+.100 valves - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 11-06-2008, 09:38 PM
the dan's Avatar
83 chevy c10 long bed
 
Last photo:
Join Date: Jul 2007
Location: middletown ct
Age: 24
Posts: 73
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
+.100 valves

just a quick confused question
is that +.100 between the valve face and the valve locks, or from the locks to the top of the stem?
or is it the stem itself?

ive asked around and got no answers
thanks guys

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 11-07-2008, 04:59 AM
Registered User
 
Last photo:
Join Date: Jun 2007
Location: TN.
Posts: 287
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
Quote:
Originally Posted by the dan
just a quick confused question
is that +.100 between the valve face and the valve locks, or from the locks to the top of the stem?
or is it the stem itself?

ive asked around and got no answers
thanks guys
the valve would be .100 longer overall length, and you would also gain .100 spring height.

sam-missle
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 11-08-2008, 12:34 AM
the dan's Avatar
83 chevy c10 long bed
 
Last photo:
Join Date: Jul 2007
Location: middletown ct
Age: 24
Posts: 73
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
thank you thats what i needed to know
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 02-04-2011, 07:25 PM
Registered User
 
Join Date: Nov 2010
Location: Pittsfield NH
Posts: 46
Wiki Edits: 0

Thanks: 2
Thanked 3 Times in 3 Posts
+ .100 valves

When you use longer valves do you have use shorter pushrods or something else painful? I am thinking of using vortec heads and modifying them for a .550 cam. Retainer to guide clearance is the issue ... noone seems to mention using longer valves as a fix ... wouldnt longer valves push the retainer up .100 and solve the issue or am I having a brain fart here?
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 02-04-2011, 07:40 PM
Smarter than i look
 
Last wiki edit: Upgrading to HEI
Join Date: Aug 2010
Location: Ontario Canada
Age: 36
Posts: 29
Wiki Edits: 2

Thanks: 0
Thanked 0 Times in 0 Posts
Yes it would increase the retainer to guide clearance, but it would also put .100 less pressure on the spring. meaning .100 worth of shims go under it PLUS whatever shim stack you would need to acheive installed (spec) height. Bank on a .060 to start. And thats if you dont get stuck with a cheap retainer which is usually +.050 anyway. Then add another.050.
Which means the spring will probably slip around cause its out of the bucket, chewing up lotsa stuff. And you'll have 40 bucks worth of springs shims in there. lol

OR you could just have a machine shop cut the guides to fit a positive seal, which cuts the top of the guide down more than enough for a .550 cam.

The best lesson i was ever taught in life? You get lost taking short cuts.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 02-04-2011, 08:01 PM
dvdkramer's Avatar
Registered User
 
Last photo:
Join Date: Mar 2010
Location: Melbourne, FL
Posts: 24
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I am looking to upgrade my Vortecs too. But slightly milder at around .510 lift. I found some springs at summit: http://www.summitracing.com/parts/SUM-174000/ And these keepers : http://www.summitracing.com/parts/CRO-86107X1-16/

The dimensions on the springs seem like they would drop right in on the stock head (maybe clean up .005 or so with a dremel) and the +.050 keepers would fix the clearance problem. Am I way off base here? I understand it is probably best to machine the head down, but for the cost of the tools I can buy these parts. Any opinions?
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 02-04-2011, 08:59 PM
ericnova72's Avatar
More for Less Racer
 
Join Date: Jan 2007
Location: S.W. Lower Michigan
Age: 47
Posts: 8,915
Wiki Edits: 0

Thanks: 19
Thanked 364 Times in 334 Posts
Quote:
Originally Posted by dvdkramer
I am looking to upgrade my Vortecs too. But slightly milder at around .510 lift. I found some springs at summit: http://www.summitracing.com/parts/SUM-174000/ And these keepers : http://www.summitracing.com/parts/CRO-86107X1-16/

The dimensions on the springs seem like they would drop right in on the stock head (maybe clean up .005 or so with a dremel) and the +.050 keepers would fix the clearance problem. Am I way off base here? I understand it is probably best to machine the head down, but for the cost of the tools I can buy these parts. Any opinions?
The +.050" keepers puts you back to needing to put .050"(or maybe more) spring shim under the spring to get the seat pressure back up to spec.

