Roller rockers are in!!!
Thread Starter
Instructor
Joined: Feb 2009
Posts: 191
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From: Woodstock IL
Roller rockers are in!!!
My 1.6 full roller rockers are in. Not much seat of the pants difference. However, it does seem to idle smoother and the oil temp seems to be about 5 to 10 degrees cooler. BTW any myths that the stock LT1 springs wont work and are dangerously close to coil bind are not true. They work just fine.
Safety Car
Joined: Dec 2007
Posts: 3,616
Likes: 5
From: Sandhills of North Carolina
If you didn't change springs that is probably the reason you don't feel any SOTP improvement. The faster the valves can open and close the better, new springs would have helped that. If you rev it up very high you will most likely have coil bind with the stock springs. Just my .02.
Team Owner
Joined: Oct 2004
Posts: 81,241
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From: altered state
St. Jude Donor '05
If you didn't change springs that is probably the reason you don't feel any SOTP improvement. The faster the valves can open and close the better, new springs would have helped that. If you rev it up very high you will most likely have coil bind with the stock springs. Just my .02.
Especially with the added weight of the rocker, almost need more seat pressure. Waste of breath though because people will do it all day and if it seems to run Ok going down the road most will convince themselves "its fine". Did it when I was young once, rockers larger cam on old springs. Seemed to run fine but couldnt figure out why it dropped power upstairs; no research, no measuring, didnt know any better back then
Team Owner
Joined: Jan 2009
Posts: 73,568
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From: Somewhere in Mo
St. Jude Donor '09-'10, '14
For you guys who have installed them, was it worth it in your opinion?
I was just looking at them last night in one of the mags and was considering putting them in my 90. I don't track mine, just a pretty day cruiser.
I was just looking at them last night in one of the mags and was considering putting them in my 90. I don't track mine, just a pretty day cruiser.
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Le Mans Master
Joined: Feb 2000
Posts: 9,715
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From: Kempner Texas
Especially with the added weight of the rocker, almost need more seat pressure. Waste of breath though because people will do it all day and if it seems to run Ok going down the road most will convince themselves "its fine". Did it when I was young once, rockers larger cam on old springs. Seemed to run fine but couldnt figure out why it dropped power upstairs; no research, no measuring, didnt know any better back then
What he did was typical. It's what lots of guys do; cut corners. I'm willing to bet that he didn't measure the springs either. Since he hasn't had a failure yet he figures everything's okay.
Absence of a negative doesn't prove a positive.
Dyno results show the power increase is in the mid-range and up, which is right where the "right" springs are needed most.
Oh, well . . .
Jake
Safety Car
Joined: Feb 2000
Posts: 3,771
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From: MANDEVILLE, LA La
Here's the difference in inches.
1:5's I:.447" / E: .459"
1:6's I: .480" / E: .490"
I believe lift under .500" is fine with the stock springs.
Dyno's say Approx. 15 H.P. Gain with Full 1:6 Roller Rockers.
I noticed a Seat of the Pants increase and the stock springs are fine after 30K Miles..
There's another post around documenting this.
Last edited by CAJUN C4; Mar 5, 2010 at 04:03 PM.
Thread Starter
Instructor
Joined: Feb 2009
Posts: 191
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From: Woodstock IL
I will say that my car does seem to rev smoother. And the only difference in exhaust tone is WOT above 4k RPM. From 4K on it does seem to make a little more rumble with the exhaust.
Safety Car
Joined: Dec 2007
Posts: 3,616
Likes: 5
From: Sandhills of North Carolina
My car had over 90K on it when I did mine (full roller Comp Cams Pro magnum) so I knew the springs had to be weak. The LT4 springs are only40.00 or so that makes it a no brainier to me not to change them out.
Team Owner
Joined: Jan 2009
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From: Somewhere in Mo
St. Jude Donor '09-'10, '14
That will be put on my to do list
Safety Car
Joined: Dec 2008
Posts: 3,588
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From: North New Jersey
From my extensive research, the way it should be done, without taking shortcuts, is (LT1 engine) full roller rockers with the full roller tips, LT4 or the recommended beehive springs...
I think the hardest part of the install is replacing the springs and or figuring out zero lash (making sure the valve is completely closed and trying to do the job in only one spin of the camshaft)...
Personally, I think I will have the most difficulty doing these 2 things... Everything else is pretty straight forward...
Thats my $.02
I think the hardest part of the install is replacing the springs and or figuring out zero lash (making sure the valve is completely closed and trying to do the job in only one spin of the camshaft)...
Personally, I think I will have the most difficulty doing these 2 things... Everything else is pretty straight forward...
Thats my $.02
Thread Starter
Instructor
Joined: Feb 2009
Posts: 191
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From: Woodstock IL
Racer
Joined: Aug 2002
Posts: 386
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From: Lancaster Lancashire
Here's the difference in inches.
1:5's I:.447" / E: .459"
1:6's I: .480" / E: .490"
I believe lift under .500" is fine with the stock springs.
Dyno's say Approx. 15 H.P. Gain with Full 1:6 Roller Rockers.
I noticed a Seat of the Pants increase and the stock springs are fine after 30K Miles..
There's another post around documenting this.
Race Director
Joined: Jan 2002
Posts: 12,264
Likes: 88
From: O'Fallon Missouri
Just a 'heads up' and a check not always made by many when changing ratios and/or cams. When I took my 87 apart for cam and springs etc. When I was doing the usual checks, I noticed the limited retainer to guide clearance. As far as I remember, .500" lift would have had the retainer hit the valve guide seals on both heads! I had to shorten the guides. Never changed cams on any other vette, so this may be either just my heads, or all '87' 128 heads or possibly others. But if you are in the .480"+ range, you need to check this out.