posted by
someone claiming to be abnormally aspirated
on
Tue Apr 27 23:13 CST 2004 [ RELATED]
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I'm sure this is an exhausted issue, but I can't seem to find the answer despite the fact that I see others have posted the same question and have not be replied to.
I know the '94 945T has a crank angle sensor with three slots that would seem to permit adjustment. That being the case, is the timing able to be checked on the car, and adjusted? If so, what is the correct timing adjustment for this car? I suspect perhaps an ever so slight pinging and have swapped out the anti-knock sensor with my '93 245 which seems to have had no discernible change in performance or alteration of what might be this slight ping, so I'm heading towards the timing issue and can't seem to find any data on the matter. I'm using premium fuel and Bosch plugs (both standard and plats, no difference).
Doesn't anyone just hook up a timing light and make timing adjustments on these cars?
Thanks for the insight.
Sincerely,
JBeechcraft
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As others have pointed out your timing is not adjustable. The distributor is fixed on the rear of the cam shaft and, provided the timing belt is installed correctly and the harmonic balancer crank pulley has not separated, the ignition system will determine the proper timing to match engine operating conditions.
If your engine is pinging as detected by the knock sensors then the ignition computer will retard the timing and this will lead to decreased performance. To reduce pinging you should first make sure your are using a quality brand of the recommended gas octane. After that you should be concerned with engine deposits, fouled/worn/mis-gapped spark plugs, worn distributor cap/rotor and dirty ignition wiring. Engine deposits are of particular concern if the car is driven a lot in the city at low rpm. An occasional good run on the highway at sustained higher revs often makes a huge difference. Perhaps the occasional addition of a quality fuel injector cleaner additive in the gas tank may also help. Also, do not overtorque the knock sensors beyond the 12-14 ft-lb acceptable range as they may become over-sensitive.
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Dave -not to be confused with a real expert
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There are no adjustment slots. The RPM sensor is bolted to the back of the block, and fits into a small notch in the bell housing of the transmission. There is no adjustment in the drive plate either. The drive plate has, welded to it, the ring with 58 slots and two voids which the RPM sensor looks at.
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john
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I dont much about the system on your engine but the 960 has a crank and a cam sensor and the ECU takes care of it all.dewfpo reported not long ago that the ECU can provide up to 60 degrees of timing.I found that interesting.
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83 242 DL -127k, 92-965-189k, 94-965-200k, 83-242 GLT-Gone, but not forgotten,83-245GLT-1'st one (the 1'st 3 currently on the road)
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Dear JBeechcraft,
Good a.m. and may this find you well. In order not to keep you in suspense until the real experts comment, my recollection is that the B230F engine cannot be "timed", in the ordinary way. The "engine control unit" (ECU) adjusts the timing, by reading a range of sensor values and adjusting accordingly.
There may be other factors, that contribute to the slight pinging, i.e., a defective sensor. I'll let the true gurus deal with those. Equally, there may be adjustments, i.e., of valve clearances, that can help.
Until the experts weigh-in, I remain,
Yours faithfully,
spook
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posted by
someone claiming to be abnormally aspirated
on
Wed Apr 28 01:06 CST 2004 [ RELATED]
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Thanks spook for your contribution. I KNEW I could count on you!
I appreciate that you did not keep me in suspence, however, I still don't get it. Let's say you just did a valve job and tore the top part of the engine down. Once you put it back together, there MUST be some way of establishing a timing baseline. There is a timing mark on the plastic timing belt cover, and a timing index mark on the harmonic balancer. While I understand that the other sensors may contribute to inputs that may relate to timing changes under various conditions, how do I know that the start point is accurate? I just have to believe that one cannot randomly pick any given setting for the crank angle sensor (with it's three large adjustment slots) and expect the system to keep itself in time without first establishing some sort of beginning? I just think there must be SOME way of setting an initial timing point after which the ignition system adapts and adjusts itself to the various inputs. I remain mystified and confused.
But thanks!
Sincerely,
J Beechcraft
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Dear J Beechcraft,
Good a.m. It seems to me that you're asking the following question: "After I removed the timing belt to change it, I accidentally turned the camshaft sprocket.How do I re-align the valves with the pistons, so that they work properly?"
Before removing the old timing belt, one must bring piston #1 up to TDC (top dead center). One does that by removing the spark plug, turning the crankshaft (with a wrench on the crank bolt), and putting a finger into the spark plug hole. As the piston rises because the crankshaft is being turned, one feels the air pressure build up. At the instant air pressure starts to ease, STOP turning the crankshaft, as the piston has begun its down-ward movement. Move the piston back up to TDC.
The camshaft sprocket can only go in one position on the camshaft, because there is a keyway on the sprocket and a key on the shaft. Turn the camshaft, until the mark on the sprocket aligns with the mark on the timing belt case. At that point, the camshaft and the crankshaft are synchonized. The valves will open/close at the right point, relative to piston movement. You can then put on the timing belt, if you're ready to do so. Until you do so, do not turn either the camshaft or the crankshaft.
At this point, you've established the baseline for the ECU to make timing adjustments.
If, for some reason, the mark on the cam sprocket or the timing belt is wrong or missing (I've seen posts to that effect), then - according to my Volvo Pocket data booklet - for the B230FT engine, the intake valves have to be set to open at 4 degrees before top dead center. On the B230F or FD the intake valve setting is 6 degrees after top dead center.
Not having done these adjustments, I do not know how to establish when one is "four degrees before top dead center", as 4 degrees of arc is a pretty small increment. Perhaps there is a special tool. I hope that those, who have done this, will educate both of us.
I hope: (a) I've not mislead you and (b) that, if this is accurate, it is also useful.
Yours faithfully,
spook
I'd guess that play in the valves - due to wear - has to be addressed by replacing worn parts or adjusting valve clearance.
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