Need some Info on Valve Guides

BiG MiKE

BiG MiKE

Driver
Ok. So im about to send my head out for a basic rebuild - with basically all new parts including:

New Tomei 256in/256ex PonCams
New BC Valve Springs
New BC Ti Retainers
New BC Valves In/Ex STD.
New OEM Rocker Arms
New OEM Valve Seals

So Should I get new Bronze Valve Guides? Do I need em? Would it machining be nessessary?

On a sidenote - Should I go back with RAS's? thanks :D see you kidz on the track soon (i HoPE)
 
bronze valve guides will help reduce friction and they have quite a long life... also very good heat transference.. copper guides are about the same and probably a lil cheaper.. but if you're going to go through all that you might as well do the guides too...
 
Honestly Mike, I would have the machinist determine if the guides are worn and need to be replaced. The process to close the clearance on the valve stem is called knurling. Its a tool that creates ridges through out the length of the guide. By knurling these guides back into proper clearance (if they need to be) you will be accomplishing two things. One being a reduction in friction because of the stem is riding on the knurled edges instead of the entire length of guide. Less friction reduces heat. Secondly the ridges will hold oil on the valve stem and guide instead of letting the oil escape out the ports.

When I rebuilt my head with everything, I priced out replacing the valve guides on my own. I was going to replace them instead of having to knurl them. Well I was talking with Nissan and new valve guides have to be knurled after they are installed into the head. So unless the guides are damaged from breaking a valve, there really is no reason to actually replace the guides as opposed to having the machinist check the clearances and knurl if necessary.

Looking at the picture you will see the knurling ridges that are found on the inside of the valve guide. This guide is broken and being replaced. The oil gets trapped in the low spots created by the ridges to keep small reservoirs through the entire valve stem.
knurled-guide.jpg
 
Last edited:
Thanks for the info Rick! I guess ill have the machinist inspect em before hand and let him tell me if I need em.

Hey One more thing - I was browsing the interwebz and a few online stores made it seem that bronze valve guides were a must for anyone looking to rev past the factory rev. limit - Is there any truth to that?
 
BiG MiKE said:
Thanks for the info Rick! I guess ill have the machinist inspect em before hand and let him tell me if I need em.

Hey One more thing - I was browsing the interwebz and a few online stores made it seem that bronze valve guides were a must for anyone looking to rev past the factory rev. limit - Is there any truth to that?
Click to expand...

Ive read a few engine blueprinting books and assembly guides and ive never heard that. Nor have I heard anyone tell me this. I would have to look it up about which guide material is "best" but its not necessary.
 
BiG MiKE said:
Most of the sites selling these valve guys have that line in their advertisements...

"If you're planning on using your engine above 7,000rpm, the factory guides will slowly develop hairline cracks and then eventually destroy themselves AND your valve stems. The RaceMax Valve Guides are your answer for reliability beyond 7,000rpm."

Source:
http://www.xs-engineering.com/xsstore/pc/viewPrd.asp?idcategory=194&idproduct=4367
Click to expand...

They said the factory valve guides are cast iron........ I have a redtop head at the shop that I ported, I know the ka guides are brass and I did not notice a difference with the sr20. Ill check again on monday to verify. As long as your machinist is not selling you work id trust his opinion on this matter. I dont think its necessary especially if they are brass.
 
A guy named JR. that came HIGHLY Recommended from a great tuner and many satisfied customers of the mazda werld... Works for Russ Racing Engines in Hollywood. Hopefully all goes well... Ill post pics of the head if I get it back tomorrow or tuesday
 
BiG MiKE said:
A guy named JR. that came HIGHLY Recommended from a great tuner and many satisfied customers of the mazda werld... Works for Russ Racing Engines in Hollywood. Hopefully all goes well... Ill post pics of the head if I get it back tomorrow or tuesday
Click to expand...

I know Junior, ask him about the valve guides. Russ Racing is on Dewey Street south of Hollywood Blvd, north of pembroke rd, east of 441.
 
240SicknessX said:
I know Junior, ask him about the valve guides. Russ Racing is on Dewey Street south of Hollywood Blvd, north of pembroke rd, east of 441.
Click to expand...
Yeah thats him - great guy - I brought it up when I was there at the shop and he said I prolly wouldnt need em but of course he was gonna inspect and let me know his findings.
 
You must log in or register to reply here.
Back
Top Bottom