Ahhhh can't pass smog!!!!!!!! - Off-Road Forums & Discussion Groups

Carnellc · #1 10-17-2009, 03:05 PM

I need some help & ideas,

This is the second time / year that I failed my smog check due to engine timing. When I rebuilt the engine, I had to replace my timing cover. This being a prior discussion on this board, I believe the the timing marks on the replaced cover are wrong. How can I correct this without replacing the timing cover? This is the only thing that keeps it from passing smog everything else passed.......

Thanks,

Carnell

LEVE · #2 10-17-2009, 03:22 PM

grind off the timing marks....

Carnellc · #3 10-17-2009, 04:10 PM

I'm not sure how that helps.. They need mark's or mark to confirm timing

Jim_Lou · #4 10-17-2009, 04:22 PM

You need to get cylinder 1 to top dead center. Then you can see how far off the timing cover marks are and adjust accordingly. There are several ways to find TDC, but my favorite is with a dial indicator and a long probe. You stick the probe through the spark plug hole so that the piston touches it just a bit before TDC. Then turn the crank one direction until the piston drops some distance, say 0.150", and mark the crank location. Then turn the crank the other way past TDC until the piston again drops that distance. TDC is exactly half way between. The accuracy increases as the drop distance increases, but for your purposes you don't have to be exceptionally accurate.

When you have TDC you can apply a home-made tab, or add the error to what mark you use to set timing. Or just put a zero mark on the cover and use an advance timing light.

LEVE · #5 10-17-2009, 04:33 PM

Since you're in California... and the smog laws are so darned strict... I doubt you'll be able to jury-rig any type of mark on the case. The law requires OEM parts, and that would include the timing cover. I doubt you'd be able to get away with re-marking the cover or attempting to talk sense into them about how you found TDC, etc.. IMHO, you'll have to bit the bullet and get a new timing cover for that engine that is specifc to the year/displacement. There ain't many choices left in California that would let you get around the problem.

Carnellc · #6 10-17-2009, 04:38 PM

The guy at the "Test Only Center" saw how frustrated I was and said for me to make a new TDC mark. I'm reading Jim Lou post and I'm trying to wrap my head around it. Is the the TDC mark on the cover? Flywheel? or both??

Thanks guys for the help

Carnell

Jim_Lou · #7 10-17-2009, 05:00 PM

Timing cover and front pulley - there's a single line on the pulley, and a tab cast into the timing cover that with marks from -2 to +12 in 2-degree steps - probably different in different years. Most commonly the 258s get set around +6 advance for best emissions. That is, the plug fires when the pulley hash is at the 6-degree mark. If you are setting the timing there but getting bad emissions you may have a timing cover with the marks in a place that doesn't jive with where the hash is on the pulley. Neither has to be in any particular place as long as the piston is at TDC when the hash is at the zero mark. If the hash is at the 4-degree mark when the piston is actually at TDC and you set the timing at the 6-degree mark the timing will actually be at 10 degrees and your HC (I think) will go way up.

Carnellc · #8 10-17-2009, 05:07 PM

Leve you can appreciate this,

I have a close friend of mine who was a professional car mechanic and a great teacher when it came to rebuilding my jeep. He moved to AZ just as I got my jeep back together and I call him when I need help. I just made that call asking him to walk me through the steps that Jim Lou gave me to find TDC. As my friend and I where talking about the TDC steps, he just said " do you want me to help you when I get there?" WHAT!!!...... He is on the road to San Diego and I didn't even know it. He should be here in a hour or so to help me. I'm a man of faith and I just love how the "Man upstairs" works some times.

Ya the TDC isn't that big of a deal, but I have allot on my plate right now and this smog issue was the last thing I need.

Some days I don't like being a grownup with responsibility.

Carnell

Carnellc · #9 10-17-2009, 05:10 PM

Thanks Jim!!!!! I'll post my results later tonight when my friend gets here to help me. I'm curious to see where the timing is at..... Last time I checked, I thought it was good.

Carnell

Carnellc · #10 10-17-2009, 08:58 PM

*****Update*****

Well the timing with the original mark on the flywheel is way off. The mark we made at TDC is even further off. so long story short, my friend feels that since the pulley was NEW when we did rebuild, that the stamp on the pulley is off or that we have the wrong one. The jeep is running to well for the timing to be sooo off if we where to follow the original marks.

So the fix..... After some time starting and stopping, we where able to make a mark on the pulley to where it points to the correct timing mark. A.K.A. 9 +- 2 BTC...... Next week I'll take the jeep back for the retest and it should pass.

BTW.. this drives me crazy that the emissions pass with flying colors but the visual check of the timing would fail the test. The test guy knows the emissions are good so who cares after that point??? Let the car pass.....

Carnell