Am I retarded or advanced?

[Mathew Zelezen]

I'll tell you, I feel retarted... I've got an 86 Syncro that backfires when I leave it in gear and cruise to a slower speed or down a hill and I can't seem to figure out why...

I've checked the exhaust for leaks and made sure everythings tight. Which makes me think the timing is off. Here's where it gets tricky:

I have a solid triple slot v-belt pulley (had it off when I replaced the seal). According to Bentley stock pulley wheels consist of two peices on a syncro and a solid pulley indicate that its an aftermarket product. It then says to add an additional 7.5 centimeters past the timing mark to the right on the aftermarket pulley. (Page 13.33)

Has anyone else dealt with this? I live at 10,000 feet... do I then advance or reatard the timing to get a little more power from the enginge?...

Sorry so long. Thanks!
_________________
87 Syncro Tintop
~Rocky J Motor
~Steedle Trans


Of all sad words of tongue or pen, the saddest are these: It might have been.

[Dogpilot]

Since this creature runs on an ignition map it is questionable if the old advance or retard thing will gain much for you at altitude (I'm at 7,000'). I would simply check the timing to be at spec. This could be a challenge with an aftermarket pulley, but mine is a three slot as well. Look for the notches, there should be two (I think). Either way, get the Protraining book off the stickies or download it from my public folder in PDF. Do the timing exactly as laid out.

I had mine backfire when I had left the rubber S boot from the AFM to the Throttle Body's clamps loose. So that may be a good place to check.

86 Vanagon Protraining.pdf
Vanagon Protraining Digifant I 86-91.pdf
Vanagon Protraining 86-91 Fuel Systems.pdf

http://homepage.mac.com/WebObjects/FileSharing.woa...mp;lang=en
_________________
Geology with a Syncro rocks!
86 Syncro Westy AKA "The Bughunter"
98 Disco I
08 Range Rover SC
08 VW Rabbit S
1951 O-1G

[tencentlife]

That instruction about the pulley in Bentley apears to be wrong. The stock pulley has a V-notch on the frontmost rim, and a dished mark on the second rim (see Bentley p.28.41). The dished mark is TDC. The V-notch is 5deg. BTDC, which is the timing setting. The motor rotates clockwise, so advanced is to the right of TDC, not to the left like it says in my book.

The timing is supposed to be set with engine hot (oil over 176F, hot indeed), by unplugging the Temp2 sender and holding the revs up at 2000-2500. Under those absurd conditions the V-notch should align with the crank seam. But to do it this way practically requires two people, bcause as soon as you unplug the temp sensor the hot engine floods and starts to die, you have to respond with the throttle immediately, it may not be able to rev at all, and who the hell is going to hold the strobe and turn the diz?

I've dispensed with that foolishness and set mine for maximum advance, which should be all in by 3000rpm at 40deg. BTDC. Google "printable degree wheel" and you will find several sites that have just that. Pick one you like, scale it to the diameter of your rearmost pulley rim, print it, and tape it to your pulley with zero aligned with the TDC mark. Then make your own V-notch on the frontmost rim at 40deg. BTDC, or 35deg. to the right of the V-notch. Rev and hold the engine at 3000-3500rpm, and your strobe should show the new notch aligned with the crankcase seam. Easy, accurate. When you point the strobe at idle the 5deg. V-notch can be seen wandering a bit around the center line.

You can play with max advance up or down a few degrees from there if you want. These engines are extraordinarily resistant to detonation if they don't have too much deck clearance. I also live and drive from 5000 to 10000 ft., and I haven't seen that this system responds noticeably to the extra few degrees of advance you would normally add for 7000ft. (1 degree per every 1000ft that is over 4000ft.). YMMV.

Your backfiring on overrun could also be due to the decel function not working properly on your FI. It depends on the TB switch closing to activate that program, so make sure it closes when you let off the pedal.

[Alan Brase]

[tencentlife]

No Al, you've got it exactly right. The diz position is how the ECU knows the crank position, and if you advance the diz the ECU will just run its map at a higher advance. What dog and I were relating as far as tuning to compensate for altitude is that this FI doesn't seem to provide the increase in power that you usually see with carbureted engines and some other FI's by dialing in a few extra degrees. It just doesn't seem to make any noticeable difference compared to the basic tune. I know from tuning thousands of aircooled engines that they all responded favorably by adding 3-5 degrees extra advance for running at 7000ft. With some T1's it was like night and daty. Not as noticeable with the Digifant. Probably has to do with the way the advance map integrates load and air density signals while running. Without having the actual lookup tables, it's all speculation.

