I checked my timing the other day. Found 10 deg @ idle and 30 when rev'd to 3,000 rpm. (i hope i don't have that backwards)

On other cars with vacuum advance, you had to pull the vac lines off before checking/adjusting timing. Anything need to be done before adjusting timing on a b230?

I checked the faq, but was unable to find any info about timing adjustment proceedures.

I plan to run elevated boost, so I would like to retard it a little.

-Steve

Timing is not adjustable. The timeng is done by the RPM sensor (which is mounted in a recess in the bell housing). The RPM sensor is triggered by a slotted ring attached toi the ring gear in automatice xmsn cars, and be drilled holes in the perimeter of the flywheel in manual xmsn cars. None of this lends itself to an easy adjustment. The EZK has highly sophisticated spark retard which does a fine job for many who run elevated boost.

Actually, I beg to differ. On the early 700 series, timing is adjustable. I have an '89 740T, and it is a trivial process to adjust the timing. You just loosen the distributor where it bolts onto the block (two bolts). Then, by rotating the distributor to the right or left you will be able to advance or retard the timing. On the 850s I know you can not adjust the timing... but on the early 700s for sure you can. I am not sure when they stopped letting you do it manually.

You must be new to the brickboard. My answer was to the question posted, about a 1990 B230FT. This car is equipped with LH 2.4 Jetronic. There is no adjustment of the timing on this and later 700 and 900 turbo cars. The 1989 and earlier North American Market 740T has LH 2.2 Jetronic on which the timing adjusts just as you have described.

John, I'm actually not new to the brickboard, been here for the last 2.5 years. I was just reading your original post as though you were talking about all 740s as you wrote "Timing is not adjustable." I assumed that the original poster might read your message the same way that I did, hence my response. I was not sure about the changeover year being 1990- hence my post about early model 700s. Thanks for the additional info though about LH2.2 to 2.4 in '90.

For the North American Market, LH 2.4 was introduced in the 1989 normally aspirated cars, the turbo cars in 1990.

my car appears to have a adjustable distributer cap. it also has degrees marked on the timing belt cover. It is a '90, but i guess they could to thrown a '89 engine in at the factory.. who knows..

Tell me this, then. If it was a '89 or earlier, what is the timing adjustment proceedure? and where is the best spot to have the timing if I'm running elevated boost?

Thanks fellas,

-Steve

Your car probably has LH 2.4 Jetronic if it is a 1990 North American Market car. The easiest way to tell is to look for the diagnostic socket on the brace attached to the left MacPherson strut tower in the engine compartment. LH 2.4 has it, LH 2.2 does not.

If it is LH 2.2, get yourself a timing light and loosen the two 10mm head bolts holding the distributor. Timing per the underhood sticker which is 12 plus/minus 2 degrees before TDC on the LH 2.2.

My friend ('94 850 and '93 850) and I ('89 740T and '86 740 GLE) were having a debate recently that I'd like concerning this very issue of computer/sensor controlled timing vs. semi-manual timing control. We actually both ended up agreeing that the semi-manual control of timing, like on the early 700s, was more durable and fool-proof than the late model automatic style. My feeling is that when you have essentially a complex logic circuit controlling the timing, all it takes is for one element of that circuit to go out and you are screwed. This has basically been his experience with his 850s, with an array of "3-2-1... 3-2-2-, etc.- which are Greek to me!" codes that are ever-present. He replaces one electronic component after another (knock sensor, O2 sensor, RPM sensor, etc.), trying to get the timing right and the idle smooth to no avail. With my '89 740T, it seems to be able to be much more durable- I manually check/adjust the timing and air/fuel ratio at each oil change interval- it almost seems like "fuzzy logic". Any opinions?

Both systems are computer controlled timing. The difference is in the initial setting, one is adjustable, and one is not.

Hello. Actually, although it may have the two bolts joining it to the block, it still may not be adjustable. What you want to look for is a pivot mount where you could loosen the bolts and actually rotate the distributor left or right. Give it a shot, you can't hurt anything, if it does not adjust, no biggie. See my earlier post for the timing adjustment proceedure for the early models, I am not aware that you need to disconnect any vaccume lines/sensors to adjust the timing, I never have. For my '89 740T, the timing range is between 10 and 12 degrees, so if it were me I would run at 10 degrees with elevated boost to retard it a bit (how many psi of boost are you running?) But, from John's post, you can't adjust the timing anyway so the point is moot...

Thanks, John and Terrence.

This engine has always been very prone to detonation. Even with 92 octane fuel, water injection, 180deg t-stat, and a 3-row rad. At this point, I can get about 10psi boost before the detonation starts. 12psi isn't good. So my consideration was to retard the timing. But it idles at 10deg so I guess there's no reason to change it.

Will oil in the intake charge encourage detonation? My turbo's been consuming oil for the last few months. When at WOT, it blows some smoke out the tailpipe. Not a lot, but it's slightly visable from my rearview mirror. My compression's good, my oiltrap and pcv system is all new and clean.

Thanks again guys,

-Steve

How bad is the pre-ignition? Is it melting plug electrodes, or just an occasional hiccup? If you are getting bad detonation at 10 psi with the timing at 10 deg., then I would think that you should check a few things first:

1. What is your air/fuel ratio looking like? Running lean can produce the symptoms you describe under engine load. Do you have an air/fuel stoic. meter? If your '90 is like my '89, you should be reading 1 + 1.0% or - .5% CO.

2. Check your plugs- first for signs of detonation and second for the correct heat range. Plugs that are too hot can cause pre-ignition.

3. Is your engine running hot? I'd think not with a 3-row radiator, and it is an obvious thing, but if you are running hot, pre-ignition can result.

I have never heard that oil in the intake could cause pre-ignition- but you may want to ask someone else about that. Check your intercooler plug- is there more than 2 tablespoons of oil? If so, your turbo could be going. But, if anything, I would think that oil in the intake manifold would cause high resistance to burn, hence just the opposite effect would occur. How much oil are you burning? One quart every 3-4K seems about average, at least for me. What color is the smoke coming out of the tailpipe? White, or blue? Blue would signify oil burning- whereas white is steam- and could indicate a blown head gasket (coolant in the oil)- but maybe you already knew that.

my plugs always come out perfect. The detonation is the occasional hiccup. Nothing severe.. the knock sensor seems to be able to catch it before it gets bad. Engine runs cool as a cuke.. :)

My dad has a device that connects to the oxygen sensor. tells me if i'm running rich or lean. i think I'll hook that up and give it a try. maybe i need a rising rate FPR.

Thanks,

-Steve