Timing chain

[Doctor510]

The part that the fuel pump rest on, does it make a difference how it’s put on there. I know it’s offset.

 

NO

[datzenmike]

Turn the crank clockwise and that slack on the driver's side will disappear. 

 

 

 

Make sure the front bolt for the thermostat housing isn't hitting the chain, right where your screwdriver is.

 

Chain can't hit the valve cover. Any mark is just stains from oil cast off.

[Trod8812]

Well the motor turns clock wise so I can’t figure out why there would be slack in it when it’s not running

[Trod8812]

The sound is definitely comingFrom near the valve cover for the front of the head

[Trod8812]

I turned the motor clockwise and the slack is still there

[datzenmike]

Well the motor turns clock wise so I can’t figure out why there would be slack in it when it’s not running

 

The point is that when running, the crank pulls down hard against the cam's resistance caused by pushing valves open against their springs. It's very possible that the crank may back up slightly from trapped compression or a valve spring pushes the cam sprocket forward slightly just as it comes to rest.

[Trod8812]

I turned it like you said and there is slightly more slack when it turns

[datzenmike]

Have someone else turn the crank slowly while you watch the chain.

[Roadster-ka]

Check that thermostat bolt. If you lose a washer from it, out can go too deep and push the chain guide over, as Mike stated.

[Trod8812]

I checked that and it’s not hitting the chain

[banzai510(hainz)]

Well I assume you tighten the slack side guide enough where the chain don't slap around

 

post 67 if that was close to that I saw it looks good on the photos

[Trod8812]

I installed the guides and tensioner so the chain was tight and I had someone look while I turned the motor and the chain was tight

[banzai510(hainz)]

run it till it breaks. Im at a loss.

[Trod8812]

It I turn the motor over by turning it by the cam sprocket bolt instead of the crank pulley bolt will it cause slack in the chain?

[Crashtd420]

It I turn the motor over by turning it by the cam sprocket bolt instead of the crank pulley bolt will it cause slack in the chain?

Yes... you should use the crank bolt...

[Trod8812]

After I turned the crank bolt it tightened the chain so I figure I will start it back up and see if if the noise stops

[datzenmike]

You can't remove something that wasn't there. When running, the driver's side will be tight.

[Trod8812]

Turns out the sound was the fan hitting the shroud at the bottom

[datzenmike]

Cheap easy fix. At least it wasn't a timing chain wedge left in.

[Crashtd420]

Turns out the sound was the fan hitting the shroud at the bottom

Good find... glad it was nothing serious..

[Stoffregen Motorsports]

Cheap easy fix. At least it wasn't a timing chain wedge left in.

I wish I could find that screwdriver that I found inside a L series front cover. It was in there at least two years before I got the motor from the guy that left it in there. That must have been noisy.

[Trod8812]

Does anyone know about 79 620 steering components. I replaced the center like and set to the same length as the old and the passenger tire is really toed out while the driver side tire is straight. Maybe another part is damaged letting it wander out?

[datzenmike]

Turn the center 'cross link' until you have the proper toe.

 

What I do is get 4 stakes or anything you can hammer into the ground and 2 pieces of string about 10 feet long. Find some level ground. Set the stakes one in front of the other and wide enough to drive the front wheels between. What you want are two parallel string lines about even with the front hubs or half way up the tires. Use a tape measure and measure across at the near and the far end and adjust so the measurements are the same. Any amount but they must be the same and the string parallel. 

 

Drive the vehicle between them, wheels straight ahead. Measure from the string in to the front leading edge of the rim on both sides and record the numbers. Do the same on the rear of the rim and record them

 

Add both the front rim measurements and then add the rear measurements. Tire alignment usually has the front very slightly toed in, so the two front measurements added should be more than the rear two measurements added together. On a 14" rim a one centimeter (0.394") difference is about 1 degree. When you make a change and adjust the front in, the rear will spread apart so re-measure the fronts and  the rears, add each pair and compare again. 

 

Don't forget to tighten the two lock nuts on the cross link.

 

The '78 (I imagine the '79 is the same) toe in is 0.20-0.28"

[banzai510(hainz)]

you need to adjust more.

If you cant do it take it in have a shopdo it otherwise youll be getting new tires in 6 months

[datzenmike]

My 620 when I got it, if you hit a puddle with one front tire and reduced traction, the other one was so toed in you would find yourself suddenly in the other lane or the gravel. It was scary. Another thing was turning a corner in town. Once the wheel was turned to a certain point the truck would turn sharply in that direction by itself and you'd have to grab it strongly and force it back. Tires were through to the cords on the insides. Previous owners are idiots.