Checking Timing
 

It's been 25-yrs since I last checked the timing on one of my vehicles. I've let my mechanic fool with the timing on this car since I purchased in 2008, and he says it's at 26-degrees at 4k rpm.

All this talk of timing, and I have nothing to offer, because I don't have the practical experience.

I searched on this forum for a "how to" on timing, but had no luck. Can anyone give me the "1--2" on what I need to do?

Here's what I can gather:
1. Disconnect vacuum hose from dizzy
2. Warm up engine to 160F
3. Connect Timing light to #1 [Back Left Cylinder]
4. Maybe check timing at idle?
5. Have someone rev engine [and hold] at 4,000rpm
6. Check/Verify Timing by? This is where I get a little lost...

Any help would be appreciated. BTW: I need to purchase a timing light, any suggestions?

Thanks!

you have it correct but you have to make sure you get a timing light with an ajustable advance knob on the back to tell how much advance.

Ok, I knew there was such a thing... So, if I "dial in" 26-degrees, then, the light should be flashing on the crank pulley at TDC? Yes?

Mooney:

Take a look at the following. The Z1 mark is TDC, to the left of Z1 is degrees after TDC, and the numbers to the right of Z1 are degrees before TDC.

Idel timing is set at 750 - 900 RPM at idel with the vacuum hose disconnected for ROW and remain connected for USA

Advance timing is set at 4000 RPM with the vacuum hose disconnected for ROW and remain connected for USA


You do not need a timing light with a readout, although they are real handy to have, the set points should be marked on the crank pully as shown below.


http://forums.pelicanparts.com/uploa...1303613492.jpg


Cole

yes

So, with a stock CDI; 964 cams; running 1.0 bar on 93 octane; adjustable WUR; Wideband AFR running low 11's at onset and low 12's at redline - - what timing setting would you recommend at 4000rpm?

Thanks

Mooney,

I would set the timing at 24* @ 4000 RPM if your going to run 1Bar. If your trying to set max timing and boost for best performance you will need to put the car on a Dyno and have an experienced tuner layout a timing curve specifically for your car. Randomly advancing timing and boost levels is SERIOUSLY DANGEROUS !!!!!

Cole

I can guarantee you I wasn't looking to advance timing to anything dangerous... Just looking for suggestions for the "safest" timing setting.

Should have been more clear... Thanks for the 24* input Cole...

Ok, probably a dumb question: is 24* BTDC more advanced than 29* BTDC? Thanks

24 BTDC is less than 29 BTDC advance.

Backing down the timing from 26 to 24 at 1bar is not a bad safety idea as conditions vary so much due to heat and fuel quality. At 26 with stock boost you should be good for any conditions with a healthy engine. Checking on a dyno should give worst case results using multiple pulls and no air through the intercooler.

true and the vacuum advance lines have a habit of overheating and melting or breaking. A couple months ago i replaced mine because it had melted so I replaced it with silicone hose and covered it with fire braid. yesterday i removed my distributor because the coil in it was shot and found the silicone line inside the fire braid had over heated got hard and cracked in two.

Ok, so I just watched a 9-min video on YouTube by MSD on setting timing. That video, along with what you guys have said, pretty much answered all of my questions...

I've ordered a timing light. When it comes in, I'll adjust to 24* BTDC at 4k rpm. Or, at least will verify that I'm already there...

Ken - what I did a while back to ensure I had good vacuum in my hose going to distributor was added a "T" in the line and capped it. When I want to check for vacuum, I remove the cap and use my finger as a temporary cap. As I toggle my finger on and off the "T" my idle changes - - this tells me I've still got good vacuum there...

Thanks!

oh OK that makes sense well when i get the EFI installed i will no longer worry about the distributor being 2 inches away from a red hot turbo and all the associated problems with coOKed wiring,,vacuum hoses.etc.

Mooney:

My recommendation on timing advance was purposely set on the conservative side. Looking at your signature you, obviously, have a very nice and well equipped example with all the right mods to make an excellent performer. As we continue down the slippery slope to enhancing the performance of our cars by adding something new you will find it prudent if you dial that timing advance back to 24*. By doing this you can test run the car, make sure the new mods are installed and operating correctly and do it safely without jeopardizing an engine. Many mods are going to require you to re tune to compensate for the changes made by the mod, as some can easily change afr's and or boost threshold. Much safer to dial back the advance a little and make sure of where you at with the change and then re tune accordingly. Then when you know it's ok, take it out and drive it like you stole it. Better to be safe than sorry !!!!

Cole

Fit adaptive per-cylinder knock sensing and let it take care of retarding the timing when the motor actually knocks, and let it have full advance at all other times so you're not leaving either response or ponies on the table unnecessarily.

