New valve springs...which ones??

[ksmmspt]

Hi,
I have 2 unmolested 87 GN motors with roughly 50-55K on both that I want to freshen up with new valve springs. I've heard from others that I do not want to use to strong a spring or I'll have problems in the near future. Which springs are recommended for a stock cam?

Also, please tell me your source as well for buying the springs. Thanks.

 

[85 ttypewh1]

cc 980, summit

 

[ksmmspt]

Just checked summits website. Is the correct part# CCA-980-12? Just want to make sure before I buy. Thanks for the input!

 

[bison]

Any set of springs is worth checking before installing. They should not be over 100psi@1.75in.

 

[85 ttypewh1]

not a 100% sure, i will look when i get home in the morning. You can install with or without the cups to raise or lower the spring pressure.

 

[Evaddave 87gn]

Need springs?

Hey i just took off a set from my new champion iron heads. They are brand new never ran, I'm going with a roller cam so I needed different springs. Let me know if your interested, you can even call tom at champion he could tell you what they rate at. I'll let them go cheap!! let me know!

:biggrin:

 

[ksmmspt]

Hey i just took off a set from my new champion iron heads. They are brand new never ran, I'm going with a roller cam so I needed different springs. Let me know if your interested, you can even call tom at champion he could tell you what they rate at. I'll let them go cheap!! let me know!

:biggrin:

Hey that would be nice. If you could find out what the psi rating, that would help. Thanks!

 

[49-blues]

The champs are about 100 lbs- i got a set also-went to roller.

 

[85 ttypewh1]

My box says they are 980-12. Do a search on here about the spring pressure. I think it is like @80 without the cups and @95 with.

 

[bison]

My box says they are 980-12. Do a search on here about the spring pressure. I think it is like @80 without the cups and @95 with.

This is correct but some will be above 100psi with the cups or shims. I wouldnt try to break in a new cam with springs over 100psi at 1.75in and definitely not over 110psi or the lobe could fail prematurely. Running up to 110psi at 1.75in is usually ok if the cam has been broken in with weaker springs. The number 3 exhaust is a problem lobe on these engines because of the location that the lifter rides on the lobe. Use one of your weaker spings on this lobe if possible.

 

[ksmmspt]

Now that I know which type to use, what pressure should I use when installing them? Remember, the cars have the stock cam (1 is bone stock, the other has some goodies including alky, 911 convertor, TE44, 009s).

The main problem I am having at the track is the car not shifting hard into 2nd or 3rd. My transmission expert believes that it's not the trans and that I might need a cam upgrade. I really didn't want to do this and others have suggested replacing the 18 year old springs first and see if that takes care of it.

In either case, I don't want to install springs that would shorten the life of the motor in any way. Thanks for all your input!!

 

[85 ttypewh1]

I am going to install mine at the lower setting. The stock spring pressure is fine, just the stock spring material was junk and made the spring weaker. I first need to do my timing chain which has over 200k on it.