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Timing chain settings

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  • Timing chain settings

    Hi Dave, recently I read a post where someone had rebuilt his FE engine. In the post you said to buy and install a Rollmaster timing set and set the crank gear at 4A. I have an idea on cam duration etc etc, but just asking what this may do on a standard cam? Does an FE run better ie torque increase, vacuum etc etc? You can run this through the forum to share the info if you like.
    cheers
    Randall (60birdaussie)

    Good question, Randall Let's start with 'stock' engines. Ford has no idea what service they will operate under so the engine components are engineered and set to average usage. That means, the car may live in hot/dry or cold climates, etc.

    Aftermarket cam setups are a little more specific, usually leaning toward 'performance' service.

    So, a stock cam is engineered to produce torque at low, mid and high rpms. If you mostly drive around town and rarely at high speeds, advancing your cam four degrees makes sense because it makes your torque curve happen sooner, valves operate slightly sooner, which also enhances vacuum. You get more torque at every light for free. The 'sacrifice' comes at the expense of high rpm torque. So, racing engines operate with retarded cams while street and 'RV' engines benefit from advanced cams.

    Now for the preliminary... How do you know 'for sure' where your cam timing is? Yes, we use timing marks but there are 'machining stacks' that can be off. And, how do you know if your new cam has 'built-in' advance/retard? There's only one way to really know, DEGREE YOUR CAM.
    Degreeing your cam costs NO more money and you can download your wheel online, print it and bolt it to your crankshaft. I will leave the procedure to extensive YouTube videos.

    Be not confused with 'standards'. In the Automotive World, everything, left and right, is referenced from the DRIVER'S seat and everything in the engine is referenced from the crankshaft. That means, advancing your cam is really retarding your crankshaft BUT aftermarket timing chain sets may have keyway choices to adjust your cam timing or to keep it "straight up", "A" or "R". These marks mean the CAM is advanced or retarded.

    A good way to know when your cam is at TDC is to measure the rocker arms opposite #1 cylinder. When #1 is at TDC, so is #6 but #1 is on its power stroke while #6 is on its exhaust stroke. With 'straight up' cam timing, when the exhaust valve is nearly closed but the intake valve is opening, right then as the rocker arms are dead even, the camshaft is at ZERO DEGREES. So now, we can determine the relationship between crankshaft timing and camshaft timing by simply looking at the degree wheel.

    That means, we can verify if we're a cam gear tooth off before installing the timing cover by looking at the degree wheel. In short, if #6 rockers are evenly open (scavenging) but my crankshaft shows four degrees before TDC, the cam is advanced by four degrees.

    I always buy double roller timing sets because they last three times longer than 'stock' chains. The brand doesn't matter to me. - Dave
    My latest project:
    CLICK HERE to see my custom hydraulic roller 390 FE build.

    "We've got to pause and ask ourselves: How much clean air do we need?"
    --Lee Iacocca

    From: Royal Oak, Michigan

  • #2
    Hi there Dave, wow that was an awesome explanation! I did have a bit of an idea of the crank versus cam relationship but not to the extent of your explanation in such easy laymans' terms.

    I had learned in my trade about cams and crank relationship but we are bound by 'standard' settings in aircraft engines as I never had the chance to work in an aviation piston engine assembly/rebuild workshop, and we are not allowed by aviation regulations to adjust from standard. ( We get new/rebuilt engines as Long blocks). Mine is gas turbines, (jet engines) which is a little bit of a different kettle of fish.

    I'll look up the you tube videos with the regard to degree wheel and degreeing a cam, but I think I need to modify the front end of my 352 first as it is an early one, (built 1959) with the thrust button and spring behind the timing cover. I still have the old factory looking chain and it looks pretty loose as seen through the fuel pump mounting.

    Dave, do you know if there is a kit available, (thrust plate, bolts etc), to modify to the later configuration as to be able to run the true roller/rollmaster type gear/chain sets of the later models of the FE engine?
    I had used them in rebuilding Clevelands but I had set them up 'dot to dot' as they were stage 1 cams, and they were far superior to the factory gear/chain sets.

    Really love your explanation, way better than was ever explained throughout my career of the good old crank/cam relationship.

    Thank God for this forum and all the 'knowledgeables' that go with it!
    cheers
    Randall

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