Austispu

Hi I currently have my head at the machine shop and wondering if a 5 angle cable job worth it. I am going to be running the GSC S2 with Map ef4 and a built bottom end.

LetsGetThisDone

iTrader: (1)

Unless they're doing some other work, like a pocket port and in shrouding the valves, no. Just get a regular valve...

Besides, the hot stuff now is a radius valve job, no angles.

Austispu

Thanks, What is a radius vavle job?

LetsGetThisDone

iTrader: (1)

Exactly what it sounds like. The valve and seat are cut with a single, smooth, radius instead of multiple angles.

CurseDSM

iTrader: (3)

Not worth it in a month it will be a 3 angle valve job and in 6 more months its a regular valve job. Not worth the cash, I would just get the 3 angle if you were going to get anything or as stated above the radius valve job.

Austispu

Thanks guys good information. I thinking of going with the radius valve job. Also my valves were all tweaked so I am going +1mm over.

splattj

iTrader: (2)

Make sure your machine shop has actually done a radius job before. It takes a specific type of cutter to do them. Heck, I'd want pictures of the job before the valves are back in. It would be too easy for them to do a standard cut since you'd probably never know the difference. Done right, it's pretty time consuming/costly compared to a factory-equiv. job.
Check this out if you want to see it done on a 4G63 style head.

CurseDSM

iTrader: (3)

Unless your going with a very large turbo 35r or above 1mm is useless. For example the shop doing my head is doing a 1mm over intake and stock size exhaust valves for 105 lb per min turbo. So with that said I would just stay with stock size. 1mm isn't that much but it will make a difference in spool.

2winscroll

I'm calling you out on this Total BS! A good 4 or 5 angle valve job will increase low lift flow numbers substantially. It will not disappear in a couple of months either, where the fu$? Did you come up with that BS? Speaking from experience, not out of my aas like some folks. I have seen 5-8% increases in total flow on a cylinder head with a good radius job. Well worth the money, in many cases you will get more from a good radius job than increasing valve size, usually because of valve shrouding.

Biggiesacks

I think it depends mostly on your goals and your budget. Are there other things you could spend that money on that would net a larger increase in performance or reliability?

nemsin

iTrader: (19)

Headwork is kind of a mystery. I would say check out BR, as he does extensive testing and does not bother with things that do not yield actual gains.
https://secure.buschurracing.com/cat...ce2a487888adcb
https://secure.buschurracing.com/cat...ce2a487888adcb

CurseDSM

iTrader: (3)

Call me out on it I really don't care. Like yourself supposedly I have had head work done and after a few months of high revs your valve job is pretty much toned down from the constant abuse your valve train puts on it. I never said you wouldn't get any gain out of it nor did I say that it wasn't a good idea. I just stated that in my (OPINION) it was a waste of money. And imagine that you think people talk out there *** on a car forum. Man you must be some kind of genus cause hate to say it bra lots of misinformation on forums. And FYI been in the game a long time (since 95 if memory serves me right) so its not like I don't know anything and that I am a noob. Been working on dsms and evos a long time my friend.

2winscroll

I do all my own work, you pay other people to do it for you because you don't know how. Trust me even with stiff springs and high RPM you won't wear the seats down anytime soon. Seen plenty of heads with over 100k still look like new. So yes it's BS when you say it will be worn out in a few months. I grind my seats 5 angles then blend in the bowls. 30-45-55-65-75

LetsGetThisDone

iTrader: (1)

I agree with 2winscroll. If a multi angle valve job wore down that fast, the valve wouldn't seal and you would need to redo the valve job. And that is simply not the case.

2winscroll

Here is a good read from an expert on cylinder heads.
5 angle valve job is one of your best bangs for your buck.

http://www.enginebuildermag.com/2008...with-the-flow/