Camshaft Information

[DriftPunk]

There is far more to grinding a cam than just duration and lift. Ramp rates/overall dwell at high lift/valve closing-opening events among other things can all change the way a cam runs. Without advertised cam specs it makes it really hard to choose a cam, other than my borthers wife's uncle had this cam and it pulled like fuck.

They grind stock cams, not cut new ones, so the ramp rate is more or less set, closing and opening events (relative to cam position) are mostly controlled by the ramp rate, and the fact that the centerline does not get changed (adding duration will make them take place sooner and end later though). All they do is cut the base circle to add lift, shave the nose for extra dwell, and cut the base circle to oval it out to add duration.
They are re-grinds, not complete new cams (except the crowers) like other vehicles.
So, duration, lift, and dwell are the main things changed.

As far as the cams go, everyone knew which made more power, and that more power = less bottom end, therefore, they chose whichever they needed more, or where in between.

Gude Bullfrogs made the absolute most power, but had bad bottom end, and loped a lot, fuel tuning was a must.
SDA street were generally considered the most mild, and easiest to run off the stock pcm without problems, Crower's more mild cam is probably about the same
American Custom Cam Stage 1/MidPenn Street cams have a little more top end than the sda's but a bigger loss in low end torque
Gude Street has about the same power as the AmCam/MP Stage 1 up top, but a little less noticeable loss on the bottom end torque.
Gude Race, and MidPenn Race are about the same gain/loss. The big Crower is a similar gain to those 2, but a little better on the bottom end.
Ian's chopstix are the best for turbos.

All the aggressive cams (Gude bullfrog, Gude Race, Midpenn Race, and Big Crower) would require fuel tuning. Ian's would be on a turbo build, so fuel tuning would be required anyway.
The more mild cams could be run off the stock pcm, with some gains, but would see better gains out of tuning.

[DriftPunk]

Another thing I was thinking of, was wouldn't you NOT want too much overlap at 0.050"? Since the headgasket is only 0.051" thick, and the piston sits 0.012" out of the hole, that leaves 0.039 clearance piston-to head at TDC, so if the valves (all 4, since there is overlap) are open 0.050" or more, they would be contacting the pistons (not sure how much extra clearance there is, factoring in the dish and valve reliefs, but that would put them 0.011" inside the piston face... Even worse if you have a shaved head.

Edit:
I forgot the dish is like 0.060" but things have got to be getting pretty close together at that point.
Then if you have the head shaved 0.040" you only have 0.010" clearance to the bottom of the dish.
Better hope you have no overlap at 0.060"

[dynonacht]

The sda cam that came in my engine I bought from 98sl2fast supposedly runs great on stock pcm and maintained good afr.

[dynonacht]

I have yet to confirm this.

[DriftPunk]

Yeah, it's pretty mild, so it runs fine off the pcm, and has a little bit of gain untuned. But with some tuning will be a lot better.

[TruboSC2]

I have a turbo cam from Gude that barely idles even with a tune lol

[Joel]

Another thing I was thinking of, was wouldn't you NOT want too much overlap at 0.050"? ...<snip>... things have got to be getting pretty close together at that point.

While you're assembling a fresh engine, clay it, then open up valve reliefs a little if needed.

For one you're just swapping cams on, make sure you're at TDC on the crank, then spin the cams to make sure they don't contact before you install the timing chain.

For either case, because the valve springs are going to put the cam under serious (although normal) tension and make it harder to tell what's going on, low-tension "checking springs" are the way to go, but you'll need a whole set. Crane cams sells them in pairs, not sure about other vendors. I've read on a few forums you can find something real similar in your local hardware store. You just need the valves to stay put when not being acted upon by the cam, so a light spring is the way to go.

The reason this isn't a typical concern is that the valves are recessed up into the chamber, instead of being right on the deck surface of the head.

[DriftPunk]

While you're assembling a fresh engine, clay it, then open up valve reliefs a little if needed.

For one you're just swapping cams on, make sure you're at TDC on the crank, then spin the cams to make sure they don't contact before you install the timing chain.

I wouldn't spin the cams at TDC, they have 0.300+ lift and even with 0.060" recess in the chamber (just a guess), 0.038" piston-to-head, and 0.060" dish... that's only 0.158" clearance at TDC

The reason this isn't a typical concern is that the valves are recessed up into the chamber, instead of being right on the deck surface of the head.

That's why I said especially with a head shave as a typical shave is 0.030"-0.040"

Side note: Does anyone know what the recess depth is factory? I'm assuming in the 0.060"-0.070" range (or more), as people have shaved the head 0.060" or so and I haven't heard any issues with starting to shave the valve faces from shaving it that far...

[anti-rice 01sl2]

I'm bumping this up. Just spoke with both Crower and ACC today. Every spec on those match exactly what we have here.

Joe, from ACC, on the other hand I spoke with for a while and he was a pleasure to speak to. According to him, they offer 3 different cam profiles. I plan on making another phone call out to them tomorrow and double check the specs I hastely jotted down while driving. None of what he told me matched what we have here at all.

[DriftPunk]

I'm bumping this up. Just spoke with both Crower and ACC today. Every spec on those match exactly what we have here.

