Lower intake swap / Vortec head & cam install on stock bottom end

Quickstop [UK] · Oct 3, 2007

Re: Lower intake swap / Vortec head & cam install on stock bottom end

That is a tremendous amount of work to prove definitively that porting the vortecs is not a necessary mod.

Did he give any indication as to what you could have done?

What pressures did he test the heads at?

Think you have saved a lot of people a lot of work there mate!

Science - it works :tup:

Sy Guy 0024 · Oct 3, 2007

Re: Lower intake swap / Vortec head & cam install on stock bottom end

What the hell? I hate to see that your gains weren't more significant, the port job sure LOOKED nice.

I spent a lot of time doing similar work to the Vortecs on my Sy, but never had them flow tested. Makes me wonder if the results are similar. :tdown:

I don't feel so bad now for not porting my new Vortecs on the Ty...

James Thomas · Oct 3, 2007

Re: Lower intake swap / Vortec head & cam install on stock bottom end

Tooky, sorry to see the results were on the low side but there are gains to be made in porting the heads "correctly". Not saying what you did was wrong.... by any means but the Vortec is a real efficent design for an O.E.M. as cast. It takes a good bit of mod work to make a "big difference". Mckenzie Racing Heads does my L-35 blower heads and 200+ up to 240 on the intake from .350 to .600 & 160 to 200 on the ex. from up .400 to .600 is the norm for his work on these street heads, but keep in mind that it's $750 for this and these are L-35's. I have a set of Vortecs that are "mild ported" which are the infamous McCoy Stage II's (junk) and the numbers are a little better than yours but damn sure not worth what they charge for them, difference is the flow picks up at lower lift (that's good).

There are a lot of variables also, especialy the valve job, what did they do on the angles? Stock, performance etc. this is one reason that head work is not cheap and it's eaiser to get bigger gains on a not so good casting that it is on one that is pretty good to start with. Like I said, there are gains to be made on the Vortec, just not easy simple ones is all. Shortly I will have a set that will be 260+ on the in. and 220+ on the ex. and I'll post the flow sheets when thay are done.

__________
James

turbodig · Oct 3, 2007

Re: Flow Results

Re: Flow Results

Tooky said:

Today I got the flow numbers back on my port work. This time I saw the flow bench, it's a SuperFlow 600 (kind of looks like an arcade dartboard cabinet.)

Code:

Intake                                          Exhaust

Lift    Stock   Ported  Diff (CFM)      Lift    Stock   Ported  Diff (CFM)
----------------------------------------------------------------------------------
0.050   31.3    30.6     -0.70           0.050   24.7    24.7     +0.00
0.100   62.6    61.2     -1.40           0.100   49.3    49.3     +0.00
0.150   97.0    94.9     -2.10           0.150   77.5    75.4     -2.10
0.200   131.3  128.5   -2.80           0.200   105.7   101.5   -4.20
0.250   159     154.4   -4.60           0.250   122.2   120.9   -1.30
0.300   186.6  180.3   -6.30           0.300   138.7   140.3   +1.60
0.350   202.5  197.7   -4.80           0.350   147.1   148.2   +1.10
0.400   218.5  215.2   -3.30           0.400   155.5   156.0   +0.50
0.450   227.3  224.5   -2.80           0.450   159.3   162.7   +3.40
0.500   216     227.4   +11.40        0.500   162.6   168.7   +6.10
0.550   219     219.7   +0.70          0.550   163.9   171.5   +7.60
0.600   217.2  220.8   +3.60          0.600   165.2
0.650                218.5                       0.650

Avg:    184.8   188.5   +3.70           Avg:    137.5   135.7   -1.80

:barf:
:roll: :tdown:

:banghead: :steamer: :screwy: :x :doh: :bad-word:

This looks like bad/inconsistent test procedures on the flow bench.

Your stock intake tests go from 227, to 216, to 219 to 217. That'd have to be a really weird head to do that. Generally, flow numbers ramp up to a peak, then level out or drop slightly.
Unless you have *major* shrouding issues, I'd strongly suspect they had a leak someplace testing your stock heads.

