RA4 intake valve's in a 6x4 head
 

I have a set of titanium RA4 intake valve's and I want to install them in place of a stock intake valve on a 6x4 head. I was told they would work, have to be shimmed because they are longer than stock 6x4 intake valve's. So the question is can they be lathe cut and re-groved for the valve spring lock, or am I better off just shimming them..

Also any input on upgrades to springs both intake and exhaust. .looking to run a .540 lift roller cam

Going by memory, a standard valve/valve spring height should be around 1.586" tall.

So if your titanium valves are .200" long you would be at 1.786" height which is very close to the normal RA-IV 1.800 valve spring height. Should be a easy mod to get to the taller Valve Spring Height and close to the geometry that the stock RA-IV engine had in production.

Tom V.

Thanks Tom V

Standard 6X are roughly 4.98. RAIV 5.20s. Heck just get some new springs to take advantage of the increased IH- a lot more choices 1.700-1.800. What are you doing for exhausts?

I have standard D port 5.10s in my 6X heads on the 400 in the 81 TA and ended up about 1.740 IH.

If those valves besides having the RA4 lenght also have the big Tulip back side of the factory RA4 valves then you will be loosing Intake air flow over what the stock basic nail head valves used in the 6X and all other D port heads have as I have seen in my flow bench testing of both valves in a D port head.

If you need further proof, then just look at the fact that no aftermarket head runs such a Tulip back Intake valve!

If your not also going to run darn close to the same lenght Exh valves in the head then you will need two different lenght push rod, and maybe custom lenght ones at that.

If it where me I would spend another 200 bucks and get the right replacement valves for those heads and leave the titanium valves on the coffee table as conversation items!

Going to give the a try, just had the heads gasket matched for RA4 intake gasket, and cleaned up the bowls, this was not an amateur job but from a friend that owns a cnc machine and does this for all types of heads.. regarding exhaust valve going with the stock 6x4 valves but upgrade to stainless steel..

I figured I have all these parts laying around and no one wants to buy them so I might as well see what I can build.

Regular Production RA-IV Intake valves are 2 Piece Valves. Ask Jim Brady how we know that.
We were at a track in Wisconsin run by Broadway Bob and Jim B did a burn out, was idling up to the starting line, and the Intake Valve head came off. Engine stopped and we could not turn it over. No real damage to the engine except replacement of the valves with ONE PIECE Intake Valves. In your case you have Titanium Valves so it should not be an issue. What is the measured length of your valves?

Tom V.

Your headed for a failure if you try and run those valves in a cast iron guide, as they MUST be used in Bronze guides unless the stems are heavily Chrome plated!
!
Does your buddy with the CNC machine also own a flow bench?

God how I love stubborn guys who want to build there motor with a part(s) that will cut there motors power output just because they have the Part(s) in hand!

And by the way my reverse flow test of a Tulip valve shows much higher levels of reversion / back flow which will cut into how low in rpm the motor can come on the Cam.

This is issue with the any motor , but with motors like the 428 and even more so the 455 due to there Bore to stroke ratio.

OMG, is this facebook?

Two different length valves? Stock length on the exhaust with a .540" roller cam?

You say you're buying new exhaust valves - why on Earth wouldn't you buy the same length valves as your intakes and save yourself a lot of headaches? Going to be hard to find springs for that cam at the stock installed height - the longer valves will help there. Would need two different pushrod lengths with different length valves also.

As Steve says, if they're the tulip head valves you're actually costing yourself power.

So how much power is lost by using a RAIV tulip valve?

I can't say with 100% accuracy due to not having control over the valve job that may or may not be done, also any porting work that could have been in conjunction with using those valves and the also the amount of lift that will be used, and most importantly the lift rate that the Cam lobes have and of course the rocker ratio used which effects the rate of opening.

With D-port heads in stock form and less then .450" lift applied to the valve I would place the power reduction at 3 to 4 percent which would also produce a power band that starts to kick in at a 3 to 4 percent higher rpm.

What makes original tuliped valves work in the RAIV heads and not in a D-port head using the same camshaft?

A flat valve works better in a RAIV head also. maybe up to 5% flow.

Please note that I am talking flow looses or flow gain across a give lift range, not just for example 8 less or 8 more cfm at let's say .250" lift , but like 10 to 12 cfm less when averaged out up to .500" lift.

Put that tuliped valve in a 455 HO or a D port head and you will see similar flow losses.

Hi Skip and thanks. Something we have known for a long time. Usually the tuliped valve will equal or slightly better a flat back valve above .600 lift on a good flowing head. Will and Steve25 seem confident about their being a power loss, I'm not sure there is. I was looking for more information. A tuliped exhaust valve usually flows a bunch better than a flat valve and we tried a back to back on a medium compression 455 and found nothing.

