The Rebirth

[Sirdeuce]

A tribute to a well maintained vehicle Bryan! My FX ran about that clean and got between 35mpg and 45mpg, depending on  how hard it was pushed. And they say older cars are just not up to snuff.

[BigMike]

And they say older cars are just not up to snuff.

I thought they say old men are not up to snuff?

[Sirdeuce]

Respect your elders.................... BOY!

[Sirdeuce]

Ok, not as close as I remember on the smog test to Bryans as I thought. Scanner ain't workin' so'o I cain't shows ya the achull thang, but......... Consider this is using a set of WEB Cams 294 grind. 244* duration(only 4* more than stock) with a higher lift of 8.15mm. And not timed properly.
HC was measured at 1002 RPM at 27 PPM, and at 2474 RPM at 34 PPM.
CO was measured at 1002 RPM at 0.01%, and at 2474 RPM at 0.01%
NO wasn't measured as we are in the backwoods and not required to do so, YET! But judging by the HC being a little rich I don't think that would be an issue. So Mike, think you might want to run a set of these cams? Might run a little cleaner if timed right too. I did try the 'hypermiling' thing on 1 tank and got 48.sumpin mpg. You don't want to drive that way! Believe me!

[Sirdeuce]

Found the test from when I got the car. It was in the same pile. just for S&G the results, completely stock, are......
HC at 1759 RPM 58 PPM and at 2019 RPM 39 PPM
CO at 1759 RPM 0.01% and at 2019 RPM 0.09%
NO at 1759 RPM 21 PPM and at 2019 RPM 18 PPM
So the WEB cams actually ran CLEANER!! Whoda thunk? Maybe try a set of 256* duration cams next.

[BigMike]

So Mike, think you might want to run a set of these cams?

Do you have another set that you are not currently using? If so would you be interested in selling them to me? I'd like to also buy back my SC TRD header. I'm gonna start modifying things starting in mid or late July.

Mike

[Sirdeuce]

Go get the set from Kevin, bring ti up here and I'll help you with the shimming. We can put the headers on too. I guess we'll just have to get by with the 264* came in the Poupe. (sigh)

[Sirdeuce]

Maybe you want to play with the 264* cams?

[BigMike]

Maybe you want to play with the 264* cams?

Tell me what you think about this. If I get my VVT cam gear to work on the intake side, then would it be better to use a shorter duration cam (something like the 294) but with a bigger lift, like 8.5mm? Because the VVT can control the rough idle and valve over lapping issues at lower RPM while taking advantage of the free flow at higher RPMs.

The only thing I don't understand yet is the affect boost will have. Obviously too much valve over lap is bad with boost, so that's why I think if the duration of the cam was kept to a minimum you could minimize the overlap.

Comparing some cams:

Grind	Duration	Lift
294	220	.322" or 8.18mm
264	218	.375" or 9.52mm
101	250	.350" or 9.89mm

WOW That 264 is exactly what I am talking about: shorter duration + taller lift. BUT, what will I need to do in order to run that large of a lift?

[Sirdeuce]

The cams I have available are a 7.9mm, 8.1mm, 8.35mm lifts. Kevin has the 7.9mm and 8.1mm. Put thr 8.1 as your intake, and the 8'35 as the exhaust. Pulley, exhaust. Get in sit down, shut up, yeeehaww

[BigMike]

Here is a great read (I'll read through it when I get time later)
Source: http://www.zerotohundred.com/newforums/toyota/86227-aftermarket-cams-for-4agze.html

Modification of an engine’s valve timing is best approached with a degree of caution. For otherwise stock engines, the mildest cams should perform well. Performance will improve with improved induction, i.e., carburetion or a more efficient injection (ported/polished throttle body) and exhaust system (headers). Modest performance increases can always be achieved by fine turning with adjustable timing gears to advance or retard the valve opening and closing.

