Ok, I'm still debating if I put my timing chain on correctly or not. I only had the one set of marks on the head. There was a little "slop" on the top chain (the side opposite the tensioner.) THe truck idles a little rough. I can't notice a problem when driving. I do want to fix the problem if it is the timing.

Of course it could be something else too. If the chain was off 1 link, how rough would the truck run? There is no loud back fire. Just a little sputter.

So, any help would be nice. If I took it to a dealer could the hook it up and diagnose it?

Thanks.

Doug

 

If the timing chain has more links in it than it's supposed to, that means there is slop in it. All marks must be precisely lined up, and the chain needs to have the correct # of links in it in order to operate correctly. I am no mechanic but I know this, it will cause your timing to be off several degrees, causing a misfire because the valves opening and closing points will not be in time with the pistons when they reach (TDC), Top Dead Center. You problably already know this, but this is just .

 

If the chain is off one link you will notice a severe lack of power.

 

Forgot to mention, if your timing chain has more links than it's supposed to, it could fly off.

 

The chain surely hasnt grown a link between the time you took it off and the time you put it back together, so.... If you say there was any slack at all on the side opposite the tensioner, then it is off a link. The side oppasite the tensioner is the side that pulls the cam around, so the crank would have rotated some before taking up the slack and turning the cam, therefore, a retard in cam timing. What will that cause? A rough idle. One link off wont really be noticable over 1500 rpm or so. If you take it to a dealership and they do power balance with wds, then it will show a dip on every cylinder on that side of the engine at idle. I see that a lot after heads have been put back on.

 

Kidtriton,

That's exactly the info I was looking for. That's what I thought too, but since I'm not real familiar with it, I thought I'd ask.

I know there was slack in the side opposite the tensioner. The chain was correct on the head, I marked that but in our haste we didn't mark the crank. Is the fix as simple as it appears? Take the timing cover off and put the chain on correctly? I know there is more work involved in getting to the chain that in the fix, but it would be worth it to have my truck back just right again.

Thanks for any more info.

Doug

 

yep. it needs to be tight on the side opposite the tensioner with the marks lined up. that will fix it.

 

Kid,

Do you think that I would have cause any harm to the head? (Assuming everything I told you was accurate and I was only off 1 link.) I might do that this weekend. I have to take it into the garage anyhow and change out a u-joint. What's another couple of hours... I know in the manual it says if you replace within 4 minutes you don't need a new gasket. How hard and fast is that 4 minutes?

Thanks.
Doug

 

dnale, I think we had a simular discussion about this a while back, sorry your still having problems. Kidtriton pretty much hit the nail on the head. My only suggestion is to correct the timing if its off and ck compression or do a cyl leakdown test to verify you didn't bend any valves before you put everything back together.

 

Mx,

We did talk about a month ago. Since then I have talked to a friend who works for roush. Granted there were several adult beverages at the time, he thought the truck would be backfiring more or run rougher. I also talked with a gm mechanic that works on the prototypes at the proving grounds (an uncle) and he thought it could go either way. I just wanted some more reinforcement to convince me to rip into it again. I think I know where my weekend is!

I should remember from the last time how to get into most things. Just need to remember the torque spec's.

If anyone wants to volunteer for me, I'll buy the beer.

Doug

 

Which gasket are you talking about? ive never heard of any 4 minute deal, but if you are just gonna slip the timing cover back off and retime it, you can use the timing cover gaskets again as long as they dont come out of place, or will stay in the grooves if they fall out. There wont be anything wrong with the heads. Ive seen a ton of these off 1 link like yours, and they only run bad at and around idle. It would have to be much more retarded to backfire and such. The longer the chain, the less 1 link will make in degrees of being out of time, and these are pretty long chains. So 1 link isnt as bad as some other engines would be.

 

kid,
On the cd I have it says something about when you remove the valve covers and the timing cover, that you are to replace the gaskets if you are not putting the valve cover or timing cover back on within 4 minutes. I didn't replace the left valve cover when I did the work originally and it was technically off for almost 48 hours and it has sealed fine.

Thanks.
Doug

 

i wouldnt wory about it. Sometimes those rubber gaskets swell and fall all out and wont go back in. Thats when to replace them.

 

Hey Kidtriton,
Wouldn't it be much easier just to check manifold vacuum to check for correct cam timing? Compare the suspected bad running engine to a known good, if the vacuum is more than a inch of mercury difference, then you know where you problem lies.

 

That 4 minute thing refers to putting on the front cover within 4 minutes of applying silicone to joints. This is so the silicone won't have already started to set before you put on the front cover.