Porting question...

[Krooser]

My W-2 heads are ported nicely and flow 294 on the inake side and 240 on the exhaust. 3/8" valves.

The valve guide bosses in the ports were virtually untouched by the grinder. I have seen the boss completely removed from some ports.

How much can I gain by thinning or removing the valve guide bosses in the ports? I'm about to pull the trigger on ordering 11/32 valves to save a bit of weight and gain a bit of flow.

[PRH]

This is one of those questions where the answer is “there’s only one way to know for sure”.

It might help...... it might hurt.
If the heads currently have an issue with the flow backing up after a certain point in the higher lifts...... then it’s more likely that the removal of the guide boss, and allowing more air to try and make it over the SSR...... will result in no gains or very minimal gains, and possibly even result in the lift point at where the port starts backing up to occur at a lower lift point than it does now.

In other words, if the ports back up now...... I wouldn’t expect trimming/removing the guide boss to show any worthwhile gains...... without additional work to the ports being done as well.

If the ports are on the verge of backing up now, removing that material around the guide could end up being the tipping point that makes the port start backing up at high lifts.

The flip side is...... opening the guide boss area might slow the air down enough as it’s going over the SSR to help cure or diminish the port backing up.

If your ports are rock solid to well past the lift point of the cam you’ll be using.... then it’s a safer bet that trimming the guide bosses will help.

All of which is why I say..... there’s really only one way to know for sure.

[Krooser]

The intake's slow down a bit at .600... the exhaust @ .500. The guy that did the test didn't push it past .600 once he saw it start to stall.

Just looking at the head you'd think taking that much material out of the way of the airflow that it would be a no brainer... but looks can be deceiving.

[rebelrouser]

No expert by any means, but the best runner is a slight taper in form. A head runner has a complicated shape, but I always went on the assumption that air doesn't like to expand and then contract. If you take out the guide boss on a stock head that is what sometimes happens. I used to p[ort several 906 440 mopar heads and if you remove the guide boss on them it always makes them back up. Just my experience. I have had some luck narrowing the boss to make it look more like the edge of an airplane wing.

[randy331]

My W-2 heads are ported nicely and flow 294 on the inake side and 240 on the exhaust. 3/8" valves.

The valve guide bosses in the ports were virtually untouched by the grinder. I have seen the boss completely removed from some ports.

How much can I gain by thinning or removing the valve guide bosses in the ports? I'm about to pull the trigger on ordering 11/32 valves to save a bit of weight and gain a bit of flow.

If your buying new valves, (and 5/16 stem are legal in the class you race) I'd go on down to 5/16 or 8 mm stems. But, not for any flow gain but for weight reduction.

And yes narrow and profile the guide boss but don't remove it.

And add as much lift as you can afford, I've never seen more lift hurt the power on any engine,.. even ones that had ports that stalled on a flow bench.

Randy

[ClassAct]

My W-2 heads are ported nicely and flow 294 on the inake side and 240 on the exhaust. 3/8" valves.

The valve guide bosses in the ports were virtually untouched by the grinder. I have seen the boss completely removed from some ports.

How much can I gain by thinning or removing the valve guide bosses in the ports? I'm about to pull the trigger on ordering 11/32 valves to save a bit of weight and gain a bit of flow.

BTDT and have the pictures to prove it. Do NOT do it. All you will do is increase the turbulence you already have and gain very little to no flow.

It's a waste of time at the very least. You can shape the guide boss but don't remove it.

[mag2555]

Iron W2 320 cfm@ 28"@ .650" lift, 3/8 stems.

[Krooser]

Well now I know....thanks.

I looked at doing a lighter valve... But with a 63lb crank and a self imposed 7200 rpm limit I doubt I would gain much.

And the locks and retainers are mucho more expensive than the more common 11/32...and finding a 5.140 valve that fits has been a bit of a challenge even in 11/32.

[hoodeng]

Is it possible to get a junker head and port all the ideas you want to try on? I have reduced a head to swarfe by progressively trying what might be worth trying.

Cheers.

[steve cowan]

Is it possible to get a junker head and port all the ideas you want to try on? I have reduced a head to swarfe by progressively trying what might be worth trying.

Cheers.

