HP 500 EFI Valve Spring Update Question
 

Looking through threads on this issue, ISKY seems to be the spring of choice-true?

What is the part # for the springs?

Retainer?

Locks?

Are any shims required or is it down to a science? Advice?

Prefer responses from motor builders that have done many of these jobs.

Re: HP 500 EFI Valve Spring Update Question
 

Hello????

Re: HP 500 EFI Valve Spring Update Question
 

You want any spring made from Super Clean Chrome silicon material. This is the material that has replaced the tool steel or the old Vasco Jet material. It was developed as a high endurance spring.

Retainers install heights vary from Mfg to Mfg. 10 degree retainers all have the same dimentions for the keeper, what varies is the ID of the keeper for different valve diameters. Use a keeper from a know cam company, there are alot of Chinese pieces floating around that are junk.

Install heights will vary. I would suggest if you are going to do this yourself to purchase a height mic. This will allow you to measure each valve and correctly shim it for pressure. I know RMbuilder has the height mics.

Take your time.

Chris

Re: HP 500 EFI Valve Spring Update Question
 

OK-Lot's of people have looked at this thread, but only one has chimed in.

How about a little help here from anyone with the correct answers.

Thanks!

Re: HP 500 EFI Valve Spring Update Question
 

Isky 8205 is the #.It will replace the spring in the 500 EFI.Install at 1.900 for 140lbs. on the seat.

Re: HP 500 EFI Valve Spring Update Question
 

Go to Power Boat magizine .

Go to April 2004 and June 2002 acticles by Teague

Re: HP 500 EFI Valve Spring Update Question
 

so what's an "8205 PLUS" ?
sure costs more...

Re: HP 500 EFI Valve Spring Update Question
 

I think it is a 8205 coated.

Re: HP 500 EFI Valve Spring Update Question
 

There is a 8205 special 150# seat / 440# open (tested for 7000 miles at 8,000 rpms) and a plus 150#/420# (tested for 850 miles at 8,400 rpms). I would think the 8005 would be be a little better on a hydualic roller motor. Just a tad lighter spring.


http://iskycams.com/partnum_template...artnumber=8205

Re: HP 500 EFI Valve Spring Update Question
 

Hmm,
I guess since I make retainers, locks, and spring cups for "companies" I don't have the right advice.

Chris

Re: HP 500 EFI Valve Spring Update Question
 

Sorry bro

Re: HP 500 EFI Valve Spring Update Question
 

How do Comp Cams 939's stack up?

1.540'' (936-975)
I.D. .697''
Seat Load 161 @ 1.900
Open Load 418 @ 1.350
Coil Bind 1.225
Rate(lbs/in) 468
Titanium Retainer 249-732,721-16
Steel Retainer 249-741-16
Cup Seat 249-4700,4770,4771,4783-16
Shims 249-4757-16

Re: HP 500 EFI Valve Spring Update Question
 

why not gold stripe 9905's with a touch less preload (for 150 on the seat)?

and I can't get isky's catalog to give me detils on the springs. some java script error.

Re: HP 500 EFI Valve Spring Update Question
 

The 8205 spring is dual with damper, chrome silicon wire
140# @1.900” / 430# @1.250”
440# rate
1.170” stack
The 8205 SP is a different inner and outer wire, outer being Super Clean Chrome Silicon with an advanced heat treat to increase fatigue resistance
150# @1.900” / 440# @ 1.300”
480# rate
1.150” stack
The 8205 Plus is again a different outer wire
150# @ 1.900” / 420 # @ 1.300
440# rate
1.120” stack
The differences in the springs are:
Wire material grades
Heat treat of the wire
Shot peen
Nitriding
Surface preparation
All of which alter the natural frequency, fatigue resistance and load loss of the spring
The upper grades are made for Isky by PSI
Bob

Re: HP 500 EFI Valve Spring Update Question
 

Mcollinstn,
The 9905 Tool Room spring is an excellent spring however seat @ 1.90 is 165#. If you install @ 1.930" you can lower the seat force to 151# and the nose to 436# @ 1.330" given the .598"/.610" lift at the valve. The chance you take is the 9905 spring stacks @ 1.160". Max lift will occur at 1.330", putting the spring .170" from stack open, with .080"-.100" being the optimum.
Bob

Re: HP 500 EFI Valve Spring Update Question
 

Now this is what i am talking about! Thanks for all of your responses.

Sonny