i was wondering if the timing belt was dependent on the ecu.
or is it just a totally mechanical hardware thing?

 

i think it depends on the water pump alone (one B18 motors)

 

It's a mechanical link between the crankshaft and the camshafts. It also turns the water pump. The ECU has nothing to do with it.

 

hmm.. well wat i really meant was that if i had a chipped p28 and then i put in a p72, would the timing change by itself to a different setting or would it stay the same?

i need to get my timing adjusted and as of now im running the chipped p28 in my gsr and was wondering if i need the p72 swapped in, in order for me to do that.
or could i just get the timing adjusted with the p28. would it all be the same?

im not to knowledgeable about timing stuff.

 

completely independent, but make sure you replace it every 105,000 cause if it breaks you screwed

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Weston &raquo;</TD></TR><TR><TD CLASS="quote">It's a mechanical link between the crankshaft and the camshafts. It also turns the water pump. The ECU has nothing to do with it.
</TD></TR></TABLE>

ahh i see. interesting.

how many other things can u adjust the timing for besides the timing belt?

 

There are 2 different types of timing:

1. Cam timing, determined by the timing belt and cam gears. This determines where each camshaft is in their rotations with respect to the crank, and to each other. It determines when each valve opens and closes with respect to piston position. Unless you have adjustable cam gears, you don't adjust cam timing.

2. Ignition timing, determined by distributor position with respect to the intake camshaft. This determines when each spark plug fires with respect to piston position. Static ignition timing is set and adjusted by rotating the distributor on its 3 bolts, but it is also adjusted on-the-fly by the ECU depending upon numerous different variables like engine load, throttle position, speed, RPM, inputs from the knock sensor, and others.

Factory specs call for each spark plug to fire right before the piston gets to the top of its compression stroke, 16 degrees of crank rotation to be exact. So when the spark plug fires, the piston is on its way up, and then 16 degrees of rotation later the piston has reached the top, and has started on its way back down.

Factory specs actually allow a range of +/- 2 degrees on either side of 16, and many people adjust it to the upper end of the range, or 18 degrees. You don't want to go past this, though, as you risk pre-detonation, a.k.a. knocking or pinging.

To adjust igntion timing you have to jump the diagnostic connector under the dash near the ECU, so that the igntion timing will remain constant at idle (not adjusted by the ECU), and then use a timing light pointed at the crank pulley. There are 3 red timing marks in addition to the 1 white mark which is top dead center on the number one piston. The 3 red marks indicate the 16 +/-2 degrees There is a pointer on the oil pump cover, and what you want to do is get the middle red mark to line up with the pointer when you shine the timing light at the crank pulley.

I don't think you would need to adjust anything when changing ECU's, but you might want to check it just to make sure it's in spec.

 

That's some really good info.

Thanks Patrick.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SOHCD16y8 &raquo;</TD></TR><TR><TD CLASS="quote">completely independent, but make sure you replace it every 105,000 cause if it breaks you screwed</TD></TR></TABLE>

105000????? I know honda says 90,000. And I have even heard as low as 60,000.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Racermech &raquo;</TD></TR><TR><TD CLASS="quote">

105000????? I know honda says 90,000. And I have even heard as low as 60,000.</TD></TR></TABLE>

90k on older hondas, but on new ones, I think 98-ish and up, they upped the recommended change interval to 105k. 60k is too soon for a timing belt change, but it won't hurt anything but your wallet!!!

 

unless u have a family member who's a mechanic and will do it for u for free

 

Yeah well, you know the saying, no such thing as a free lunch. Just make sure the person doing this "free" work is doing it correctly, and using only OEM Honda parts.