Head Work for Build

[DSMsamurai666]

I'm working on a 4g63T build for around 350hp hopefully. I was going to get the head checked for warpage and redecked if necessary. I'm sure the head needs to have the valve seats redone and the 3 angle refreshed. Once I get the head back I was going to do new guides, springs, valves, cams, and cam pulleys all Brian Crower. I already have the cams and pulleys. Once I get a chance to have the trans rebuilt I was going to further upgrade the fuel system and up the boost so the motor will eventually be more powerful, but I don't know how much more. My question is should I have the angle merely recut to refresh the 3 angle or should I get it upgraded to more angles and should I have the head cut to fit .5 mm or 1.0 mm oversized valves or should I keep the stock valve size? Beyond that I was going to port the runners and polish the head myself. Am I missing anything that ought to be done on the head? If my build doesn't need the better angle job and the oversized valves, what type of build would require them? Also when should the lifters be upgraded? I have a second 4g63 block and head that I may build better than this one someday and I was just curious. Thanks.

 

[BogusSVO]

sounds like a decent head build. but you have the order a bit mixed up.
IF the head has be run hot, Start with having it pressure tested for cracks that would leak coolent.
If you know how, disassemble the head and Do all your poet and polish work, If you do not know how to disassemble the head, have the machine shop your going to use, disassemble the head, and clean it, Then you can pick it back up and do your port work.
Once your done with you PnP, take it back to the shop, and have them change the guides,if needed,when the guides are changed you will need to have a valve job done.
Then the head will be surfaced, tell the shop that is doing the work, what head gasket you plan on using, composite or MLS, each requires a diffrent surface finish.
If you plan to run your used stock valve springs, Have them tested, they are probly weak already and need replaced.
As far as your SS Valve size, stock or .5mm or +1mm over, MY thoughts are if your buying new valves, get the +1mm and have the seats cut for them. AS long as the machine shop you choose has the proper equipment, and a knowlagable machinist that will set the valve train up correctly.

If you check in the newbie forum, you will see posts on ....
http://www.dsmtuners.com/forums/new...face-4g63t-cylinder-head-mls-head-gasket.html

Why to have your Valves back cut

How to Test Valve springs

4G63T Valve spring Info

How to change Valve guides In a 4G63T head


look over these posts and you will have a better understanding of what you are looking to have done.

 

[My1GLaser]

Keep the stock valve size. People run 11s & 10s with basically stock heads with the exception of cams and maybe springs/retainers.

I have +1 valves and it was a waste. An 18g falls off too fast near redline with stock Volumetric Efficiency. Adding larger valves, cams, SMIM all increases VE which is hard to benefit from until your turbo can outflow your motor. I am pretty sure all I did was make the 18g fall off faster with cams & +1mm valves. , plus I believe it slows spool some too, which narrowed my powerband even more, but what did I know back then when I was first starting out? Now I am ready for an HX-40!

Be careful porting. I would only recommend cleaning up the casting flaws and maybe gasket matching the ports, but don't go crazy because it can kill flow and velocity. DON'T POLISH THE INTAKE RUNNERS. It can cause the fuel to puddle and really screw with the fuel atomization.

I wouldn't do the guides unless they are messed up/out of spec.

A valve job is a good idea while it is getting resurfaced b/c it doesn't cost much.

Stock springs are pretty stout. They can test them at the shop and save you from buying new ones for no reason.

 

[BogusSVO]

Keep the stock valve size. People run 11s & 10s with basically stock heads with the exception of cams and maybe springs/retainers.

I have +1 valves and it was a waste. An 18g falls off too fast near redline with stock Volumetric Efficiency. Adding larger valves, cams, SMIM all increases VE which is hard to benefit from until your turbo can outflow your motor. I am pretty sure all I did was make the 18g fall off faster with cams & +1mm valves. , plus I believe it slows spool some too, which narrowed my powerband even more, but what did I know back then when I was first starting out? Now I am ready for an HX-40!

Be careful porting. I would only recommend cleaning up the casting flaws and maybe gasket matching the ports, but don't go crazy because it can kill flow and velocity. DON'T POLISH THE INTAKE RUNNERS. It can cause the fuel to puddle and really screw with the fuel atomization.

I wouldn't do the guides unless they are messed up/out of spec.

A valve job is a good idea while it is getting resurfaced b/c it doesn't cost much.

Stock springs are pretty stout. They can test them at the shop and save you from buying new ones for no reason.

I think you have some misinformation, First, puddling will not happen on modern EFI multi point EFI, now with a carb or TBI injection. How Puddling happens is when the fuel particales drop out of the air charge, BUT since the fuel is atimized/sprayed on to the back of the valve on an EFI engine, the atomization happes at the fuel injector tip, NOT further up the air inlet tract like with a carb.
But dirty fuel injectors and/or low fuel pressuer will cause puddling at the back of the valve.

Now yes the VE will effected with larger valves, an increse will occur. which in turn should help the turbo spool sooner, beacuse now air flow has been improved to the turbo along with mass. All which is needed to spin the turbine/hot side of the turbo.

If you have not ported before, do not try to change the short turn radii, just a good clean up/gasket match of the intake/head/exhaust manifold


Now My1GLaser, I think you may have more issues with your cams, than the +1valves,
Were the cams degreed to the crank? How much overlap do you have based of your CLA? and centerline?
Too much over lap will not hold much pressure, for the simple reason that both the Intake and the exhaust valves are open, therefore letting more of the new air/fuel charge out of the exhaust .

 

[talonfromtenn2]

If it's already at the machine shop, why not have them port and polish the head? They should be able to put it on a flow bench and sqeeze out the most air flow...a lot better than a home job. Shouldn't cost much more on top of what you've listed already.

 

[BogusSVO]

If it's already at the machine shop, why not have them port and polish the head? They should be able to put it on a flow bench and sqeeze out the most air flow...a lot better than a home job. Shouldn't cost much more on top of what you've listed already.

Port and polish will add about $300-$600, with flow bench work to the rebuild, and that is if the shop is equiped with a flow bench, and the flow bench has the proper attachment to flow a 4g63.

I use a Superflow 600 with dual manometers and flow com. and flow heads at 27 inches of water.