You can certainly run high advance with little risk of detonation on these. The published specs are for 40 +/- 5deg. @3000-3500rpm anyway, so 45 isn't out of range. As I've said many times, the combustion characteristics with a wide quench band make the engine very ping-resistant. That is provided the deck clearance is at 0.040" as designed. If an engine has the low-comp Cofap pistons or similar, it can definitely get detonation with too much advance, as the quench effects are lame with 0.080" clearance. But then, if a motor has that trash inside, the first thing to do is tear it down and put in the right pistons to get the thing to burn fuel the way it was designed.

I have a new 2.2 with 9.7:1 static CR, 8.8:1 dynamic at sea level, 7.8:1 dynamic at my typical altitude. Convention is that dynamic CR should be in the 7 to 8 range to avoid pinging on pump gas. I've had this thing set at up to 45deg. and there's nary a ping on mid-grade fuel. I'm still playing with the optimum setting (takes time when the highway is your dyno), but it's nice to know that I can go that much or higher without risking damage.

[Alan Brase]

Well consider that 45° is the best of an old guy's memory from 8 or so years ago. I did eventually take that motor out because it had a bad random knock in it. It has way too much camshaft thrust clearance. What did I do wrong? Well, it still has 60k or so on the rebuild, but I was hoping for more.
Doe anybody have any experience with the new Chinese 96mm P's &C's?
I've got a set available to me. Just wondered if it was worth the trouble. (Would not if the c/r is dow much.)I guess this is a thread hijack.
Al
_________________
Al Brase
Projects: 67 sunroof bug, 67 Porsche 912 Targa, 70 Westy
Dec 1955 Single Cab pickup WANT 15" BUS RIMS dated 8/55, thru 12/55
To New owners: 1969 doublecab, 1971 Dormobile
Vanagons:
80 P27 Westy JUL 1979, 3rd oldest known US
83 1.6TD Vanagon, 87 Wolfie Westy daily driver, swap meet home

[tencentlife]

If it's the QSC set you're referring to I have them in my new 2.2. But they run about 0.75 mm too low in the cylinder, so mine are on 5.5" rods and the tops shaved to zero deck. That brings the piston cc's to 41 and the static CR to 9.7. Using them on stock rods would give you the same low-comp lame-quench situation as the Cofaps and AA's. They are pretty good P&L's, Teflon skirts, light weight, heavy cylinders (made to 96mm, not bored), but unless you do similar mods they won't give you a very good motor.

Oh, and the rings and wrist pins are worthless, so you have to find suitable ones.

[Mathew Zelezen]

Dog/TenC/69DC,
Ok, you are WAY over my head now... but thank you for the advice.

I'll check the intake hoses, decel on the TB switch and my timing with the dish mark...

Tenc, I googled "printable degree wheel" but didn't come up with anything similar to what you're talking about. Have a site I could research instead?

Cheers guys,
And please, thread jack away... you've answered my question.
_________________
87 Syncro Tintop
~Rocky J Motor
~Steedle Trans


Of all sad words of tongue or pen, the saddest are these: It might have been.

[tencentlife]

Here's one:

http://www.lucasinjection.com/Degree_wheel_100.jpg

If you have one of the fancy advance timing lights, you don't need thie degree wheel. Just dial in the desired advance and when you rev to 3000+, the TDC (dished) mark will align with the case seam.

[Dogpilot]

IF you can locate the two marks, fill them in with chalk, it fluoresces in the strobe. Then get one of these:

http://www.iequus.com/product_info.php?product_id=3568&category_id=1_20

You can get them at Sears, Checkers etc. for about $80. You can then time it on the 7° mark (the second one) and then set the advance on the digital light to 35°. I used feeler gauges to substitute for a second person. I just inserted enough of them to get the 3000 rpm's between the stops on the throttle body. Then I disconnect the temp II connector. Then check the timing for the 35° position.
_________________
Geology with a Syncro rocks!
86 Syncro Westy AKA "The Bughunter"
98 Disco I
08 Range Rover SC
08 VW Rabbit S
1951 O-1G

[tencentlife]

I just took this measurement to advise someone on another thread, so I'll add it here:

To make a mark on your pulley for 40deg. total advance, the mark is 2" clockwise from the 5deg. V-notch.

[Mathew Zelezen]

Alright Gentlemen,
I printed out the degree wheel and marked 35 degrees (why doesn't my keyboard have a degree symbol?) clockwise of the 5 degree v notch with some white-out. I ran the van until the oil was nice and hot, pulled the temp sender, my fiancee graciously kept the rmp's at 3000 and I lined up the white-out mark with the crankcase seam with timing light in hand. The van runs well but my idle is now around 1500 with the idle screw fully tightened in the throttle body housing...
Did I do something wrong or is this indicative of yet another problem?
_________________
87 Syncro Tintop
~Rocky J Motor
~Steedle Trans


Of all sad words of tongue or pen, the saddest are these: It might have been.

