Good day all,

I recently replaced the valve seals on my '66 Toro's engine and while I was doing this I remembered to check for slack in the timing chain. A procedure was recommended to me, on here, a while back so I checked it out. I rotated the engine CW by hand until the timing mark on the balancer lined up with 0 degrees on the pointer and then I rotated it CCW and watched for movment on the rotor. As soon as I saw movement, I checked the balancer and the mark lined up with about 8.5 degrees. I assume this is a pretty slack timing chain? How much would you say is too much? I would guess that my ignition timing is also thrown off a bit because of this? I have noticed that at the factory spec 7.5 degrees BTDC spec isn't quite right for my car and it definitely prefers to be advanced a bit.

It's definitely the original nylon timing gear in this car because I know the full history of the car. I would suspect that the nylon is deteriorating pretty significantly at this time and causing the loosness in the gear. I think I'll run the car as is for now but will plan on changing the gear set out next fall. Just wanted to get your opinion on the slack in the gear. Thanks!

 

Seen worse than 8.5° The biggest concern is the nylon teeth breaking off clogging the oil pump intake screen and/or the chain jumping a tooth causing valve to piston interference. Some will say it won't happen,

The ignition timing can be corrected by turning the distributor, the valve timing becomes retarded due to chain stretch which cannot be adjusted. Put it on your calendar to replace. I don't know on a Toro how hard it is to pull the fuel pump but if it isn't overly difficult the nylon gear could be viewed via a borescope through the fuel pump rocker arm hole in the block.

How many miles on the engine? Was it clean inside under the valve covers? If it is clean and under 100k I wouldn't sweat it right now.

 

It completely slipped my mind to check behind the fuel pump. I had it off and I've also got a fancy articulating borescope......missed opportunity there!

80,000 miles on the engine and extremely clean under the valve covers ( I think anyway). See my pics below that I took before I put the valve covers back on.


Drivers side 1

Drivers side 2

Pass side 1

Pass side 2

 

Clean and at 80K, my position is to plan on replacing the chain and gear set but I wouldn't hesitate to drive it; however, it would be best not to run it extra hard. If the engine was 10 years old with 80K it would be a different story but the concern now is the age of the nylon teeth on the cam gear causing them to break off.

 

Interesting to see the A.I.R. tubes in the heads for what I guess is the California emissions system. Not something I am familiar with.

 

Oh man, they're such a pain in the ***. I had to remove the exhaust manifolds recently and those buggers made it so much harder, especially on the passenger side where there's less clearance. The front of the engine, on the driver's side, is just full of pipes, checkvalves, and hoses for that system. I'd really like to get rid of it.

 

The non-AIR motors use a differently calibrated carburetor. Aside from that, finding plugs for the holes in the top of the exhaust ports may be difficult.

 

Yeah, I've got them all here. My car came with the AIR carb Qjet PN 7036250 and I've got both the standard Toro Qjet PN 7026250 and the early 70's 1966 Service Replacement 7041312 Qjet on hand. I measured all the calibration points with a precision drill set and the differences between them are so small that they're pretty much the same. The only big difference I can find is that the 7036250 AIR carb has an adjustable idle air bleed as opposed to the fixed idle air bleed on the 7026250. The serv replacement, however, does have this adjustment (it's under a triangular clip on the internal vent).

 

There is a reason the Ford 300 inline six runs forever, and that is because the cam is gear driven like most industrial engines.
I installed a metal gear set, and enjoy the whine.

I think it was 2023, I had to fix a timing cover coolant leak on my Ford 429 engine.
I wound up buying a Summit Racing new timing cover.
In the process, I looked up the acceptable timing chain slack, which seems like it was around 5/8-inch slack side.
Well, the 429 slack measured near to 1-inch, so I installed a new Cloys roller timing set with metal gear teeth.
I did not attempt to see what kind of degree of rotation to take up the slack on the old or new.

 

The Tornado got the extra wide timing gear/chain set.

 

Don't think I've ever seen an "extra wide" timing gear/chain set for an Olds motor. I am familiar with a "heavy duty" timing chain for them that Mondello, and probably others, had.

 

I’ve only ever found the wide sets on Toronados. they were never apart either. Here toro on left and the normal on right

 

That would be cool but they're supposed to be the same as the other Big Blocks. Maybe they're all bigger in that group? Never know though, lots of weird differences in the Toronado world. Maybe I'm missing something.