Questions about 1 over sized valves?

[boblong6]

I am still learning about the motors but I am building my motor and I have 6bolt block and a 7 bolt head and I am running a gt35r turbo I got the block 20 over and I going to be sending out my head to get machined but I was wondering when I send my head out I plan on getting a 5 angle valve job and 1mm over size valves but i was wondering is it worth doing all that what are the benifets from it when i get that stuff done my goal is 500+ any suggestion I will take into consideration and what you guys tell me I will learn from!

 

[BogusSVO]

First not all machine shops will install the +1mm valves the same way.
Nor will they use the same equipment.

If the +1mm valves are installed with the stock throat, then there will be little gain.

This will help explain.
http://www.dsmtuners.com/forums/cylinder-head-short-block/438429-4g63-head-build-modified.html

Now have you decided on what Brand of valves, springs/retainers,guides and cams you are going to run?
What head gasket have you selected?


BTW, a 5 angle is 3 on the seat and 2 on the valve.

 

[white92talontsi]

Agree with Bogus, Spend your money else where.

 

[boblong6]

i just ordered Brian Crower springs and retainers, I am going to run hks or brian crower 272 cams, supertec guides and valves, I have a set of 3mm lifters. Havent figured out what gasket yet. I am using ARP head studs.

 

[GsxAZman]

Im surprised nobody has mentioned this yet but if your using arps than you need to drill out the holes on the head the studs go through for proper oil clearance. Bogus svo or a search should be able to chime in on how much more to drill it out. Thats an important step.

 

[boblong6]

I know i am going to have to have them drill them out. I just am wondering is it worth it doing it and when you do it what do you gain from it and how much?

 

[BogusSVO]

i just ordered Brian Crower springs and retainers, I am going to run hks or brian crower 272 cams, supertec guides and valves, I have a set of 3mm lifters. Havent figured out what gasket yet. I am using ARP head studs.

Since you ordered BC springs and retainers, why did you not order the BC valves and guides at the same time?

You need to figure out if you are going MLS or composite, so the proper surface finsh can be put on the head.

Oh, now that brings up, Did you have the block decked?

Im surprised nobody has mentioned this yet but if your using arps than you need to drill out the holes on the head the studs go through for proper oil clearance. Bogus svo or a search should be able to chime in on how much more to drill it out. Thats an important step.

I have not gotten that far yet!

Also to make it easy to find all that info, click the link in my sig line.

I know i am going to have to have them drill them out. I just am wondering is it worth it doing it and when you do it what do you gain from it and how much?

Yes it worth doing, if you want to be able to get the head down the studs and have decent oil flow to your cams and HLAs.

 

[JacksonAuto]

Before coming up with specific plans for the head, have a machine shop disassemble and evaluate it thoroughly. If the stock guides are worn, which is likely, then you will need to replace them and go with oversized valves.

I will mirror what Bogus has said. Be sure that your machine shop of choice is familiar with building high performance boosted engines. Make sure that they cut the seats larger to accomodate the larger valves along with opening up the throat to eliminate a bottleneck.

 

[BogusSVO]

JAM.... He has all new parts on the way, including bronze guides.

So whom ever gets the build, has the full deal to work over, as long as the casting is in decent shape, and he seats have not been sunk from a few valve jobs.

 

[boblong6]

the block has been deck I planed on having them redeck my head also. I didnt order my valves and guides yet cause i was low on cash at the moment my car just got painted.

 

[BogusSVO]

the block has been deck I planed on having them redeck my head also. I didnt order my valves and guides yet cause i was low on cash at the moment my car just got painted.

Post up a good pic of the surface finish on the block.

The block is bored and honed .020 correct? So you have pistons all ready?

What brand of pistons?

What is your PTW?

 

[boblong6]

the block is honed and bored .020. i dont have pistons but i plan on running je or wesico. i have Brian crower rods i will email you a pic of my block Bogus.

what your email so I can send it to you

 

[BogusSVO]

Just post the pic in the thread.

You understand that the block may have to go back to the shop to be honed again, if you do not have enough Piston To Wall (PTW) clearance?