Donate!
Welcome, Guest. Please Login or Register :: View Members
Pages: 1 2 3 4 
Send Topic Print
Big Bore Engine - Part 2 - Head (Read 182 times)
DragBikeMike
Serious Thumper
*****
Offline

SuzukiSavage.com
Rocks!

Posts: 3257
Honolulu
Re: Big Bore Engine - Part 2 - Head
Reply #30 - 07/19/20 at 23:33:30
 
The port work is complete, it’s time to set up the valves for a big cam.  I will be running the Web 402 on this engine.  With the LS650 rocker arms, duration on the 402-grind is about 240°/240° (measured at .050” valve lift), and lift is about .400”/.374”.  The stock valve springs can’t handle the lift, they coil bind at .400” lift.  Also, they aren’t strong enough to maintain valve control with the cam’s aggressive opening ramps.

Web sells a spring kit for the 402-grind.  When I tried to order that spring kit Web was out-of-stock. Their supplier (RD Valve Springs) could not provide a delivery date.  Things looked bleak.  The Web sales rep had no idea when the kit might be available again, or even if the kit would ever be available again.

After a lengthy search, I came up with these.
Back to top
 

SuperTech_Springs.jpg

Knowledge is power.
  IP Logged
DragBikeMike
Serious Thumper
*****
Offline

SuzukiSavage.com
Rocks!

Posts: 3257
Honolulu
Re: Big Bore Engine - Part 2 - Head
Reply #31 - 07/19/20 at 23:34:20
 
At about $15 bucks a copy, these SuperTech springs are a bargain (if they hold up).  I load tested all eight springs and they were very close to the SuperTech specs.   If you plot the load test data you can see that the ST springs are substantially more robust than the stockers, but just shy of the RD springs that Web provides.  The ST springs can also handle the lift.
Back to top
 

SuperTech_vs_RD_vs_Stock.jpg

Knowledge is power.
  IP Logged
DragBikeMike
Serious Thumper
*****
Offline

SuzukiSavage.com
Rocks!

Posts: 3257
Honolulu
Re: Big Bore Engine - Part 2 - Head
Reply #32 - 07/19/20 at 23:35:02
 
Dimensionally, the SuperTech springs suite the application.  The stock retainers fit just fine.  Installed height agrees with the LS spec.  The finish is good, very smooth, no stress risers evident.  Things are looking up.  The ST spring is on the left, stock spring on the right.
Back to top
 

SuperTech_vs_Stock_12.jpg

Knowledge is power.
  IP Logged
DragBikeMike
Serious Thumper
*****
Offline

SuzukiSavage.com
Rocks!

Posts: 3257
Honolulu
Re: Big Bore Engine - Part 2 - Head
Reply #33 - 07/19/20 at 23:36:15
 
Now that the spring problem is out of the way, time to address valve travel.  There must be enough room between the bottom of the spring retainer and the top of the valve guide seal to accommodate the higher lift cam.  When the valve is fully open, you want some room between the retainer and seal.  Web specifies a minimum of .030” clearance, while Kibblewhite specifies .060”.   I have always used .060”.
 
This is the measurement in question.  It needs to be about .060” more than the specified valve lift.    
Back to top
 

Retainer_to_seal_2.jpg

Knowledge is power.
  IP Logged
DragBikeMike
Serious Thumper
*****
Offline

SuzukiSavage.com
Rocks!

Posts: 3257
Honolulu
Re: Big Bore Engine - Part 2 - Head
Reply #34 - 07/19/20 at 23:37:30
 
There are several ways to address the clearance problem.  One is to use different valve spring retainers.  The other is to trim the valve guide to make it shorter.  I opted to use different retainers.  Kibblewhite spring retainers 30-30105 with cotters 30-30106 solved the problem.  They also reduce the weight of the valve assembly to provide a little more cushion for high rpm operation.

It’s also pretty easy to trim the guides.  I did that on the Stage II head when I installed the 340b cam.  That cam has .420” lift and I was able to achieve sufficient clearance by trimming the guides, and that was with the stock retainers.

In the interest of full disclosure, I had some trouble with identical Kibblewhite retainers about a year ago.  I was going to try them on the Stage II.  I had done some minor machining to prep them for use with the stock valve springs and noticed what I thought was an inclusion.  When I examined the retainer at 5x magnification it was evident that the defect was a crack.  Further examination revealed that all four retainers were riddled with cracks.  I contacted Kibblewhite and they stood by their product.  Standup guys all the way.  They asked that I send them the retainers and they replaced them with two full sets.  Even though I had tampered with their part they still stood behind it.  Good company.  Gotta hope those cracks were an anomaly.
 
Here you can see why the Kibblewhite retainers will allow more travel before the bottom of the retainer hits the guide seal.  But, like all things hotrod, fix one problem create another.  See how much higher the top of the retainer is.  That could hit the underside of the rocker arm.  It will have to be checked.
Back to top
 

KW_vs_Stock_Retainer_Fitup_2.JPG

Knowledge is power.
  IP Logged
DragBikeMike
Serious Thumper
*****
Offline

SuzukiSavage.com
Rocks!

Posts: 3257
Honolulu
Re: Big Bore Engine - Part 2 - Head
Reply #35 - 07/19/20 at 23:38:13
 
Here you see the Kibblewhite retainer and cotters next to stock components.  Note the position of the bead in the cotter.  That is a key element in the final position of the retainer on the valve stem.  As the bead is positioned lower in the cotter, the retainer assumes a higher position on the stem.
Back to top
 

KW_vs_Stock_Retainers_2.JPG

Knowledge is power.
  IP Logged
DragBikeMike
Serious Thumper
*****
Offline

SuzukiSavage.com
Rocks!

