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Volodkovich
Re: Ford F250 rockers
#12
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Quote:

nzdatman wrote:
How soon?


Aim is 1st June this year.

Quote:

lamb_daiquiri wrote:
Will you be regrinding old cams or producing brand new ones? It's better to avoid reducing the base circle too much as it increases the loads on the cam surface/ shortens cam/ lifter life.

Sounds like you've got all the gear to make new cams from some nice 4140 round stock, nitride them after finishing and they'll last a very long time. I was very impressed with the wear life of the nitrided 4140 gear I had made for a prototype at work. No good for my application though because it needs lubrication otherwise it'll destroy the mating part! (In this case a ss304 gear with 14x the number of teeth).


I will be doing both, although steel cams will cost a lot due to gear machining so I don't think they will be very popular - Not too many people want to spend $1000 on a cam for an A series when you can regrind for $200 and get the same result. I'll likely have two options, case hardened 8620 and through hardened EN30b tool steel. The problem with changing cam material is steel doesn't hold oil like chilled iron (factory cam) so you have to be careful with lifter material and compatibility with the cam.

Reducing the base circle does not increase the load on the cam. The nose radius does reduce for the same profile at a smaller base circle diameter (which increases nose stress) but this is easily countered by designing the cam profile's negative acceleration curve over the nose. I have never heard of cam wear issues on correctly reground & run-in A series cams.

Posted on: 2016/3/2 20:32
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ddgonzal
Re: Ford F250 rockers
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Quote:
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Can't get additional lift out of regrinds unless they first build up the lobes ...

Not true! ... You just reduce the base circle diameter (often smaller than the original cam core) and then machine the core to a smaller diameter.

Thanks for the correct explanation. I was wondering why anyone would even bother to offer a cam with less lift than stock

Posted on: 2016/3/2 8:34
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lamb_daiquiri
Re: Ford F250 rockers
#10
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Will you be regrinding old cams or producing brand new ones? It's better to avoid reducing the base circle too much as it increases the loads on the cam surface/ shortens cam/ lifter life.

Sounds like you've got all the gear to make new cams from some nice 4140 round stock, nitride them after finishing and they'll last a very long time. I was very impressed with the wear life of the nitrided 4140 gear I had made for a prototype at work. No good for my application though because it needs lubrication otherwise it'll destroy the mating part! (In this case a ss304 gear with 14x the number of teeth).

Posted on: 2016/3/2 8:28
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Chris39
Re: Ford F250 rockers
#9
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Hey guys.
Thanks. I rally appreciate the feedback.

Posted on: 2016/3/2 8:15
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nzdatman
Re: Ford F250 rockers
#8
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Quote:

Volodkovich wrote:


I'll be producing some top end cams with modern polynomial designs and CNC ground for the A series soon.


How soon?

Posted on: 2016/3/2 7:30
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Volodkovich
Re: Ford F250 rockers
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Quote:

ddgonzal wrote:

Quote:
just get a cam with some more lift
YES

The problem is many cams have less lift than stock. The more expensive ones have greater lift. Can't get additional lift out of regrinds unless they first build up the lobes, adding considerably to the cost, or using a NEW cam blank
* Stock A12 8mm lift (.315 inch)
* Stock GX 8.4 mm lift (.331 inch)
* JUN 74 6.5 to 7.2 lift
* Isky DB-88 .297 lift
* Isky DB-99 .338 lift
* JTS 104CB .409/.408
* JTS 140-6 .430/.432
* Wade Cams: .379 to .470


Not true! I have personally reground many factory A series cams to high lift (even the NISMO profiles) without issue. You just reduce the base circle diameter (often smaller than the original cam core) and then machine the core to a smaller diameter.

You are right about a lot of profiles having lower lift than stock though, mainly due to a lot of cam grinder's having no ability to make new profiles (they just use what masters they have and most of the time these are 30 years old).

I'll be producing some top end cams with modern polynomial designs and CNC ground for the A series soon.

Posted on: 2016/3/2 4:12
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ddgonzal
Re: Ford F250 rockers
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Some say 1.6 was a stock offering. I dunno. Been a long time since I messed about with a Falcon Six. Put many miles on a 1979 Fairmont, but it had hydraulic lifters

Quote:
just get a cam with some more lift
YES

The problem is many cams have less lift than stock. The more expensive ones have greater lift. Can't get additional lift out of regrinds unless they first build up the lobes, adding considerably to the cost, or using a NEW cam blank
* Stock A12 8mm lift (.315 inch)
* Stock GX 8.4 mm lift (.331 inch)
* JUN 74 6.5 to 7.2 lift
* Isky DB-88 .297 lift
* Isky DB-99 .338 lift
* JTS 104CB .409/.408
* JTS 140-6 .430/.432
* Wade Cams: .379 to .470

Quote:
If you are chasing 10/10ths you'd be better off with some aftermarket roller rockers.
Yes indeed. Rollers are good for fractional improvement due to reduced friction. High lift is good for major changes. The modern cam profile has fast-open, fast-close, high lift profile and doesn't rely on duration change only like those cheap regrinds

Lastly, if you are going to use 1.6 rockers, tell your cam grinder so they can choose an appropriate profile. Whether or not 1.6 works well with a stock cam is unknown -- you can try it and let us know after 20,000 miles if the cam, valve stem ends or valve guides are worn

Posted on: 2016/3/1 21:45
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Volodkovich
Re: Ford F250 rockers
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I thought the 1.6 rockers are aftermarket replacement only?

Mine look exactly as pictured above.

Posted on: 2016/3/1 19:48
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ddgonzal
Re: Ford 250 rocker arms
#4
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There are two variations:
* 1.50 ratio
* 1.60 ratio

The 1.50 is not a large increase over the A-series 1.44. The 1.6 is fully adjustable

Attach file:


jpg  ford_six_rockers.jpg (65.65 KB)
174_56d4ec2b19515.jpg 750X563 px

Posted on: 2016/3/1 1:11
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Volodkovich
Re: Ford F250 rockers
#3
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I have a set here and they look to be a waste of time. They don't have any appreciable ratio increase over the factory rockers and also the adjuster nut tapered with no locknut and the ball is too large for A series pushrods.

I'm sure they can be made to work but really just get a cam with some more lift. If you are chasing 10/10ths you'd be better off with some aftermarket roller rockers.

Posted on: 2016/3/1 0:56
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