I have seen some discussion lately about passing our very strict California Emissions tests and timing issues. My practice has been to set the timing to 8 Deg and carry my distributor wrench with me and tweak as I go so I really never know where my timing is set. I just tweak for results. I also understand there is a curve adjustment on the vacuum advance input port.

I will be doing the smog test as well in the next week or two and wanted to know "By the book" timing procedure with a really good timing advance light and how do I tweak the curve adjustment for maximum efficiency? I think my 400 needs some more adjustment because it performs really well on the highway but is often sluggish on lower RPM's if I need more power. Also my exhaust is really stinky (No pun intended) My truck is a one ton (F-350) and is exempt from many of the emissions devices including a cat.

 

Well I don't know for factory timing, but to set it to get the most out of it, rev it till the timing marks stop moving, and while holding the engine to that rpm, turn the distributor to set the timing between 34-38 (total) degrees. Total should be all in by 3-3500rpm. This is without vacuum advance of course, and it has to be plugged off to do the procedure above.

 

OK thanks, I'll try that later today. Any input on timing curve adjustment from anyone?

 

Steve

My power is still out so I'm camping at a friends house. I don't have the spec's in front of me. Make sure your vac advance canister is working, ie holds vac.

Start hunting for a good "pass or don't pay" smog testing place. I know the guy here and if hes not too busy will sniff it and give me a thumbs up or down.

If yours "stinks" it is probably rich or could be our great "gasoline" we are subjected too these days.

In the mean time make sure all looks "official" under the hood. Do they dyno where you are? For my year they just inspect and sniff.

If the can is good you might try turning that distributor wrench screw out 1 turn and see what that does. I think lighter spring tension quickens advance timing.... Guessing here...

.

 

Yep, you can change the curve by swapping in different weight/thickness springs. The lighter the spring the sooner it advances.

 

OK I just nosed my truck in the garage and I'm going to check all those things now.

Old School-
I gave a local shop some business when my wife's Suburban AC needed work and I was too busy to fix it so I already built up a good relationship with this shop.

You're still without power!?!?! Any ETA yet from PG&E?

OK going to hide under my hood now....

 

I'd be surprised if your truck would pass. Mine is a 79 F250, same engine. As far as I know, truck 400 engines did not come with a 4 barrel option. That would fail mine right away. If it's junk from the factory, it must remain junk for life. Makes a lot of sense, huh! Still wrestling with mine. Failed idle CO. New carb on order, but it's already expired by now, so I risk a ticket if I drive it. Grrrr!

 

The power made it back on this afternoon. Yea! But the phone is another story so no phone or dsl till.... the 9th? Gotta love that!

 

Checked timing and I found it at 12 Deg at idle and 25 at high RPM. I adjusted the timing to 35 deg at high rpm and seems to be doing OK however I'm getting some pinging at low RPM's under a load like going up a hill. Would tweaking the curve help eliminate the pinging?

Wife is sending me to the store, O-Joy.... so this will conclude my timing adjustemts for the day. At least I'll be taking my truck and after a good bath today (The truck that is) it will look good going to Costco. I packed my timing light and wrench behind the seat so I can tweak as I go.

I checked all the hoses and EGR Valve and all is working properly.


I know how it is, I had an F250 before and it's very frustrating. In California even though you don't pass smog yet you can pay the reg fee's so at least you will be current and not get dinged with penalty's. You can even get a temporary sticker that would allow you to drive it until you pass smog. As for me having an F350 helps a lot and the mechanic said as long as it has a working EGR valve and passes the tailpipe test I should be good.