Me again, new problem

[EWC]

So there are a few ways to do this but I'm with WAR , don't turn the engine over if the timing marks are not lined up . If you did lose the chain chances are the valves are bent . I would take the cam gear off , this drives the injection pump , and see where the " dots " are on the cam and crank gears . They don't have to be lined up but when the crank is straight up the cam needs to be at 6 or 12 o'clock . 6 is good as that will line up with the crank , 12 just means you have to rotate the engine 1 revolution to get dot to dot . Worry about the chain first and then the injection pump timing .

 

[Husker6.5]

Ditto what @WarWagon just said. Do NOT turn anything until the front cover is off and you are looking at the timing gears and chain to see what has grenaded and why you found a piece of the timing chain. To not do so could mean that those new heads just became very expensive boat anchors if you bend the valves turning the engine over, even if by hand. If you find that the timing chain has indeed broke, post pictures immediately before attempting anything else and come back here for further instructions. With an interference engine there will be only two options if that chain broke. 1) Remove both heads, check for valve/piston damage before proceeding further. 2) Do a chain and gear set reinstall from this position without pulling both heads (difficult, but can be done) without bringing #1 to TDC, then VERY carefully and slooowly turn the engine over by hand two full revolutions to check for any interference and pray that nothing bent/broke when the chain went or that you don't bend/break anything in turning the engine over by hand. Option #2 is only for those with a pair of brass cajones the size of basketballs and/or a fat wallet and/or three grand room on the credit card.

 

[Newguy1998]

DO NOT ROTATE THE ENGINE!!! You may be lucky. Your timing set may be broken or hanging on by a thread. You need to know before rotating the engine.

When you are looking at (you have torn the engine down to) the timing set aka the suspect chain you can decide what needs to be done. You either lost one part of the double roller chain and it's still hanging on or you have a completely busted chain where rotating the interference engine is just going to bend valves. If the chain is completely broken you may as well pull the heads or engine as some of the valves/pushrods are going to be bent. You may be lucky and had the chain snap on shutdown and didn't bend anything. This is why rotating the engine is a BAD idea: don't do more damage. (Valves are expensive per each.) If you do rotate the engine rotate it in it's normal rotation NOT BACKWARDS! Any loose parts can do damage going the other way or decide to snap from a different tug.

When you can tell what is going on then and only then can you spin the engine over to TDC making sure the cam is rotating with the crank. (A key could have sheared off as well.)

As an aside this broken chain may be from the past with a lazy mechanic leaving FOD in the oil pan. Replace the chain anyway because you are there and it stretched out. You can inspect the chain completely with just the water pump removed. Then and only then continue teardown if required. You may only need to remove derbis from the oil pan from a past repair.

Timing is easy : line up the marks with each other on the sprockets. Then line up the marks on the IP gears.

So there are a few ways to do this but I'm with WAR , don't turn the engine over if the timing marks are not lined up . If you did lose the chain chances are the valves are bent . I would take the cam gear off , this drives the injection pump , and see where the " dots " are on the cam and crank gears . They don't have to be lined up but when the crank is straight up the cam needs to be at 6 or 12 o'clock . 6 is good as that will line up with the crank , 12 just means you have to rotate the engine 1 revolution to get dot to dot . Worry about the chain first and then the injection pump timing .

Ditto what @WarWagon just said. Do NOT turn anything until the front cover is off and you are looking at the timing gears and chain to see what has grenaded and why you found a piece of the timing chain. To not do so could mean that those new heads just became very expensive boat anchors if you bend the valves turning the engine over, even if by hand. If you find that the timing chain has indeed broke, post pictures immediately before attempting anything else and come back here for further instructions. With an interference engine there will be only two options if that chain broke. 1) Remove both heads, check for valve/piston damage before proceeding further. 2) Do a chain and gear set reinstall from this position without pulling both heads (difficult, but can be done) without bringing #1 to TDC, then VERY carefully and slooowly turn the engine over by hand two full revolutions to check for any interference and pray that nothing bent/broke when the chain went or that you don't bend/break anything in turning the engine over by hand. Option #2 is only for those with a pair of brass cajones the size of basketballs and/or a fat wallet and/or three grand room on the credit card.

Thanks for your concerns but...

The truck ran like hell since I did the head gaskets and right up until I noticed the broken half chain link. I have no reason to believe it has any issues other than the chain and possibly scared gears.

Also noticed the missing link after the timing cover was off. Turned the crank to find TDC because did tons of research and couldn't find out how. Everything seems fine, timing marks lined up. I'm optimistic I'll have her running by the weekend. Then book it in for a TDCO next week.

 

[1994ch]

If the chain was still holding the two gears together in time you should be good to go.

 

[Husker6.5]

Damn lucky. The 6.5 gods must have been in a good mood that day. Triple check to make sure that chunk of timing chain link bouncing around in there didn't cause any collateral damage to the IP gears, cover, etc.