In discussing and comparing camshaft designs, there are three important parameters to keep in mind. First is the lift, or how far the valve comes off the seat. Unfortunately we seem to forget from time to time that there is theoretical valve lift and net valve lift, and because the 4A-G is an over head cam design there is little difference between the two. The camshaft acts directly on the valves through the shim and bucket (lifter, follower).

The second important parameter, is the duration. This is the length of time, measured in crank degrees, that the valve is open. There are usually two methods of stating this measurement. Advertised duration is normally what you see when looking at a catalog and the second method is usually stated at some point in the valve lift height. (None of the major suppliers for the 4A-G do this for reasons unknown). Thus directly comparing one camshafts duration against another would only be useful for comparing camshafts from the same manufacturer.

The last parameter to keep in mind is where to set the camshaft. It can be set by the beginning of the valve opening or closing or at maximum lift, lobe center. The lobe center is usually between the opening and closing angle, but not necessarily so, especially if the opening and closing ramps are not symmetrical to each other.

Depending on how fast the valve is lifted, the high lift cams (generally recommended for 9mm and up) require under bucket shims to keep metal pieces in their proper spot. If cylinder filling capacity is the same between a seemingly long duration cam and a high lift cam, a fat, flat top cam lobe, not having very much lift may try an aggressive (square shape), valve opening and closing. This is to try and gain the advantage of increased flow by allowing the valve to open sooner and close later, which can result in tremendous stress on the cam and lifters. On the other hand, a pointy Hi-lift cam may have reduced stresses to the lifter but may increase stress to the valve spring to the point of binding the spring. As a practical matter there is a point at which increasing lift has little benefit in increasing efficiency and is obviously depended upon operating RPM. Therefore the design of each valve train component is dependent on a cam feature. The valve spring is affected by the lobe height, and the lifter & shim is affected by the cam ramp and/or flank.

The area on the cam lobe that determines the rate the valves open and close is the ramp. The ramp is that part of the lobe that takes up or allows the re-establishment of clearance in the valve train. Ramp designs have a great effect on throttle response, low speed torque, and valve train reliability. This is the hardest to measure and usually not published. The Ramp design separates manufacturer's designs from another. Moreover, the duration and lift are usually advertised numbers and are not necessary a good way to compare one design to another. The .9835” diameter of the shim will only allow so much aggressively quick opening before the cam lobe catches the edge of the shim or is popped out of the lifter like a tidily wink. An under bucket shim configuration will allow added safety by protecting the shim and allowing greater contact area, e.g., ~ 1.102” dia. of the lifter (bucket). Though it is more time consuming in setting and maintaining the proper valve lash, clearance.

Note, when measuring a cam profile the area of contact between the cam lobe and the lifter, i.e., the width of the shim, has a profound affect on the rate of change (crank degrees per inches (mm) of valve Lift) the valve and valve train will under go. So if your are calculating loads and acceleration of the valve train, it is best to measure crank degree change per lift with a wide flat surface, simulating the lifter, rather than using just the point of the dial indicator. This would give you a better indication of the cam’s actual duration.

The larger the duration and lift a camshaft has, the more it becomes necessary to have a better induction and an exhaust system. Since the engine is an air/fuel pump and the more air/fuel you can pump into it on any given stroke the more potential power you can gain. Higher lift allows for potentially more air to flow, while increasing the duration allows the air/fuel to rush in longer. Notice that I have used the words “potentially”. This is because efficiency depends on what is before and after the valve, not to mention the valves themselves. The more radical cams require higher compression pistons and greater valve spring clearances and/or spring rates for higher lift, and preventing valve float. A camshaft is part of the induction system and it must be tuned with all the other components within that system to work to its full potential.

