Gurr

Wuddup folks. I got a 94 pickup that has had some timing issues. Owned by brother, sold to mom, driven by sister's boyfriend. It's a fun little family...

What ended up happening was that my sister's boyfriend was learning stick and downshifted to the wrong gear. Revs jumped up high when the clutch was released and started to run like ˟˟˟˟. I figured the timing chain jumped a tooth. Got a kit and pulled it apart. Mark on the pulley was about 2 teeth advanced, guides were broken, and the chain had actually eaten through the guide around the crank sprocket on the timing cover at some point.

Put it all back together and find out that there is no compression. Everything seems together alright....I'm aware of how the valves are on these. I'm just curious in confirming bent valves. Rockers move seemingly fine. and it looks to be at TDC when I rotate it around. Marks end up at the top and rotor is at 1. It just seemed strange because before I took it apart, it still felt like there WAS compression. Then I theoretically put it at TDC and lost what it did have. Does this sound right?

Thanks guys!

Co_94_PU

iTrader: (-1)

Two teeth off could be enough to cause interference I imagine.

Which "marks" are on the top (12 o'clock), be more specific "bright links", cam dimple, or cam dowel? Cam dowel is the correct answer, or it needs reset.

You have the valve cover off? Check the valve lash, if you didn't adjust them and they are out of spec it indicates maybe a stuck valve or maybe the cam timing wasn't right, or they are just really worn..

Verify its at tdc compression, crank pulley to zero, insert a straw into #1, wiggle the crank back and forth a little and the straw should stay still and the #1 rockers should be floating off of the valves. Put some air in the cylinders when they are at tdc compression and listen for leakage in the intake and exhaust indicating the valves aren't seated.

If you dont have ability to do the leakdown test, you can rotate the crank (by hand) with the sparkplugs inserted you should be able to feel each cylinders compression stroke. Or you might even notice it sounds off while cranking.

Gurr

The dimple and the pin are the same location. All of the marks line up which leads me to believe it's the valves. Here's some pics to show where it is with no compression.

Co_94_PU

iTrader: (-1)

The dowel lines up with a valley, the dimple is on a tooth. IE they can't both be at twelve/vertical. But the photo looks good. The crank is off a little, not enough to suggest the pulley spin on its rubber for certain (still easy to pull a plug and check). Distributor looks in the right ball park also, you can be more certain by drawing a line on the distributor housing with a straight edge and sharpie while the cap is on.

How were the valve clearances? A bent valve should show up testing this, but not a cracked or other damage.

Co_94_PU

iTrader: (-1)

PS did you do a compression test, did it not sound right, or is it just not firing off?

Gurr

Ah! I see what you mean with the marks.

I guess I'll check the valve lash...makes the most sense. It's like nothing is resisting the starter motor, the sound of no compression. Turning by hand also is pretty easy with no fight of pressurizing the cylinders.

Before I pulled it apart, the timing mark on the pulley was pretty far advanced(like I was saying 2 teeth). However, I was not aware of this pulley slip issue at the time. I should have double checked TDC with the pistons and valves before pulling apart.

Gurr

Next question is how far off would the valve lash be if they were bent? Intakes are at 0.012" at the most when they should be at 0.008" the engine is also cold. I would imagine a bit more of a gap.

I also put something in the spark plug hole when I cranked it by hand to make sure piston was at the top...everything seemed fine. I don't have a compression tester with me, unfortunately...I should have gotten one earlier today.

Gurr

Welp! Problem solved....there was nothing wrong the whole time.

Apparently, when this engine gets cranked over it sounds like no compression. Put it all back together and just cranked it a bit longer and it started.

Thanks for your continuous input CO. I really appreciate it. Needless to say, I'm happy it did all work out in the end.