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Discussion Starter #1
This has probably been asked many times, but what was the reason behind retarding the cam timing 8 degrees on 460's ? Also is a 87 460 a rolled motor (roller lifters and rockers) I have also heard that there are 2 different weights for externally balanced 460's :confused:
 

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If I remember correctly the timing was retarded for emission reasons....the later fuel injected engines had straight-up timing sets. There has never been a "roller" 460 from the factory either lifters or rocker arms.....I have never heard of different counterweights on externally balanced 460's.....
 

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Thank you Jeff , I wonder now if I change to straight up timing it will make my 79 F350 not pass Calif. smog tests ???
 

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It was done to reduce low speed cylinder pressures by causing the intake valves to close later to reduce nitrous oxide emissions. This type of emissions were tougher to clean up than hydrocarbons which could be dealt with by using AIR and or a catalytic converter. Low compression ratios as well as EGR were also used to help with nitrous oxide emissions all at the expense of engine efficiency, exhaust gas temperatures and performance.

I'm not sure if it'll pass smog or not if you change the cam timing.
 

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Cloyce variable timing gear sets

Hi, I'm new to your site and have questions regarding the Cloyce variable timing gear sets.
I have 97' F250 H.D. 4X4 E4OD trans, G code, XLT, 4.10 gearing, super cab.Completely original as right off the line, stock tires wheels, heavy duty tow package, even the original heater hoses, its never been apart. It has 240 K on it and I'm the second owner, I got it with 28K on it. The only thing I have changed is put Cat Back exhaust, and changed the front hubs to manual engage type. The best pick up I have ever had.
I have all the factory manuals for it as well, and still can't find the answer to some of my questions.
I'm replacing a leaky front timing cover. When I went looking for an OEM cover I was told they are discontinued. It was then that I discovered this engine was set up for California emissions. It has a crank sensor mounted to the cover. I bought a Cloyce variable chain & gear set. There claim is if you set it on the advance position it advances the cam 4 Degrees. and is suppose to give the engine more low end torque. If set at the retarded it produces more high end torque & H.P.
My question is (finally)
Are these engines retarded from the factory? How much?
I don't see anywhere it shows the torque rating at 4K RPM ?
They show the rating of 400 lbs torque at 2200 rpm, and the HP rating at 4K rpm not the torque at 4K rpm.
I tow reasonably heavy trailers with it, and usually in 4th gear, so the rpm is higher. Thats why I'm looking into this cam gear change. With out knowing what the 4K torque rating is, I don't know where to apply the cam setting.
Any help will be greatly appreciated,and sorry for the long message.
Max
 

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No need to change your timing set to an adjustable one, ALL fuel injected 460's have "straight up" timing sets. They are not retarded sets like earlier timing sets.
 

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Thanks for the reply, I am aware of the factory sets these EFI engines straight up on the crank gear, thank you. I'm looking for more info on the actual differences that's achieved when setting the Cloyce gear to the either advanced or retard position. Cloyce claims that setting it in the advance position gives the engine more torque at lower RPM, and setting it on the retard position gives the engine more "Top end HP". As I mentioned before I can't find any info on what the "Torque" is at in the "Top end". Ford specs states the peak RPM is 4K, and 400ftlbs of torque at 2,200 RPM but does not say what the torque is at 4K "Top end range" 4K seams awful high to me, my truck runs 2,250 RPM @ 70 mph in OD and around 3K out of OD. I have never seen what it runs at 4K. It has E40D trans, 4.10 gears, and stock tires & wheels. I'm looking for more torque at the 3K to 3,500 RPM range. I tow several different trailers ranging from 4K lbs. to 15K lbs. in the Arizona mountains, and heat. So again what is 3K range considered? High range? or Low range? and what is the torque at 3K to 4K ? I called Cloyce and they couldn't answer this question either. I need to know this because I have the old timing set off the engine and ready to reassemble it.
Thanks again for any input on this subject,
Max
 

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It depends a lot more on just retarding the timing to gain top end power
 

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Are these engines retarded from the factory? How much?
Hi Max. No.

I don't see anywhere it shows the torque rating at 4K RPM ?
They show the rating of 400 lbs torque at 2200 rpm, and the HP rating at 4K rpm not the torque at 4K rpm.
HP is a simple calculation from torque and rpm. Either calculate it yourself with:
TORQUE = HP x 5252 ÷ RPM
Or, use an online calculator such as Spicer's:
https://spicerparts.com/calculators/horsepower-torque-calculator

With out knowing what the 4K torque rating is, I don't know where to apply the cam setting.
Actually it doesn't matter. As changing the cam shaft timing with retard or advance simply shifts the power curve up or down from where it is now; the simple questions are:

  • Do you want a small increase in perceived power at lower rpm, at the cost of power at higher rpm? Then advance the cam.
  • Or, do you want a small increase in perceived power at higher rpm, at the cost of power at lower rpm? Then retard the cam.
It's a trade and compromise. For more explanation of the relationship between torque and horsepower, grab a cup of coffee and study this: Power & Torque

David
 
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