The cam designer wants to design a cam that will open the valve as quickly as possible and hold it open as long as needed for cylinder filling and close the valve at the correct time and in the process keep all of the metal pieces intact. Cam grinders and racing engine builders are seeking a rectangular valve lift profile. This is an ideal that cannot be approached, but if it could the valve would remain closed until you wanted it open and then it would be fully opened instantaneously. It would be held there for complete cylinder filling, and then it would be closed instantaneously. The height, lift, of the valve opening would be the height that the flow bench or trial and error showed would produce the desired maximum amount of filling.

In reality, the cam must be designed to open valves before the piston starts a stroke and it also must close the valves after the completion of the stroke. The intake charge can be visualized as being “parked” in the port waiting for the valve to open. As the valve opens further, the velocity of the intake charge grows. Opening the intake valve before the piston ever reaches TDC (top dead center) the cam designer is already taking advantage of the situation and allowing the intake system to build up a maximum amount of velocity or inertia to aid in cylinder filling. As the piston goes over TDC and starts downward, the velocity of the air/fuel mixture increases as the intake valve reaches maximum lift. Even after the piston reaches BDC (bottom dead center) and starts back up on the compression stroke the intake valve is still open, allowing more air/fuel to enter. The compression stroke does not develop enough pressure against the incoming mixture flow to interfere with this flow until the piston is part of the way up the stroke. It is said that the intake charge has inertia.

On the exhaust side, the valve is opened long before the end of the power stroke. In theory it would be nice to keep the intake and exhaust valve closed until the piston reaches the very end of the power stroke to take advantage of all of the pressure created by the combustion. In practice, the bit of burning gases that are left is not worth fooling with since the peak cylinder pressure is over before the halfway point of the stroke (discounting emissions). By opening the exhaust valve early, the velocity in the exhaust port can begin to exit and thus the piston on the next upward stroke will not have to fight to get the exhaust gases past the valve and into the port. The exhaust valve is left slightly open as the piston is once again brought up to top dead center. This is done to help scavenge as much of the residual gas as possible still in the combustion chamber.

In a typical turbo set-up, they will run relatively short duration (less over lap) cams. Otherwise they will blow all the intake charge into the exhaust side, or worse, reversing (reversion) the exhaust gas into the intake. The pressure, intake or exhaust, will find the easiest path to flow, and if it is easier to go straight through the cylinder, equalizing the difference in pressure and decreasing the amount of work the turbine can do, it will. You will not only lose the air/fuel charge that could have gone into the cylinder but decrease the efficiency of the exhaust turbine as well. The typical GSR turbo-charge Honda is running lobe centers (max lift) between 112 and 108 degrees, with 235° VTEC duration above 4,000 RPM.

On the other hand a 4A-GZE runs a positive displacement “air pump” that is dependent upon the motors RPM and not the hot exhaust gases that a turbo motor would depend upon. So increasing the duration and lift for that engine could have some benefits. It just thinks it is below sea level any way. (running at higher atmospheric pressures)

An interesting aspect of cam duration is the use of a dual pattern or different duration cams for the exhaust and intake. When used correctly, a different exhaust duration from the intake can broaden the torque range, but generally speaking they will not deliver as much peak torque as can be found with matched cams in a narrower RPM range. This is not all bad because it is still torque that wins races. Typically you will see the exhaust cam one step lower in duration than the intake to broaden the torque range, but I have not seen anything that says you can not do it the other way around.

Trying to select a cam duration to use for racing (or street) is going to be a compromise. With this in mind, the camshaft requirements for a road race, street or drags would be considerably different than for a super speedway event using a Formula Atlantic prepared engine where the RPM band is very narrow and/or has the use of a close ratio gear box.

One of the factors that must be weighed is the need for some balancing between intake and exhaust flow. This is governed by flow capabilities of the head and intake manifold in addition to, as said before, on the existing induction and exhaust system and on where you want the torque and horse power to be, and how flat or how limited the useful RPM range can be. Now this depends on the weight of the vehicle, momentum changes (acceleration and deceleration), gear ratios, track conditions, etc.

