[fittyfod]

I had a local machine shop order me a cam for my 302. I asked for Wildly Mild Street performance- Daily driver...

He got me a J2N grind Cam-from somehwere- 205/215 112 degrees?? 265/275 .450/.475
Hes gone so Im on my own. Need to understand what I have. Now my problem:

It seems the engine will max out at 4500-4750RPM.
Stops producing hp and torque. Just seems sort of low.

Now the valve job included oversized intake and exhaust valves in stock truck heads that were supposedly decked. I cant be sure. Machinist didnt measure them. I was just told they were decked when I got this engine that this machinist went through for me.

So Im considering changing out the springs for something stiffer. But need to understand. Any help would be appreciated!

b

[turbolover]

That's a good daily driver cam, and the power peak sounds about right. Change the springs if you have float problems otherwise leave it alone.

[ericnova72]

If the valve springs are old or don't match the cam it would be the first thing to look at, but there are other things that can produce like symptoms. The rpm point you describe is the typical point for valve float to occur with weak springs.

Cam should run right up to 6000 easily, might be done on power ar 5500-5800 but should have no problem revving to 6000+.

A little more detail about the engine would help - carb, intake, headers or not, ignition initail timing and total timing, fuel pump size and line size, anything else you want to add to help pin things down.

[chevyguy13]

That is a pretty mild cam. 205 is your intake duration @ .050 lift. 215 is your exhaust duration at .050 lift. (This is how long your valves stay open)

The 112 is your lobe seperation. (How far apart, in degrees, that your intake and exhaust lobes are.)

The 450 is your intake lift and the 475 is your exhaust lift. (How far the valves open) IMO this cam will be fine with stock heads/valve springs. Im not sure where the cam stops making power, but its probably some where around 5,000 RPM. The cam will most probably have a stock sound, maybe a little chop, but not much with that 112 Lobe seperation. If you are "running out of power" that low in the RPM range, it could be a number of things. (Carb, timming, week valvesprings causing valve float, etc.) I hope I answered your question...

Chevyguy13

[fittyfod]

Originally Posted by ericnova72

If the valve springs are old or don't match the cam it would be the first thing to look at, but there are other things that can produce like symptoms. The rpm point you describe is the typical point for valve float to occur with weak springs.

Cam should run right up to 6000 easily, might be done on power ar 5500-5800 but should have no problem revving to 6000+.

A little more detail about the engine would help - carb, intake, headers or not, ignition initail timing and total timing, fuel pump size and line size, anything else you want to add to help pin things down.

Im concerned its not exactly what I wanted...I wanted to be a little more aggressive I think. I was expecting the engine to have a lope to it and have some more balls. The engine does not lope at all at idle.
45-4750RPM seems just too low to stop making power. As for the engine specifics:
Holley 600cfm carb out of the box no adjustments made
Weiland Dual plane intake 7013 I think?
Pertronix Billet Dist vacum advance and MSD 6a Ignitor, flame thrower coil
timing is currently at 15 degrees BTDC I believe or after? I just remember marking 15 and 0 on bal. Read that 15 is the way to go...
Sanderson Shorty headers
Fuel pump is a Holley HP, I think its 7 PSI internal regulator.
I have not measured vacum
Fuel line is 3/8 Hard line from pump to 3 feet before carb, then filter to carb.

[techinspector1]

Originally Posted by chevyguy13

That is a pretty mild cam. 205 is your intake duration @ .050 lift. 215 is your exhaust duration at .050 lift. (This is how long your valves stay open)

The 112 is your lobe seperation. (How far apart, in degrees, that your intake and exhaust lobes are.)

The 450 is your intake lift and the 475 is your exhaust lift. (How far the valves open) IMO this cam will be fine with stock heads/valve springs. Im not sure where the cam stops making power, but its probably some where around 5,000 RPM. The cam will most probably have a stock sound, maybe a little chop, but not much with that 112 Lobe seperation. If you are "running out of power" that low in the RPM range, it could be a number of things. (Carb, timming, week valvesprings causing valve float, etc.) I hope I answered your question...Chevyguy13

Good explanation. I have a Crane catalog in front of me that describes a very similar cam, part number 113901. RPM power range 1200-5000, 204/216, 260/272, 112, 0.427"/0.454", timing events -5/29/45/-9, Excellent low end torque and horsepower, smooth idle, daily useage, off-road, towing, economy. Used primarily in 305 and 350 near-stock engines for mild performance applications, 2200-2600 cruise RPM's, 8.0:1 to 9.5:1 static compression ratio advised.

[techinspector1]

Originally Posted by fittyfod

So Im considering changing out the springs for something stiffer.

