question about offset valve locks
Thread Starter
Advanced
Joined: Sep 2004
Posts: 72
Likes: 0
question about offset valve locks
I have 87 corvette aluminum heads (These are the 128 not the 113 heads). The valve retainer to valve seal height apperars to be only .450-.470"". I would like to install a .500" lift cam without machining the valve guides down.
I noticed crane, among others, offer an offset valve lock.
Can I install crane offset valve locks (#99095-1) that have a +.050 install height to give me the extra clearance?
I noticed crane, among others, offer an offset valve lock.
Can I install crane offset valve locks (#99095-1) that have a +.050 install height to give me the extra clearance?
Drifting
Joined: Dec 2002
Posts: 1,861
Likes: 4
From: Houston TX
If he shims the spring seat the same that he offsets the valve locks, he doesn't get the extra spring clearance he needs, though you do bring up a good point. I would recommend against using the stock springs with the higher lift cam because of closed spring pressure, as he stated. That being said, if you're using aftermarket springs that have sufficient closed pressure, then using offset locks is a common practice for what you're trying to do. HOWEVER, do keep in mind that just because you have 0.500" between the closed position and bind positions on the spring, this does NOT mean you can run a 0.500" lift cam, because you WILL loft the valve some, even if you don't overrev the engine. If I'm assembling a valvetrain for a 0.500" lift cam, I want at LEAST 0.550" of spring movement between closed and bind. If you bind those springs with the engine running, BAD things happen. Just FYI.
Pro
Joined: Oct 2004
Posts: 510
Likes: 5
From: Pipe Creek TX
Z51 - I think you missed his point. He needs retainer to guide clearnance , not a coil spring issue.
He wants clearnance between the bottom of the retainer and the top of the valve guide.
Is this correct Quickglass?
He wants clearnance between the bottom of the retainer and the top of the valve guide.
Is this correct Quickglass?
Thread Starter
Advanced
Joined: Sep 2004
Posts: 72
Likes: 0
That's correct.
I need to increase the clearance between the bottom of the retainer and the top of the valve guide.
The springs won't be a problem since I will be changing them anyway. The real problem is I don't want to remove the head to machine down the valve guide.
I need to increase the clearance between the bottom of the retainer and the top of the valve guide.
The springs won't be a problem since I will be changing them anyway. The real problem is I don't want to remove the head to machine down the valve guide.
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by QuickGlass
The springs won't be a problem since I will be changing them anyway. The real problem is I don't want to remove the head to machine down the valve guide.
RACE ON!!!
