 
     |
| 1.6 rockers vs 1.52 rockers - pros and cons (Page 4/6) |
|
lou_dias
|
MAR 02, 07:18 PM
|
|
| quote | Originally posted by Notorio:
So what did you end up getting? I can't find the 1.6 ratio, 10 mm stud, Comp Cams rockers kit that includes the pushrods, at any price. |
|
I also ordered Crane 3/8" stud adapters... CRN-99148-2 and I ordered 6 of them since they are sold in pairs.
The 10mm side goes in the head and leaves a 3/8" stud for the 1.6 roller rockers...
Here's the link:
http://www.summitracing.com/parts/CRN-99148-2/[This message has been edited by lou_dias (edited 03-02-2015).]
|
|
|
|
unboundmo
|
MAR 03, 03:22 PM
|
|
|
|
sardonyx247
|
MAR 04, 08:10 AM
|
|
| quote | Originally posted by unboundmo:
Sorry sardonyx.. i have to differ on appearance.. I have the Crane 1.6 full rollers and they look beautiful!.. I love GOOOOOLD...!! I haven't had any problems running them. I included comps performance springs and running a 260/260 comp cam... Major difference from riding in other 3.4 swaps.. I'm also 9.25:1 compression (stock camaro compression for this engine) - i wanted to be reliable... but then I also have Ross forged pistons and ARI H-beam forged rods. - lighter weight and stronger than cast... to better performance. I am faster and more pep than a 4.6L mustang till about 3rd gear due to the breathing of the iron heads.
I too run Mobil1 with lucas additive..
|
|
You are comparing apples to oranges, I have roller TIPPED you have full roller rockers, the crane roller TIPPED rocker arms are just crap.
BTW the breathing MYTH, is just that, a myth, do the math. It has long been put out on here but yet I have no problem in the upper RPM. again do the math. (with the correct VE, etc the air flow is NOT the problem) The coil is the biggest problem past 4500 rpm. Just saying....
|
|
|
|
unboundmo
|
MAR 04, 11:12 AM
|
|
Sorry bro... But You don't have to be so rude about it.. Do the math crap. I wasn't saying that yours were in anyway bad.. Thought you mentioned appearance? Edit to say My mistake.. I see you are not comparing full roller
Also to come.. About doing the math...Maybe that's why in my garage I have the 3coil pack conversion, crank sensor, 7730 ecu and all the other things needed.. I'm just trapped with Cali smog and need a way around
Just sayin
and actually, I like my setup and have had no problems for years also so.... Just was putting it out there for others to decide[This message has been edited by unboundmo (edited 03-05-2015).]
|
|
|
|
unboundmo
|
MAR 05, 12:03 AM
|
|
|
..meant to edit post above.. Sorry [This message has been edited by unboundmo (edited 03-05-2015).]
|
|
|
Patrick
|
MAR 05, 03:58 AM
|
|
I love this shot... the way the rockers in the foreground are focused nice and sharp, and they get progressively blurry in the distance. Excellent framing and lighting as well. 
| quote | Originally posted by unboundmo:
|
|
|
|
|
|
lou_dias
|
MAR 05, 08:53 AM
|
|
2.8 pistons are flat top and the GM V6/60 performance book says iron heads with flat top pistons can support up to .510" of lift.
3.4 pistons are dished... I haven't looked at a stock 3.4 piston in a really long time but if the dish is wide enough, it could allow for more lift.
So adding 1.6 ration rockers on stock or mild performance cam will not cause an issue with piston-valve clearance. The real issue is your springs. I don't think stock springs support much over .460" lift. I think the Crane double springs support around .500" lift. So that's the issue you should pay attention to.
|
|
|
|
Raydar
|
MAR 05, 07:35 PM
|
|
| quote | Originally posted by lou_dias:
...
So adding 1.6 ration rockers on stock or mild performance cam will not cause an issue with piston-valve clearance. The real issue is your springs. I don't think stock springs support much over .460" lift. I think the Crane double springs support around .500" lift. So that's the issue you should pay attention to. |
|
I found that to be the difference between using a Crane 260 or 272 cam.
The lift for the 260 was .427/.454, I/E. The lift for the 272 was .454/.480, I/E. The 260 is widely reputed to work with stock springs. The 272 will not, without binding the coils.
(Strangely enough, if you add 1.6 rockers to a 260, you get the identical lift specs as a 272.)
With an iron head V6-60, I have never heard of anyone having piston/valve clearance issues with any of the commonly available aftermarket cams/rockers.
Valve springs have always been the "gotcha" as long as I've cared enough to pay attention. (Which is not to say that it hasn't happened. But if it did, I missed it.)[This message has been edited by Raydar (edited 05-30-2015).]
|
|
|
|
zzzhuh
|
MAR 05, 07:52 PM
|
|
| quote | Originally posted by Raydar:
(Strangely enough, if you add 1.6 rockers to a 260, you get the identical lift specs as a 272.)
With an iron head V5-60, I have never heard of anyone having piston/valve clearance issues with any of the commonly available aftermarket cams/rockers.
Valve springs have always been the "gotcha" as long as I've cared enough to pay attention. (Which is not to say that it hasn't happened. But if it did, I missed it.) |
|
So would 1.52 rockers work with a 272 cam and get better performance than a 260 with 1.6's?
|
|
|
|
Arns85GT
|
MAR 06, 10:47 AM
|
|
What he is saying is that both are the same. I used the 1.6 roller tips on the stock cam. Irrespective of whether I used a stock coil or big coil, the revs went clean right past 6k with lots of strength. I also used stock springs. No float, no problems. If you go to a higher lift you probably want the beefier springs
For streetability though, you want the cam that gives you torque in the 1k to 3k range and not the track version which gives you peak torque at 6k - 7k.
All that said, building a 2.8 is not something that is easy. As in all engine builds it has to be done exactly right. Much easier to swap, having done both.
Arn
|
|
|
|