The exhaust looks believeable, though.

The seat cut will make a huge difference on how it behaves low lift. Did you post seat widths in this thread someplace?

Maybe it was done and not mentioned, but I never saw any back-cuts on the valves or face cuts. That'd help the numbers some, too.

Later,

It's just a six · Oct 3, 2007

Re: Lower intake swap / Vortec head & cam install on stock bottom end

This is a good reason for the amature backyard mechanic should not port your own heads,(no flames please,just making a statement here.)

If you do not know how to port heads,you should not do it. Plan and simple.
You can really mess up the flow.

There is a lot more involved than just opening up the ports.

Do your self a favor ,(you guys debated on porting your heads) send your heads to a professional shop.

Again,,,, no flames please.

fivetodrive · Oct 3, 2007

Re: Lower intake swap / Vortec head & cam install on stock bottom end

It also makes you wonder what part of the porting in the car craft article made the difference. In the following graph it makes you wonder why they put an asteric on the exhaust but not on the intake...

Tooky concentrated on the throat and did not do anything to the exhaust port size or even the walls. You can still see a casting ridge on the the following picture.

What are the side of the exhaust ports on erue's heads??? I just wish we had some more pictures of the car craft article...

Just throwing out ideas...

Tooky · Oct 3, 2007

Re: Lower intake swap / Vortec head & cam install on stock bottom end

Quickstop [UK] said:
That is a tremendous amount of work to prove definitively that porting the vortecs is not a necessary mod.

Did he give any indication as to what you could have done?

What pressures did he test the heads at?

The heads were tested at standard 28". The shop did mention that some lesser shops have a smaller flow bench than the SuperFlow 600 and they test at 10" and then apply a correction factor to "produce" 28" numbers.

One thing I forgot to mention, after flowing the stock castings, the shop mentioned the flow "going turbulent" at high lift. I thought that was strange since they were bone stock. (And I assume turbulence is what's responsible for the fluctuating numbers after ~.450".) When I had them flowed after porting, the same guy again commented on the turbulence. He said when they run the flow bench, it's like a giant vacuum cleaner and they have to shut the doors and windows because it's so loud. He said once my heads hit turbulence, it really started to howl and you could "hear" the air not flowing smoothly. He used some analogies of a whistle, or water going down a drain in a tornado.

Think you have saved a lot of people a lot of work there mate!

Glad to hear it, the time & money spent certainly didn't save me anything! What a kick in the nuts. At least you guys get the results for free.

Science - it works :tup:

I Can Do Science, Me!! :lol:

Tooky · Oct 3, 2007

Re: Lower intake swap / Vortec head & cam install on stock bottom end

The valves and valve seats are all 100% stock and untouched, never-run. I was trying to save money, but got some similar advice from some experienced head porters after showing them my flow results before/after. One guy in particular said:

"You MUST do a valve job, and correctly I might add, in order to unlock flow. Seat angles, throat area, chamber transition, valve head angle, and backcut angle all play HUGE rolls in getting a port to flow more.
I've done plenty of those vortec's and unless you change the valve job on both intake and exhaust, you are wasting time and money."

It would have been nice to know that ahead of time.

Another guy said "Put a nice valve job on the heads and backcut the intake valves and I'd bet you will see an improvement from bottom to top on the intake numbers.

On the exhaust, you probably need to give the SSR a nice gentle roll. When you opened the throat you probably made the air want to go straight up more and lost the airs ability to make the turn to some degree."

Finally a couple guys agreed that proper use of the flowbench is important, it's possible a mistake was made or inconsistency. One guy had a good idea for someone who has access to play on a flowbench: use clay to "restore" the port to it's original form and see if the flow comes back, and then take a little off at a time to find out where the trouble area is.

If I was going to do this again, I would have definitely just left them unported. (Except maybe the intake port matching). It's obvious that the areas I changed are worth insignificant amounts of flow (one area gained a max of 11cfm, but I'm 99% sure you'd never feel or notice such a tiny gain). Ed Hess claims he ran 9.9s with unported Vortecs except for bigger valves (and obviously a valve job).