Generally speaking a short duration cam will produce more torque at lower RPM range. There are two reasons for this. The engine builds up more cylinder pressure and the cylinder pressure is put to work for a longer period of time. And as the duration increases the torque will move up the RPM range. Remember your engine and ignition system must be up to the task. As you can see by the following table listing numerous camshafts, a turner can choose from many different configurations, and a competitive racing program will have tested most of them.

One of the many tricks that early hot rodders used to do (and still do) was to grind camshafts to the lift and duration desired. Reground stock cams have a reduced base circle which changes the valve train geometry, requiring many special mechanical modifications to make it work properly. (See Photo)



Because the 4AG has a cam lobe on either side of a cam bearing journal, it makes it critical that adequate clearance is given between the lifter (bucket) & shim and the bearing journal surface. The reduction of the cam lobe base circle, without extensive head modifications, requires the use of thicker shims. This will increase valve train reciprocating mass and inertia (adding stress and increasing the potential for major failure). Too thick a shim necessitates radiusing the edge to clear the cam bearing journal, increasing the possibility that the cam lobe will grab the shim and flip it out. An alternative would be to narrow the cam shaft bearing, but this would cause greater wear on the bearing caps and/or increase oil loss (lower oil pressure). Another alternative would be to reduce the bearing journal diameter, but that would require welding up the bearing caps and reboring them. For your information the size of the first cam bearing journal/oil seal surface should be (1.3768” ~ 1.3791” (34.97 ~ 35.03mm) dia. The journal diameters between the lobes should be 1.0610” ~ 1.0616” (26.949 ~ 26.965mm) dia.).

Therefore it is strongly urged that reground cams (Bull Frog, PAECO, etc.) not be used. Use only cams ground from new billet stock, e.g., HKS, TRD, TODA POWER, TOYOTA, etc. My suggestion is that if TRD, i.e., Formula Atlantic engine supplier, or one of the others that have extensive 4A-G racing experience do not do it, then you should be really skeptical that someone else would or does anything different. Regrinding a camshaft only removes material that the 4A-G needs to maintain the base circle the same size as the bearing journal.

With that said, it is also recommend that you follow all the recommendations the manufacturer of the cams has to offer. They have done the testing and spent the money. Typically they will also recommend changing the valve springs. The stock valve springs should not only be replaced, but also upgraded to ensure that the valves can follow the new and sometimes more radical cam lobe profile. The stock valve springs are only capable of ».318” (< 8.0mm) lift. With the stock installation height of 1.366” (34.7mm), they bind at 1.048” (26.6mm) compression and they will float some where above 8,000rpm. Nevertheless one should always check valve spring squareness, free height and installation height spring force. One should never take a chance on valve springs that do not look similar to the stock Toyota parts, or to well-established racers like TRD’s or Toda’s parts, in the number of coils, the width and height of the spring, and thickness of each coil. High performance alloy steels, heat treating, stress relieving and the most efficient coil spring design are pretty common to the industry (especially those that know 4AG).

(See Photo)



Also note that stronger springs mean greater friction and greater wear on the cam lobes and shims. It is one of those compromises that trade valve float for life. Use the best oil and filter (frequently) you can buy to make your investment last longer.

When installing the camshaft, start by following the manufacturing recommendation. For folks with a little more ambition the cam can be tuned. You will need a degree wheel and a dial indicator and knowledge of the Top Dead Center (TDC) and Bottom Dead Center (BDC) of the engine. This will establish the base line from which tests can be made and the cams advanced, retarded, separation increased or decreased as desired.

Using adjustable cam sprockets can optimize the performance of any cam. This allows for “degreeing” in the proper cam timing for the particular engine and intended use. This procedure is best carried out on a dynamometer so that quantifiable results can be measured. The advancing or retardation of cam timing will affect the peak power of the engine by moving the power band up or down the curve. There are many adjustable cam sprockets to choose from, each differing in design from all aluminum to using steel (less thermal expansion), but the most convenient to use are the ones with precision markings to allow for track turning and returning to the original settings.