Many make the mistake of only looking at the lift capability of the spring and don't realize the seat and open pressures are equally important.

...that shortcut analogy again...
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 02-04-2011, 09:24 PM
dvdkramer's Avatar
Registered User
 
Last photo:
Join Date: Mar 2010
Location: Melbourne, FL
Posts: 24
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
To counter the loss in pressure, maybe I can buy "overkill" springs rated slightly higher than what is recommended for the cam. The springs I linked above have a higher open pressure by about 32lbs, and a slightly lower seat pressure than what was recommended by comp cams for my situation.

I am trying to mimic Comp part# 986-16:
Installed Height (in) 1.750 in.
Seat Pressure at Installed Height (lbs) 132 lbs.
Open Height (in) 1.250 in.
Open Pressure (lbs) 293 lbs.

Summit part# 174000
Installed Height (in) 1.750 in.
Seat Pressure at Installed Height (lbs) 125 lbs.
Open Height (in) 1.200 in.
Open Pressure (lbs) 325 lbs.

So it's close but no cigar. It looks like a loss in pressure, while open, could actually be advantageous, but it would be lacking in the seat pressure.
I'm sure there is some formula or calculator to figure it out.
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 02-04-2011, 09:54 PM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 59
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
Using keepers that give a taller installed height also use up some of the clearance usually needed to keep the rocker arm from contacting the retainer and not the valve tip, so this has to be verified to have enough clearance.

Springs are available for a taller installed height created by a longer valve and still have adaquate seat and open pressures, however the entire set-up has to be mocked up and clearances checked to determine if such a scheme will actually work w/the parts you have. And a complete set of longer valves isn't cheap.

That's why it is often cheaper and easier to just remove a bit of height from the guide boss and/or the bottom of the retainer (if just a small amount of extra clearance is required) to get adaquate clearance for a particular cam.
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 02-04-2011, 10:15 PM
sbchevfreak's Avatar
Licenced Automotive Technician
 
Last photo:
Join Date: Feb 2004
Location: Land of big Easter eggs, Alberta
Age: 34
Posts: 1,604
Wiki Edits: 0

Thanks: 8
Thanked 9 Times in 9 Posts
This doesn't work. You will end up with problems, like has been stated about shortcuts. IIRC, you don't want anything more than .090" of shims under a spring, total. More than that, and you end up with "spring walk", chewing up shims, guide seals, retainers, ect. Unfortunately, the only real way to do this is to machine the guides down to accept more than the standard .470" lift. In reality, by the time you spend the money on the shims, valves, special valve springs and the many hours of time involved in trying to "cheat", you would have been time and money ahead to just have had the guides done. If you think about it, the more shims you have, the more things that could come apart while the engine is running, and it already has enough of those.
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 02-05-2011, 11:53 AM
F-BIRD'88's Avatar
Yada Yada Yada
 
Last photo:
Join Date: Oct 2005
Location: Ontario, Canada
Posts: 9,547
Wiki Edits: 0

Thanks: 3
Thanked 331 Times in 328 Posts
Why not buy the tooling you need to use the right larger diameter dual springs
and shortened guide height. Then when you are all done sell them off as a kit for modifying vortec heads for high lift.

Lots of people looking to do the same thing.
Sell them off on ebay, Craigslist, Kijiji, racejunk.com.
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 02-05-2011, 01:54 PM
Registered User
 
Last photo:
Join Date: Apr 2007
Location: Seattle, Wa
Posts: 6,686
Wiki Edits: 0

Thanks: 3
Thanked 403 Times in 348 Posts
Quote:
Originally Posted by the dan
just a quick confused question
is that +.100 between the valve face and the valve locks, or from the locks to the top of the stem?
or is it the stem itself?

ive asked around and got no answers
thanks guys
first off you have to be careful with stem length changes in most cases they are talking about total stem length changes where the relationship of the stem tip to retainer distance is the same. But it can also be where the retainer locks at the same distance from the valve head face and there is more distance between the retainer and the end of the stem. This is a dumb question that needs asking going in before you make the purchase.

