Help please? TPI/Vortec head bolt/valve spring questions.
#1
Help please? TPI/Vortec head bolt/valve spring questions.
Putting vortec heads on my L98. I have a used head bolt set from a 96 pickup with these heads.
1) They aren't TTY, right?
2) Why is the tightening sequence changed from the previous? It's not just X ft lbs. It's now so many ft lbs + X degrees. Can't I just torque them the old way? What's the difference?
Heads are new GM #12558060
Same as these, actually:
https://sdparts.com/details/gm-perfo...parts/12558060
The cam is a Lunati Voodoo. 213/219 - .454/.468
http://www.lunatipower.com/Product.aspx?id=2323
Do I need to check retainer clearance or spring bind with this? If so, what's the easiest way to do that? How can you tell is a valve spring is binding? If the coils touch? Is there some minimum distance I should be looking for here?
1) They aren't TTY, right?
2) Why is the tightening sequence changed from the previous? It's not just X ft lbs. It's now so many ft lbs + X degrees. Can't I just torque them the old way? What's the difference?
Heads are new GM #12558060
Same as these, actually:
https://sdparts.com/details/gm-perfo...parts/12558060
The cam is a Lunati Voodoo. 213/219 - .454/.468
http://www.lunatipower.com/Product.aspx?id=2323
Do I need to check retainer clearance or spring bind with this? If so, what's the easiest way to do that? How can you tell is a valve spring is binding? If the coils touch? Is there some minimum distance I should be looking for here?
#2
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Car: 1983 G20 Chevy
Engine: 305 TPI
Transmission: 4L60
Axle/Gears: 14 bolt with 3.07 gears
Re: Help please? TPI/Vortec head bolt/valve spring questions.
I would not reuse the 1/2" head bolts as I have had one break in the past. The older 5/8" ones I only reuse once. You can get a new set of Felpro head bolts for under $50.00. They come boxed for one head, so you need two boxes (about $20-25 each) Cheap insurance against having to do it over again. I have always used the older torque method. I go in 3 steps, 45-55-65 ft/lbs. Have not had an issue yet.
As for lift for the stock head, I don't even check until I get around .490". The Ramjet 350 has .459/.481" lift with its 1.6 rockers on a production head.
As for lift for the stock head, I don't even check until I get around .490". The Ramjet 350 has .459/.481" lift with its 1.6 rockers on a production head.
Last edited by Fast355; 09-11-2015 at 10:26 PM.
#4
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iTrader: (2)
Join Date: Jan 2005
Location: Hurst, Texas
Posts: 9,970
Received 379 Likes
on
323 Posts
Car: 1983 G20 Chevy
Engine: 305 TPI
Transmission: 4L60
Axle/Gears: 14 bolt with 3.07 gears
Re: Help please? TPI/Vortec head bolt/valve spring questions.
Further improving my point about used head bolts, the factory GM bolts are even cheaper than the Felpros I usually use.
https://sdparts.com/details/gm-perfo...parts/12495499
https://sdparts.com/details/gm-perfo...parts/12495499
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