some valvetrain questions

[Aproductions]

Which is better, 1mm OS valves or just the standard?

and should I get bronze valve guides or the stock iron ones?
also is the machine work different if I get new stock ones vs the bronze ones?

If someone could fill me in about these it would really help.

 

[NOSLO2PT0]

For YOUR car, I'd just stick with the stock size valves. 1mm over valves are for guys looking for BIG HP (700+). Also, the bronze valve guides are just fine.

 

[Aproductions]

what is the difference in getting new stock guides, or new bronze guides.

is the machine work any different or anything?

 

[LiquidX]

If you aren't looking to go racing or getting he most out of the head then standard valves are fine. You only need to replace the guides if they are out of spec or damaged. To install them means going to the machine shop to have them at proper height.

 

[snowborder714]

Next time please create one thread for your question, not two.

And no bumping your thread just to ask the same question over and over. You can do some searching to find out some answers on your own and come back with some educated information to post along with your question.


And the Newbie forum is not where you should be posting. You're a Proven Member, so use the appropriate forum next time.

 

[Jerkychew]

The bronze valve guides are harder and dissipate heat better. I think on these particular cylinder heads they have to do extra machine work to install the proper guides which have a large outer diameter. In order to install the over-sized valves additional machine work will also have to be done. Unless you are going for big HP numbers just stick with the original guides which can be knurled and sized if needed, and keep with the stock valves. Otherwise you are spending more money than needed, when you can spend it on larger power gains elsewhere.

 

[Aproductions]

The bronze valve guides are harder and dissipate heat better. I think on these particular cylinder heads they have to do extra machine work to install the proper guides which have a large outer diameter. In order to install the over-sized valves additional machine work will also have to be done. Unless you are going for big HP numbers just stick with the original guides which can be knurled and sized if needed, and keep with the stock valves. Otherwise you are spending more money than needed, when you can spend it on larger power gains elsewhere.

Well I would feel more confident if I did the full head refresh.

the prices are as followed: (I am looking at 3 kits)

1. Standard SS valves, topline lifters, and bronze valve guides. $211.60

2. Oversized valves, topline lifters, and bronze guides. $216.60

3. Standard SS valves, topline lifters, and stock iron guides. $192


you are saying the bronze guides are better than the stock ones so I would want to get them, so that eliminates choice 3.

now since I am getting the bronze guides, shouldn't I just get the oversized valves anyways since the guides require machining anyway?

and would I have to do machining if I went with the new stock iron guides or only if I go with the bronze ones?

I mean the choices are really close in price so yeah.

thanks.


and snowborder714 I'm sorry and I will start posting in the appropriate forum

 

[steve]

now since I am getting the bronze guides, shouldn't I just get the oversized valves anyways since the guides require machining anyway?

The oversize valves can actually hurt airflow through the head unless you also have cams with more lift. Or at least that's what the guys you actually work on DSM heads tell me.

 

[Aproductions]

well I was planning on getting delta regrinds.

either 272s or 264/272 combo.



would those be enough?

 

[Zex4g63]

The oversize valves can actually hurt airflow through the head unless you also have cams with more lift. Or at least that's what the guys you actually work on DSM heads tell me.

+1. Low lift is hurt due to shrouding. That's how the flowbench shows it so take it as you will.

 

[Aproductions]

well like Steve said, If I have cams will it be worth it?

basically I wanna know which of these 3 kits to get.

1. Standard SS valves, topline lifters, and bronze valve guides. $211.60

2. Oversized valves, topline lifters, and bronze guides. $216.60

3. Standard SS valves, topline lifters, and stock iron guides. $192


and 3 questions I have that I am confused on are:

do new stock iron guides need to be machined just like the bronze ones?

and are the oversized a better choice for me if I have cams?

how much $$$ is the machine work for oversized valves vs standard valves?


sorry I am just trying to clear all this up

 

[Zex4g63]

well like Steve said, If I have cams will it be worth it?

basically I wanna know which of these 3 kits to get.

1. Standard SS valves, topline lifters, and bronze valve guides. $211.60

2. Oversized valves, topline lifters, and bronze guides. $216.60

3. Standard SS valves, topline lifters, and stock iron guides. $192


and 3 questions I have that I am confused on are:

do new stock iron guides need to be machined just like the bronze ones?

and are the oversized a better choice for me if I have cams?

how much $$$ is the machine work for oversized valves vs standard valves?


sorry I am just trying to clear all this up

Those cams are small. My opinion is stock size valves and bronze guides. Machine work would be about the same at an honest shop with the right equipment.