In general, advancing both camshafts increases bottom-end power and retarding both cams will increase top-end by giving higher peak RPM power. On twin-cam engines, changing the lobe center separation between exhaust and intake will change the valve overlap. This can be used to improve top-end or bottom-end, but this depends on the critical placement of the intake closing and exhaust opening events. The placement of both events has a significant effect on power, i.e., exhaust valve opening determines the beginning of the exhaust cycle and cylinder blow down, and the placement of the intake closing event fixes the balance between cylinder filling and intake reversion. It must be emphasized that this is only a generalization and that you must perform dyno/track testing to fully realize the benefits. In the absence of a dyno, timed acceleration tests can be performed. These acceleration tests can also be performed using a precision accelerometer.

Tuning the cam to the specific engine operations, i.e., acceleration from a stop, between two RPM ranges, etc. will maximize what is important to you. Peak horsepower is only impressive on a dyno. By its self, it will not improve track times. Note, when adjusting the cam sprocket, make sure the ignition timing is corrected between each cam adjustment. The exhaust cam drives the distributor and any change to the exhaust cam will change the ignition timing. After changing the cam timing and correcting the ignition timing, the fuel calibration must also be checked. Cam timing has a profound effect on the air/fuel mixture and if not optimized for each cam timing setting you will not know if the effect of the change in cam timing is positive or negative.

The following list is typical literature power band information for the 4AG naturally aspirated configuration. The information is general and provides a good idea of what you can expect from the cams. The actual performance of any given cam in your engine depend on several variables including type of induction system, carburetion or fuel injection, exhaust system, valve spring rates, compression ratio and the normal environmental factors such as fuel, ambient temperature and humidity etc.

The 4AG intake and exhaust cams are interchangeable, providing that the exhaust cam has the distributor gear (not necessary for digital spark advance systems). Remember, too much cam will make the engine run worse, not better. The power will come on higher in the RPMs. Idle will be poor and emissions will be bad (if you cared).



View of shims wiped by an 8.3mm lift HKS cam shows it is using all the available area. The Ramp design is critical, so that the shim edge does not catch the cam lobe. Also notice the under cut in the bearing saddle. Extra thick shims will interfere with the cam-bearing journal. Therefore it is critical the base circle of the camshaft not be less than the diameter of the cam bearing.

[BigMike]

4A-GE 16V Camshaft Comparisons:

Duration
Lift
Intake opening
Exhaust opening
Comments

232°
7.1mm
8°BTDC
47°BBDC
Stock 4AG(Z)EU used on 90~91 Hi-comp. AE92 and supercharged AW11. P/N Intake 13501-16030. Ex. 13502-16020, Good turbo cam. Keeps exhaust pressures high without blowing back though intake manifold.

240°
7.56mm
9°BTDC (Stock -max lift @ 111°)
51°BBDC (Stock -max lift @ 111°)
Stock 4AGEU used on AE86 and AW11. P/N Intake 13501-16010. Ex. 13502-16010. Some have found good power setting the maximum lobe lift for the exhaust at 100°BTDC and intake at 100°ATDC. For more bottom end power retard the exhaust 4° and advance the intake 3°. For more top end, advance intake 4°and exhaust 3° from stock settings.

244°
.322” (8.2mm)
Web – p/n 45-082, Grind number 294; Duration @ .050” lift is 218°. Increases overall power. Ground on new billet cams. Works with factory injection or carburetors.

248°
7.45mm
HKS - p/n 2202-RT030, Can be used on 4AGZE

250°
.350” (8.9mm)
Web – p/n 45-092, Grind number 101; Duration @ .050” lift is 228°. Increases mid and upper RPM power. Ground on new billet cams. May cause fair idle on fuel injected engines.

256°
7.6mm
TRD - no longer available. Good bottom-end power and plenty of mid-range for passing.

