Roller timing chain on a 250

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This question might sound overly simplified, but I was under the impression that the inline 6 gained a lot of its smoothness from a balanced valvetrain. Even accounting for a wilder camshaft, it would seem that if a valve is opening, another is closing and so it would seem irrelevant whether the spring seat pressure were in the 400s or even beyond.

Not to discount the importance of having a true roller timing chain at all, but is spring seat pressure the reason? I'm very interested in the thread as I may very likely follow in your footsteps. I'm just asking how valve spring pressure should impact stress on the timing chain.
 
bluestang65":pbof0ali said:
This question might sound overly simplified, but I was under the impression that the inline 6 gained a lot of its smoothness from a balanced valvetrain. Even accounting for a wilder camshaft, it would seem that if a valve is opening, another is closing and so it would seem irrelevant whether the spring seat pressure were in the 400s or even beyond.

Not to discount the importance of having a true roller timing chain at all, but is spring seat pressure the reason? I'm very interested in the thread as I may very likely follow in your footsteps. I'm just asking how valve spring pressure should impact stress on the timing chain.

The stock spring pressure on a 250 is somewhere around 150 lbs open. I don't have to tell you that the mechanical "lever" that pries open that spring is the timing chain. Given that the timing chain that Ford so wisely chose to install, and the little metal chicken peen dowel on the cam to keep it properly clocked is barely adequate, it becomes a necessity when increasing the spring pressure by 2.5 times. The stock chain, prone to stretch is also reponsible for keeping the "event" timing accurate of when those valves are supposed to open, and close was/is further incentive to go through the [*]hell[*] of making a better mouse trap.

[*] Really??? You cant even say H *ll here?
Don't big boys play here too?
 
Econoline":2fixghsm said:
Come on Mike, I think this is awesome! I'm in awe of what your doing with that 250, way beyond my skill set. Over the top :beer:
I agree. It'll be interesting to see dyno results
 
Hello Mike. I just discovered this thread and read through it - very interesting. I usually hang out on the 240/300 forum and neglect the rest. Your build-up reminds me of some of the issues I had to work through to put a crossflow head on a 300 (oil pan, damper, keyway, valve springs, rocker arms, valve cover, yadda, yadda). I missed a lot of what plans you have for the vehicle, what type of vehicle, etc. so I don't know how high you plan to rev it, how much boost etc.

Did you ever consider a belt cam drive like a Jessel setup?

Some 300 racers who run crossflow heads to the extreme have bored the cam journals to a larger size, enabling a larger base circle on the lobes and a stronger cam in bending. With extreme spring pressures the cam billet has a tendency to deflect and not deliver the advertised lift to the valve. They also add additional bearing supports inside the block. Not saying you'll need all that (some of those guys have valve lift in excess if one inch!), just an FYI.

Good luck with your project. I for one find it interesting.

EDIT: I JUST READ YOUR VEHICLE DESCRIPTION ON YOUR SIGNATURE LINE
 
Two or three companies make the old APT Fast conversion (http://www.aptfast.com/)

with "white box" vernier adjustable belt drive kit for the venenerable A series 948/997/998/1098/1275 Mini Austin Healey Sprite MG Midget Morris A30. Since the Ford 200 uses the BMC A series double roller timing chain set, an easy swap.

The extra space in the 250 cam to crank distance would require a new Titan or Pirelli Isoran belt, but its doable

1.TRIGGER http://picclick.com.au/vernier-adjustab ... 39617.html

2. West classic Belt Drive Conversion Kit CAJJ3328 from http://west-classic.ch/data/documents/AH_2.pdf

3. MINI SPARES KIT http://www.minimania.com/Adjustable_bel ... _C_AJJ3328

Both use a Titan or Pirelli Isoran/ Innocenti Mini belt kit
 
Mike1157,
Funny that this is the first time I've seen this tread!! It's been here for 2 years and it just got bumped to the "new posts".

I would've commented on your timing chain way back when for sure! Nice to see someone else give that a try! I assume it was a success?

The one in Kelly's car is still working just fine!

Later,
Will
 
Will, since this topic has come up time after time recently, could you or would you create a sticky as to how you did it or make a link to your original thread discussing it. Thanks!
 
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