 

[Aproductions]

ahh we have a winner

so basically 272 cams aren't big enough to get any benefite from oversized valves

so I should get stock sized valves, so option 2 is out and people are saying that bronze guides are better than the stock iron ones....so that takes care of option 3

and I just saw the edit, machine work would be the same if not close.


thanks.

I will go with the stock sized valves, topline lifters, and bronze guides.

 

[LiquidX]

Holy Hell dude, did you even bother reading? The guides are just what the name entails, guides. I'd they are fine then nothing needs done and the amount of heat transfered is negligible for what ever reason it's worth. If your stock valves are fine as well just get them cut and reuse them. You will just be wasting money by throwing un needed parts at it. If your stock stuff is fine re use them.

At least replace the valve seals however.

 

[Jerkychew]

I do agree with liquid, why spend the money when you don't need to.

 

[BogusSVO]

ok....
Bronze guides MAY require more work when installed, normally they need to be reamed/honed to get the proper stem to guide clearance. so yes it could cost more if that has to be needed

Iron guides will be just fine on most build ups that that spend 99% of the time on the street, yes Iron guide run a bit more clearance and need a bit more oil to keep lubed

the up side to iron over bronze is that if you generate more heat (over heat, run lean, bad tune) that you stand less of a chance of the valve being gaulled to guide and sticking

When changinging the guides, the seats will have to be cut to bring the center line of the guide back inline with the centerline of the seat.
http://www.dsmtuners.com/forums/newbie-forum/341218-how-change-valve-guides-4g63t-head.html

now as far as stock to +1mm os valves....

If the machine shop installes the valves properly, then you should see a gain in flow throughout the valve lift.

as someone above me said, Unshrouding the valve helps, but the bowl needs to be opened up also,

if the valve seat is just cut to fit the valve, and the throat of the bowl is not opened up then it should flow about like a stock valve.

also +1mm valves can be used as a "repair valve" if the head has been valve jobed a time or two, and the seats are getting low, a +1mm valve will bring the valve seat closer to spec, and that will also bring the valve tip, and spring installed height back into spec.

I do this often , so I do not have to change valve seats.

 

[Aproductions]

the up side to iron over bronze is that if you generate more heat (over heat, run lean, bad tune) that you stand less of a chance of the valve being gaulled to guide and sticking

so the stock guides are better?

 

[GSXSixteenG]

the up side to iron over bronze is that if you generate more heat (over heat, run lean, bad tune) that you stand less of a chance of the valve being gaulled to guide and sticking

Bogus, I thought the concept on bronze valve guides was to reduce galling because of a lower friction coefficient. But it also has higher thermal expansion coefficient, so maybe this is what you referring to. Maybe I'm just thinking about it too much.

 

[Aproductions]

I am just going to take it to a shop and get it confirmed if it needs guides and stuff.

I just wanted to replace the worn parts for a piece of mind.

 

[BogusSVO]

Bogus, I thought the concept on bronze valve guides was to reduce galling because of a lower friction coefficient. But it also has higher thermal expansion coefficient, so maybe this is what you referring to. Maybe I'm just thinking about it too much.

what your saying is true, bronze guides used in a all out race build, non street driven car is great. This is a limited use car, being run for short periods of time, and mostly checked over inbetween runs.

but I perfer iron guides in street engines, no matter if they are 88 hp or 880hp

if a sensor, tune, fuel pump goes weak, and you run lean for a bit, the guide expands, the valve stem expans, then the clearance is gone, valves lock up in the guide and meet the pistons.

you will find other head builders, that will say bronze is fine for the street, and that fine.

But ask them if they will cover the cost of parts and labor if the valve gaulls up for any reason

I rather give up 1HP (if that) to the friction caused by the iron guide for the safety gained by the extra clearance.

 

[Colt4G63 also]

Hey Bogus SVO, while we're on the subject of valve guide clearance, is it normal to be able to feel some side to side play in the valves when the springs are off?

When I built my engine I just had the head cleaned and milled, and I lapped the valves and installed revised lifters, valve seals, BC cams, and BC springs. I noticed a little play between the guides and valves. It doesn't burn a drop of oil, but when you free rev the engine there's sometimes a little tapping sound around 3000 rpm.

Am I on borrowed time?

Ps: As far as I know they are stock guides.

 

[BogusSVO]

yes a little play is normal, but VERY little

with out mic'ing the valve stem, and ball gauging the guide ID, it is hard to explain how the "feel" should be

the tapping you hear, may still be lifter tic.. due to low flow of oil to the HLAs.