The 250 Timing Chain

[Econoline]

I know this has been discussed and I have read through all the various topics posted regarding the timing set for the 250 but I am still a little confused. I want to replace my timing set so I've been looking into it. My 250 is a '70 and I understand I want a pre '73 chain.

There has been a lot of discussion that the available sets are all late era retarded. But when I look for a set I find 2 different sets available from at least 2 companies and probably sealed power as well(with a couple of hitches ). First are the ones available @ Autozone and Advanced Auto and maybe elsewhere, the "SA Gear" #73083 @ $38 for '69-'72 250 & #73016 for '73 on. Next is Cloyes, while no set is available for '69-'72, parts can be bought to make a set those being #C363 chain, #S415 crank, and #S414 cam @ ~$70. The '73 on is available in set #C3016 with the only part difference being the cam sprocket #S442 vs S414 for the early version.

To complicate things further, I present these 3 pictures, notice the "SA" in the casting.

Cloyes S414:

"SA" late:

"SA" early:

On the "SA" late set, if you look close, you can see S442 on the cam sprocket as well as "SA" and so on and S415 on the crank sprocket showing that this "SA" set is in fact Cloyes, the difference may* be in the chain which may* be a Cloyes C354 which is a cheaper chain than the C363. If you look at the "SA" early set it has the S415 sprocket but the Cam sprocket is completely different, and not the S414

Any light any one can shed would be great. At this point I think I'll just peice meal an all Cloyes set together with the C636, S414, and S415

I feel like Mike Myers welcome to schprokets

 

[xctasy]

Does10s awesome post on the "one link less" reversed SBF Double Roller timing chain set was a delight. It covers off the two kinds of 250 timing chain. The part numbers are just a back drop, there is an early narrow timing chain, and a later wide one. That's all you really need to know. There were three types of cam retard via the crank sprocket, and two similar sprockets can be listed differently due to the sproket retard, which is a mandatory aftermarket supplier requirement.

viewtopic.php?f=5&t=58314&p=447439&hilit=SBF+Timing#p447439

You can either get the early "straight up" version, or the "retarded" later one. Both are junk.

Later,
Will

{quote="drag-200stang"]Will,

You're not doing anything wrong. When I was working with Ak Miller on my turbo set up, he asked me why don't I try a larger 250? and I asked him which engine had the least amount of vibration problems. He said the 250 had problems with timing chains and the early narrow one was better. That was almost 35 years ago and they still have problems.

Broncoman,

It's the longer stroke that causes the chain's problems. When the engine is under heavy load and high rpm the crank tends to whip back and forth. It's the nature of the long crank shaft and the long stroke with the 120 deg. firing cycles.

Like I mentioned in another post, the 200 uses the same cam. I use a high volume 250 oil pump (custom made) and have run stiff springs and pretty wild solid lifter cams with no chain issues at all. The chain is, of course, shorter. But the 302 doesn't seem to have issues and they are a link longer.

Will, your set up looks nice, good luck with it.[/quote]