200 vs 250 balancer

m in sc":1t7asac8 said:
no, crank end sizes are different.

what IS the end size?
I would like to have the end turned (on my 250) to mount a double chain/gear from a 200.
* Would the tc cover from the 250 still fit?
* Do U think a specific year set would be more desirable (as in the '69 set is better for the 250)?
 
chain length is different, and the 250 chain is super wide compared to a 144-200. (fail to see need for double roller)I have anew chain coming from cloyes for my 250 actually, today.

seems like a lot of work to fit a balancer. why not get the balancer bored out, and have anew keyway cut in? would be cheaper i am sure,
 
Ford made the changes because of when they tool up for parts, the line managers look if the any new comming part will fill the design requirments. An existing part, mixed with another, amortizes the cost of a whole new part. So if Ford had, say, firebrand head or parts scheduled for a 351 Cleveland, they would preview the parts in , say a Boss 302 before the first year.

what IS the end size?
I would like to have the end turned (on my 250) to mount a double chain/gear from a 200.
* Would the tc cover from the 250 still fit?
* Do U think a specific year set would be more desirable (as in the '69 set is better for the 250)?


Nominal 1-3/8" diameter crank snout for US 250, a nominal (and unique!) 1-1/4" for everything else small I6 (144-170-187-188/3.1 liter-200-221/3.6 liter-Aussie 250, Ohc 3.2, 3.9/4.0). I4 OHV 2.3 and 2.5 liter crank snout is the same.

The US 250 is common to the Cleveland/335 length, and SBF Windsor/Cleveland/335/BBF (FE/FT/385 Lima) crank snout diameter.

The us dampers are 5 3/4 for the pre 78 200 engines, and 6 1/4 for the 78+200. I think the 250 might have had two sizes as well.

The 250 out ring is the 200 outer, but the innner ring is different to suit the longer water pump snout and bolt and crank diffrences. The bolt on the 200 is 9/16" with nominal 1-3/4" long thread, while the 250 uses the SBF Windsor/BBF (FE/FT/385 Lima) bolt.

In addition, Ford Dearborn had some pretty strict durability matters, and the use of the V8 crank snout has torsional vibration reduction and durability advantages ffor the US 250 engine. With respect to using the SBF Windsor cam chain, it is a good move!. The 250 previewed the first of the long snout water pumps (later adapted to the Aussie 3.3 and 4.1, and US 1978 on Fox 200/3.3). The long snout water pump allows the triple and quad belt ancillary drives to fit the air pump, a/c, power steering and dual belt alternator and water pump drive.

The inner part is all you need, you can get them used, and have the later 200 outer rebound to the 250 inner. Ford Dearborn are masters of the parts scramble, but it works, and you've just gotta find the right parts.
 
xctasy":34gm5d9t said:
Ford made the changes because of w...nd you've just gotta find the right parts.

humm...a lill 2 complicated 4 this duffis

I thought I could fit a double roller timing chain & it's gear (which the 200 has) to a 250 (which is unavailable) 4 added 'low rev grunt' by having a machinist turn (lathe) down the larger diameter of the 250 to the smaller 200 & re-grooving a keyway onto it...
 
Nien, nien. Duffis smuffis. :nono:

Nah uh. Its a little bit too simple! 302 timing chain reversed? Easy! Click on this Chadmister!



Sorry, the gear drive, its Diecrest Engineering.

Just too simple to machine a crank part down to fit a commerically available sprocket part. Its around, it works. Its simple to adapt. Anything else is just bull pucky. 1.375" vs 1.248" on the crank shoulder is easy to machine down. Or the internal part can be broached up 1/8". Choice is yours.


viewtopic.php?t=56560
balldrick":20bhu03o said:
Well got my bottom end together today. Went pretty well, had a problem with a bottom oil ring it bent and i noticed a rub mark when i turned the motor over. (The one thing ive learnt is dont by cheap tools).Heres a couple pics.200 rods with 4.6l rover stroker pistons.
Diecrest eng. geardrive.
engineb.jpg


balldrick":20bhu03o said:
JackFish":20bhu03o said:
So tell us about the gear drive...
Gday JackFish, Its from a company here in Aus called Diecrest Enginering it was advertized to fit the 250 crossflow but as you can see it fits the Aus 250 pre-crossflow as well. This one is adjustable thay also make a non-adjustable a bit cheaper. It seems well made and the only mod needed is to file a slot in timeing cover. I dont know if they will fit the American 250?
 
ahh, a 302 chain? Remove a few links? What's the other components (& processes)?i Diecrest Eng. &...
Does the oem timing cover still fit ?

