Timing Chain quick Questions

[mn_ski]

Planning on doing timing chain on my '98 5.7L. My timing cover is leaking. I don't have anyway to know if the chains even need to be done but "as long as I am in there" is the case this time. So my questions:

Since the ECM sets the timing, how do I know if I did a good job/ how can I verify that everything is ok once i put it all back together? Aside from catastrophic failure or some obvious indication?

Even before I open things up can I look at what the ECM is doing with the timing? What should the ECM be doing with the timing at idle? I am just looking for ways to verify my work. I can get a scan tool from the auto parts store. I believe that will read timing.

I have a Holly metal timing cover and a Cloyes 9-1157 chain to go in. I will see if I have to drop the oil pan or not. Hoping not but if I do it looks like I have a blue gasket on the pan so hopefully that is the re-usable one. Any advice is greatly appreciated.

 

[Schurkey]

1. You're almost certainly going to have to lower the front of the pan, although perhaps not remove it entirely.

2. That timing set should be correct. You have three keyway options; DEGREE THE CAM and use whichever keyway comes out with the closest-to-OEM cam timing. Be sure to match the CORRECT marks on the two sprockets.

3. Cam timing, and ignition timing are not related on the Vortec 5.7L engine. There's no reason to check ignition timing as a guide for getting the cam timing set properly. However, if you checked the "Cam Offset" or whatever your scan tool calls the crank sensor/cam sensor synchronization, you'd have a double-check of the cam timing correctness. NOT loosening the distributor makes this check possible.

4. I'm not familiar with the Holley timing cover. IF (big IF) the cover doesn't have provision for alignment pins, you'll need to align the cover using the torsional damper hub before tightening the timing cover bolts. One way or another, the timing cover seal MUST be nicely aligned with the damper hub.

5. If the damper hub has a groove worn into it from the old seal, you can cram a repair sleeve onto the damper hub. About $7 out of Summit; probably more if purchased locally. Lots of companies supply them. Fel-Pro and Timken to name two.

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[packer0440]

TBH the timing chain doesn't usually go bad unless the engine is extremely high mileage or has other major issues... I have had the cover off on two different trucks, one with 100k, other with 300k, no noticeable difference in timing chain slack, both were fine. If you are confident in your ability to do it correctly, go ahead though while you have it apart.

I second the above comment on the dowels/alignment pins and the sleeve. Nothing worse than seeing a leak from something you just spent a bunch of time and money fixing. Also consider a new oil pan gasket if it's starting to seep, might end up cracking when you loosen the pan anyway.

 

[GoToGuy]

Ignition timing, cam timing .

 

[mn_ski]

I appreciate the comments/input. Looking through the factory service manual it even says to lower the front of the pan to get the timing cover in and out. My concern was with getting the pan to re seal with out having to drop the whole thing out and put in a new gasket. My pan gasket is only 10 months old and seems to be leak free. 235K on the engine for reference.

 

[L31MaxExpress]

TBH the timing chain doesn't usually go bad unless the engine is extremely high mileage or has other major issues... I have had the cover off on two different trucks, one with 100k, other with 300k, no noticeable difference in timing chain slack, both were fine. If you are confident in your ability to do it correctly, go ahead though while you have it apart.

I second the above comment on the dowels/alignment pins and the sleeve. Nothing worse than seeing a leak from something you just spent a bunch of time and money fixing. Also consider a new oil pan gasket if it's starting to seep, might end up cracking when you loosen the pan anyway.

Depends on which chain you have. The single rollers last forever. The link style fail early. I have seen them loose enough to jump teeth in under 100K miles on well maintained engines. I think engines that idle a lot kill them. I build my engines with single rollers and two small holes in the outside oil gallery plugs.

 

[mn_ski]

I build my engines with single rollers and two small holes in the outside oil gallery plugs.

I am installing a single roller. How about those gallery plugs? I am guessing you add holes to them? Do yo happen to have a picture of the holes you are mentioning?

As for the oil pan and how far to drop it down the factory service manual says to leave the back bolts in and loosen/ remove the front ones to allow the front of the pan to drop down. Since I am doing this in my garage on stands and I guessing I will be able to lower the front of the pan down enough to slide the timing cover in place?

 

[L31MaxExpress]

I am installing a single roller. How about those gallery plugs? I am guessing you add holes to them? Do yo happen to have a picture of the holes you are mentioning?

As for the oil pan and how far to drop it down the factory service manual says to leave the back bolts in and loosen/ remove the front ones to allow the front of the pan to drop down. Since I am doing this in my garage on stands and I guessing I will be able to lower the front of the pan down enough to slide the timing cover in place?

I typically buy ones that are threaded, tap the block for screw in ones if it is apart. I probably still have a dozen of them left, I think they are for a stock big block application. I suppose the stock ones could easily be drilled. Just have to be careful where the shavings go. Perhaps grease on the drill would capture the chips well. Never tried. The hole needs to be about 0.035". On a fresh build I typically change to screw in before the engine is final cleaned for assembly. I have seen the staked press fit ones pop out a few times. When they do you lose oil pressure and the lifters will not oil on one bank or the other.

Here is a LT1 block with screw in oil plugs that were already drilled. This is off Ellwein's website but it was just a quick picture I found detailing where the holes need to be.

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[L31MaxExpress]

I am installing a single roller. How about those gallery plugs? I am guessing you add holes to them? Do yo happen to have a picture of the holes you are mentioning?

As for the oil pan and how far to drop it down the factory service manual says to leave the back bolts in and loosen/ remove the front ones to allow the front of the pan to drop down. Since I am doing this in my garage on stands and I guessing I will be able to lower the front of the pan down enough to slide the timing cover in place?

I can almost never save these oil pan gaskets. The RTV sticks to them and the front portion ends up ripping off when you attempt to separate the gasket. I even tried with a pan gasket that had only been run on the stand and ended up splitting it. If you can get the timing cover off without breaking the oil pan gasket, you are more patient and gentler than I am.

Over the years I have gotten to where I will pull the engine vs working over the fender or under the truck. Takes me ~1 hr to pull the engine and I can work on it on the stand with free access to everything. Roll the engine over as needed. Makes it easier to regasket and check everything as well.

If my engine stand had not been 100 miles away, I would have pulled the engine in the van for the head bolt fiasco I just went through.

I have also rolled new main and rod bearings into several of these engines without removing the pistons or crankshaft. I have seen bearings with substantial wear and crankshafts that are near perfect. Simply rolling std bearings into it restores the oil pressure and quiets the engine noticeably.

 

[mn_ski]

That would be nice to pull the engine and work on it but I am afraid that would lead to scope creep, lol! Thanks for the info all. I am still debating if I perform this work myself or not. Reading a few other threads I found it seems that getting the pan loose enough to clear the timing cover while in the truck maybe its own job by its self. I need to crawl under the truck and take a look to determine how much time I want to spend down there!