M20 Oversize valves

[E30-325iS]

Thanks Digger, it is definitely worth explaining as I don't have as much knowledge as I would like, and any input no matter how trivial or basic it may seem is most welcome, hence the thread.

[tinkwithanr]

Glad to hear the IE valves are improved, never hurts to have another quality option for BMW parts.

Also, later today I'll get a picture of my VAC valves. They are slightly different than those in Digger's pictures (coated, maybe a slightly different shape to the head). It would have been nice to have this kind of info in one place when I was shopping around for parts before.

[E30-325iS]

Thanks Tinkwithanr, looking forward to the pics.

[einstein57]

Anyone have info on the valves TEP sells?

[tinkwithanr]

Here are some pics of VAC's valves. I can't speak personally about any of the other options, but I am very happy with my purchase. The machine work and finish was top notch, my machine shop (whom specialize in billet aluminum CNC'd big blocks) even commented on how nice they were.



+ 1mm Intake Valve (43mm)





+1mm exhaust valve. Here you can see the difference in the head shape on the intake and exhaust valve (intake in the rear of the pic). Like Digger mentioned before, these have a flatter crown on the intake valve to help aid flow. The exhaust valve has a more tradition bell shape to it.




And here are some pics of them installed:

[SpecM]

do the seats have to be opened up any special way to use +1 valves?

[digger]

Here are some pics of VAC's valves. I can't speak personally about any of the other options, but I am very happy with my purchase. The machine work and finish was top notch, my machine shop (whom specialize in billet aluminum CNC'd big blocks) even commented on how nice they were.



+ 1mm Intake Valve (43mm)





+1mm exhaust valve. Here you can see the difference in the head shape on the intake and exhaust valve (intake in the rear of the pic). Like Digger mentioned before, these have a flatter crown on the intake valve to help aid flow. The exhaust valve has a more tradition bell shape to it.




And here are some pics of them installed:

out of curioisty when did you buy those valves from VAC and was the a brand name on the stem?

[whodwho]

They look like the Black Nitrided Supertechs

[digger]

They look like the Black Nitrided Supertechs

which are the same as the one i got from PPF (i.e have the backcut already done), but i am wondering if VAC now use the Manley ones instead becasue that is what i got late last year

[tinkwithanr]

I got them roughly a year ago. I don't recall seeing a name on the stem when I looked them over, and they are currently installed so I can't check.

[ROLLingKING]

VAC ftw

[e30conv2]

Vac Motosports or Metric Mechanic is the way to go. Ireland Engineering has mostly Asian parts. Our E30's are German. Most Asian parts are compromised in manufacturing German aftermarket parts believe me I have been working on German cars for twenty five years plus. You get what you pay for 99 percent of the time.

[tinkwithanr]

Correct me if I'm wrong, but I don't think IE imports their parts. While there may be differences between the vendors, the cost of the parts along with the target consumer is also different.

If I'm just rebuilding a stock head to go on a stock bottom end, it makes sense to spend half the price for a valve that will match the performance of the other components in the build. Likewise, considering the amount of money I currently have in my stroker build, the $250 difference in price was minimal and gave me valves that would be a better match for the rest of my build.

[digger]

i'd only be looking for oversized valves if overboring the block on a stroker so that the amount of shrouding between the valve and cylinder essentially doesnt change.

MM dont even use OS valves so what does that say for the size of stock valves? or their heads? Either stock are way too big as it is or MM are too small.

without some decent head work i dont think the OS valves would do much, the seat needs to be modified accordingly and you want a multi angle valve job.........where does it end?

[SkiFree]

V Ireland Engineering has mostly Asian parts. Our E30's are German. Most Asian parts are compromised in manufacturing German aftermarket parts believe me I have been working on German cars for twenty five years plus. You get what you pay for 99 percent of the time.

IE: $276 for full set [NOT made in China, Tawain, etc]).

?