Intake cam lift?

[SlushWagon]

I was at a pick-a-parts this morning looking for odd bits to my sw2 and I walked by a 96 auto sc2, noticed the valve cover hadn't been touched or much of anything in the engine bay. Didnt plan on it but I walked out with everything I needed plus a intake camshaft.
Got home and measured for lift, I'm getting a steady .353 across all of the lobes. Is this a tipical measurement? I was looking at getting the smaller Crower camshafts but as far as lift goes this stock one has just a hair more. I'm expecting the Crower would have more duration though.

[fetchitfido]

'00ish-'02 specs are a bit buried here: http://www.differentracing.com/tech_...nginespecs.htm
'91-'99iish are here: https://sixthsphere.com/showthread.p...ft-Information

[billr]

I'm only going to peek into this "rabbit hole", but doesn't the '00-'02 have rockers? I don't think those lifts ('00-'02)are pertinent to the '96 the OP grabbed/measured.

[Waiex191]

My '99 has rockers as well.

[OldNuc]

They are better described as roller followers with minimal lift multiplication and the 99+ cams have slightly different profiles but the final lift is comparable and the various early years have slightly different specifications as well.

[SlushWagon]

From what I could tell the 96 had the ssme style as my 94. Been hard to find any pre-99 dohc in my area and from I know those are when the heads switch things to a roller.
Fletch thanks for the link, that's where I remember seeing am info. If their measurements are right on the duel intake swap then I don't see the point in getting the small Crower cam now.

[Saturn Night]

Originally Posted by billr

I'm only going to peek into this "rabbit hole", but doesn't the '00-'02 have rockers? I don't think those lifts ('00-'02)are pertinent to the '96 the OP grabbed/measured.

1999 has flat-tappet camshafts and lifters, like the 1991-1998 DOHCs. 2000-2002 has roller camshafts and roller lifters.

[OldNuc]

Incorrect! 99 is a narrow head engine just like the 00, 01, and 02. All parts swap and the cams have roller followers. The final valve lift is likely identical to the 98. If you are real curious it is relatively easy to measure.

[NWSaturn247]

Good to know OldNuc, thanks! I figured only '00-'02 had the rollers. Makes just a little more efficient?

https://youtu.be/2-HgHYJb-FQ

Looking forward to inspecting when I replace the valve cover gasket.

[OldNuc]

No, the issue was generated by the EPA deciding that they were going to make a rule eliminating zinc and phosphorus from engine oil. They did not actually make a complete elimination rule but it did cause all engine manufactures to scramble to address the proposed issue. This stared several years before the 99 engine hit the market and the head redesign was to address what became a non problem.

[NWSaturn247]

Thank you OldNuc. Just wondering the change that caused the slight uptick in EPA rating in '99+ models

[OldNuc]

The usual reason for those minor changes are the result of a change in the mandated test routine. There is nothing obvious in the engine design that would account for it.

[Saturn Night]

Originally Posted by OldNuc

Incorrect! 99 is a narrow head engine just like the 00, 01, and 02. All parts swap and the cams have roller followers. The final valve lift is likely identical to the 98. If you are real curious it is relatively easy to measure.

My mistake. I looked up a complete, used head, and it showed "99-only" for an interchange. I checked the Saturn P/N and GM shows the cams as 1999-2002 interchange.

Sorry about that, Nuc.

[OldNuc]

The heads are different because of the intake manifold and EGR porting.

[Saturn Night]

Originally Posted by NWSaturn247

Thank you OldNuc. Just wondering the change that caused the slight uptick in EPA rating in '99+ models

When the Saturn S-Series was in production, the EPA used to actually test the cars with an exhaust gas analyzer, to estimate fuel consumption based on the emissions content calculated. They drove the car on a chassis-style dyno meter, for up to 10 miles, simulating both city driving(stop and go), and highway driving(0mph-55mph constant).

I agree with Nuc, there wouldn't be much of any noticeable difference in the design of the engine, that would net an average of 1 extra mpg.

Differences observed in EPA testing could be brand of fuel, atmospheric conditions on the testing day, and/or the driving habit of the person conducting the test.

The only real benefits of a roller camshaft vs a flat-tappet style camshaft are the potential to rev to higher rpms and a minuscule gain in mechanical engine efficiency.

I can only site one anecdotal reference to roller camshafts having little impact on fuel economy: my 1984 Pontiac Fiero & my 1991 Pontiac Grand Am

Both had/have 3-speed automatics with lockup converter. Both had/have the 2.5L Iron Duke engine. The Fiero was rated at 91hp @ 4,200 rpm(132 lbs-ft @ 2,800 rpm) and observed fuel economy was about 26mpg(about 260 miles on its 10.2 gal tank). My Grand Am is 200 lbs heavier, rated for 110hp @ 5200 rpm(135 lbs-ft @ 3,200rpm). Both cars have about the same drag coefficient, which is correlated to observed fuel economy. The THM-125C transmission uses similar gear ratio and final drive ratio in every car it was equipped to. Major difference was the torque converter, as Duke-equipped THM-125Cs had a different stall speed than the less-powerful Chevy 2.0L OHV TBI, Chevy 2.2L OHV TBI, and Chevy 2.2L MPFI/2200 SFI models used up to 1996.

The changes in performance of each engine are due to four changes within the engine: 1984-1987 Pontiac 2.5L engines have no balance shaft, HEI distributor ignition, gear-to-gear camshaft timing, and flat-tappet camshafts.

1988-1991 Pontiac 2.5L engines have the balance shaft, DIS ignition, a roller camshaft, and a timing chain.

My Grand Am observes about 25mpg(350 miles on its 14.0 gal tank), despite the improvements to the engine design for both thermal and mechanical efficiency that are above mentioned and despite having broader torque curve between peak torque rpm and peak HP rpm range(2,000 rpm range as opposed to the more narrow 1,400 rpm range of the older Dukes).