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6.5 timing chain replacement question

E

elimclamb

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clayton, nc
Hey guys. I just bought my first diesel a few months ago. It is a 1994 6.5 td. I had to replace the oil pan gasket and I noticed that the timing chain was pretty sloppy and loose. I don't feel like it has the power that it should so I figured this would be a good start by installing a double roller chain on it. I'm pretty good with a gas motors and I've changed plenty of chains on them. Is there anything special that I need to know or is it just as simple as lining the timing marks up? I know there is the ip gear too. Do I need any special tools etc? Thanks in advance!
 
Welcome to the board. There are alot of very knowledgable peeps here. I´m not one of them. I thought it was pretty straight forward. I would replace the chain with a complete timing chain kit and do the harmonic balancers at the same time. Oh and the water pump too. g
 
Welcome.

Timing chain looseness on 6.5 and 6.2 diesels is more or less normal after 30K miles. They do not stay tight very long! Honestly 'why bother'? High mile engines usually have cracks in the blocks and need major work. Best to leave it alone.

To get power you need to adjust the timing to make up for the standard chain slop. Then check out everything like the lift pump operation etc. Then get rid of the restrictive GMx turbo for a bigger one, exhaust system to 4", and get it tuned.
 
Thanks for the input. It only has 175,000 miles. I figure it should last me a good while longer. The chain was really loose. Would a cloyes double roller set hold up better than other brands? What do you need to adjust the ip? Do you need a computer or can it be done by just adjusting it by hand?
 
Cloyes is the best chain from what I've heard.

www.pmdcable.com has GMTDScantech for the 94-95 yr trucks, it's the best bi-directional scanner available to time these trucks
 
WarWagon said:
Welcome.

Timing chain looseness on 6.5 and 6.2 diesels is more or less normal after 30K miles. They do not stay tight very long! Honestly 'why bother'? High mile engines usually have cracks in the blocks and need major work. Best to leave it alone.

To get power you need to adjust the timing to make up for the standard chain slop. Then check out everything like the lift pump operation etc. Then get rid of the restrictive GMx turbo for a bigger one, exhaust system to 4", and get it tuned.
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good advice. mine was so sloppy that i had too much smoke from unburned diesel and i couldn't get it to stop. mine was straight forward.
 
It is reasonable to expect to re-gain lost power with a new timing set. After all it affects cam timing as well as injection timing.

If you've had success with doing timing sets on others, you will be fine.

Everything is the 'dot to dot' deal.

Cloyes is now made in china. I think Federal Mogul makes them as well. Do some investigating.

The 6.2 and 6.5 is a double row chain from the factory.
 
thanks for the helpful input! Will i even have to remove or loosen the injection pump at all? i know these questions may sound simple and dumb to you guys but i'm just trying to cover my butt before i dive into this.
 
I had 30K on my new Cloyes timing set when I pulled the engine back out for a screw clamp left in the intake incident. It was just as sloppy as the 175K chain that came out of two failed 6.5's. It stretched really quick and I had to reset the timing to compensate.
Cracks in the block and failed head gaskets are common on 200K mile 6.5's.

1/2" of slop is the go -no go spec from GM... yeah, that is a lot!
 
wow@warwagon. thats ridiculous! getting only 200k out of a diesel is pretty sad. why does anyone even buy these anymore if thats the case? at the cost of fuel and parts why even bother? a big block gasser last that long or longer!
 
elimclamb said:
wow@warwagon. thats ridiculous! getting only 200k out of a diesel is pretty sad. why does anyone even buy these anymore if thats the case? at the cost of fuel and parts why even bother? a big block gasser last that long or longer!
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WW beats the crap out of his trucks climbing 10% grades.
 
NVW said:
WW beats the crap out of his trucks climbing 10% grades.
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Understatement of the year! :thumbsup:

Some go longer than 200K, but, quite a few have head gasket issues around 200K. Cracking failures happen at any time, but, usually are found on tear down for other reasons.

Why own a 6.5?

I can get a replacement military 6.2 engine for $1200 with less than 30K on it. (a 6.5 is a bored out 6.2 and the heads are bolt on interchangeable with minor mods.)

My 6.5 gets 1MPG better than a modern gasser towing. 4MPG better with an A Team Turbo. So from 6MPG gasser to 10.4 MPG diesel with A Team Turbo is quite a profitable difference.

You can get a 6.5 truck cheap, drop 2K into it to fix it up plus a 1K turbo and tune and run with a early Common Rail Dodge.
 
Cloyes gears are Made in the USA. Their chains are made in China.

Does anybody know of a Made in the USA chain? 250,000 miles. I'll let it ride if my only option is a made in China chain. I just don't see much future in that.
 
If you want to do the timing once and know it will be exactly the same 200K later, go with a gear set, they don't ware and get loose.... everyone has pro's & con's about the gears, I for one like them...
 
I'd only use gears if I had a crack free WELL seasoned and freshened up block of a Navistar. Other wise I'm just gonna run my chain and if it looks REAL bad I might replace it. Maybe try new gears with the old chain? OEM chain is USA the gears also wear so maybe they can be replaced and take the slack back to normal.

On the other hand, on my hay baler I replace chains every year and run the original gears until one fails (very rare). Those are adjustable though.
 
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