If I were going to do this, I would also pin the rocker studs. More spring pressure might exceed the pressed-in pressure and pull the studs out of the heads.
http://performanceparts.com/part.php?partID=183135

You should also realize that more spring pressure puts more stress on the lifter/lobe interface, so you want to start covering your butt with extreme pressure lubricants in the oil. Here is a list of screw-ups that a fellow can do when installing a flat tappet cam. I suggest you read them over and take the appropriate action....extreme pressure lubricants that used to protect the cam have been removed from off-the-shelf motor oils because they plugged up catalytic converters, costing the OEM auto makers money on warranty claims.
http://www.crankshaftcoalition.com/w...ips_and_tricks

[fittyfod]

Originally Posted by techinspector1

Good explanation. I have a Crane catalog in front of me that describes a very similar cam, part number 113901. RPM power range 1200-5000, 204/216, 260/272, 112, 0.427"/0.454", timing events -5/29/45/-9, Excellent low end torque and horsepower, smooth idle, daily useage, off-road, towing, economy. Used primarily in 305 and 350 near-stock engines for mild performance applications, 2200-2600 cruise RPM's, 8.0:1 to 9.5:1 static compression ratio advised.

That is interesting. I can punch it and the thing goes but I would be dissapointed if it craps out at this RPM

What would cause the engine to reach 4500 RPM shift to third (C4 trans) then goes down to 4k and hangs there for a few seconds then starts to build again but the engine seems to be maxing out- not making much power after that.
That intake I have is in the 3500-6500 RPM range.

[fittyfod]

Originally Posted by techinspector1

If I were going to do this, I would also pin the rocker studs. More spring pressure might exceed the pressed-in pressure and pull the studs out of the heads.
http://performanceparts.com/part.php?partID=183135

There arnt any rocker studs- ITs the fulcrum style rockers with a bolt. Non adjustable

[techinspector1]

Originally Posted by fittyfod

There arnt any rocker studs- ITs the fulcrum style rockers with a bolt. Non adjustable

Sorry, when I saw 302, I automatically thought 4.00" x 3.00" Chevy.

[ericnova72]

Besides the possible valvespring issue, Could be timing, but I'm thinking small engine size versus vehicle weight, it just can't make enough power to pull well in third gear, not enough torque or torque multiplication. The 5.0l 302 Mustangs are the same way unless they have a lot of gear in the rear axle.

[turbolover]

If you want some lope with good midrange get a cam with about 210/210 duration and a tight lsa- like a 106. Sounds like you may have valve float.

[techinspector1]

Originally Posted by fittyfod

Im concerned its not exactly what I wanted...I wanted to be a little more aggressive I think. I was expecting the engine to have a lope to it and have some more balls. The engine does not lope at all at idle.

The machinist may have saved your butt and you don't even realize it. More cam with a lope requires more duration/shorter LSA which in turn requires more static compression ratio which in turn requires more torque converter and more rear gear. You cannot have a lopey cam in a motor with low static compression ratio. It won't work. You want lopey, take the motor apart and rebuild it 10.0:1 to 10.5:1 static compression ratio. Conversely, you can use one of those fosdick Thumper cams at 9.0:1 static compression ratio.

Originally Posted by fittyfod

Sanderson Shorty headers

In my opinion, junk. If you want to make power, use long tube headers.

Originally Posted by fittyfod

Fuel pump is a Holley HP, I think its 7 PSI internal regulator.

Too much pressure. Holley recommends 6 1/2 psi MAXIMUM. More pressure than that will overpower the needle and seat and blow raw fuel into the intake manifold, giving you tuning fits. Fit another pump that provides 5 1/2 to 6 max.

[fittyfod]

Originally Posted by techinspector1

The machinist may have saved your butt and you don't even realize it. More cam with a lope requires more duration/shorter LSA which in turn requires more static compression ratio which in turn requires more torque converter and more rear gear. You cannot have a lopey cam in a motor with low static compression ratio. It won't work. You want lopey, take the motor apart and rebuild it 10.0:1 to 10.5:1 static compression ratio. Conversely, you can use one of those fosdick Thumper cams at 9.0:1 static compression ratio.


In my opinion, junk. If you want to make power, use long tube headers.


Too much pressure. Holley recommends 6 1/2 psi MAXIMUM. More pressure than that will overpower the needle and seat and blow raw fuel into the intake manifold, giving you tuning fits. Fit another pump that provides 5 1/2 to 6 max.

Ok Reading the paperwork for the fuel pump- Preset at 7psi. I put in a regulator
Intake is a Weiand Action Plus 8124- "for engine speeds of 5500

Am I just at the top of this thing or can I squeeze more power out of it. It aint doing it for me...

[fittyfod]

Originally Posted by techinspector1

The machinist may have saved your butt and you don't even realize it. More cam with a lope requires more duration/shorter LSA which in turn requires more static compression ratio which in turn requires more torque converter and more rear gear. You cannot have a lopey cam in a motor with low static compression ratio. It won't work. You want lopey, take the motor apart and rebuild it 10.0:1 to 10.5:1 static compression ratio. Conversely, you can use one of those fosdick Thumper cams at 9.0:1 static compression ratio.


In my opinion, junk. If you want to make power, use long tube headers.


Too much pressure. Holley recommends 6 1/2 psi MAXIMUM. More pressure than that will overpower the needle and seat and blow raw fuel into the intake manifold, giving you tuning fits. Fit another pump that provides 5 1/2 to 6 max.

2400 stall converter, 3:25 rear gears in Ford 9" with the C4 Tranny

off the line its ok but not impressed at seat of pants...
Cruising on the highway is easy 2500 80 MPH...I like this but want to keep making HPs and torque for atleast a little while after 3rd gear...