Haku

I know there are some other posts about this, but I can't find the answer I need. Background on this is I spun a bearing last spring and have been building this engine over the summer. It has the street RV head and the crawler cam, and the rest is pretty much stock. Finally got it all put together and went to start it and it will crank over just fine, oil is getting to all the places it needs to be, I have fuel pressure and spark everywhere its supposed to be.

Here is where I get confused. I think its a timing issue, but I can't figure out if its distributor timing or the timing chain that is off. I know its easy to get the disto 180 degrees off but I have double checked to make sure that when its 5 degrees BTDC with cylinder 1 in compression, it points at the number one plug. I also think I got the timing chain right, but now I'm confused since it won't start.

The really weird thing is that I am getting air movement/pressure going the opposite direction. Every couple cycles the AFM audibly claps slams shut, and at one point it actually blew the crossover hose (lightly tightened down) right off the AFM. This is making me think that I got the timing chain wrong, but as far as I can tell everything is correct. Doesn't mean it actually is, but I can't figure out what exactly is wrong. It will crank and crank, but won't turn over and then will push air backwards.

Any help is appreciated. If you are in Denver and want to come over and help me figure it out (and you've done all this before) then I'll definitely buy a couple beers and dinner.

Josh

1990yota-pickup

read back through your manual..

MR2

I would try pulling the valve cover off and double checking that the mechanical timing of the timing chain is correct. If you do need to adjust it, it isn't too hard to pull the gear off, and rotate it as needed. You might need to play with it a little bit, roatating the crank with a 19mm, while holding the gear/chain in your other hand.

#1 cyl at TDC, timing mark on the lower pulley lined up to Zero degrees.

The little dimple on top of the cam gear should be just slightly left of 12 O-clock.

Then line up the distributer again so the rotor points right at the #1 wire.

Hope that helps.

BajaRunner

Make sure the cam gear is at ~12 o'clock, and the front two rocker arms for #1 are loose (valves closed). Inspect by pulling out the spark plug and with a screw driver and light that the #1 piston is up. Maybe you are off by a tooth or so.

Id be inclined to have someone turn the motor by hand for you while you watch the piston. It will float up at the top for a few degrees, and when its right in the middle of its top dead center stroke, stop, and make damn sure that the dimple on the cam gear is at 12 o clock and that your rotor is pointing at #1.

While someone cranks the motor, are you able to set timing? Are all your vacuum lines hooked up? Did you adjust valves cold? I just used .008 for intake and .012 for exhaust for cold (this is actually the factory settings for warm) and the valves are set at .007 and .011 when warm and I like the fact that the valves are just a tad less noisy.

Haku

Thanks guys. The FSM is a bit unclear about how to do it, and like most of the "it won't start" threads, it turned out that the disto wasn't lined up correctly.

For anyone who searches and finds this thread, take the valve cover off and check to make sure that the dimple on the cam sprocket is pointing to 12 o'clock (as the fine people above posted). Its super duper easy to get it backwards, since you can have the timing mark on the crank pulley at 5 degrees BTDC, and the #1 cylinder up with the distributor rotor point at #1 position, and still have it wrong i.e. 180 degrees off. I hate to say I read all of the other posts about this, but the whole "backwards flow of air" thing was throwing me for a loop and I hadn't seen any reports of that elsewhere.

Needless to say, the truck is running now and it runs quite well too. I'm stoked, as this has been a long and frustrating project so far. Still have to do final timing and readjust the valve lash once it warms up, but I'm just glad it turns over and runs consistently.

camo31_10.50

when the notch on the cam sprocket of my 22R was at 12oclock, my cam dimple was at about 11:45.

Ted at Engnbuilder told me this is correct for my 261*cam