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Old 04-10-2004, 05:47 PM   #1
GuyLR
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Default Stock Lift of EJ25 and EJ22 Cam?

Can anybody tell me the lift specs for intake and exhaust on the stock cams for Phase 2 EJ2.2 and EJ2.5 engines?
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Old 04-13-2004, 02:42 PM   #2
Section 8
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Lobe height, or valve lift?
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Old 04-14-2004, 12:05 AM   #3
ttboy19
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Wish I knew. Free bump.
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Old 04-14-2004, 09:46 AM   #4
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Quote:
Originally posted by Section 8
Lobe height, or valve lift?
Either, since I think the rockers are the same so the lift ratio would be too.

I'm trying to see if there is any advantage of the 2.5 cam over the 2.2 for my 2000 OBS. The duration is very similar on intake and exhaust but the 2.5 has a couple of degrees more overlap. If the lift is more then I'm going to find a set of used ones to try.
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Old 04-14-2004, 12:55 PM   #5
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I suggest reading this thread
http://forums.nasioc.com/forums/show...light=cam+lift

as well as the one in it that I linked to......should give you the answers....or at least info you're looking for.
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Old 04-14-2004, 01:42 PM   #6
GuyLR
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Quote:
Originally posted by legacy777
I suggest reading this thread
http://forums.nasioc.com/forums/show...light=cam+lift

as well as the one in it that I linked to......should give you the answers....or at least info you're looking for.
Thanks Legacy777. Looks like I had the overlap spec backwards as the 2.2 cam actually has 8 degrees vs. 7 degrees for the 2.5.
Also the lift is only different on the intake lobe where the EJ25 cam has 0.753mm (0.030") more. There are 4 more degrees of exhaust duration on the 2.5 cam. Probably not enough difference to warrant a swap unless that one degree less overlap upped the dynamic compression a bit???? I might try it if I can score some free cams.

Here are the specs from that thread:

cam base circle 34.00mm

EJ22
Intake Lift-Service limit 4.632mm
Intake Lift-Standard 4.732-4.832mm
Exhaust Lift-Service Limit 5.157mm
Exhaust Lift-Standard 5.257-5.357mm

EJ25
Intake Lift-Service Limit 5.385mm
Intake Lift-Standard 5.485-5.585mm
Exhaust Lift-Service Limit 5.517mm
Exhaust Lift-Standard 5.257-5.357mm

Cam Timing

EJ22
IVO:2 BTDC
IVC:50 ABDC
EVO:46 BBDC
EVC:6 ATDC

8 Degrees valve overlap

Intake Duration 232 degrees
Exhaust Duration 232 degrees

EJ25
IVO:1 BTDC
IVC:51 ABDC
EVO:50 BBDC
EVC:6 ATDC

7 Degrees valve overlap

Intake Duration 232 degrees
Exhaust Duration 236 degrees
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Old 04-14-2004, 09:30 PM   #7
Section 8
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Your comparisan has a flaw.

Again you need to know the lift of the valve to compare the two if you are comparing SOHC heads.

What you have is the actual cam lift, the differences between base circle and the highest point of the lobe. What you want to know is the distance the valve actually travels. To find that, you need to find the racker ratio, as it is NOT 1:1, so the difference is going to get larger than mearly comparing lobe measurments.

To complicate things, the intake and exhaust have different ratios.

Intake is something like 1.4 and exhaust is 1.38. Either way, don't believe everything that you read, you need to verify from multiple sources.

cheeRS,

Greg
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Old 04-15-2004, 07:34 AM   #8
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Quote:
Originally posted by Section 8
Your comparisan has a flaw.

Again you need to know the lift of the valve to compare the two if you are comparing SOHC heads.

What you have is the actual cam lift, the differences between base circle and the highest point of the lobe. What you want to know is the distance the valve actually travels. To find that, you need to find the racker ratio, as it is NOT 1:1, so the difference is going to get larger than mearly comparing lobe measurments.

To complicate things, the intake and exhaust have different ratios.

Intake is something like 1.4 and exhaust is 1.38. Either way, don't believe everything that you read, you need to verify from multiple sources.

cheeRS,

Greg
That's right but the rocker lift ratios on the two engines are the same so the percentage difference of lift does not vary between the two. On the intake side that would be about an extra 1.05mm of lift at the valve.

The valve timing specs match those givien me by a dealer tech that were printed out from an SOA source so I'm pretty confident they are for real.
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Old 04-15-2004, 08:50 AM   #9
Section 8
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Then why didn't you use the percentage? Because you didn't think about it till just then.

I never said anything about the two heads compared to each other, I told you how to compare the two cams for a functionary comparisan becasue your's was invalid.
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Old 04-15-2004, 09:22 AM   #10
GuyLR
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Quote:
Originally posted by Section 8
Then why didn't you use the percentage? Because you didn't think about it till just then.

I never said anything about the two heads compared to each other, I told you how to compare the two cams for a functionary comparisan becasue your's was invalid.
No, It's because I understand rocker ratios and just needed the specs on the cams. Thank you very much
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Old 04-15-2004, 10:33 AM   #11
Section 8
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Riiiiiiight. If that was the case you would know that the actual lobe measurement is absolutly worthless once it is in the head.

You didn't, and you made a bogus assumption. You realized it after the fact.

Another problem with your posts is that less overlap does not increase dynamic compression. It is an RPM dependent variable. At low RPM more overlap loses dynamic compression, at higher RPM you gain dynamic compression with more overlap.

For someone who knows so much about the topic you sure have an over simplified view on a multiple items that lead to ignorant blanket statements.

cheeRS,

Greg
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Old 04-15-2004, 11:48 AM   #12
GuyLR
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Thanks for setting me straight Section 8. I got what I was after and I hope you did too. TTFN
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