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Valves Question


MrNvgtr

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I just found this old post by Visionaut and it got me thinking. I just ordered new stainless intake and exhaust valves from Ireland in their stock sizes for my E12 head. What Visionaut says below confuses me though. It sounds like I could and should get larger valves. Does he mean that I also need to machine out the holes?

AFAIK, Mahle 'piano-top' 9.5:1 pistons are for the E12 head only. While not absolute, many consider a late casting E12 head to be the best - it has the larger intake valves already. (But it's not too tough to resize an 121 head to fit them too.) You might want to check out Mahle 8.5:1s, Max-sil or JE pistons.

Basic street port/polish might be all you should consider (port matching - intake & exhaust to match gaskets, and intake manifold). It won't make a big difference, but better flow is a good thing.

It might not be advisable to go to larger valves than E12 size. Without lots of other induction mods it mightl actually hurt vs help performance.

HTH...

Michael Rose

'91 Porsche 964
'00 Dodge Durango
'13 Honda Pilot

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Guest Anonymous

The holes... are also refered to as "seats" They are steel inserts pressed into the head. If your trying to stick E12/21 valves into a 121ti head then you will need to machine out the seats to accept the larger valve.

I just found this old post by Visionaut and it got me thinking. I just ordered new stainless intake and exhaust valves from Ireland in their stock sizes for my E12 head. What Visionaut says below confuses me though. It sounds like I could and should get larger valves. Does he mean that I also need to machine out the holes?

AFAIK, Mahle 'piano-top' 9.5:1 pistons are for the E12 head only. While not absolute, many consider a late casting E12 head to be the best - it has the larger intake valves already. (But it's not too tough to resize an 121 head to fit them too.) You might want to check out Mahle 8.5:1s, Max-sil or JE pistons.

Basic street port/polish might be all you should consider (port matching - intake & exhaust to match gaskets, and intake manifold). It won't make a big difference, but better flow is a good thing.

It might not be advisable to go to larger valves than E12 size. Without lots of other induction mods it mightl actually hurt vs help performance.

HTH...

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Ok, got it.

But if I ordered Ireland's "stock" 2002 valves for my E12 head, am I good? They aren't open yet to ask them that question. Thanks.

The holes... are also refered to as "seats" They are steel inserts pressed into the head. If your trying to stick E12/21 valves into a 121ti head then you will need to machine out the seats to accept the larger valve.
I just found this old post by Visionaut and it got me thinking. I just ordered new stainless intake and exhaust valves from Ireland in their stock sizes for my E12 head. What Visionaut says below confuses me though. It sounds like I could and should get larger valves. Does he mean that I also need to machine out the holes?

AFAIK, Mahle 'piano-top' 9.5:1 pistons are for the E12 head only. While not absolute, many consider a late casting E12 head to be the best - it has the larger intake valves already. (But it's not too tough to resize an 121 head to fit them too.) You might want to check out Mahle 8.5:1s, Max-sil or JE pistons.

Basic street port/polish might be all you should consider (port matching - intake & exhaust to match gaskets, and intake manifold). It won't make a big difference, but better flow is a good thing.

It might not be advisable to go to larger valves than E12 size. Without lots of other induction mods it mightl actually hurt vs help performance.

HTH...

Michael Rose

'91 Porsche 964
'00 Dodge Durango
'13 Honda Pilot

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Guest Anonymous

then yes if you have a e21 or e12 head the "Valve - Exhaust - factory" and "Valve - Intake - factory" will fit your head fine. You will need to probably lap the new valves into their seats. A cheap and easy way to check for good seal is to pour water or mineral spirits down the port. After about 2 minutes very little fluid should have gone down. Like it shouldn't move more than a 1/4".

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Guest Anonymous
then yes if you have a e21 or e12 head the "Valve - Exhaust - factory" and "Valve - Intake - factory" will fit your head fine. You will need to probably lap the new valves into their seats. A cheap and easy way to check for good seal is to pour water or mineral spirits down the port. After about 2 minutes very little fluid should have gone down. Like it shouldn't move more than a 1/4".

Slightly off topic: Over many years of driving, I have suffered worn valve guides and seals but never a burned valve. I also used the 46mm valve from the newer heads even on my 121 head. My question is what do the aftermarket stainless valves offer over the stock valves? How are they different and why are they presumably superior?

Thank you

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Generally OEM valves are two piece fusion welded together. Aftermarket valves like Manley are machined out of a single piece of stock, advantage strength, reliability and some flow improvement due to the backside radius. Exhaust valves can be sourced in Inconel and other superior heat heat handling stainless alloys. Combined with beryllium exhaust seats this lowers exhaust valve temperature and minimizing the main detonation source in a internal combustion engine. Which translates to the ability to use higher compression ratios and more ignition advance, making more power. Stainless valves are not limited to high speed engines, the EMD GP30 series locomotive engine uses swirl polished stainless valves, roller cams, and they never see 2000 RPM

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Guest Anonymous

Thank you for the reply. I assumed there are advantages to stainless or even titanium valves, but as I mentioned, I have never had any valve failures/fatigue with the OEM offerings after 20+years of very had use.

