Friday, April 30, 2010

timing is critical

Arse-Freeze-a-Palooza back in November was pretty great, but the Mystery Machine wasn't exactly running at top form - timed all to hell, it couldn't be made to top about 4500-4800rpm. We tried a few different things - cpu troubleshooting, vacuum (we kind of eyeballed the vacuum lines when we put the new engine in, and Laz swore up and down he plugged everything in to the right place), distributor timing. None of it made much difference, and we limped our way through the race.

So then we parked the van for the winter and conveniently ignored it for a while. But now that Goin for Broken is right around the corner, we thought it would be nice to regain the use of our many missing horses (and our turbo, which wasn't really working either).

After some more fruitless poking around, we eventually discovered (via some googling and much experimentation) that our problem was, as we initially suspected, related to timing. We'd already marked the flywheel and reset the ignition timing to spec, but doing so had given the van a disturbing smoker's cough.

Once we lined up the cam pulley at TDC, and were putting things back together, we consulted the manual, eyeballed everything, and...

JDH: And the lines on the crank pulley line up with the arrows on the block, right?
Rob: ...those are supposed to line up?


Since we had it mostly apart anyway, we also replaced the timing belt.

From Mystery machine rebuild

When we put it all back together - magic! It totally works!

As soon as it was running well again, we noticed a lot of hissing, and found an uncapped vacuum line (which used to go to the A/C) which we'd never noticed, due to not having actually generated any boost. The super-high-tech vacuum gauge threaded through the firewall confirmed, while hooning up and down an unsuspecting quiet residential street, that we're getting up to 7psi now.

Now, if you ever need to re-time a gen-2 dodge turbo, you should check out the instructions on, here: "Cam timing on 2.2/2.5 Chryslers". But in general this was easier than I expected - once the belt was off and we'd given up on the pre-existing timing entirely, we lined up the holes in the camshaft pulley with markers on the block, lined up the markers on the crankshaft pulley, and then, once the belt was back on, re-timed the ignition timing to spec. (The crankshaft pulley ended up being 2-3 notches off from the camshaft, depending on how you count.)

There, we fixed it!
From Mystery machine rebuild

(I am not in the picture. I am holding the camera, poorly.)