ZZ4 cam full specifications - Third Generation F-Body Message Boards

91Z28-350 · 05-31-2005, 01:41 PM

The ZZ4 cam always comes up in conversations here, but there doesn't seem to be a whole lot of information about it other than the .050 spec. Here's a full spec, which I think is interesting to some folks

Code:

         EPI, Inc.
          (Engine Performance Improvements for Diverse Vehicles)
PO Box 115,  Amboy WA, 98601    360-247-5858  (FAX: 247-5859)   www.epi-eng.com

February 11, 2005

ZZ-4 Cam Lobe Analysis
ZZ-4 Camshaft P/N 10185071

GM ZZ-4 Roller Hydraulic  208-316/222-340/112                                          
PV=787-785/839-814; CV@.003:=101/083; PA=369-252-330/371-230-322
                
                                  LIFT    DUR.      OPEN        CLOSE      AREA
 Lobe              Intake        -----  ------  -----------  -----------  ------
 Centerline        112.10 ATDC   0.006  264.18   16.38 BTDC   67.81 ABDC   23.04
 .050 Lift C/L     112.52 ATDC   0.020  237.33    5.08 BTDC   52.26 ABDC   22.88
 Runout            0.00090       0.050  208.32    8.36 ATDC   36.67 ABDC   22.39
 Peak Open  Acc.   0.000370      0.100  177.68   23.05 ATDC   20.73 ABDC   21.26
 Peak Nose  Acc.  -0.000253      0.150  151.91   35.84 ATDC    7.75 ABDC   19.66
 Peak Close Acc.   0.000328      0.200  125.29   49.23 ATDC    5.48 BBDC   17.32
 Lift @ TDC        0.0295        0.250   93.57   65.21 ATDC   21.22 BBDC   13.74
 Lobe Separation   112.1         0.300   45.47   89.25 ATDC   45.28 BBDC    7.06
 Peak Velocity     .00787, -.00785
 Closing Velocity @ 0.003: -.00073

                                 0.31556  --- PEAK CAM LIFT ---
                                 0.47033  --- PEAK VALVE LIFT w/1.50 rocker---
 
                
                                  LIFT    DUR.      OPEN        CLOSE      AREA
 Lobe              Exhaust       -----  ------  -----------  -----------  ------
 Centerline        112.10 BTDC   0.006  273.10   67.30 BBDC   25.80 ATDC   26.28
 .050 Lift C/L     111.12 BTDC   0.020  249.40   55.52 BBDC   13.88 ATDC   26.12
 Runout            0.00070       0.050  221.65   41.95 BBDC    0.30 BTDC   25.62
 Peak Open  Acc.   0.000373      0.100  191.82   27.44 BBDC   15.62 BTDC   24.48
 Peak Nose  Acc.  -0.000232      0.150  167.24   15.38 BBDC   28.14 BTDC   22.89
 Peak Close Acc.   0.000321      0.200  142.23    3.06 BBDC   40.83 BTDC   20.65
 Lift @ TDC        0.0492        0.250  113.62   11.13 ABDC   55.24 BTDC   17.37
 Lobe Separation   112.1         0.300   75.76   29.97 ABDC   74.27 BTDC   12.08
 Peak Velocity     .00839, -.00814
 Closing Velocity @ 0.003: -.00072

                                 0.34040  --- PEAK CAM LIFT ---
                                 0.50760  --- PEAK VALVE LIFT w/1.50 rocker ---

If you use Comp Cams method the ZZ4 cam has an ADV duration of around 264/274. Crane Cams using 0.004 tappet lift for their cams. What also is notable is that this cam should probably be installed with a 4* advance instead of straight up. The opening points are very late compared to performance cams from Crane Cams, Comp Cams, Lingenfelter, etc.

The other thing to note, is duration wise this cam is very close to the 08-302-8 cam, but it has different max lifts. The ramp rates seem OK, kind of like the non-XE Comp Cams, but the intake lobe seems lazy compared to the 08-302-8 cam. The exhaust rate is about the same as the 08-302-8 cam, but with extra lift. It's hard for me to say which cam would be better, the 08-302-8 or this cam. I'd think, however, if you're heads can handle the lift of the ZZ4, you may have better choices in the 08-304-8 or the 08-501-8 cams.