I thought the sodium filled versions were good for heat resistance, but are you saying that I can push things even harder with the stainless? I would expect the answer is yes for titanium since it is obviously lighter, but I am not certain about its strength over stainless.

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Hi Michael. Been a while, hope all's well with you.

Yeah, as others have already indicated, if you've got an E12 head, it has the 'enlarged' stock valve sizes already (inlet = 46mm, exhaust = 38mm, the exhaust being 1mm larger versus the earlier M10 heads). The IE SS valves in the stock E12 sizes should be fine (and a nice value vs. stock valves). You could also elect to go with the IE oversize SS valves, which come in 47mm inlet and 39mm exhaust sizes (using reamed seats).

Looks like you're looking to do a big engine overhaul, huh? Been seeing a lot of Q's from you lately ;-)

Take care,

Tom

Where we goin’? … I’ll drive…
There are some who call me... Tom too         v i s i o n a u t i k s.com   

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First Titanium valves are not practical street parts, stems and keeper grooves are not that durable. Ti's big advantage is weight, when valve lift is approaching 1 inch, all mass reduction is important, even the use of Titanium valve springs is common now. On the street Ti intakes might work ok, but definite no on exhaust.

Sodium filled exhaust valves are effective but very heavy, read not good in high speed engines. The cooling works well with sodium valves, and most aircraft recips, Waukasau, Hercules Continentals truck engines a few production car engines had them, the 427 Ford for one.

The stainless valve when combined with the Beryllium Copper seat is quite effective and even some production Honda's had them (I believe that is the source of the technology). Most NASCAR teams Indy motors Cosrworth. Imores and endurance road racers utilized the technology, but it is limited to availability. The grindings from Beryllium Copper are toxic and carcinogenic, so finding a machinist to install them is an issue.

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Yeah, well I'm not doing everything "yet" but we'll see as we go. Primarily I'm using a stock 2.3 liter S14 crank, Schrick 304 cam (because I can't figure out what the heck cam I have), stock rods, and possibly 92mm JE pistons (TBD). The further I get into this, I might upgrade more, but we'll see. The intake will be all TWM from the ported manifold out to the CF airbox. I'm using Haltech EFI. Among other things, I'm removing the roll cage, removing solid rear subframe mounts (replace with stock with urethane inserts), removing EPO, cleaning up all wiring and cabling (it was a damn race car),, upgrading to a 5-speed, aluminum radiator, oil cooler, brake booster delete, etc etc etc. All of this is a 100% learning experience for me, so we'll see how it goes. I'm trying to filter all the questions I have so I don't become 'that guy'. My car is actually at M20Curtis's house and he's helping me out big time with his knowledge and wrenching skills.

Back to the topic. Now I'm confused again after what you just said. I bought IE's SS intake (46mm) and exhaust (38mm) valves. They don't mention anything about fitting specifically an E12 head. Did I get the right size or not? What you said completely threw me off.

[Edit] Ok, I read it about 5 times and now I understand. I'm cool.

Hi Michael. Been a while, hope all's well with you.

Yeah, as others have already indicated, if you've got an E12 head, it has the 'enlarged' stock valve sizes already (inlet = 46mm, exhaust = 38mm, the exhaust being 1mm larger versus the earlier M10 heads). The IE SS valves in the stock E12 sizes should be fine (and a nice value vs. stock valves). You could also elect to go with the IE oversize SS valves, which come in 47mm inlet and 39mm exhaust sizes (using reamed seats).

Looks like you're looking to do a big engine overhaul, huh? Been seeing a lot of Q's from you lately ;-)

Take care,

Tom

Michael Rose

'91 Porsche 964
'00 Dodge Durango
'13 Honda Pilot

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I dunno- I race stock valves, and they hold up fine

as long as I don't do anything really dumb...

like try to make them and the pistons share the same

space at the same time.

The BMW valves appear to be manufactured as one piece.

They're also extremely tough- I tried to slim some down to

make chamber work safer, and it took a LOT of abrasive.

And there were very limited sparks- it's not a pure ferrous alloy.

The valve material won't have much effect on the engine's function-

mostly just it's longevity. The sodium- filled valves will cool themselves

better...

I suppose, if you're at the furry edge of durability, it'd matter

a lot, but unless you're running custom rods, steel rockers and

custom pistons, the stock valves aren't the limitation of the engine.

And I'm not really sold on the theory that the stock valve sizes are a limit

to performance... until you get into the 8k range.

but wtf do I know...

t

"I learn best through painful, expensive experience, so I feel like I've gotten my money's worth." MattL

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