Fuel Efficient Cam Regrinds : General Info
 

Delta Camshaft of Tacoma Washington are the guys that regrind Standard Metro Cam Shafts to XFi.
Having read numerous posts on the XFi, got me to thinking and I just sent them the following email.
What does anyone here know about regrinding cam shafts for improved fuel economy? Are there other questions I should be asking? Anybody here have experience with this other than Metro Xfi?

You can definitely get more efficient cam profiles through regrinding, by basically moving the valve timing to create more power on the low end, rather than high.

However, I am not so wise about the mechanics of this other than in theory, I'm sure someone else will chime in soon. :thumbup:

It's done all the time for performance applications and can be done for FE, but guessing specs isn't going to be the best way to go about it. You really need a flow bench for the particular head you're working on and some experience on matching the characteristics of the particular engine as well. Since high performance pays, you won't find many FE cam grinds. You could always contract someone to do it, but the cost might not worth it. If you want to do it anyway, you might want to inform the shop of which rpm ranges to concentrate on (the ones you'd use as a cruise speed(s) most often). If you need to send them a head to work from, you might as well have them do some work to it, too. I would imagine some of the HP tricks for lower rpm would also help FE as better breathing reduces pumping losses, but that's a guess.

If you're going that far, you might want to play around with intake runners, also, to maximize the efficiency of the rpm range you're optimizing. The longer the runner, the lower the rpm it helps (when the intake valves close, they send a pulse back through the intake tube. This pulse reflects back whenever it hits a volume of a different size. This pulse can be used to help push more fuel/air into the cylinder the next time the valves open. The longer the intake extends before a change in volume reflects the pulse back, the longer it takes the pulse to travel the distance back and forth. This increases the optimum time between valve openings, which would correlate to a lower rpm. This creates a minor 'supercharging' effect, which may sound bad for FE, but would improve your torque at lower rpm, allowing a smaller load on the engine or taller gearing at a given speed. This should be especially useful on small engines which are generally built for higher rpms as that's the only way the car manufacturers can publish impressive sounding horsepower figures. A notable exception was the EA81 engine in my 1984 Subarus, which made enough torque off the line that I could dust off far more impressive machinery up to about 20 mph, but ran out of breath after 5k rpm. Only had 73 HP as advertised, but if it had been built for higher rpm, it probably would have made over 90, yet been slower in town and probably wouldn't have allowed the gearing where 5th was as tall as that in my Mazda 3). It might not be so easy with modern vehicles using plenums (large volume before the intake runners that lead to the individual cylinders), but spacers between the head and intake could fit, depending on the engine, space available, and about how much additional length you'd need. Why not do this anyway without all the cam work? You could, but it won't have as much of an effect as a tuned system would.

That was probably way more than you wanted to know.

Thanks, evolutionmovement.
Probably more than I'll know what to do with, but definitely not more than I wanted to know.

Yesterday, I was reading the web pages in the "Tech Area" of Delta Camshaft's web site (under reconstruction, but parts of it are still up at the moment (but maybe not by the time you click on the following links).

• BASIC CAMSHAFT KNOWLEDGE
• HELPFUL TIPS
• CAMSHAFT TUNING TIPS
• IMPORTANT NOTES

Reading CAMSHAFT TUNING TIPS has me wondering if offset bushing/keys aren't the place to begin?
I'm guessing that the last sentence means the same as their "IMPORTANT NOTES"?

I think its definitely worth looking into. Actually doing the work is very hard though. Even camshaft timing changes requires an aftermarket or custom pulley. Expensive stuff to have done.

Some Honda engines have adjustable cam sprockets readily available on the aftermarket, but you'd have to hunt for anything else. I would think that if your car is commonly used among low budget racers, you could probably find something. Not sure how much mileage improvement you'll get from a cam timing adjustment, though. I'd be interested to find out.

Spent some time today researching camshaft timing/degreeing in general and Ford Escort 1.9L/2.0L SOC degreeing in particular. Here is what I've found so far.

GENERAL INFO: Four Common Methods of Degreeing a Camshaft.

1. Use an adjustable cam drive gear.
   • ~$150 and up if available.
   • Finest possible adjustments.
   • Especially good if you intend to adjust for various (race) conditions or are tweaking.
2. Use a crank shaft sprocket cut with multiple keyways.
   • Most any machine shop can cut the extra keyways.
   • Most high performance timing chain sets come with multiple keyways in the lower crank sprocket.
   • Keyways are spaced at equal degree intervals.
   • Possible adjustment is +-(number of keyways -1) degrees.
3. Use use offset keys in the standard crankshaft sprocket keyway.
   • Least expensive ~ $35-$45 for a set of 4.
   • These will be engine specific. Not sure how hard they may be to find. Could have them machined from an oversize key. Probably less expensive than having keyways cut???
   • Often used in conjunction with sprockets with multiple keyways.
   • General recommendation seems to be not to use them for more than +-4 degrees as keystock becomes to thin - subject to premature failure.
4. Eccentric camshaft bushing can be used with camshafts that use a dowel pin for indexing.
   • Sources thus far have not discussed pros/cons other than camshaft must use dowel pin for indexing.

Two general write ups on degreeing a camshaft.

• Short, sweet and to the point.
  Quote:

  Degreeing In Your Camshaft means synchronizing the camshaft’s position with the crankshaft. A few degrees of misalignment can affect the engine’s operation dramatically. If there were no manufaturing tolerances, you would only need to line up the marks on the timing chain sprockets and the cam would be degreed, but with a group of components (the camshaft, crankshaft, timing chain, and sprockets) all with their own standards and tolerances that when installed, can stack up against you. You can never be sure that the cam is in it's correct position. Whenever possible, always degree in your cam.

• From Crane Cames more info including special tools you might want but may not need?

Degreeing a camshaft aimed at MGA owners, but includes general info worth reading.
Ford Escort Specific Info:
Adjustable Cam Drive Gears appear to be out of stock.
A write up of how to degree Escort 1.9L/2.0L SOC engines using the above out of stock adjustable gear.

You can get adjustable cam gears with a simple google search, and you can usually find them on eBay very cheaply. A degree wheel will help as well.

There are adjustable cam gears readily available for more than Honda engines... many DSM, Subaru, Honda, and several Ford engines are quite popular for tuning, and thus, have aftermarket support.

ACG's are one of the most common first mods, although mostly used for aesthetics, rather than actual tuning. They come in second to shiny parts and under drive pulleys.

Easily found for Escort 1.8L DOHC engines.
Less easily found for Escort 2.0L DOHC.
My simple google (Ford Escort Adjustable Cam) and eBay searches only turn up OUT OF STOCK for Escort 1.9/2.0L SOHC.

My current daily driver ('99 Escort LX 2.0L 5sp MT) and normal daiily driver ('94 Escort 1.9L 5sp MT - currently down for the count - until the snow finally melts) are both SOHC.

Only the low priority, desperation (eg. both daily drivers broke down or me with broken leg/arm), alternate, backup ('99 Escort ZX2 Sport 4sp AT) is DOHC.

So find out how many teeth your cam gear has, and match up one from another car...

I'm pretty sure the cam gear from the 2.3 FWD Ford engine is the same, but I'm not positive about it. The next time I go to my favorite junkyard, I"ll even count them up for you.