[Alan Brase]

Maybe. I'd really look for vacuum leaks, even in the METAL tubes going to the heads.
To get the degree symbol:
Hold down ALT, and hit 2,4, 8. (No commas!)
Al
_________________
Al Brase
Projects: 67 sunroof bug, 67 Porsche 912 Targa, 70 Westy
Dec 1955 Single Cab pickup WANT 15" BUS RIMS dated 8/55, thru 12/55
To New owners: 1969 doublecab, 1971 Dormobile
Vanagons:
80 P27 Westy JUL 1979, 3rd oldest known US
83 1.6TD Vanagon, 87 Wolfie Westy daily driver, swap meet home

[Dogpilot]

to put it in a nutshell, yes. Things I have pointed out before:

Things that can affect the idle:
Throttle Switch: unplug it and see what happens, does the idle rise?
Vacuum Leaks: inspect all the hoses and boots for cracks that may only open at certain times
Do you have AC? If so check the signal wire to the idle computer, if it thinks it went on, it will raise the idle.
Power Steering Switch: If it thinks the pump is at the limit, it raises the idle, check the lines for potential shorts,
Sticking throttle valve or accelerator cable. It can possibly have a spot where it likes to keep the throttle from closing all the way. Lube the front and rear points and the return springs, check them both to ensure they are always doing their return job. The cable may be a little tight, so it may not let the throttle valve close all the time and not let the Throttle switch do its job. You need to put a beeping continuity tester on it and check it by using the accelerator pedal not by hand in the engine compartment.

TK added the valve to the charcoal canister to the list. Timing is one step, mixture is one after that. All these items interrelate, until you have them all in line adjusting one affects the other. It requires a systematic step by step run through on all the usual suspects. Then you go back and keep tweaking them all until it is all in line.
_________________
Geology with a Syncro rocks!
86 Syncro Westy AKA "The Bughunter"
98 Disco I
08 Range Rover SC
08 VW Rabbit S
1951 O-1G

[ProvoCyclist]

Hey guys, really dumb question, but ive been following this with a good deal of interest. So with all this talk of retard and advance, which way do i turn the dizzy to advance it?
_________________
Clark
Current: 1986 Tintop GL 2wd, stock 2.1L, manual trans, Savanna Beige Metallic LH1V.
Past: 1985 Sunroof GL, 2wd, Subaru 3.3L, manual trans, resprayed to Diamond Silver L97A

[tencentlife]

The rotor spins CW so you turn the body CCW to advance. Timing is based on the relative position of these two components.

[Mathew Zelezen]

Oooooh, (and here I am all ready to kick my throttle switch's arse)...

So I don't disconnect the Temp Sender... I'm setting the degree wheel 35 degrees to the right of the 5 degree v notch, keep it at 3000 rmp and adjust the mark to the centerline. (I don't have an advancing timing light... just a regular strobe.)
Gotcha, I'll let you know what happens after we get back from this hike.
Thanks.
_________________
87 Syncro Tintop
~Rocky J Motor
~Steedle Trans


Of all sad words of tongue or pen, the saddest are these: It might have been.

[puravidadon]

Thanks for all the useful timing information. Ever since I had a mechanic tune up my 87, I noticed less power than normal. It also ran a little hotter. I even had him recheck the timing and he said it was ok. I bought a timing light like Dogpilot mentioned and set the timing @ 35 degrees. With all the great tips it was a peice of cake. Now I can accelerate up hills if needed. What a difference!

Thanks guys
_________________
1974 Thing
87 westy (automatic) 2006 - 2010
70 dune buggy 2007 - 2011
98 Suzuki Sidekick 2006 - 2012
09 F-150 Lariat
Kona Fire Mountain MTB
Marin Hawk Hill MTB

[Alan Brase]

[tencentlife]

Yep, really sluggish throttle response, low top-end power, and running hot all point to retarded timing. Sounds like what puravidadon had going on.

I want to stress that either method will get you to the same place on the wbx motor, either doing the T2 disconnect/rev 2000/set at 5deg. method, or the total advance method.

But the total advance method is basically applicable to all 4-cycle spark-ignited piston engines. If ever in doubt about how to time an engine, with specs unavailable, it's always a safe bet to rev it to 3000rpm and set the total advance to 38 deg at sea level. You can add 1 degree for every 1000' that is more than 4000' ASL (Matthew Z, in Telluride at 9000'ASL, could add 5 extra degrees advance). This will get you very close, and you can make smaller adjustments from there as to best throttle response vs. where it begins to ping. Some engines like a little more advance, a few a bit less (I would be suspecting carbon buildup in that case), and some can tolerate much more without pinging but that isn't necessarily where they make their best power. Roadtesting will tell.

Since most engines, no matter what they are doing to timing at idle and low rpms, bring their total advance to around that number, by setting total advance there, you essentially reverse engineer the idle setting. It will usually check out as correct as well if you have the total advance set right.