town.

I know how an engine runs when its too retarded, but how will it run when too advanced? I know it will ping if it truly is too advanced but what are the horrible symptoms you speak of?

FGZ

Besides pinging, overheating is the other one I've heard of.

AdmiralYoda

Eh...sort of. Too retarded timing lets the exhaust gases hang out in the cylinder too long and leads to overheating quicker. The cylinders stay hotter longer and the exhaust valves get hot. Too advanced timing can make an engine run hot but more because detonation is trying to melt the pistons.

I guess I'm just used to caveman timing. Advance it till it pings, then back it off a couple degrees. No pinging....no melted pistons. Or so I thought anyways until the experts here have made me second guess myself.

Terrys87

iTrader: (1)

It has been a while for me but I have forgottent to tighten the distributor hold down bolt and if I recall right, the distributor went all the way clockwise ( advanced or retarded?) and gave me the Cherry Manifold. Might keep an eye out for that. Sometimes you got to think outside of the box for different things for improvement. 5 degrees just seems about the best for me.

AdmiralYoda

Clockwise = retarded. Makes sense.

snobdds

Have you even pulled the valve cover to confirm cam timing or the dizzy to confirm ignition timing. We have no base to take your numbers from.

I still think your a tooth off and just compensating for that. I've seen a 22re run at 10* and it was not pretty...

AdmiralYoda

snobdds....No, the valve cover has never been off. The engine is as quiet as a church mouse and doesn't leak from the valve cover so there has never been a reason to take it off.

But now you've got me paranoid. Thanks. But for the heck of it I might as well give it a shot. Help me refresh my memory.

1. Rotate engine until cylinder 1 is at TDC and cylinder 1's lifters are closed.
2. Verify dot on cam is at 12 o'clock. Or is it 11:50, 11:55? That's the part that always trips me up.
3. Verify timing chain mark lines up with camshaft mark.
4. Rotor should be pointing at cylinder 1 right?

Thanks.

RJR

Assuming OP used a timing light, 12 degrees is 12 degrees. It matters not whether or not the distributor is off by a tooth. That will only affect the available range of timing.

That being said, the ECU ultimately controls the actual timing. The setting at idle is just a starting point. The ECU will use the knock sensor and the rpm and airflow maps to calculate actual timing, which for any rpm above idle will be far advanced from 6 or 10 or 12 degrees. Advance at 3000 rpm can be upwards of 60 degrees.

If the knock sensor is working, my guess is the 12 degree advance will have no ill effects, nor will it help performance much either, except coming off of idle. Once the engine gets up to speed, the ECU advances timing to the onset of pinging, and then continuously adjusts it on a cycle by cycle basis to stay right at the pinging threshold. It can and will easily compensate for mucking around a few degrees with the base timing.

All this assumes that the '87 22RE uses electronically controlled timing. If it's using the old-fashioned vacuum and centrifugal advance, then indeed you are at risk of engine damage with too much base timing advance.

AdmiralYoda

Before I left for the 50-60 mile trip on the highway I backed the timing off to 8 degrees. I figured I might as well bump it up slowly rather than just go for it.

It ran great. 5th gear the whole time on the highway with 31's and it was running great. I may continue to bump it up even more but there really isn't much need to at the moment.