I think this is a fair enough statement but if you are doing some sort of R and D so to speak you will want to have a decent valve job first in my opinion.can get pretty expensive fast on test heads.

[hoodeng]

On the engine i do i have spare heads that are of no real value until someone wants to buy them.
That said, there are three types commonly submitted for porting, one went 84 to 99, 99 to 2017 and 2017 to present. The earlier heads were two valve and the later four valve.
Over the years i have test ported the heads relevant to the era till they go backwards, there has been no significant cost with seat cutting as i only go up a couple of valve sizes that will go over a stock seat, although i have tried every angle within reason,valve to port ratio, short turn apex, valve shape, bowl to port face id and taper etc. In the early days i found what was common opinion did not always relate to more air .

When i got my first bench [110] i got to try stuff other people had been selling,,what a surprise!! there were people making easy money of of notoriety and not ability, [they also were not testing their work] another major step was getting as much as we could on the dyno, this was probably the biggest game changer after the flow bench. As with this product we do a lot of engines that are of the same configuration.

These heads can also become uneconomical to re work if oversize seats etc are installed compared to after market performance heads. We do get guys that insist on re worked stock castings.

This precipitated for a lot of guys the statement " There are more tears than cheers on the flow bench and dyno!"

Cheers.

[steve cowan]

On the engine i do i have spare heads that are of no real value until someone wants to buy them.
That said, there are three types commonly submitted for porting, one went 84 to 99, 99 to 2017 and 2017 to present. The earlier heads were two valve and the later four valve.
Over the years i have test ported the heads relevant to the era till they go backwards, there has been no significant cost with seat cutting as i only go up a couple of valve sizes that will go over a stock seat, although i have tried every angle within reason,valve to port ratio, short turn apex, valve shape, bowl to port face id and taper etc. In the early days i found what was common opinion did not always relate to more air .

When i got my first bench [110] i got to try stuff other people had been selling,,what a surprise!! there were people making easy money of of notoriety and not ability, [they also were not testing their work] another major step was getting as much as we could on the dyno, this was probably the biggest game changer after the flow bench. As with this product we do a lot of engines that are of the same configuration.

These heads can also become uneconomical to re work if oversize seats etc are installed compared to after market performance heads. We do get guys that insist on re worked stock castings.

This precipitated for a lot of guys the statement " There are more tears than cheers on the flow bench and dyno!"

Cheers.

Good post and appreciate your response, the reason I posted my comments was for myself having training wheels" ON " regarding head porting and flow testing I have sized cylinder head to what I think is close on CSA for application and then had a good valve job done from machine shop and found previous testing has become irrelevant, a few respected guys on this forum have advised me to get the valve job done first and then work from there

[hoodeng]

Yes Steve, get the seats cut first. On the stuff i do there are a number of stem protrusions used that leave an array of chamber drops, i do get a radius blend out from my top cut [2V]that helps chamber blending, and the bottom inlet angle to port id is at 90°so i have a margin to work to. The exhaust seat to port angle i get is 88°to give me a bit of blending material on account the seats in these engines are not symmetrical to the casting.

On the current four valve i am pretty much just generating a top cut with a +1mm valve, but where it runs close to the chamber edge i get the radius blend out that cuts into the head face this it not a problem as i am boring the cylinder anything from .140" larger up to .313" larger, there is enough tdc valve clearance to deck the heads to increase comp.

Cheers.

[mag2555]

For 2.145" valves just go to Ferrea.
They will start with a BBC 2.19" and make you 8 of em at a cost that is not a wallet breaker!

Even with a limit of 7000 I would go for the 11/32" stems as even at starting at 4000 rpm it eases the loads by a lot in terms of spring control.

[mt-engines]

Well now I know....thanks.

I looked at doing a lighter valve... But with a 63lb crank and a self imposed 7200 rpm limit I doubt I would gain much.

And the locks and retainers are mucho more expensive than the more common 11/32...and finding a 5.140 valve that fits has been a bit of a challenge even in 11/32.

Trick Flow has a 2.165 5.200 ls valve 8mm stem w beadlock groove. use a -.050 lock
TFS-32600211

install new guides and cut the valves down.
or run more lift and installed height.