 

[WarWagon]

These engines generally run great up to the moment they let go: with zero prior warning. One other note when you are putting the timing set on they slide on together and are very tight from the chain. This is normal. What's not normal is spinning the engine with the chain and having it go slack - tight - slack. "B" brand chain sets can do this from sprockets being slightly off center and you don't want to run it. Cloyes has been the best for me.

 

[Husker6.5]

Be glad it's not a MOPAR B or RB block with those damned nylon cam gear teeth! Had to replace the timing chain set twice on my 360 powered '72 D100 Adventure Sport from the nylon teeth breaking off the cam gear!

 

[Newguy1998]

These engines generally run great up to the moment they let go: with zero prior warning. One other note when you are putting the timing set on they slide on together and are very tight from the chain. This is normal. What's not normal is spinning the engine with the chain and having it go slack - tight - slack. "B" brand chain sets can do this from sprockets being slightly off center and you don't want to run it. Cloyes has been the best for me.

Since this was an easier job that I expected I'll be putting in gears from Leroy once funds are available.

Does it matter what direction the chain goes in? Is it marked?

 

[WarWagon]

Only the sprockets matter. Chain is like a tire and goes on either way. Whitewalls in or out?

 

[Newguy1998]

Sooo,
My guess is the chain has been loose for a while. Eventually breaking and wearing a hole in the cover. I hope to have the gear and chain off tomorrow after I find a puller. At least I finally found my mystery oil leak.

 

[Will L.]

Wow, seen that only 2 times before. Fingers crossed no other damage.

Unfortunately looks like the head job should have been a minor rebuild.

 

[Newguy1998]

Wow, seen that only 2 times before. Fingers crossed no other damage.

Unfortunately looks like the head job should have been a minor rebuild.

Minor rebuild? I don't follow...

Hey, you would know. I found a parts engine, ds4 out of an H1. Unknown date code. Will the timing cover be the same?

 

[Will L.]

Yup, it will work.

The minor rebuild was just saying if everything was done at once-

 

[Newguy1998]

Yup, it will work.

The minor rebuild was just saying if everything was done at once-

I know what you mean, I'm getting awful good at tearing down a 6.5. And Have a few "well used" 13mm & 15mm sockets. I appreciate all your help Will. Btw, I have a set of 4 genuine gm '98 c/k truck + diesel repair manuals, and what your sent me is waaaaay better...

 

[WarWagon]

Will meant "Overhaul" - Fix what broke and freshen up known wear items like rings and the chain. A rebuild with machine work on a 6.5 is cost prohibitive when you can get a new Optimizer longblock.

 

[Newguy1998]

Will meant "Overhaul" - Fix what broke and freshen up known wear items like rings and the chain. A rebuild with machine work on a 6.5 is cost prohibitive when you can get a new Optimizer longblock.

Maybe when you guys get one. By the time I pay exchange, GST, duty and freight, it is easier for me to get a rebuilt from a local engine builder

 

[DieselSlug]

DO NOT ROTATE THE ENGINE!!! You may be lucky. Your timing set may be broken or hanging on by a thread. You need to know before rotating the engine.

When you are looking at (you have torn the engine down to) the timing set aka the suspect chain you can decide what needs to be done. You either lost one part of the double roller chain and it's still hanging on or you have a completely busted chain where rotating the interference engine is just going to bend valves. If the chain is completely broken you may as well pull the heads or engine as some of the valves/pushrods are going to be bent. You may be lucky and had the chain snap on shutdown and didn't bend anything. This is why rotating the engine is a BAD idea: don't do more damage. (Valves are expensive per each.) If you do rotate the engine rotate it in it's normal rotation NOT BACKWARDS! Any loose parts can do damage going the other way or decide to snap from a different tug.

When you can tell what is going on then and only then can you spin the engine over to TDC making sure the cam is rotating with the crank. (A key could have sheared off as well.)

As an aside this broken chain may be from the past with a lazy mechanic leaving FOD in the oil pan. Replace the chain anyway because you are there and it stretched out. You can inspect the chain completely with just the water pump removed. Then and only then continue teardown if required. You may only need to remove derbis from the oil pan from a past repair.

Timing is easy : line up the marks with each other on the sprockets. Then line up the marks on the IP gears.

EDIT: Didn't realize Newguy already tore into it!

I second this. Timing is almost stupid easy if your don't unbolt the IP from the front cover you will be removing. Each sprocket has dots on it for lining up.

As you can see here I left the IP on the cover. I couldn't clean it as well as I wanted but I didn't have GMTD Scan back then. The IP pulley can only go on one way. Just make sure you go out and get the torque specs for the job. It is gonna be time consuming, id say a solid weekend job for the backyard mechanic.

 

[Newguy1998]

I marked the top of the IP and cover with a punch in a feeble attempt to keep the offset close all the while knowing it would need to be redone. Especially since I have to replace the cover, which I found for $75 at a local wrecker. I ordered new sprockets they're not going to be here till next. Gives me time to install my new transmission cooler and WT grille.

 

[WarWagon]

Love to see pics of the failed chain.

 

[Newguy1998]

Love to see pics of the failed chain.

Hope to have it off today sometime, I'll post them asap