[Need Help] Timing Chain Slack Question

[OwnerCS]

While manually turning the engine through some cycles to make sure everything is in order before I finish up, I'm questioning the slack that I see moving around on the passenger side chain. The slack starts with the upper guide, then moves down toward the crankshaft, then the tensioner moves up and down as the slick area moves back up to the upper guide. While turning the crankshaft, this slack makes a loud pop when the chain slaps the guides.

This slack appearance seems to be more pronounced depending on specific camshaft lobe position combination instead of a consistent amount that is always present. There is a small about of slack movement around the drivers side chain -- but not like the passenger side.

Is this cam to chain slack leading and lagging something that is resolved by the HLAs and real RPMs once oil pressure resumes?

Is this slack the source of the noise that Jesda and Wes reported makes you think the engine is going to blow up until the oil pressure returns?

I can sure use some guidance from club brethren here before I go any further as I would rather be safe than sorry.

Upper Guide Slack


Crankshaft Slack



While replacing the guides, I always had the chains cinched or wired up to avoid any jumping. In this picture you can see I have the tensioner keeper released.

[OwnerCS]

Here's a picture of the timing mating marks, silver/gold chain links and crankshaft key line up below. I had to position everything like this so I could get it all into one picture.

According to the examples in FSM section EM. I think all is synchronized.

The picture will expand if you click on it.

[subtle_driver]

Bro, what you are experiencing with the slapping sounds and the slack in different areas is the cam lobes loosing and gaining tension depending on their positions as they contact the rocker and push down the valve springs.

Rotate the crank clockwise slowly, till you have tension on the top and the right side of the chain on one bank or one side. note the position of the hydraulic tensionor, should be extended to take up slack on the left side. Then look at the opposite bank and do the same thing.

Basically you look fine to me. The crankshaft is pulling the chains and has constant tension, the hydrolic tensioner just takes up the slack and prevents it jumping teeth.

[OwnerCS]

SD I sure appreciate your help!

Bro, what you are experiencing with the slapping sounds and the slack in different areas is the cam lobes loosing and gaining tension depending on their positions as they contact the rocker and push down the valve springs.

That is it.. The lobes with cam movement cause the chain to gain and loosen depending on their position. The gain in tightness causes the chain to slap the nearest guide.

Rotate the crank clockwise slowly, till you have tension on the top and the right side of the chain on one bank or one side. note the position of the hydraulic tensionor, should be extended to take up slack on the left side. Then look at the opposite bank and do the same thing.

The max tensioner travel when the slack area moves near it is in the picture below. Basically as I rotate the crank, the tensioner travels up and down by the gap shown on the tensioner below. The driver side moves up and down approximately the same travel distance as the picture below. However, the driver side chain doesn't slap the guides as violently as it does on the passenger side -- which makes the pop noise.

[subtle_driver]

don't worry about any of that.
both tensioners are different. just make sure all is tight and correctly mounted and the marks are spot on. install the covers and rev it to 9,000rpms!!!! J/k

just double and triple check the TDC marks when they have tension and put it back together!

[Q451990]

And don't be afraid of the hellacious tapping and rattling noises it will make on startup. Apparently the tensioners need some time to pressurize for the first time. It's sort of a right of passage at T3 to listen to your Q sound like it's going to explode on the first startup after a guide replacement. I wonder if turning the engine over with the starter for a minute or so with the injector fuse unplugged would avoid all of that - but I didn't get to test my theory...

Heath

[OwnerCS]

I'm thinking about spraying a shot (e.g. a very small amount) of Royal Purple Maxfilm synthetic lubricant into each cylinder when the piston is positioned at full downstroke. Then use the starter to spin the engine over several times to get the oil flowing all through the system while I have all of the spark plugs removed. The lubricant can coat and protect the cylinder walls during the initial spin rotations until the pump starts distributing oil.

I can tell you that the transmission pump sends ATF pouring out of the hose that connects to the radiator when I turn the engine over by hand only after a few partial revolutions. Just me manually rotating the crank when checking the timing line up caused a lot of fluid to be pumped out.. I take that as a good sign..

[subtle_driver]

lube up the timing chains a little with oil before start-up, you will be just fine.