ill soon be getting my ITR head back and wanted to know if i should invest in the "bronze valve guides". do the heads come stock with some or not. they cost about $5 a piece. are they worth it. anyone using them

thanx

 

only if you are running harder stainless steel valves. Otherwise stick to stock guides.

 

wheres a good place to pick them up at.. my head is empty and if the stock ones are like $1 cheaper, i might just go with the bronze

 

Ditto

 

Any headporting or cam shop like Portflow.com or Webcamshaft.com can sell you bronze valve guides.

There are 4 bronze alloy types as far as I know:

manganese bronze

nickel copper bronze

nickel aluminum bronze

silicon aluminum bronze

Bronze guides are softer than the cast iron guides. I'm not a metallurgist but from what I understand the addition of 4-5% nickel hardens the guide for better wear. The copper or manganese or silicon adds to the heat transfer rate of the guide. Since 25% of the valve stems heat is shed onto the guide, the ability of the guide to lose this heat adds to its longevity and ability to run tighter clearances.

The downside of a bronze guide is it's wear over time.

The upside of bronze guide is the heat conduction, resistance to seizing, and the ability to run tighter valve to guide clearances. Cast iron guides cannot shed heat as well and may seize and so you cannot run as tight a clearance with them. Tighter clearances allow the valve to seat strike more squarely with less valve stem wandering.

Once again if you look at the cost of a typical bronze guide, the cost of a Jun bronze valve guide is a total rip off. Overpriced. In comparison, the jdmhondaparts and portflow bronze guides are 1/3 the price at $5/each.

Most people use Ampco 45 nickel copper bronze guides (like Webcam).

I have used silicon aluminum bronze guides with standard sized stainless valves. They lasted about 3 years with a 9300 rpm redline.

If this is not a race only engine and you are using ITR valves, I suggest you stick to new cast iron stock guides and have the machine shop hone them to size rather than reaming them to size. They will last longer. You know that they have to heat up the head evenly to 300 degrees max. to install these right?

cheers







[Modified by Michael Delaney, 12:50 PM 8/10/2002]

 

if the stock guides are bad, then maybe and onlyh because they are cheaper than
stock. otherwise no.

 

the thing is i dont have stock guides.. im starting from scratch.. so far i have stock valves.. i might go with stock guides, but the bronze ones are like $1 cheaper.

 

once again you guys have to realize that there is a trade off to going hardcore race only parts in a street engine that "races" for fun on weekends. That trade off is wear. The stock guides will last longer if they are installed correctly in a street engine. If you are going for a 12 -16 pass motor that humps at 10K rpm then a lighter bronze guide with tight clearances are great. It's like the stainless steel valves...nice on a race engine...not nice on a street engine.

Once you get to the level of being seriously racing to make some money there is no grey area transition with compromises for driveability. It's either a full out race engine or it's not. In this case it is black & white. I'm just suggesting to you from my experience having done the bronze thing, use the stock guides....you'll thank me in 3 years...because you won't be sinking money in to replace them.


[Modified by Michael Delaney, 5:29 PM 8/10/2002]

 

good info.. thanx fer yer help. ill just stick with stock.. is acura the best place to get stock ones for the price??

 

Ok, Michael Delaney, I see your reply. I have a '95 GSR head that I'm getting a light port&polish, portmatch and a 3 angle valve job done to it. The use of the car is that I'm looking for 400+whp with the set-up I have. The thing that still boggles me is, should I go with SS valves on the EXH. side, stock on the INT. side with stock guides. Now I run the HELL out of my car everyday and I'm going to be entering it in racing events but, it's also my dailydriver. The block has been sleeved and Arias pistons at 84mm with Eagle rods. I'm wanting to get 375+whp on pump gas at around 18-20psi and 425+whp on race gas at 21+psi. ECU is Hondata. Anyhelp will be greatly appreciated. . . . . . . Thanks


Jeramy


[Modified by WykidEG, 3:36 PM 8/24/2002]


[Modified by WykidEG, 3:37 PM 8/24/2002]

 

^^^

 

there's no doubt that stainless valves survive high heat conditions much better than stock valves. In turbos running that much boost, of course a stainless valve would work well. The use of the bronze guides is based on the clearance advantages and compatibility issues I raised before. The question is: how long will they last? how long will the valve seat last? what seat pressures are you running? how often do you do your valve adjustments and check your seat pressures? When you run that much boost, it might as well be called a race engine. I'd like to know how long race engines last daily driven...(rhetorical question)

If you are running that much boost then yes, stainless valves and bronze guides may be worth the expense. They do not however necessarily guarantee longer life.


[Modified by Michael Delaney, 12:21 AM 8/26/2002]