Joe, from ACC, on the other hand I spoke with for a while and he was a pleasure to speak to. According to him, they offer 3 different cam profiles. I plan on making another phone call out to them tomorrow and double check the specs I hastely jotted down while driving. None of what he told me matched what we have here at all.

Would be great to get some confirmation on that.

[anti-rice 01sl2]

According to Jim, who by this point thinks I'm trying to rip off his specs lol.

Stage 1
IN/EX .340 x 250°

Stage 2
IN/EX .370 x 260°

Stage 3 he won't sell to just anyone, require the Kawasaki lifters for sure, and they mostly match the specs seen for what you guys are calling stage 2 above.

[siris]

According to Jim, who by this point thinks I'm trying to rip off his specs lol.

Stage 1
IN/EX .340 x 250°

Stage 2
IN/EX .370 x 260°

Stage 3 he won't sell to just anyone, require the Kawasaki lifters for sure, and they mostly match the specs seen for what you guys are calling stage 2 above.

So should I change the op?

[DriftPunk]

Yes.

Change:
- American Custom Cams Stage 1: (IN .370 x 270°/EX .340 x 260°) to "- American Custom Cam Stage 2: (IN/EX .370 x 260°)"
and
- MidPenn Race: (IN .400 x 260°/EX .380 x 256°) - [Now American Custom Cams Stage 2]* to "- MidPenn Race: (IN .400 x 260°/EX .380 x 256°) - [Now American Custom Cam Stage 3]*"

and add:
- American Custom Cam Stage 1: (IN/EX .340 x 250°)

Should read:

Brand & Name: Part Number (Intake Lift x Duration/Exhaust Lift x Duration)

- American Custom Cam Stage 1: (IN/EX .340 x 250°)
- Crower: E46973 (IN/EX .350 x 250°)
- Gude Street/Strip: SACS01 (IN/EX .360 x 225°)
- SDA: (IN/EX .368 x 220°)
- American Custom Cam Stage 2: (IN/EX .370 x 260°)
- Gude Pro Race: SACS04 (IN/EX .400 x 238°)*
- Gude Bullfrog: (IN/EX .400 x 240°)*
- MidPenn Race: (IN .400 x 260°/EX .380 x 256°) - [Now American Custom Cam Stage 3]*
- Crower: E53887 (IN .400 x 264°/EX .392 x 275°)*
- Gude SOHC: (IN/EX .410 x 261°)
- Ian Chopstix Turbo: (IN/EX .370" x 284° (@ .001"))

*Will need solid lifters
Also note that all these specs/measurements and aftermarket cams with the exception of the mystical SOHC Gude cam are for the 91-98 heads.


Also, American Custom Cam has a Gen 3 cam grind, and a SOHC cam grind. Or so I've heard. Don't know the specs though.

[TruboSC2]

I wonder how heavy of a3rd gen cam

[mostmint]

FWIW I measured some stock cams (from a 95 DOHC) for total lift:
.347 intake
.336 exhaust

Where did you get your Crower info? I was looking on their website and found no reference to those parts #s or Saturn. Clearly they exist I'm just wondering costs and how to acquire.

[DriftPunk]

2nd gen cams specs are .340" lift intake, .335" lift exhaust. I measured mine ( I have some that I pulled from a 94 and a 98 ), and had my numbers verified by a cam shop.
The Crower info is from the cam card number. You have to go to http://www.crower.com/cam-card-finder/ and put in the number.
E46973 and E53887
The "E" designates it as a custom work order

From their site:

If the number on the cam starts with a letter it is a custom ground camshaft not a catalog or shelf camshaft.

[anti-rice 01sl2]

So I received my stage 2 cams from ACC yesterday. A pic of the cam card...

[siris]

So I received my stage 2 cams from ACC yesterday. A pic of the cam card...

How much did you pay for them @anti-rice 01sl2

[anti-rice 01sl2]

Don't remember man. Like $200+

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[hinsonracing]

Okay guys I need some serious brass tacks and hard facts. I'm in no way new to working on cars and engines (Master ASE certified for 12 years), however, I am new when it comes to modifying from stock. I dirt track race my saturns and have built my own engines. So far I have racked up some wins and championships, but competition is getting tougher to keep up with and out run. I have had luck with just stock bores and simple dual intake swaps with a lightweight flywheel. I want to dig a little deeper and here is where I need some help/advice. I want to degree my engine in a little better because I have roughly .060" shaved between the head and block. I already know that the precise timing has been changed do to the machine work but I am having trouble with the figures I've measured trying to degree (please NOTE math is not my forte) Here is what I have measured.

I apologize if my TDC, ATDC, Acronyms aren't right. I am used to just assembling with factory marks.

Intake @ .050"
Opens at 10 degrees ATDC
Closes at 26 degrees ABDC

By what I have learned reading on the subject her is my equation for the intake.

10 + 226 = 236
235÷2 = 118
118 - 107.25 (centerline) = 10.75 degrees retarded?

Being I have dual intake camshafts I dont have a real solution for the equation but here is my measurements.

Exhaust @ .050"
Opens at 50 degrees ABDC
Closes at 168 After ABDC

Any and all actual help not opinions would be greatly appreciated.