256°
7.9mm
Toda - p/n 02.TD.CS4AG0S1

256°
8.35mm
HKS - p/n 2202-RT031, Can be used on 4AGZE

256°
8.5mm
Toda - p/n 02.TD.CS4AGBF2, Recommended to use Toda’s valve train kit, i.e., under bucket shims

256°
9.0mm
Toda - p/n 02.TD.CS4AGCJ1, Recommended to use Toda’s valve train kit, i.e., under bucket shims

257°
.398” (10.1mm)
Web – p/n 45-131 (Hard-weld), Grind number 286; Duration @ .050” lift is 226°. Designed for off-road and stadium racing. Requires under bucket shims.

264°
7.6mm
26°BTDC
68°BBDC
TRD - no longer available. Increased performance, needs headers, more performance with higher compression. Mfg. recommends setting the cam at max lift for the intake at 106° ATDC and exhaust at 116°BTDC.

264°
7.9mm
Toda - p/n 02.TD.CS4AGCJ2

264°
8.35mm
HKS - p/n 2202-RT032, Can be used on 4AGZE

264°
8.7mm
Toda - p/n 02.TD.CS4AGCJ3, Recommended to use Toda’s valve train kit, i.e., under bucket shims

264°
8.9mm
Toda - p/n 02.TD.CS4AGAI1, Recommended to use Toda’s valve train kit, i.e., under bucket shims

272°
7.5mm
TRD - p/n intake, 13501-AE871, ex. 13502-AE871. Increased performance, needs headers, more performance with higher compression, approaching limits of stock EFI, works best with side drafts. Ex. max lift set at 98° BTDC. In. max lift set at 100° ATDC. Will work with new (suggested) factor valve springs.

272°
7.8mm
Toda - p/n 02.TD.CS4AG0C2

272°
7.9mm
Toda - p/n 02.TD.CS4AG0A2

272°
8.35mm
HKS - p/n 2202-RT033, Using both intake and exhaust on a stock Supercharged 4AGEZ has less bottom end below 3,000, strong mid to high end power.

272°
8.5mm
Toda - p/n 02.TD.CS4AG0P1, Recommended to use Toda’s valve train kit, i.e., under bucket shims

272°
8.7mm
Toda - p/n 02.TD.CS4AG0B2, Recommended to use Toda’s valve train kit, i.e., under bucket shims

272°
8.9mm
Toda - p/n 02.TD.CS4AGAI2, Recommended to use Toda’s valve train kit, i.e., under bucket shims

272°
9.9mm
Toda - p/n 02.TD.CS4AG0P4, Must use Toda’s valve train kit, i.e., under bucket shims

272°
10mm
TRD - p/n ex. 13502-AE831. N2 and Rally cam has good bottom-end torque and strong mid-range, revs to 7,500 RPM. (requires race engine prep. and mod.s) Ex. max lift set at 100° BTDC

272°
10.3mm
Toda - p/n 02.TD.CS4AGCJ4, Must use Toda’s valve train kit, i.e., under bucket shims

276°
.384” (9.8mm)
Web – p/n 45-021 (Hard-weld), Grind number 119; Duration @ .050” lift is 240°. Good overall power for off-road racing. Requires under bucket shims.

280°
10.3mm
Toda - p/n 02.TD.CS4AG0J4, Must use Toda’s valve train kit, i.e., under bucket shims

284°
.395” (10mm)
Web – p/n 45-071 (Hard-weld), Grind number 110; Duration @ .050” lift is 256°. Strong mid and upper end power for off-road racing and pro-rally. Requires under bucket shims.

288°
7.5mm
57°BBDC
TRD - p/n intake, 13501-AE861, ex. 13502-AE861. Very strong power increase from 4,000 to 7,000 +RPM, less bottom end (does not idle very well). Used as an exhaust cam with 304° intake in TRD rally car (max lift @ 98° BTDC). Will work with new (suggested) factor valve springs.