Read this over and have to agree with F-BIRD'88. This seems a awfully Mickey Mouse way of solving the lift problem. a .1 shim is a lot to stack a spring. This will have to be more than a pile of washers, this thing will have to be anchored to keep in position and shaped to capture the spring and keep it in position.

You should just buy the tool or have the machine shop cut the guide for the proper clearance.

The .1 longer valve stem is actually made for some aftermarket heads that raise the intake port which then pushes the spring pad and rocker stud boss upward. To compensate for the higher spring pad and rocker stud position the valve stem length in increased. This keeps the rocker geometry to the stem and the stud lenght to the rocker the same only needing a longer push rod.

What you're doing will change the rocker geometry forcing it to be higher on the stud. If you don't actually run out of threads for the retainer nut, you will create a condition where the stud will see higher bending moments at its attachment point to the head, this very likely will result in broken studs. You will also need longer push rods to keep the geometry correct between the rocker and stem.

I can see how what you want to do can work, but I also see some unintended consequences that could be major problems. I think a more conventional solution of cutting the guide height is the technically safer and certainly more cost effective route.

Bogie
Reply With Quote Quick reply to this message
  #13 (permalink)  
Old 02-05-2011, 04:05 PM
Registered User
 
Join Date: Nov 2010
Location: Pittsfield NH
Posts: 46
Wiki Edits: 0

Thanks: 2
Thanked 3 Times in 3 Posts
Really I had just found a good deal on a set of Ferrea 5000 + .100 valves and thought they might be a good start to the assembly of an uncracked set of bare 906's . I have heard factory vortec valves have a special back-cut that enhances the flow of the heads so wasnt really sure the Ferreas would be a plus or minus. I wish I had a diagram or worksheet or something that would enable me to understand and "paper trade" various elements of valve train geometry with enough accuracy to at least buy parts that will work. My plan so far has been to buy exclusively CC parts matched to the xfi-252 roller cam I will use so I wouldnt get in much trouble. Valves arent on the list. Not sure I will buy their rockers or studs. I did see they sold seats for the springs, CC 4705 for 26918 springs. Was wondering how they work with shims and whether they would keep the springs from dancing. Would you machine the head so the spring seat would fit in a cup tight then be able to place the shims inside the spring seat for installed height adjustment?
Reply With Quote Quick reply to this message
  #14 (permalink)  
Old 02-05-2011, 04:35 PM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 59
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
The 26918 springs don't need any seats- the spring rides on the head.

The cam has a lift of about 0.550"- just machine the guide for the lift, use the #787 retainer- NOT the metric LS retainer- and set the installed height correctly. No need to enlarge the head's spring seat.

I would recommend screw in rocker studs and guide plates be used- you'll want to be sure that you do NOT use self aligning rocker arms if you use guide plates. That cam is supposedly designed for 1.6 ratio rockers.

Use an adjustable push rod or Comp's p-rod length checker to determine the right p-rod length to get the geometry correct.

The Ferrea valves (I first had said to skip them) may be OK- the springs are spec'ed at an installed height of 1.8" (stock is 1.7"). The backcut of the stock Vortec valves can be easily duplicated on the new valves.

If you are using an OEM roller block set-up, you may need different lifters- the OEM lifters can disengage from the dog bone retainers at lobe lifts above 0.354". Your lobe lift is 0.344", but I would want to check to be sure there's no problem.
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
best way of adjusting valves SBC ??? Augusto Engine 35 03-22-2011 05:04 AM
Lapping New Valves - Help leejoy Engine 14 11-10-2007 08:56 AM
NASCAR, Unleaded Fuel and Titanium Valves QuenchPiston Engine 18 12-26-2006 08:18 PM
Adjusting Valves and Fuel Pump Install demitristewart Engine 5 08-09-2006 10:10 AM
Worth it to put bigger valves in stock seats??? sizemoremk Engine 3 08-13-2005 12:19 AM


All times are GMT -6. The time now is 03:04 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.