When I rebuilt my engine, I noticed the timing chain had a bit of play. I unfortunately did not change it since I was in a rush to get it back together. Is this play too much? What would the symptoms be? Any affect on power or mileage? I am having a rough idle and knocking noise, but I think it is unrelated.

If I change the timing chain, do I also have to change the gears? Or can I keep them if they look to be in good shape?

 

Dealer's choice, but I have always replaced them as a set (gears & chain)...just because I don't want to have to go back in. worn gears/stretched chain will most likely show up as retarded or advanced timing and if warn enough could jump teeth and that could definitely cause rough idle, etc.

Lucky8 has the set for like $65: https://lucky8llc.com/collections/di...-chain-set-kit

 

Change them, they are toast. Always change gears and chain at the same time, no if, ands, or buts. A rough idle will be the first clue of bad chain/gears. Rebuild my 03 and 04...both had about 135K and rough idle prior...cleaned the idle right up and acceleration.

 

I agree that the chain should have been replaced, but I wouldn’t worry about it until a convenient time. A sloppy chain will affect valve timing and power. I’m not sure if fuel economy will be affected much. Chains rarely fail outright though. Also, while I agree in principle about replacing the gears, my understanding is that the available gears are not very good.

 

Unless the gears are OEM NOS I wouldn't trust a single Britpart or AllMakes4x4 Chinesium Timing Gear! I have "attempted" to install several all were either formed wrong or were not true. New chain yes (also be careful of the Chinesium crap) Made In Mexico I'd trust a lot more than the crap I've seen coming over on the boats lately from China.

 

FWIW, I just replaced this chain because I dont expect to be in there again anytime soon.

I did NOT replace the cam sprocket because the tab on the OEM replacement did not fit into the notch in the cam shaft.

Fortunately there was very minimal wear on the sprocket.

 

Big time changey change. I ended up ordering aftermarket sprockets, was appalled by the casting, and ended up going to the dealer of all places (right down the street and needed to keep moving) and got LR ones. Incredible difference in quality and this might be the last time you'll replace them.

Also just as an aside... this project is one reason why I just love these old boyes. The same procedure on any modern car, even my L322 that's using a 90's derived engine, is SO involved. This adorable engine is just so easy to love with its simplicity. No tensioners, no phasers, nothing about it is super buried. Just an honest couple sprockets and a simple chain.

 

I have a D2 and a P38. They have to be the easiest vehicles to work on that were sold in North America in the last 30 years.