Engine Swap. Timing??

[adsm08]

Setting the syncro doesn't need the engine out. You get cylinder 1 to TDC compression and set the vane in the window on the syncro body. There was a special tool but it's only purpose was to verify alignment. It had a gap that would only drop on when the vane was in the right spot.

 

[Sharky146]

So, the cam synchro is driven by the cam gear at the back of the engine. It looks a lot like the bottom half of a distributor, but the cap/rotor have been replaced with a cam synchro sensor that sends signal to the coil pack and tells it when/where to fire. Besides controlling ignition timing, the synchro also has a shaft out of the bottom that drives the oil pump, so if the synchro fails, your oil pump stops pumping and the engine has no oil circulation. That smokes an engine in no time. Synchros have a bearing at the bottom that can get starved for lubrication and seize. It usually chirps before it seizes completely.

The cam synchro isn't actually on the lower intake. The lower intake actually contours around the synchro which is mounted to the top of the engine block. It's possible to swap intake manifolds without touching the synchro. If you installed the synchro from the old engine into the new donor, you should've matched the orientation of the new one with the orientation of the old one. There are special tools for this. If you switched out synchros between engines, and special care wasn't taken to insure alignment, then it's definitely possible that it's misaligned. If you didn't touch the synchro at all, and it's the synchro from the 07 that's still in the 07 block, it's less likely to be misaligned because it was probably running well enough when the donor truck met its fate.

I think the Haynes manual I used had a procedure for making sure the cam synchro alignment was correct, but it involved setting the engine to TDC and some other things that are easier to do with the engine on a stand than in the truck. It's been almost 10 years since I did mine so details are hazy. If you didn't touch the synchro, I'd look at other, easier things first before tackling synchro alignment or replacement.
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My mistake. You’re right. The cam synchro is attached to the block, not the manifold. Thank you for the detailed explanation. I picked up this project to increase my knowledge and understanding of this stuff. Thanks to you guys, I’m learning a lot as I bring this truck back to life.

 

[Sharky146]

So, the cam synchro is driven by the cam gear at the back of the engine. It looks a lot like the bottom half of a distributor, but the cap/rotor have been replaced with a cam synchro sensor that sends signal to the coil pack and tells it when/where to fire. Besides controlling ignition timing, the synchro also has a shaft out of the bottom that drives the oil pump, so if the synchro fails, your oil pump stops pumping and the engine has no oil circulation. That smokes an engine in no time. Synchros have a bearing at the bottom that can get starved for lubrication and seize. It usually chirps before it seizes completely.

The cam synchro isn't actually on the lower intake. The lower intake actually contours around the synchro which is mounted to the top of the engine block. It's possible to swap intake manifolds without touching the synchro. If you installed the synchro from the old engine into the new donor, you should've matched the orientation of the new one with the orientation of the old one. There are special tools for this. If you switched out synchros between engines, and special care wasn't taken to insure alignment, then it's definitely possible that it's misaligned. If you didn't touch the synchro at all, and it's the synchro from the 07 that's still in the 07 block, it's less likely to be misaligned because it was probably running well enough when the donor truck met its fate.

I think the Haynes manual I used had a procedure for making sure the cam synchro alignment was correct, but it involved setting the engine to TDC and some other things that are easier to do with the engine on a stand than in the truck. It's been almost 10 years since I did mine so details are hazy. If you didn't touch the synchro, I'd look at other, easier things first before tackling synchro alignment or replacement.

My mistake. You’re right. The cam synchro is attached to the block, not the manifold. Thank you for the detailed explanation. I picked up this project to increase my knowledge and understanding of this stuff. Thanks to you guys, I’m learning a lot as I bring this truck back to life.

 

[Sharky146]

White smoke is burning coolant so thats not good...

And a major exhaust leak before the o2 sensor will cause the truck to run rich since the o2 sensor is reading less fuel in the exhaust than is actually there.

Question for you about the white smoke...

The cylinders are making good compression and the oil on the dipstick looks good too (although it’s very clear since it’s new). It seems that if coolant was making its way into the crankcase, then I’d have a blown head gasket (indicated by lost compression) and milky/foamy looking oil. Is there another way to get coolant into the combustion process which would cause the white smoke?

Also, you mentioned that the exhaust leak at the manifold it

 

[Sharky146]

Sorry...I hit “post reply” on accident.

Also, you mentioned that the exhaust leak at the manifold could cause the engine to run rich. Could the rich mixture be related to the rough running and smoke also?

FYI, I’m running just water as coolant right now while I’m troubleshooting. Not sure if that matters.

Today I’m going to remove the troublesome exhaust manifold from the head and try to seat it to the Y-Pipe by itself. Maybe that will help me get a better connection. I bought an exhaust gasket (picture attached), but it doesn't seem to fit right. The gasket isn’t required, is it? I didn’t notice one on the other side. Once I get the manifold securely on the Y-Pipe, I’ll bolt it back into the head.

 

[Dirtman]

Coolant passes through the intake manifold so a leak there could introduce coolant into the combustion chamber with no loss of compression or coolant/oil mixing. And yes a rich condition can cause rough runnng and smoke, but smoke from fuel is black.

Black smoke = fuel
Blue smoke = oil
White smoke = coolant.

What do the plugs look like? Are any of them alot cleaner than the others? Or alot blacker than the others?

 

[Sharky146]

Coolant passes through the intake manifold so a leak there could introduce coolant into the combustion chamber with no loss of compression or coolant/oil mixing. And yes a rich condition can cause rough runnng and smoke, but smoke from fuel is black.

Black smoke = fuel
Blue smoke = oil
White smoke = coolant.

What do the plugs look like? Are any of them alot cleaner than the others? Or alot blacker than the others?

Gotcha. Here are the plugs. They’re new and all look slightly different. Most of them look a little dirty and wet to me, but I’m no expert.

What do you guys think?

This is the order of the photos:

Passenger side front
Passenger side middle
Passenger side back
Driver side front
Driver side middle
Driver side back

I wasn’t able to work on the exhaust manifold today. Hopefully I’ll get to it tomorrow.

 

[Sharky146]

Update:
I got the exhaust manifold leak fixed. I was using hardware store bolts on the leaky side, which turned out to be too long. I assumed that the bolts would pass thru the threaded holes in the manifold, but they don’t - they stop. So I cut down and die-cut the bolts to the proper length and now no more leak. I guess that’s what’s happens when you assume.

Engine is still running poorly though. I’m going to do the following for trouble shooting.

1. Check fuel pressure at the rail.
2. Clean mass air flow sensor and throttle body.
3. Continue to check for vacuum leaks.

 

[Sharky146]

I found the cause of the poorly running engine!

It was a vacuum leak like many of you suggested. The leak was where the EGR meets the upper intake manifold. One of the bolts wasn’t tight enough.

I learned a cool trick from YouTube on how to find a vacuum leak. While it was running, I sprayed a little carb cleaner around the vacuum areas under the hood. I found the leak when the RPM rose slightly while spraying the carb cleaner around the EGR. Tightened the fitting, and now it runs like a top!

Thanks for all your help on this project guys.