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.

The way it works on a metro is to just drill a new indexing hole halfway around the sprocket. Just make it half a tooth off for 9 degrees since a full tooth off is 18 degrees :)

Thanks for the offer. Please do and any other measurements you might care to take.
The nearest junk yard to me is just over 20 miles away and I have no idea of how far to the nearest you pull it style junk yard.

But it's not just number of teeth.
Tooth shape (round tooth) and belt width to match water pump and camshaft gears.
Shaft hole size to match crank.
Keyway width.

yeah, those are all considered as well, but with most MFG's, they keep a certain standardization to their engines. The 2.3 and 1.9 share a transmission pattern and a few other things, and can be interchanged with the 3.0 FWD or RWD platform without changing the transmission.

3.0's will fit in Escorts. I've done it. :P

I'll probably just walk into the yard and find a couple cars with D-grade engines, then swap the gears on them and see how it lines up/etc. If I can keep proper timing with the new gear, after 4 full turns, then the gear works. If the sizing looks good, it usually is. As much as people would like engine parts to be an exact science, often times, good enough really is *good enough*.

Crankshaft sprocket, right?
Does a roll pin or some such go through the indexing hole?
No keyway?

FWIW Already skimmed through http://ecomodder.com/forum/showthrea...html#post26075

If a moderator happens to read this, please change the title of this thread from FE Cam Regrinds : General Info to Cam Timing and Regrinds : General Info

I agree.
Probably should have said eyeball rather than measure.
Probably would have said eyeball if I'd know that just swapping gears around might even be an option.
Out here on the N. Central SD prairie, U-pull-it Junkyards are just an urban legend. ;)

On a metro there is a roll pin on the cam. Just drill a new hole and you are good :)

I did a test on mine and drilled 4 extra holes and with a combination of moving the belt a tooth and the extra holes I could adjust it to about anywhere. Turns out on a stock xfi cam 3-5 degrees is best and on a stock cam 5-10 is best.

As far as changing the cam profile itself, the best place to ask is somewhere that does custom cams already. Some place like comp cams or lunati. I had a custom comp cam made once for a sb chevy. Not really sure if they do every engine but they would probably be able to wild guess and make a better profile than I could work out on my own.

Thanks for those leads. Haven't heard back from Delta yet.

I've only been thinking about this for a few days now, but a this point I'm think aero mods first and degree and possibly regrind at the next timing belt interval - about five months for the wagon if I get it back on the road soon. (So ready for the end of Still Winter. We have four seasons here in SD: Almost Winter, Winter, Still Winter and Road Repair. ;))

I've already thought about this being applied to a vtec engine or others that employ different sets of cam lobes...I'm sure the "low cam" could be ground with less lift and duration to provide more low end torque and better mpg, while still retaining a high power lobe for top end. There would be a bit of a flat spot in the midrange but I'd put up with it for the mpg gains.
Doing this to a regular engine would obviously be at the cost of horsepower but regrinding the lobes smaller should be fairly simple as no material has to be added to the cam like when they make larger more agressive ones.

For most regrinds, even if you're lowering the lift, you're still going to change things like lobe separation angles and duration to get the most efficient cam you can... that said, you'll still need to have material added before you can change some of those parameters while keeping the cam's lift profile tame enough to not start loping when you're idling at 500 or less RPM (yea, you can make your engine idle that low w/ the right cams.)

In fact, the 225 inline 6 cylinder Chrysler engine was noted to have been able to idle at speeds less than 200 RPM, and has once been said to idle at 50 RPM without stalling, but no oil pump function could be recorded at speeds that low.

This would be another advantage of solenoid-based valve timing events, rather than a mechanical cam controlling them. You could have the computer controlled valves opening enough to keep the air flowing reliably into the cylinder at extremely low speeds, still maintaining enough power to counter-act the frictional losses of the engine, which would burn significantly less fuel than idling at 800-1000 RPM for the average engine. Even 600 RPM vs 100 RPM is no comparison in terms of fuel use.

Solenoid based valve action would also allow the engine to be infinitely tunable for it's specific displacement, meaning that after all tuning took place, the engine's only weak point really would be it's displacement in terms of going further for FE or Power.