I'm not sure if it does "work" in a RAIV head.. It may work better in a RAIV head due to the higher short turn compared to a 455HO head or d-port. The deeper the bowl the more they tend to help. Hemi's seem to work good with a tulip valve, their intake ports come close to flowing straight at the back of the valve. A shallow port wants to flow across the valve and the tulip blocks it's path.

That seems like a lot of speculation.Might work good in the class room, but I'd need to see dyno numbers to believe it.

Do you think a tulip valve would work better on a wet flow bench at higher lifts?

I've run RA4 length valves in iron heads for years for the better valve spring installed height.
The op also said they were Titanium and I have never seen a Titanium valve with a tulip face
Just my 2cents

,540 lift w. 6x stock valve installed height is no bueno. The spring coils will stack up solid.

Use the RAIV valves you have and pickup a set of 1.77 RAIV Exhaust valves (Ferrea is fine). Have your shop machine the seats for them. I'm sure someone is going to say you need to rework the throats but that is BS. The throats behind the seat are way larger than the 1.77" exhaust valve and are not restrictive as is. Also, you don't need new hardened seats installed as the seat area is already induction hardened far enough outside the seat area.

You will gain additional exhaust flow, have the correct installed height to accommodate your cam's lift and can use the same length pushrod on intake and exhaust.

I have to agree with Neighbors Complaint, I have used a lot of Ferrea over the years, know the owners, spent time at their shop in Florida, currently have a set of Ferrea valves in a ported Edelbrock set of heads done by Keith Wilson.

My heads use 1.71" diameter Exhaust Valves and flow 260 cfm at .600 lift thru the exhaust ports. That is at 25" water test pressure. No need for 1.77" valves in most heads, even under boost conditions.

Tom V.

You know darned well it's impossible to answer that question with a hard number. It will be combination dependent.

The bottom line - do the tuliped valves hurt flow? Yes they do, particularly at lower lifts. If you have two heads that are basically identical but one flows less than the other at lower lifts, which is going to make more (or less) power over the RPM range?

Not sure that is why I asked. I believe the answer could be found if enough effort was applied. A tuliped valve will pick up exhaust flow considerably compared to a flat valve nine times out of ten. We tested a tuliped valve compared to a flat valve and found nothing. So I'm certainly not convinced there is going to be a big difference if the same test was done on the intake side.

Do you think a tuliped valve would flow worse on a wet flow bench compared to a flat valve?

Are titanium valves supposed to be used with a specific type of valve guide material? Bronze maybe?

Hah.... Now you have. Lol

Valve on the left is titanium and the one on the right is a factory RAIV. The back sides are close but the front aren't nearly as deep which helps with the compression. Some of the aftermarket valves modeled after the RAIV's are bricks.... If I remember correctly they were around fifteen grams heavier than the factory valves.

Bronze guides are recommended. Bronze guide liners will work in a pinch but will not dissipate the heat transferred by the titanium valve as well.

A whole of CFM is king in this thread when it comes to making power.
Flow benches can lie. An engine is nothing like a flow bench.
At what rpm is there a steady 28" being pulled for a couple seconds??
What is the fuel doing on a flow bench?
I have personally see flow loss lead to power gains. So cfm on a flow bench doesn't always lead to power gains or power losses

When I got my bare SR 614s in '88 few valve choices. C&A had SS replacements made my SI like factory tuliped and heavy . Ended up using D port SS SpeedPro V3923 exhausts and flat V1825 intakes and picked up flow.

Also one day flowed a buddy's 614 with factory valves then swapped in his HO heads flat valves and picked up flow, and lost it with the RAIV tulip in the HO heads. All these heads had 30 degree intake seats.

The fact is that if a loss in Intake air flow makes for any amount of better upper rpm power ,that is then telling you the simple fact that with your motors combo of Cam, CID and level of rpm that the minimum port area in your Intake tract is not enough due to the velocity in that local area being too much.

So cfm is king and more cfm has to translate to more power?

Not if the combination is not right , but you have to have a minimum flow of X to make Y horsepower. IF you are below that you can't make the power. That is not saying the car/chassis can not be optimized to go faster with less HP.

Lots of opinion, little first hand knowledge and not much participant discussion going on here.

A few years ago we pulled a good running well tuned single plane manifold off a 446 cid engine and replaced it with another single plane manifold that flowed 30 cfm more. The car picked up nothing!

So now we have a FACT ..... Increased cfm doesn't translate to guaranteed power!

I have another fact;

A thousand horsepower engine will not pick up or loose 30-40 horsepower by switching to a tuliped intake valve.

Amazingly it might pick up 30-40 horsepower by changing from a steel valve to a titanium valve and the power gain would come with zero change of CFM in the intake tract.


I'm not sure if that is one fact or two facts but the fact of the matter is the facts are starting to pile up. :D

Seems like a reasonable back to back test of the same port on a flow bench would do.