Posts: 3257
Honolulu
Re: Big Bore Engine - Part 2 - Head
Reply #36 - 07/19/20 at 23:39:39
 
With the Kibblewhite retainers and cotters, I now had ample valve travel.  I can run the 402-grind cam with no fear of collisons between underside of the retainers and the valve guide seals, and there is enough margin to permit the installation of the higher lift 340b cam.

With the retainers sitting higher on the valve stems, the spring installed height will increase.  The springs have to be shimmed to restore the installed height to 1.300”.  I haven’t found any suitable off-the-shelf valve spring shims.  I use 5/16” x 1-1/4” fender washers.  These cheap washers (of questionable pedigree) work out pretty good.  The manufacturing quality control is sooooooo bad that the thickness of the washers varies wildly.  Perfect for coming up with shim stacks of varying height.  This bulk package ranged in thickness from .051” to .078”.  Fortunately, the tops and bottoms of the washers are parallel within .001”.  No Leaning Towers of Pizza.
Back to top
 

Washer_Sizes2.jpg

Knowledge is power.
  IP Logged
DragBikeMike
Serious Thumper
*****
Offline

SuzukiSavage.com
Rocks!

Posts: 3257
Honolulu
Re: Big Bore Engine - Part 2 - Head
Reply #37 - 07/19/20 at 23:40:28
 
Then all ya gotta do is drill out the 5/16” hole to suite the valve guide.  A step drill works great.  The 1-1/4” OD fits the cylinder head perfect.
Back to top
 

Washer_Machining2.jpg

Knowledge is power.
  IP Logged
DragBikeMike
Serious Thumper
*****
Offline

SuzukiSavage.com
Rocks!

Posts: 3257
Honolulu
Re: Big Bore Engine - Part 2 - Head
Reply #38 - 07/19/20 at 23:41:11
 
When you reassemble the head, you place the appropriate stack of shims under the spring seat.  You must end up with a spring height of 1.300”.  I use a spacer of predetermined thickness along with dial calipers to verify installed height.  Spacer thickness added to caliper reading equals installed height.
Back to top
 

Installed_height_1_300_001.JPG

Knowledge is power.
  IP Logged
DragBikeMike
Serious Thumper
*****
Offline

SuzukiSavage.com
Rocks!

Posts: 3257
Honolulu
Re: Big Bore Engine - Part 2 - Head
Reply #39 - 07/19/20 at 23:41:58
 
If your shim pack exceeds about .100”, you need to start worrying about the spring seat interfering with the guide seal.  Pay attention to the clearance between the guide seal and spring seat.  Here you can see how nice the fender washers fit.  There’s two stacked up here.  I like to label them with an engraver.
Back to top
 

Install_Shims_22.JPG

Knowledge is power.
  IP Logged
DragBikeMike
Serious Thumper
*****
Offline

SuzukiSavage.com
Rocks!

Posts: 3257
Honolulu
Re: Big Bore Engine - Part 2 - Head
Reply #40 - 07/19/20 at 23:42:33
 
Don’t forget to drop that spring seat on before you drive home the guide seal.  It’s a terrible waste of a seal.  I’m embarrassed to admit I’ve done it a time or two.  You should also verify the spring installed height before you drive on the seal.
Back to top
 

Drive_the_Seal_2.JPG

Knowledge is power.
  IP Logged
DragBikeMike
Serious Thumper
*****
Offline

SuzukiSavage.com
Rocks!

Posts: 3257
Honolulu
Re: Big Bore Engine - Part 2 - Head
Reply #41 - 07/19/20 at 23:43:36
 
Make sure that the spring seat doesn’t interfere with the seal.  There must be some clearance here.  You should be able to spin the seat around the guide.  If not, you will have to take it apart and trim the spring seat.  I use an old used guide seal to check this.  That way I know that things are right before I drive on the new guide seal.  I hate to waste these seals.
Back to top
 

Seal_Installation_Clearance_markup_2.png

Knowledge is power.
  IP Logged
DragBikeMike
Serious Thumper
*****
Offline

SuzukiSavage.com
Rocks!

Posts: 3257
Honolulu
Re: Big Bore Engine - Part 2 - Head
Reply #42 - 07/19/20 at 23:45:17
 
Now it’s time to lube up the valve with assembly lubricant.  I really like the RedLine stuff.
Back to top
 

Lube_Valve_2.JPG

Knowledge is power.
  IP Logged
DragBikeMike
Serious Thumper
*****
Offline

SuzukiSavage.com
Rocks!

Posts: 3257
Honolulu
Re: Big Bore Engine - Part 2 - Head
Reply #43 - 07/19/20 at 23:46:08
 
Break out the trusty valve spring compressor.  I’ve had this old girl since I was a kid.  I think she’s better than 50 years old.
Back to top
 

Spring_Compressor_2.JPG

Knowledge is power.
  IP Logged
DragBikeMike
Serious Thumper
*****
Offline

SuzukiSavage.com
Rocks!

Posts: 3257
Honolulu
Re: Big Bore Engine - Part 2 - Head
Reply #44 - 07/19/20 at 23:47:02
 
Install the springs, retainers & cotters.  Repeat until all four valves have been installed with their springs shimmed to the correct installed height of 1.300”.   Note that all the springs have a liberal coat of assembly lube.  Ready for break-in.
Back to top
 

Ready_to_Go_1_2.JPG

Knowledge is power.
  IP Logged
Pages: 1 2 3 4 
Send Topic Print


« Home

 
« Home
SuzukiSavage.com
12/08/22 at 11:18:50



General CategoryRubber Side Down! › Big Bore Engine - Part 2 - Head


SuzukiSavage.com » Powered by YaBB 2.2!
YaBB © 2000-2007. All Rights Reserved.