Have you considered asking this question of adjustable cam gears on a ford eskort forum. I thinks it's FEOA or something like that??? There ought to be plenty of knowledge over there.
So what's with the ZX2 being the third string bench rider? :D They are a plenty fine car, although I see your getting 50+ mpg with your wonder wagon...ZX2 adjustable cam gears are easy to find and relatively afordable...TeamZX2.com...

No, I haven't considered asking on those forums.
Googled them and found numerous posts indicating current unavailability of NEW adjustable timing gears for SOHC (Single Overhead Cam) engines. - The performance tuners all want DOHC (Dual Overhead Cam) engines like came in the ZX2s.

I'm glad you posted though, think I'll give them a try for a USED adjustable timing gear for SOHC.

Unless you have milled your head and wish to re-align your timing with an adj. cam pulley, adding one to a SOHC is pretty pointless. Advancing the pulley means all your valves will open sooner but also close sooner, which basically does the same thing as just tweaking your timing instead. On a dohc engine the pulleys can be adjusted to open the intake valves earlier and open the exh. valves later for some gains in HP(or other way for more efficiency).
Most anyone I know of that has tried a SOHC adj pulley on the dyno has found -0- to the be the sweet spot, except on engines with a shaved head obviously.

Does it do the basically same thing?
Won't the first affect the amount of air flow at given engine speed and throttle opening - (causing the ECU to adjust timing as well?).
While the second only changes raw timing - which may or may not result in the ECU adjusting timing? (My '99 2.0L has anti-knock sensors. My '93 & '94 1.9Ls don't.)

No shaved head, but the engine has 160K on it; presumably tolerances are no longer OEM.
Were those people tuning for: performance, fuel economy, both?
My primary concern is fuel economy - not sure my sweet spot would be their sweet spot.

Thats a tough one because we were tuning for HP.
I guess in theory if you retarded the timing so the intake valves opened later, the engine would draw in a little less fuel/air mixture on the downstroke PROVIDING your intake valves already close well before the piston hits bottom. This could have adverse effects of running hot however due to the also now retarded exhaust cam lobes which now also open and close "late". Gonna have to leave that one to someone more knowledgable of cam timing.....

I've generally found that most of my cars have gotten better mileage and performance by doing upgraded plugs, wires, cold air intake, and exhaust. I also slam the timing as far advanced as I can get and back it off a little once it starts to ping a little.
I'm one that believes a WAI is for those who can't restrain their gas pedal foot, as less air can be delivered by either less dense warm air or a throttle that is a little less open passing cold air, but the car drawing cold air will have the ability to make more HP at WOT than the one drawing in hot air.
Energy theory in general states that the more temperature difference there is the more energy is released, so I would think that cold air/fuel would provide a slightly more efficient burn, where as warm air could actually cause knock in some engines requiring a richer mixture/less timing and therefore worse mpg.

[QUOTE=TestDrive;96390](My '99 2.0L has anti-knock sensors. My '93 & '94 1.9Ls don't.)QUOTE]

Pull that knock sensor plug off the sensor of the ZX2. It doesn't work righ and will randomly pull timing when you don't need it. It will pull 6 degrees without any incremental change and goes off all the time. It may not add mpg's or hp but it smooths out the power curve considerably and makes it a much more enjoyable car to drive. This is one of the first things I did to mine and the surge that I had been trying to find for years disappeared :)
BTW, there's lots of free type mods you can do to the ZX2 to make it more fun and enjoyable to drive. Of course I'm a ZX2 nut, so take what I say with a grain of salt ;) Of course you could wander over to Gassavers and see COZX2's ZX2 get over 100mpg to get some real bad ideas :D

Also, the ZX2 intake timing gear is not on a keyway so it is fully adustable as is :)

TestDrive - if you have a DOHC and a SOHC, you should count the teeth on both.

One of the DOHC's gears may interchange with the SOHC. (The DOHC will have 2 gears that are both a 2:1 ratio to the crank, for those who would argue otherwise.)

So if the SOHC and the DOHC both have a 18 tooth crank gear, then they'll both have 36 tooth cam gears, the only difference is the DOHC has 2 of them.