Net and average CFM gain/loss would be indicators of a HP gain/loss.

Fact -my RAIV headed 400 picked up 2mph and .2 with smaller headers who would have thought. Also did the same additional increases with a reverse split cam the heads flowed 85% E/I ratio and if flipped the bench on suction the exhaust flowed 90% of the backwards! The motor with the initial cam (288/296 UD) dynoed identical HP and TQ numbers with an HO intake a Torker and a Torker II. At the track with a bigger solid cam the Torker KILLED bottom end that I could not tune out but picked up 2 mph on the top end.


Also would not have thought my step 1 3/4-1 7/8 headers with just a short 1 3/4 tube the same size as an E head exhaust port would have lost 30 HP on my buddies 461 Dave Bisshop ported E head 461!
So yes you can have less flow and make more power. I think Jim Hand showed that with his combination-but lots more guys able to make the HP to run 11s,10s with more flow and an Eddy head that they could with iron D port heads. I would be way too many variables unless you flowed then dynoed a set of heads with flat valves, then put in tuliped.

If I had the tuliped titanium valves I'd use them.

Hi Paul!

I would very much love it if you could go into more detail about that manifold swap without any performance gain story that you posted here about please?

In peticular if the manifold you swapped on had more port runner area on average per runner then the Intake that was being run before on the motor?

Let me relay a similar end result story that I had with a buddy of mines 408 cid SB Mopar that was running in the top of the 9s in the 1/4 at the time.

I had ported his Brodix heads up to a 315 cfm@28" flow level and cleaned up / port matched his Mopar performance Intake a few years before and now, as we all do wanted more power.


I took a look at his heads again and it seemed that I could pick him up more Intake flow if I could get a bigger valve in the motor, but that could not be done without making a bad cylinder shrouding situation take place.

In then looking at his intake manifold which had a huge runner expansion rate I found that with clay I could neck the runner down and pick up 30 to 35 cfm, all in the same lift range his Cam was providing.

I then broke out my Tub of epoxie and made the changes.

That next weekend at the track with no less better air then what he had the last time the car ran he lost darn near a full second in ET.

This is proof positive that too much port velocity created by a combo of unneeded air flow and not enough minimum port area is a guarantee disaster, just like on the opposite side of the coin where you have too much port area and not enough average port velocity that the motor wants in the power band it's built to run in!

In terms of header size needed just concider this tid bit.
The Butlers 446 cid 1200 hp twin turbo , 8000 plus rpm motor makes that 1200 hp thru 2" headers!!
Why you folks making well under that hp level think you need 2 1/4" tubes is beyond me?

Travis Q and I agreed on that Header Diameter for the 446 engine (2" header is actually
smaller than 2" as all exhaust pipe is measured by the outside diameter not the INSIDE DIAMETER). Most headers are .060" wall thickness and two walls opposite of each other for the actual area so Butlers exhaust plumbing was actually a 1-7/8" flow diameter per pipe.

Tom V.

The one on the left looks like stainless from the picture and even if it is titanium I don't consider that a "tulip" face. Just my 2¢

After seeing the RA-IV disaster (Valve head came off a race car engine) I personally would never put one of those "2 piece" manufactured valves in any engine I would ever own. Might be ok on a show car driven on and off a trailer but not on a engine that is raced, street or track.

Tom V.

No matter how you look at it the facts are piling up in this thread :D

Since no one else will share their opinion, do you think a tuliped valve would flow better on a wet flow bench than a flat back valve at higher lifts?

Sure, it was a ported Warrior that flowed less and it was replaced with a basic ported Victor that showed a lot of promise on the flow bench. Both combinations were thoroughly tested with spacers, shift points and different size carburetors.

We've also ran into this on a couple of BBC that we ran on the dyno, picked up intake flow considerably and found zero change across the board.

Interesting you look at a tulip valve from the dimple in the front. I always looked at it by the Hershey Kiss shape on the back. You can have one without the other but can't have much of a dimple without the cone shape on the back. I Googled "tulip valve" and it seems to be described both ways.

I'm quite certain that's a titanium valve in the picture I posted.

I agree with you 100%. At one time the factory valves were all that we had to choose from for a "shelf" deal. The fact they are all atleast forty years old is another good reason to avoid them.

Tom what is your opinion on a tuliped valve? I'm seeing quite a few four valve heads that the OEM is stuffing tuliped valves in.

Flow is constant on a flow bench, Flow in a real engine it is pulsing ( stopping starting ) with each valve hit

You have pockets of air / fuel pushing and pulling each other ( pressure differentials ) making their way through the intake tract ( simplified )

Seemingly useless open areas may be a good place to bunch up ( storage of higher pressure) waiting for a place to go on the next hit

And where the pulse is of lower pressure you would want minimal CSA to generate speed quickly

Pulses can be thought of like a frequency on a oscilloscope display that change with rpm