M20 Oversize valves

[E30-325iS]

I'm begining to gather parts to build a 3.0 lt stroker and I am planning to use +1 mm oversize valves.

After a bit of Googling I've come up with a few sources.
VAC
Ireland Engineering
Top End Performance
and
BuyImportPerformance.com

There is not much information on any of the above, so I'm interested in peoples experience, knowledge or opinions with any or all of the above.
Also interested if anybody knows of any other sources of good quality valves or has bought from BuyImportPerformance.com
TIA

[burkey001]

Why not go to the source Supertech valves?

[tinkwithanr]

I have the VAC +1 valves, and the quality is top notch. I can't speak for other brands personally, though I have seen the machining on the ireland ones and it wasn't in the same ballpark.

[digger]

i have some sample valves from VAC, IE, PPF. Use VAC they use manley valves FYI, stay away from IE the quality differenece is evident from the moment you see them. Otherwise use PPF (supertech)but more pricey IIRC. The VAC ones are significantly lighter than stock and the IE ones arent. PPF are a bit lighter than stock.

[SkiFree]

What Digger and tinkwithanr are alluding to are the old standard size intake and exhaust valves (and the Duetchman Debacle). The finish left a bit to be desired, and frankly I wasn't happy with them either, so that's why we've got the new versions.

At this point that is out-of-date incorrect information.

Contrary to what Digger says, the IE +1mm valves are lighter than factory. (intake oem: 82grams intake +1mm ie: 79grams). Though remember a gram is the weight of about one piece of printer paper.

New vs. old STANDARD size valves, note that there's now a swirl polish on the backside as well, this is on the oversize valves as well.

[einstein57]

I've heard good things about the performance out put on TEP built heads and their valves are swirl machined IIRC. I plan on getting the IE or TEP valves when its time to build my replacement motor.

[digger]

What Digger and tinkwithanr are alluding to are the old standard size intake and exhaust valves (and the Duetchman Debacle). The finish left a bit to be desired, and frankly I wasn't happy with them either, so that's why we've got the new versions.

At this point that is out-of-date incorrect information.

Contrary to what Digger says, the IE +1mm valves are lighter than factory. (intake oem: 82grams intake +1mm ie: 79grams). Though remember a gram is the weight of about one piece of printer paper.

New vs. old STANDARD size valves, note that there's now a swirl polish on the backside as well, this is on the oversize valves as well.

Here are the valve masses

INTAKE (Left to Right)
OEM 42mm 80g (Osvat)
PPF 43mm 73g (Supertech)
VAC 43mm 67g (Manley)
IE 43mm 79g



EXHAUST(Left to Right)
OEM 36mm 69g (Osvat)
PPF 37mm 73g (Supertech)
VAC 37mm 65g (Manley)
IE 37mm 71g



i maintain that the IE are not signiifcantly lighter than stock.

if i made out that IE were crap then it was harsh, they just arent as good as the VAC and PPF ones but are cheaper

[MR 325]

I would not hesitate to run the IE valves, in fact Myster-e is planning to build a head with them soon!

[E30-325iS]

Thanks everyone for your replies, it's terrific to get every ones views and to be able to see the differences side by side.

[SkiFree]

\
i maintain that the IE are not significantly lighter than stock.

if i made out that IE were crap then it was harsh, they just arent as good as the VAC and PPF ones but are cheaper

I agree with you, the VAC/PPF are certainly lighter, and they certainly should be for how much they charge as you pointed out. (VAC: $539 for full set, IE: $276 for full set [NOT made in China, Tawain, etc]).

It depends on the immortal question ... Value Vs. Weight, and that's a question that depends on the individual. I think we have a similar mind-set, just differing perspectives.

[MR 325]

Exactly Andrew, DOUBLE the price! (Much like everything VAC sells)

The weight of a valve is hardly a concern.

[whodwho]

The weight of a valve is hardly a concern.

Depends on your target RPM and how much spring it will take to get you there with the added weight to keep from floating all adds up to needing extra spring pressure and the wear associated.

[digger]

they are lighter because the the head is flatter (less tulip shaped) which is what the M20 intake port needs due the port geometry (valve port angle) for better flow. This seems to be what schrick did with their valves though i havent held them in my hand.
In a performance engine valve control is very important so you can use faster ramps to give high valve lifts and area under the curve, without needing to use crazy durations which narrows the power band. Being able to use less spring pressure will help the rockers out aswell.

VAC and IE cater to slighly different markets

[SkiFree]

I didn't ask how they were lighter, and what effect it has. You're explaining engine dynamics 101.

VAC and IE cater to slighly different markets

It depends on the immortal question ... Value Vs. Weight, and that's a question that depends on the individual. I think we have a similar mind-set, just differing perspectives.

Again, similar thought process, differing perspectives

[digger]

I didn't ask how they were lighter, and what effect it has. You're explaining engine dynamics 101.

Again, similar thought process, differing perspectives

i think it was worth explaining that being lighter wasn't something that should be overlooked when choosing a valve, as eluded to be the case from a different member. Not everyone is aware of engine dynamics or the significance or lack of valve mass so it might help others be in a better position to choose if they want to pay a premium for the last few %. i have edited my post so that it wasn't directed to you.