288°
7.8mm
Toda - p/n 02.TD.CS4AG0C3

288°
8.3mm
HKS - p/n 2202-RT034, Can be used on 4AGZE

288°
8.5mm
Toda - p/n 02.TD.CS4AG0P2

288°
8.7mm
Toda - p/n 02.TD.CS4AG0B3, Recommended to use Toda’s valve train kit, i.e., under bucket shims

288°
10.0mm
Toda - p/n 02.TD.CS4AG0I1, Must use Toda’s valve train kit, i.e., under bucket shims

288°
10.0mm
TRD - p/n ex. 13502-AE821. Rally cam has less bottom-end torque more HP on top, revs to 8,000 RPM. (requires race engine prep. and mod.s) Max lift set at 100° BTDC

288°
10.35mm
HKS - p/n 2202-RT035, Can be used on 4AGZE

296°
11.0mm
TRD - p/n ex. 13502-AE951. Used on the late model AE92 Hi-comp. Head with slightly different porting configuration. Intake max. lift set at 102° BTDC.

300°
10mm
62°BTDC
76°BBDC
TRD - p/n ex. 13502-AE811. Japanese N2 racing cam. has less bottom-end torque more HP on top, revs to 8,000 ~ 10,000 RPM. (requires race engine prep. and other mod.s). Max lift set at 102° BTDC, exhaust and 98° ATDC, intake.

304°
7.5mm
52°BTDC
65°BBDC
TRD - p/n intake 13501-AE851, ex. 13502-AE851. Japanese Group A racing cam, very strong power increase from 4,500 to 7000 RPMs. (requires race engine prep. and mod.s) Max lift set at 100° BTDC, exhaust and 100° ATDC, intake. Will work with new (suggested) factor valve springs.

304°
7.8mm
Toda - p/n 02.TD.CS4AG0C4

304°
8.3mm
HKS - p/n 2202-RT036, Can be used on 4AGZE

304°
8.5mm
Toda - p/n 02.TD.CS4AG0P3

304°
8.7mm
Toda - p/n 02.TD.CS4AG0B4, Recommended to use Toda’s valve train kit, i.e., under bucket shims

304°
10mm
62°BTDC
76°BBDC
TRD - p/n intake 13501-AE801, ex. 13502-AE801. Japanese N2 & Formula Atlantic racing cam. has less bottom-end torque more HP on top, revs to 8,000 ~ 10,000 RPM. (requires race engine prep. and other mod.s). Max lift set at 102° BTDC, exhaust and 98° ATDC, intake.

304°
10.35mm
HKS - p/n 2202-RT037, Can be used on 4AGZE

304°
10.5mm
Toda - p/n 02.TD.CS4AG0C1, Must use Toda’s valve train kit, i.e., under bucket shims

304°
10.7mm
TRD - p/n exhaust 13502-AE881

304°
11.0mm
TRD - p/n intake 13501-AE951, ex. 13502-AE901. Used on the late model AE92 Hi-comp. Head with slightly different porting configuration. Intake max. lift set at 102° ATDC.

310°
10.5mm
Toda - p/n 02.TD.CS4AG0T1, Must use Toda’s valve train kit, i.e., under bucket shims

312°
11.0mm
TRD - p/n intake 13501-AE901. Used on the late model AE92 Hi-comp. Head with slightly different porting configuration. Intake max. lift set at 102° ATDC.

320°
10.0mm
TRD - p/n intake 13501-AE811

320°
10.8mm
Toda - p/n 02.TD.CS4AG0A4, Must use Toda’s valve train kit, i.e., under bucket shims

320°
11.0mm
TRD - p/n intake 13501-AE881


4A-GE 20 valve Camshaft Comparisons:

Duration
Lift
Intake opening
Exhaust opening
Comments

256°
8.5mm
Toda - VVT intake. AE101 4AG 20valve

264°
8.7mm
Toda - VVT intake. AE101 4AG 20valve

256°
8.5mm
Toda -exhaust. AE101 4AG 20valve


* Note Toda has 20 different profiles for the 4AG 20 valve.