The ZZ4 cam is heavily biased towards exhaust, and I'm wondering how well the stock ports and chambers on the 081/083 heads would do with this or if it would be better to stick a 1.6 rocker on the intake and keep the 1.5 on the exhaust.

The advantage of the ZZ4 cam is cheap, but one may be better off in the long run with a better cam like the 08-304-8 (266HR) or the 08-501-8 (XR264HR) when you try to make up the "deficit" on the intake lobe for the ZZ4 cam, such as getting 1.6 rockers for the intake.

I don't have enough experience with cam timing and head flow rates to say how well of a match this cam is to the stock 081/083 flow. This comes up quite often, but it's difficult for me to truly quantify the micro differences of the cam in relation to the heads (most people who pick up the ZZ4 cam look to do it on relatively stock/unported heads).

What do you all think? Would the XR264HR have too much flow for the 081/083 stock chambers/ports (assuming the valve guides are cut for the lift of the ZZ4)? How about the 08-304-8? How does this compare to the 08-302-8?

For reference, you can also get the full LPE cam specs from LPE cam.

91Z28-350 · 05-31-2005, 10:08 PM

No comments? Here I thought it would be interesting to spend more in depth detail on the ZZ4 cam and cam selection. Oh well. How about the interpretation that it should be installed with 4* advance?

Damon · 06-01-2005, 02:52 PM

Well, maybe I'm the only one, but I found it extremely interesting. I agree that it's a pretty mild cam in terms of accleration/deceleration rates, but it IS production cam and the factory does not like to "push the envelope" and beat up the valvetrain if they're holding the warranty on it! Plus modest ramps leave plenty of headroom to work just great with 1.6 rockers!

Agreed, if that spec is right, the cam is about "straight up" as judged by .050 event points. If you look at the centerline at .006" lift you'll notice it's even 4* further retarded than that. Advertised duration centerlines are typically 4* further retarded than .050 centerlines becuase modern cam lobes almost always lift the valve faster than they close them at low lift points. The ZZ-4 cam seems to fit that typical mold just like most other cams do.

That's the long way around the barn to say.... I agree you should probably consider installing the ZZ-4 cam 4* advanced at the chain for most applications. Then again, it's not a very big cam and I don't think it necessarily needs the low-mid RPM torque bump that a 4* advance would offer. Probably makes plenty of torque even without the advance so the engineers left it straight up to help "stretch" the upper RPM performance of such a short duration cam.

Thanks for posting the info

Mark 89Formula · 06-01-2005, 08:09 PM

I like this stuff too. I had a used ZZ3 cam measured a while back and the date agrees very closely with what you've posted. The delayed intake timing is interesting. TPIS advanced the intake about 7 degs and exhaust about 5 degs on the ZZ9 compared the ZZ3/4. I think Damon is on to something relative to extending the usable RPM range by installing the ZZ4 straight up. I'd be tempted to install it straight up with a LTR TPI setup.

An interesting thing that the Cam Pro Plus showed was that the ZZ3 set the exhaust valve down much more gently on the seat than another street performance cam I had measured at the same time. I expect it would be quite a bit quieter and easier on the valve train, something to consider for a daily driver. I have a few more cam measurement files saved off that you might find interesting. Drop me an email if you'd like a copy.

The XR264HR should make an awesome LTR TPI cam. I'd even be tempted to have a custom cam ground that combines the intake lobe of the XR264HR with the exhaust lobe of the XR270HR if running the stock 083 heads since the exhaust flow of these heads is so bad. You basically end up with a slightly hotter ZZ9 clone.

D's89IROCZ · 06-04-2005, 09:34 PM

thanx alot for this . I have been trying to find it for a bit now

all I can add is I like this cam . from just off idle it really makes some power but leaves alot to be desired up top.