I was reading somewhere about the highest lift you could read on the stock valve springs but I can't find that post anywhere. I am looking into a Comp Cam camshaft with .440" intake and exhaust lift. Would 1.6s be too much lift more the stock vavle springs? Should i bump down to 1.52s??

 

"Anytime" you play with a cam change you change the springs.
It's almost a given......

 

The stock valve springs will not even accept 1.6 ratio rockers on the stock cam.

 

What spring would you use for the 1.6 rockers?? I do not want to pay to have my heads machined

 

I have
Crane 99915 Retainers
Crane 99848 Springs


stock cam, 1.6 rockers, and I belive space to go more.

 

could I run a .440" lift with a 1.6 rockers??

 

i am running .500 lift intake and .520 exhaust with 1.5 rockers and crane springs. if i can run .520 lift, you can run .440 lift with a little machine work. i am however thinking of going to 1.6 rockers but i believe that i am gonna need to split the valvecovers and i spent the last week painting the valvecovers all pretty and such.... really don't want to have to do more sanding and painting.

 

Thats the combo I have planned to use when I get around to building my 3.4 block.

.440"i/.440"e cam with 1.6 rockers instead of the 1.5's = .469"i/.469"e

And is about the max you can get and still be computer friendly with the MPFI at idling and vaccuum operation of the ECM.

I plan to ship my heads to Supersix along with my own springs and titanium seats & retainers for him to install onto the heads for me

 

I think what he is askiing is what's the maximum lift you can have without coil bind or guide interference.

I understand your question, but don't have the answer

 

YEs Eric that is my question.

 

i was just looking at them yesterday as a cheaper alternative to the crane springs but they won't support my cam, so i need their performance springs p/n 330585.<--- theese handle .560 lift

the stock springs part number is 10207475, and max lift is .420
unless it is a 3.4 and then it is 12363215, and it doesn't say about the max lift

hope this will help you, dusty

Shaun

 

by the way that was from gmpartsdirect.com

 

Dean Please send me an email.
I may have a closer alternative for you.
As in Torrance

 

I am putting the comp cams 1.6 roller rocker did I need to change the springs ect.

Paul

 

I am putting the comp cams 1.6 roller rocker did I need to change the springs ect.

Paul

 

Paul, I recall you saying you bought one of the new HT3.4's. That high output GM crate motor already has better valve springs installed onto it than the factory 2.8's that came in the HO heads on the 3rd gens.

That motor with the rockers it came with (1.5's) has a total overall lift of .427'i/.454"e

The springs that GM put into it are machine in at a closed height of1.70" and have a max open height of useage of 1.20" meaning they have an overall maximun lift usage of .500"

By putting 1.6 rocker onto the motor without any other changes you will get an overall lift of .455"i/.484"e.

YES, You can add them with the valve springs you currently have in the HT3.4. (Note: the '93-'95 Camaro 3.4 does not have these springs added, they have the same cam and springs as the '87 and up 2.8 & 3.1 motors)

 

Dusty, sorry I missed this reply by you beforehand. I basically gave you a response that you could not add them unless you change your springs. That cam AND 1.6 springs WILL require the heads to be romoves and the spring pockets machined for a new installed height spring. Dale got away with using a spring and retainer that is a step up but the same base so no machining is required, however, he is only running the stock cam and 1.6 rockers. I am running the stock cam and 1.52 rockers with stock springs- its all I could do on this motor without pulling the heads.
The max lift on fatory valve springs is in fact .420" and I am at .415"e right now with the stock cam and 1.52's

Search my old post labeled "Build sheet" under "AGood2.8" on what springs and retainers I plan to use for my build using that same cam and 1.6 rockers.

 

Eric

That is correct I bought the HT 3.4 160 HP crate engine. I am sure you have seen my posts about it. Holley 390 4 brl. Edelbrock performa intake. Mallory Dizy. headers all this in a 1700 lbs. car. Again thank you to you and everyone else who gave input to my question. Once we get this all together I will let you know waht the tale of the Dyno.

Paul

 

I met someone today at the solo II autocross that is putting a 3.4 in an Opel GT. Should be interesting!

 

I think my TVR comes in a few hundred pounds under the Opel GT

Paul