HD/ Performance 1.9TD Cyl. Head. Valves,springs,guides,etc.

[subsonic]

(I guess a lot of this info will also apply to the 1.6 head as well.)

I am going to have a nice repaired blank 1.9IDI head core in a few weeks. Looking for some info.

Heavy Duty valve springs/ Heavy Duty dual valve springs.  Has anybody used them?
 
What’s the diff between the two?

What is the benefit over stock?

Does this mod only help prevent float at high RPM ( and by the way, what the hell is "float"?) or is there an over all benefit?

I have heard that some HD springs for gassers are just diesel springs.  Any truth to that?

Lifters.  OEM is all I have seen in my searches.  Any improvements to be had in this department?

Valves.  I understand that the stem Dia. changed around 96.  The smaller dia. has been recommended for a bit more flow.  Thoughts on this?

             What about valve size, cut and coatings?
  I was looking in the TT web site and they had a boatload of VW 8V head valves.  High flow, oversize, undercut, 7 or 8 stems, Black nitride treatment coated valves, stainless, etc :?  This is like the " What’s the best turbo for my car" question.  Lots and lots of different possibilities.
 
Will any of these fit the 1.9 IDI?
http://www.techtonicstuning.com/showcategories.asp?catid=28
Any additional work that can be done on the valves for better flow?

Valve Guides.  I see Bronze, Silicon/ Bronze, Magnesium/ Bronze or Phosphor/ Bronze etc. Someone want to give me the low down on why you would consider one better than the other?

I'm sure I am not the only ones with questions.
School is in session!
Lets build it up!
 :twisted:
Subsonic

[stewardc]

HD springs bring the valves closed at higher RPMs. If the valvetrain can't catch up to the cam profile, the valve will float open when it should be shut. My old 327 chevy would float the valves at about 4700 rpm.....no more revs. This is often a problem with high RPM gas engines, but not so much with diesels (lower revs).
The main thing here is better retainers and locks, so they don't give way and drop a valve. Diesel springs are probably not as good as gas ones since they aren't meant to rev so high. Mine are Comp Cams items (springs, locks, retainers)
I went for the larger diameter valve stems, myself,(new unused head) but ported the head for much better flow.
Guides are pretty well all the same. Use new ones and synthetic oil, and you'll not develop problems there.
I hope this helps and am open to criticism.

[lord_verminaard]

Remember that when running high boost, the pressure can sometimes keep the valve open longer when combined with higher rpm's- sometimes the stock springs cannot handle the combination of high rpms with high boost.  At least "a little more than stock" (we are not talking 9000 rpm race springs here...) valve springs should be used for anybody running high (20+) psi boost.

Brendan

[subsonic]

The main thing here is better retainers and locks, so they don't give way and drop a valve.

Do these come with the Spring set, or are these seperate items?  
Are these made of a different material?  What makes a better retainer and lock?

Guides are pretty well all the same. Use new ones and synthetic oil, and you'll not develop problems there.

SO why all the different materials?  Any one know the differences or benifits of one over the other?  Friction, heat dissapation, longevity..?




lord_verminaard wrote:

At least "a little more than stock" (we are not talking 9000 rpm race springs here...) valve springs should be used for anybody running high (20+) psi boost.

So is there a mid grade HD spring set?
What the heck is the difference between HD and HD dual spring sets?

[subsonic]

Does anyone know what Dave at Passenger reccomends for lifter springs, retainers etc to go with his performance cam?

[DVST8R]

I know in Malone's franken Engine we ran HD valve springs and retainers. I think they were autotech? I'm sure Dave would remember.

[subsonic]

I just called Crane Cams about springs.  They said that to help me select springs they needed to know:
 What was the req. spring pressure at the seat?
What was the compression rate?

That info is cam specific right?

