Re: 7º vs 10º Locks
[Re: pittsburghracer]
#1455993
06/21/13 06:28 PM
06/21/13 06:28 PM
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Joined: Dec 2009
Posts: 339
Gilroy,CA.
mopardude318
enthusiast
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enthusiast
Joined: Dec 2009
Posts: 339
Gilroy,CA.
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7º Locks -vs- 10º Locks
10º locks must be better than 7º locks because the number 10 is a bigger number and everyone knows bigger is better! Not only that, but all the pro races use them so they must be good! Right? Yeah, but like everything else in this business, there are trade-offs when building an engine.
For example:
You like the rough idle but you lose vacuum,
You want to run a high rise intake but don’t want a hood scoop,
You want to drive it to work every day and still run in the 9’s.
You always trade off something to get something else. And so it is with valve locks. They are, and have, trade-offs too!
I like 7º locks because they “wedge” or “lock” the retainers and valve stems tighter than the 10º locks and thus reduce the opportunity for retainer and spring wiggle and flopping around. “Flopping around? What are you talking about?” If you have ever disassembled used heads with 7º locks you will understand, because it is very difficult to break the retainers and locks loose. Whereas the same situation with 10º locks doesn't “lock” very tight and they kind of float around while the engine is running.
The floating around situation can sometimes be seen on the underside of the rocker arms. With the looser 10º locks the retainers and springs can wiggle around and actually contact the bottom of the retainer. The contact does not hurt the rockers but it doesn't look good to the customer. And, it actually reduces the life of the springs. Probably encourages breaking as well.
History 101: About 30 years ago the cost of titanium retainers drove some racers to try and use aluminum retainers to save weight and cost. Yes, aluminum is even lighter than titanium. Racers found that most of the time, aluminum retainers were a disaster. They tried coating them and other “fixes” but if the valves floated a little, the springs got weak, or the engine was over-revved, the 7º locks pulled right through the aluminum retainers and the valves fell into the cylinders destroying the hone job (among other things). Another problem was that if the springs had dampers, the damper would saw right through the soft aluminum too. But, they were light and cheap. Well, they were cheap to start with!
It didn’t take long before aluminum retainers were about as popular as Obama at a Tea Party rally. However, someone came up with the idea of using “blunter” 10º locks for the aluminum retainers. Which I have heard actually worked and lived. I even know credible racers that got 7º locks and aluminum retainers to work and live but by that time the aluminum retainers had a reputation, like the I.R.S. and you couldn't give them away. Like many failed ideas, some good came out of the aluminum retainers, and in this case, it was the 10º locks.
At first the 10º locks were only used in applications where spring pressures were very high, say like 300# or more on the seat and over 600# open. And in my opinion, that is where they should stay. Now days, with spring pressures “over the nose” (open) of nearly 1200# the 10º locks are mandatory. Some of the high revving (8500+ rpm) small block owners with the trick short travel hydraulic lifters tell me tales of the looser locking 10º locks “unlocking” at those rpm’s because of all the wiggling around that eventually allowed the valves to fall down into the cylinder and ruin their hone job.
All that being said, in my opinion, with the open spring pressures used on flat tappet or street roller cams of 550# or less open, 7º locks are the way to go.
Dave Hughes
408 Stroker 533 HP 520 FT LBS...........................1970 Dart RMS AlterKation
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Re: 7º vs 10º Locks
[Re: mopardude318]
#1455995
06/21/13 06:42 PM
06/21/13 06:42 PM
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Joined: Oct 2003
Posts: 7,506
Az
Crizila
master
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master
Joined: Oct 2003
Posts: 7,506
Az
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Quote:
7º Locks -vs- 10º Locks
10º locks must be better than 7º locks because the number 10 is a bigger number and everyone knows bigger is better! Not only that, but all the pro races use them so they must be good! Right? Yeah, but like everything else in this business, there are trade-offs when building an engine.
For example:
You like the rough idle but you lose vacuum,
You want to run a high rise intake but don’t want a hood scoop,
You want to drive it to work every day and still run in the 9’s.
You always trade off something to get something else. And so it is with valve locks. They are, and have, trade-offs too!
I like 7º locks because they “wedge” or “lock” the retainers and valve stems tighter than the 10º locks and thus reduce the opportunity for retainer and spring wiggle and flopping around. “Flopping around? What are you talking about?” If you have ever disassembled used heads with 7º locks you will understand, because it is very difficult to break the retainers and locks loose. Whereas the same situation with 10º locks doesn't “lock” very tight and they kind of float around while the engine is running.
The floating around situation can sometimes be seen on the underside of the rocker arms. With the looser 10º locks the retainers and springs can wiggle around and actually contact the bottom of the retainer. The contact does not hurt the rockers but it doesn't look good to the customer. And, it actually reduces the life of the springs. Probably encourages breaking as well.
History 101: About 30 years ago the cost of titanium retainers drove some racers to try and use aluminum retainers to save weight and cost. Yes, aluminum is even lighter than titanium. Racers found that most of the time, aluminum retainers were a disaster. They tried coating them and other “fixes” but if the valves floated a little, the springs got weak, or the engine was over-revved, the 7º locks pulled right through the aluminum retainers and the valves fell into the cylinders destroying the hone job (among other things). Another problem was that if the springs had dampers, the damper would saw right through the soft aluminum too. But, they were light and cheap. Well, they were cheap to start with!
It didn’t take long before aluminum retainers were about as popular as Obama at a Tea Party rally. However, someone came up with the idea of using “blunter” 10º locks for the aluminum retainers. Which I have heard actually worked and lived. I even know credible racers that got 7º locks and aluminum retainers to work and live but by that time the aluminum retainers had a reputation, like the I.R.S. and you couldn't give them away. Like many failed ideas, some good came out of the aluminum retainers, and in this case, it was the 10º locks.
At first the 10º locks were only used in applications where spring pressures were very high, say like 300# or more on the seat and over 600# open. And in my opinion, that is where they should stay. Now days, with spring pressures “over the nose” (open) of nearly 1200# the 10º locks are mandatory. Some of the high revving (8500+ rpm) small block owners with the trick short travel hydraulic lifters tell me tales of the looser locking 10º locks “unlocking” at those rpm’s because of all the wiggling around that eventually allowed the valves to fall down into the cylinder and ruin their hone job.
All that being said, in my opinion, with the open spring pressures used on flat tappet or street roller cams of 550# or less open, 7º locks are the way to go.
Dave Hughes
good info / history. I went through the aluminum retainer era. Wasn't pretty.
Fastest 300
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Re: 7º vs 10º Locks
[Re: Crizila]
#1455996
06/21/13 09:58 PM
06/21/13 09:58 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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I use the 10* on my W-9.... its 320# on seat and near 900# open.... I've had them off 6 times and they look perfect but if I run light pressures I would run the super 7s which is really 8* but I'm not talking a flat tappet 
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Re: 7º vs 10º Locks
[Re: topside]
#1455999
06/22/13 01:06 AM
06/22/13 01:06 AM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
Hmmm.
Seems to me that a 10* has more surface area than a 7* does.
I can't imagine any aluminum I'd want to use for a retainer.
If the 10* stuff doesnt have enough pressure it wont
wedge in to lock it in place... its all about the spring
pressures to what degree stuff you need.. big pressure
needs big angle... lower pressure lower angle
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How about filling us non-subscribers in 
Been running Hughes 7 degree locks, retainers, springs, for many years trouble free. " I like mine tight "! 
although I don't know what the spring pressure change-over ( 7 to 10 ) should be? BTW, your seat pressure is my open pressure 
. 