The issue with setting the timing at fixed values is that even with everything else set perfectly, the point at which the motor will detonate will vary according to at least a couple of things that can vary widely - like ambient temperature (and thus charge temperature) and the octane of the fuel.

On the other hand, if 29 BTDC (for RoW) was considered safe by the factory, how much more advance do you think you could safely run with race gas - or on a crisp winter's day? Or both?

Oh No !!! here we go again with adaptive per-cylinder knock sensing. Greatest thing since sliced bread and only $1200 to tell you have had detonation after it happens.
Kind of like when you promised your girl friend you wouldn't c--- in her mouth.

Yes, ROW advance was 29* from the factory @4000 RPM and .8 Bar.

You can run 34* of advance at 4000 RPM with 1.2 - 1.4 Bar of boost consistently with $500 worth of WMI and have zero detonation.

Cole

Jesus Cole, I'm laughing my fool ass off here and about spit a mouthfull of Merlot all over the computer screen. You just slay me to the max sometimes. Gawd.....!!!! I never told my girlie friends that, just held them by the ears. Look out, we're likely to be sensored.
Timing is good...just make sure it goes safely away before you're on the max torque curve, my opinion for what it's worth. WMI may be the ultimate ticket, just make sure you keep a spare mason jar of white lightening in the glove box to make up the meth-mix when you run out in a pinch.

Gimp,

I was going to apologize and then I decided screw it. I'm just sick of the endless spark knock sensing infomercials.

On these old CIS sleds Spark Knock Sensing does not detect detonation well, and it will not prevent detonation period, it might on occasion tell you you have detonation, a loose rocker, chain slap, loose engine tin, or detect one of the other 100 noises these old girls make any time you crank them up.. If it were to detect detonation it still can't do anything about it unless you spend another grand for a sophisticated controller or ignition system that retards timing or kills a cylinder. Although, unless you can retard timing or kill the cylinder within a couple milliseconds your too late anyway. It's like putting the condom on after the fact, it aint going to catch s---
because it's too late.

On a new factory equipped Knock Sensing System they may work fine and if so GREAT. But it is not practical, affordable, or dependable enough for most of us poor smucks with these old cars. In the last 22 years with the sled I've had enough smoke blown up my a-- about the latest and greatest, do all, be all gizmos. and I guess there just isn't enough room left for this one. About as pratical as Ovomit's electric car.

This has to be one of the more confusing topics to research for us newbies. Timing isn't confusing, where it should be set for an 87 930 with some mods is confusing! I've read hours of posts and I still don't know where to set it. I just threw a light on mine and at idle with both dizzy lines disconnected and capped it's at 5* AfterTDC, which jives with the workshop manual for a US model, but the workshop manual assumes the car is stock with emissions gear.

I have no emissions gear, B&B exhaust, 964 cams and a larger turbo, but keep it at .8 bar. It seems from what I've read that I should ignore idle timing and set the 4000 rpm timing to 24* BTDC, but is that with both dizzy lines on or off?

From what I understand, on the dizzys with two lines, boost causes the ignition to retard off some of what the mechanical advance is adding in. So if you set it to 24* with the lines off, it will be around 16* with them on and on boost.

When I connect both lines, the idle timing is still 5* ATDC. Should there be any vacuum advance at idle?

I'm really interested in timing right now because I have a crazy soft spot off-idle up to 1800 rpm or so. I know that turbo lag is to be expected, but seriously, my two year old on her tricycle could outrun me to the next mail box. After that it's great up to redline. Fuel pressures, spark, AFR, vacuum leak tests all check out. Timing is next.

I know dyno tuning with a good mechanic is ideal, but I don't have either of those available anywhere near where I live, and besides, I bought the car to tinker with myself. Timing is one of those things you can really screw up with bad consequences, so I want to get it right in my head before tinkering.

Mark H, your car is vaugely similar to mine (don't be insulted, I know yours is much cleaner and better sorted!), do you have the two dizzy lines and do you set your 4k timing with them off, and to what?

Mooney, did you ever get to working on yours and what were the results?

Dear Cole:

John is fully capable of answering your comments, but I ask if I could have the pleasure of replying to you.

It's so easy for self proclaimed experts such as you to blast away on someone or something you know nothing about. We know that to be a fact by your comments.

You didn't even get the price right. You quoted $1200. Our products are half that amount or less.

Why would we not want everyone to know about our products? Who wants to spend thousands of dollars repairing a blown engine, when you can protect it.

It's not an infomercial, it's a service!

When you talk about knock sensors not working, you are calling us liars and for the grateful customers that get on forums and tell how the SafeGuard saved their engine, are you calling them liars as well?

Our name is Precious to us!

Think twice before spewing your poison on forums about technology you know nothing about.

In case you want to address comments to me, I'm John's wife. I'm the "S" in J&S.

Shirley Pizzuto