In general, cam profiles for power and performance will have more lift and more duration... cams for better FE, less duration but usually about the same lift as stock. I base this on several race cam profiles I've played with, my Geo's Xfi cam, and a 1975 Ed Iskenderian "Mile-A-More" grind for a 327cu in Chevy V8 I stuffed into a Vega back in 1978. Less duration seems to net mpg gains in most engines is the trend, but I'm sure their are exceptions.

I'll also add that cam profiles are not just guessed upon, but the process for developing a new profile for a given application is done in itterations. Engine sofware like "Engine Analyzer" are a good place to start, you can run simulations from your PC, which had been very helpful for me in choosing a better profile for a race engine. But you need specifics, I had all of the data at my figertips from which to work, like intake runner volume and most important cylinderhead flow table for those particular sets of heads I was building an engine around. Not having meaningful REAL information and plugging it into software would likely be and excersize in "GIGO" or "Gabarge In, Garbage Out".

I had worked with cam grinders late Babe Erson in Anaheim, Ca and more recently, Dema Elgin now in Santa Rosa, Ca.

My advice to anyone serious about having a custom cam ground for any purpose, is to read up on cams at http://www.elgincams.com/ to become familiar with the terminology at least, then keep an open mind and talk with veteran Dema (or some other gray haired old timer cam grinder near you) about your goals to see if he can help you. Unless you are trying to set some world record, you will get very close to optimal in one try. Trying to figure out what blank to start from, how far to advance or retard the cam timing is way premature, my advice is to find an expert and give him your business.

Dema has taken cast cams and built up the lobes with hard weld, so we could change lobe centers adn increase lift, has built me a couple billet 8620 steel cams from my supplied blanks, but the knowledge base from which cam grinders work is increadible. BTW, he has my Xfi cam that I need to pick up.

Good thought, it's conceivable that the DOHC application may fit and work just fine on the SOHC, but based on different part numbers for each application (both OEM non-adjustable and aftermarket adjustable) it almost for sure won't work the other way around. (Maybe a wider timing belt or something??) I'll have to look into it, but ...

What I have is two running cars, one resurrectable (close encounter with a deer) car and one spare engine that fits the resurrectable. Only one of the cars has a 2.0L DOHC engine - the running 1999 Escort ZX2 2dr 4sp Automatic. Only one of the cars has a 2.0L SOHC engine - the running 1999 Escort SE 4dr 5sp MT. The resurrectable 1994 Escort LX Wagon 5sp MT and spare 5sp MT transaxle are both 1.9L SOHC (same as 2.0L but different bore and emissions). I hardly drive the ZX2 - just enough to keep the battery charged and the seals wet. It's my insurance against the daily driver (me or the car) suddenly needing serious repair. In the case of the car it means I still have something to drive every night while I do the repairs myself. In the case of myself, it means a broken or badly sprained leg, arm, wrist doesn't put me temporarily out of a job. The short and sweet is I'm not tearing into the engine of the ZX2 to count teeth, until the Wagon is backup and running.

Thanks for the info, but see just above about why I won't be digging into the ZX2 real soon.

Thanks for the post. At this point I'm mostly thinking about the possibility of inexpensively experimenting with timing adjustments to the OEM cam. I'll still be looking into cam regrinding, but it's a low priority.

Think I've heard of Elgin before and believe they're well thought of in performance/racing circles. If I don't hear back from Delta pretty soon, Elgin will probably be next on my list of people to contact.

Perhaps generally, but not in all cases, if you know how much you want to advance it. I.E. a Metro cam gear comes off fairly simply and you just have to drill a hole in the right spot to advance it.

There is room to drill many such holes with slightly different offsets relative to a tooth, so just leave the belt cover off while you experiment.

I don't disagree that you could do that. But, I think ideally you use a milling machine with a rotary table to get the timing exact enough. Did you have another idea?

Not sure what you mean by "exact enough". I did mine with an easy cheezy drill press (the kind that hold your drill) after some careful figuring. It works very well and didn't cost a dime.

By exact enough, I'm thinking +/- 1°.

How did you hold the cam pulley in the vise? And, how did you locate the drill hole?