Roller timing chain for 250

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ausxb":3q8l2unj said:
Mike the Dowel pin is 1/4 inch diameter. Here in Aus I went to a local bearing company and bought a 1/4" roller and cut it to length and pressed it in the hole. Now I have a hardened dowel pin. Another thing to ponder the cam gears are an interference fit and need to be pressed on. The dowel locates the gear and the retaining bolt stops the gear coming loose. Hope this helps.

It does. Since I'm modifying the cam gear to fit, I can have my machinist cut it just shy of sliding on, so It'll become a press on.
 
I knew the 240/300 used a keyway and assumed the 200/250 did also, and the SBF used a dowel pin arrangement. Just didn't know which setup you were trying to follow with this approach.
 
The stock 250 US crank has the Windsor 221/255/260/289/302/351 and 335/385 series 351C and 429/460 crank snout of about 1.375, while the Aussie 221 and 250 I6 has the same crank snout diameter as the 144/170/187/200. That's a nominal 1.244 less a tolerance, similar to the small block Chevy V8 which is 1.255".

We have the

1. US 250 56 link 1 and 0.625" wide 42/21 teeth system
2. The US 144/170/200 50 link 42/21 system
3. The Aussie 200/250 52 link 42/21 system
4. Does 10's 56 link, 42/21 teeth system
5. Balldricks Ridgecrest Gear drive
6. And now the HSC 46 link 34/17 system


See "The 250 Timing Chain" http://www.fordsix.com/forum/viewtopic. ... 76#p547876, which includes "SBF timing set installed on Kelly's 250!"

and "US 250 Owners: Nuclear Timing Chain HSC/US 250/Oz 250" http://www.fordsix.com/forum/viewtopic. ... 64#p547664

The differences are itemized intimately.
 
Correct me if I'm wrong...but isn't it impossible to have a "57 link" chain?

I'm under the impression that Does10's chain is 56 link.
 
397-M-6268-A302.jpg



Ooops, you are awake, that's right, one link has two prongs, So one link less than 58 pins is actually 56 pins, not 57...dough

Normal name/sign convention for chains is

fig-1.1.gif




Edit time and penance from me :banghead:
 
Personally I hate welding on anything machined or trying to machine any weld. Have you finalized any plans yet? Did you find a pin with your cam? The stock US cam holes and pins seem to be about 5 or 6 thousandths larger than 1/4". What is yours? If you do decide to retain stock locating arrangement it looks like the best place for the keyway would be opposite the V8 dowel pin and maybe away from the oil slots. Wouldn't hurt to make the pin taller than stock making sure there's no vertical clearance or side clearance also to allow the pin to roll over. It looks like a letter F drill looks to be about the right size. You'd have to check this with what you have. I have used cobalt drills on some very tough material. Seems very tough and resilient. That might be a source for a pin.
 
I am going to have the cam gear opened up to the 250 cam snout size. I haven't looked for the pin, I figured it was a throwaway even if he supplied me w/ one. How would I know whether the pin he supplied me with (if he did) is hardened or not ( smack it w/ a hammer?)

Right now, I'm finishing my intake, so I haven't given it too much thought.

The objective will be to use whatever hardened pin I can find that fits the hole. If that happens to be a "F size" cobalt drill bit, then all the better,..I'll be able to source one at Fastenall. I was hoping to broach the existing SBFcam dowel hole in the new gear to act as my keyway for that drillbit dowel,....but if the hole is too big, then I guess I'll have to clock the gear 180 degrees, and cut the keyway opposite the existing dowel pin hole.
 
You can test the hardness with a file. If the dowel is hardened, you will not be able to even scratch it with the file. The same is true for the cam, it is going to have a Rockwell hardness the same as a bearing race or more, and you are not going to drill it, you will only be able to EDM a hole in it. I think im still a little fuzzy on what the new roller cam uses for timing gear indexing. It has a snout like the 240/300, but uses a dowel pin like the SBF instead of a keyway like the 240/300. So there is no keyway seat cut into the cam snout at all? If not, there is no need to broach a square hole in the timing gear, you will need to drill a round hole in the timing gear to match the round dowel pin
 
CNC-Dude":1u4ep2f9 said:
You can test the hardness with a file. If the dowel is hardened, you will not be able to even scratch it with the file. The same is true for the cam, it is going to have a Rockwell hardness the same as a bearing race or more, and you are not going to drill it, you will only be able to EDM a hole in it. I think im still a little fuzzy on what the new roller cam uses for timing gear indexing. It has a snout like the 240/300, but uses a dowel pin like the SBF instead of a keyway like the 240/300. So there is no keyway seat cut into the cam snout at all? If not, there is no need to broach a square hole in the timing gear, you will need to drill a round hole in the timing gear to match the round dowel pin
There is a hole drilled perpendicular in the snout of my roller to accept the dowel pin that us stick on 250.
 