[Tony2ltr]

Maybe I can help, This is what I do for turbocharging a setup that was previously non-turbo.  It only takes in a partof the equasion, but it will get you closer:
1. stock spring pressure on a given engine is meant for 14.7psi (atmospheric pressure)
2. If you are boosting, say 20 psi, that is 20 psi over atmosphere that will be pushing on the back of the valve head.
3. the spring rate needs to be increased to keep the same valve closing rate under boost.
4.      PressureXArea=Force
5. What is the surface area of the backside of your valve head?
 (roughly the diameter of the face divided by 2, then times itself (radius squared)Times 3.14) then do the same for the stem, and subtract this from the other number.  if you do some precise measuring on the back of the valve you might get closer.
6. so lets say your valve has an area on the backside of 1.5 inches squared and you are running 20 psi boost:
7.     20psiX1.5=30lbs of pressure that needs to be ADDED to your stock spring rate to compensate for 20psi of boost.  This will keep your valves from floating at stock rpms under boost.  If you want to rev higher than stock, start with a good natually aspirated spring pressure for the cam you are using, and add the boost compensation to it.
8,  BUT, YOu are right, a good cam supplier should be able to give you this information for your application.
And,,,,this is only my opinion of how to get to the proper end.  I am no engineer.

Hope this helps:
Tony

[subsonic]

So I am getting all my parts together for the head.

Here is what I am replacing.  Have I missed anything?

Bronze valve guides--should these be in or out for the port job?
valve stem oil seals
Lower spring seats
HD Dual Valve springs
Upper spring seat
Light weight Hydraulic cam followers /lifter

New intake and exhaust valves.  The smaller dia. stems.

Not sure if I need to R&R the seats.  If I do, can anyone reccomend a good/ upgraded replacement?

Thanks, Jim

[Tony2ltr]

Guides should be in for the port job, blended in without losing the length that sticks out into the runner.  I think you are wasting time with the light weight followers, these would be important for a gasser, but I don't think the rpms necessitate them in a diesel, IMHO...Let a good machine shop decide about the guides(sorry, I meant seats).  If you machine or replace them, make sure you have the machine shop set each seat face at the same (near exact) height. Otherwise you may end up with large variances in combustion chamber cc.  I have run into this many times with machine shops that are used to daily driver overhauls.  I think it is even more crucial on a diesel.  Get a nice three angle valve job, and blend the top and bottom angles into the port and combustion chamber for nice flow.  Make sure you cc each combustion chamber after all your headwork and polish the chambers lightly (take any large sharp edges out) Adjust CC to the largest chamber of course.  If your machine shop doesn't use it, use prussian blue to check the seal of each valve after lapping in with a fine compound.  Hand lap them, don't use a machine. And be careful not to get too much lapping compound into the newly HONED guides.  If the machine shop is trying to size bronze guides with a reamer, find a new machine shop!  There is also another way to size them with a ball the right size hammered down through which "presses" the guide out to size.  I have heard this is a good way.  You could also send the head out after polishing to get the combustion chambers coated.  A nice polish on piston tops and combustion chamber though, will help the heat energy drive the piston, without escaping into the water jacket.  Yes, take any sharp edges down on the piston tops.  I would send these out to be friction coated on the skirts and maybe temp coated on the tops, your call.

Good luck,
Tony

[Tony2ltr]

(EDIT!!)from the previous post.
  I AM A TARD, and had a gasser head in my brain when i wrote this!!.  Because the diesel head is flat, it would be really hard but not impossible to get a cc for the "chamber"  But make sure all your valves are new and sit at the same installed height.  You can still polish any sharp edges off, just make sure you do the same work to all of your valve areas. Coatings will help.

Sorry,
Tony

[Audi80]

"Valve chamber" is ~3cc. There is a big difference in compression ratio if there is 0,5cc difference.

[subsonic]

SInce my bentley is for the US 1.6 diesels, can someone pass me the valve sizes for the 1.9 intake and exhaust?  I am looking for the ones with the smaller stem diameter.  7mm instead of 8mm I think.

Thanks, Jim

[Jvan_wert]

Quetion for Tony2ltr.

I'm kinda confused. If valves open into the combustion chamber why would you need heavier valve spring to close the valve if you use more boost.  I was always taught that heavier spring where needed when you put in a cam with a faster ramp speed or increase your rate of acceleration for example by fuel injecting a previously carbureted engine(not applicable to diesels) and or reducing engine rotating mass(only safe way to do this on a diesel is a lighter fly wheel). Using lighter internal on a diesel would not be a good idea.

[subsonic]

I was told that the HD springs will help at higher rpm, and if you are running boost greater than the stock springs were designed for.  More boost pushing down on the intake valve trying to open it up.  If I run 20-30 lbs of boost, that is just about double what the stock springs had to deal with I think.