The 2nd pic - gear drive (al la 300/4.9) isn't for Sarah (the '70/'77 bronk).
 
chad":1e03y1x3 said:
ahh, a 302 chain? Remove a few links? What's the other components (& processes)?i Diecrest Eng. &...
Does the oem timing cover still fit ?

The 2nd pic - gear drive (al la 300/4.9) isn't for Sarah (the '70/'77 bronk).

All questions answered. :beer:

viewtopic.php?f=1&t=60577
dayman":1e03y1x3 said:
What is the best timing chain set to use for a 250?

Do any have a crank gear with multiple keys to allow for advancing or retarding camshaft?

If not, how do you degree the cam?

Thanks


See viewtopic.php?f=3&t=63577&p=486127#p486127

Does10s":1e03y1x3 said:
Definately not the same. The center to center of the crank to Cam is the same distance I believe, but the crank snout diameters are different.

I did a SBF double roller timing chain swap on my Wife's Falcon with a 250. There's a tread on here somewhere with the specifics.
It's isn't a bolt in set up for sure. It will take some modifications.

But it seems to work very well!
Later,
Will


and http://fordsix.com/forum/viewtopic.php? ... ng#p447439

Does10s":1e03y1x3 said:
Well it looks like this is going to work! Kelly's shortblock is reassembled! It's not running yet, but will be in a few weeks. She races again Labor Day Weekend.

I've been at this for awhile waiting patiently for my machine shop to finish up the required machine work.
Anyway here's what I did to get this to work. This is NOT a bolt in!
1. Turned the cam snout down to match that of a SBF.
2. Drilled dowel pin hole into first bearing race journal just like a SBF.
Clay Smith should be able to do the above two items if you special order a cam from Mike. (I just used our cam)
3. To get the sprocket-to-sprocket alignment correct, we removed .050" from the crank. This allowed the crank sprocket to move further aft.
4. Installed the crank sprocket backwards. Yes backwards. Again for alignment. (makes for real fun degreeing! :unsure: )
5. Fabricated my own thrust plate. The SBF cam sprocket needs a thrust plate that is .250" thick. I Just copied the 250 one and increased the hole size to clearance the dowel. I have a radius of .118" worth of thrust plate holding the cam in the block. This is probably sufficient, but I'm going to fab up a "cam button" out of SBC version. Just for insurance.
6. Shortened the chain by 1 link.

Note the counter sunk thrust plate bolts. This was to clear the roller bearing billet sprocket. Also note the very long crank woodruff key.
http://memimage.cardomain.com/ride_imag ... medium.jpg
Now we have a double roller, billet cam sprocket, multi-indexed crank sprocket with 9 keyways, and we no longer have that stupid little dowel pin!!!
http://memimage.cardomain.com/ride_imag ... medium.jpg
Bigger pics athttp://www.cardomain.com/ride/686815
I'll let you know how it goes!
Later,
Will
 
m in sc":1387oov7 said:
that for a us spec 250?


The Small Block Ford 289/302 timing chain conversion is for the US spec 250. See the red engine above, Mike1157's

Nominal 1-3/8" diameter crank snout for US 250, a nominal (and unique!) 1-1/4" for everything else small I6

(144-170-187-188/3.1 liter-200-221/3.6 liter-Aussie 250, Ohc 3.2, 3.9/4.0). I4 OHV 2.3 and 2.5 liter crank snout is the same.

The gear drive in the Phantom Menace Purple engine is baldrick's, for the Australian spec 250, which also only fits the 8.425" block 188, 9.38" tall deck 200 and 8.425" tall deck 221. Each of those has a cam spaced out further from the crank.

That's it. The Australian 250 crank is basically just the crank snout diameter different from the US 250. (There is one other minor, non issue difference, the thrust bearing). Grind the crank snout down from 1.375 to 1.248" snout the US 170 and 200 uses, recut the keyway and the Diecrest Geardrive will fit the US 250 crank.
 
gotcha. seems like a whole lot of work for a double roller chain, especially as large as the stock 250 one is.

is the benefit the indexible gear?
 
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