Well.
I guess I now have "cause for concern".

All I've heard is how un-machinable, and how "diamond hard" the cam, and it's related surfaces are gonna be.

Taking CNCdudes last reply on how to do a hardness test on a potential cam dowel,..I decided I'd try the same on the cam snout. There
is a ragged edge at the dowel pin, so I thought I'd attempt to smooth it w/ a mill file.

Now only did the file smooth the burrs, I could easily cut a notch in the surface just by turning the file on edge

z0kw.jpg

This isn't even 30 seconds of deliberate work.

The front cam journal where the SBF dowel pin would have to go?
12on.jpg

That wasn't a 5 count using only light pressure and a new high speed steel (not cobalt) bit in my hand drill.

Now, given that i have this cam, that I can file the snout w/ a standard mill file, and drill the front journal w/ a standard bit, a hand drill, and light pressure,..do I have cause for concern here?
 
ANNDD
I get my 56 link chain from the supplier in Washington. He says that this is the "good India chain", but from what I know about chains, the Dido chain that came w/ my set looks superior to the 56 link India special. So, all in all I got this butter soft cam, and this india chain w/ what looks almost like roll pins holding the thing together. I feel like all I need now is a fuse and a match to set this bomb off.

lvxq.jpg
 
Yes, I would be concerned it is too soft. I have had cams that had a very sharp edge on the side of the lobe that needed deburring and it would just laugh at a file, and I had to use a cartridge roll abrasive to knock off just a tiny burr. I would call Comp or Crane and see what they would charge to check the hardness of it to make sure you don't have any lifter/lobe wear issues ahead of you.
 
CNC-Dude":391dpbq4 said:
Yes, I would be concerned it is too soft. I have had cams that had a very sharp edge on the side of the lobe that needed deburring and it would just laugh at a file, and I had to use a cartridge roll abrasive to knock off just a tiny burr. I would call Comp or Crane and see what they would charge to check the hardness of it to make sure you don't have any lifter/lobe wear issues ahead of you.

There is a place here that can do that for me I believe. Was there anyway that just the wear surfaces were hardened, and not the whole thing?
 
Usually when cams are copper plated, that masks areas where the heat treating is not needed to penetrate but just a certain amount. But for cams that aren't copper plated, it is probably equally heat treated all over, and should have a uniform hardness everywhere, even in non-wear areas. I would at least call Comp or some of the others and ask what Rockwell scale and hardness their roller cams are, then you'll have something to compare against.
 
Tighe Cams Induction harden the lobes and journals so you have .080-.120" depth of hardness around your lobes & journals. Unlike the copper plated cams that are case hardened maybe .020". Also the material they use is 5160 steel which is a tough material. So where you have drilled is not hardened and that shoud be OK. Hope this helps.
 
Our roller lifters here in the US are designed for 8620 cams. Hope their compatible with the Oz cams for Mike's sake. Thanks for the info ausxb, that just made up my mind which direction i'll be going with my cam.
 
The Lifters will be fine on Mikes cam. I was also thinking about you hardened locating pin and would be loathed to use a cobalt drill for that purpose. If you use a needle roller it is much stronger. Try this, put a long needle roller in a vise and try to bend it with pliers or something it will bend, then put a cobalt drill or a carbide drill in the vise and try the same, I think you will find the drill bits break very easily. Being super hard usually means super brittle. Hope this helps.
 
ausxb":2hhr4kpx said:
The Lifters will be fine on Mikes cam. I was also thinking about you hardened locating pin and would be loathed to use a cobalt drill for that purpose. If you use a needle roller it is much stronger. Try this, put a long needle roller in a vise and try to bend it with pliers or something it will bend, then put a cobalt drill or a carbide drill in the vise and try the same, I think you will find the drill bits break very easily. Being super hard usually means super brittle. Hope this helps.

Thanks Ausxb. I was asking CNCdude whether that process is actually possible. Now I'm not gonna go trying to file a cam journal just the same, but I sure hope that you're right about the hardness of the wear surfaces.

As for whether or not I use a hardened drill bit as a dowel, that just now became a mute point. I can walk into my area engine parts supplier, and buy the proper hardened cam dowel for the SBF application cam gear now that that option just opened back up.
 
emailed Dean Tigue concerning the cam, this is his reply. Good enough for me. (y)

Good Morning ,
The fact that you can machine the camshaft in that area is normal.
Heat Treatment we use is Induction Hardening,
This is a heating and rapid cooling in areas that need to be hardened only.
So the lobe and the journals will be around the 60 – 62 Rc hardness.
The rest of the core will be around the 32Rc Hardness, This is a little softer than a high tensile bolt.
If you are drilling the hole make sure you use coolant and keep the drill sharp.
The material we use is 5160 and it does work harden very quickly, and then you will need a carbide drill.
 
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