304°
10.8mm (Fr, Rr)
10.2mm (Ctr)
TRD - p/n Intake 13501-AE001, AE101 4AG 20valve

304°
10.8mm
TRD - p/n Ex. 13502-AE001, AE101 4AG 20valve

Listing of part numbers illustrate factory differences. Part numbers may vary depending on original country of sale and are subject to change without notice and may no longer be available. Check with your supplier.

Crank angle reference with #1 piston; BTDC = Before Top Dead Center, ATDC = After Top Dead Center, BBDC = Before Bottom Dead Center

Duration, lift and opening and closing angles are approximate. Different manufactures measure and report cam shaft profiles differently and are sometimes over stated and optimistic. Spec. comparisons could be misleading and better suited for comparison between the products within one manufacture.

Requires race engine prep. and mod.s refers to ports enlarged & polished, 32mm intake valves & 27.5mm exhaust valves, under bucket shims, machined spring seats for greater installed height, at least 12: 1 compression and small combustion chamber.

Note each tooth of the camshaft sprocket equals 20° of crankshaft rotation. (36 teeth on cam, 18 teeth on crank)

HKS Cams are ground to exact specifications from new billets of high nickel iron alloy that equal or exceed the OEM units.

Toda is the oldest supplier of 4AG racing cams in Japan and currently uses Toyota factory blanks as a basis for their billets.

TRD camshafts are precision-ground from new billet stock.

Web-Cams camshafts are precision ground onto new cast alloy stock, double heated for long life with some profiles having a welded hard-face overlay (Hard-welded) for increased durability on their higher lift models.

Toyota shock shims are available from 2.5 ~ 3.3mm thickness.

Typical profile of a camshaft with its features defined.

References:

TRD - Corolla, Levin, Sprinter, Trueno special Edition Bible, TRD Toyota Racing Development Japan, published 1996.

Toysport, Joji Luz, Gardena California

Club 4 AG Technical Bulletin Board respondents, Bill S. and Psycho

AKH Trading U.S.A., TODA Racing, Irvine California

High Performance Honda Builder’s Handbook, by Joe Pettitt, 1996, Cartech publications, Brooklands Books LTD.

Web Cams catalog and article titled In search of the “perfect” Camshaft, Cam-Tech. by Bruce Simurda, with assistance from Web-Cam, Riverside California
Send User a Private Message

[BigMike]

The cams I have available are a 7.9mm, 8.1mm, 8.35mm lifts. Kevin has the 7.9mm and 8.1mm. Put thr 8.1 as your intake, and the 8'35 as the exhaust. Pulley, exhaust. Get in sit down, shut up, yeeehaww

Yeah, this sounds really, really great Bill. I really like the unequal cams, I like the higher exhaust lift. What are the difference in durations of these cams? I would like to go this route in late July when I start adding some power to the engine.

Thanks man,
Mike

[Sirdeuce]

As for the adjustable timing gear, split the overlap. More at idle, or low/no boost, and increase at higher RPM's. Keep the cams the same duration. If you want to play with the overlap to see what you want before you get the pulley built you could use a set of my cams. I'll pull the AEM's off the FX, they're easy enough to read. I have a degree wheel you could use to get your baseline cam timing. If you need, I can walk you through the use of the degree wheel.

[Sirdeuce]

Sorry, those lifts went with the previous stated 264* cams. I have a set for my engine running 264* with an 8.7mm lift for my exhaust, and a 9.0mm for the intake. I'm a little reserved about the exhaust as the 8.35mm would give a slightly better torque curve. I could go with a 256* 8.7mm lift on the exhaust, but I would lose a bit of HP in the process.