Another thing I'll say, this test tells me that without a proper before/after flow test, claims about the flow of ported heads are worthless! While talking to the machine shop about my bad results, he commented that I'm "a real technical guy", and that he hardly ever gets customers who want to flow test their heads before and after. He says most don't even flow them after porting (or if they do; they have no baseline to compare to).

I would be skeptical of anyone selling ported heads claiming big flow without the numbers to prove it. It would seem that anyone who really knows what they are doing, would certainly have flow numbers readily available.

Tooky · Oct 3, 2007

Re: Lower intake swap / Vortec head & cam install on stock bottom end

fivetodrive said:
It also makes you wonder what part of the porting in the car craft article made the difference. In the following graph it makes you wonder why they put an asteric on the exhaust but not on the intake...

Good call Aaron - I was thinking the exact same thing on the way home from the machine shop. Car Craft did do a valve job, chamber work, and opened the pushrod pinch on the intake, three things I didn't do. Things never seem to work out like they do in the magazines, do they? It's hard to believe they would gain 60 CFM where I gained about 8cfm with similar work except the valve job and chamber mods. There must be more I missed than just what it seems.

That asterisk is interesting; they used a flow pipe on the exhaust (where the big gains show up in their numbers) but not on the intake? What were the numbers without the flow pipe? We'll never know.

What are the side of the exhaust ports on erue's heads??? I just wish we had some more pictures of the car craft article...

turbodig · Oct 3, 2007

Re: Lower intake swap / Vortec head & cam install on stock bottom end

Tooky said:
Good call Aaron - I was thinking the exact same thing on the way home from the machine shop. Car Craft did do a valve job, chamber work, and opened the pushrod pinch on the intake, three things I didn't do. Things never seem to work out like they do in the magazines, do they? It's hard to believe they would gain 60 CFM where I gained about 8cfm with similar work except the valve job and chamber mods. There must be more I missed than just what it seems.

That asterisk is interesting; they used a flow pipe on the exhaust (where the big gains show up in their numbers) but not on the intake? What were the numbers without the flow pipe? We'll never know.

Makes me think their flow bench wouldn't reverse flow, so they had to hook a tube to the exhaust to draw through it.

For the costs involved in getting your seats and valves done, it'd be worth it.

The last 1/4 inch around the valve can make or break the whole thing...

fivetodrive · Oct 3, 2007

Re: Lower intake swap / Vortec head & cam install on stock bottom end

So how much would a valve job add to the cost? I bet you could get that done in a day at the most...

Did the guy say to do a 3 angle valve job or what?

I have an old set of vortec heads on the shelf that may just need to be flow tested before and after a valve job. I think it would be an interesting thing to do. Especially since I have no interest in porting a set. Well maybe no time is a better answer.

Also thanks for the pics!

P.S. I would paypal you $20 to do another flow test just for my own curiosity... But you would have to do your style of writeup on tuning...

Tooky said:
writing a tuning how-to guide has been on my list of projects for a long time. I really think I could illustrate it with a lot of DataMaster snapshots, TunerPro snapshots, and real-world explanations. I just gotta get my butt in gear and do it one of these days.

It's just a six · Oct 3, 2007

Re: Lower intake swap / Vortec head & cam install on stock bottom end

A bad valve job,or someone that does not know how to do a performance valve job can make or kill your cylinder head flow.

Correct angles,seat widths,throats & more add up to a great flowing head.

On another note,
on your pics of your cylinder heads, it looks like you really did not take away too much material.

Did you perform a stock intake/exhaust port cc volume & after you ported them?

To get close to flowing 270 - 280 CFM (or so) on those heads, you need to take away a lot of material,but then it gets really thin & you could break into water jackets.

Syclone#892 · Oct 3, 2007

Re: Lower intake swap / Vortec head & cam install on stock bottom end

Just an FYI Ed Hess was running unported vortecs with 2.05 and 1.60 valves. I sold him those heads when I got my new engine those were done by JWaller right when the whole vortec thing started happening 4 or 5 years ago.

Sorry to hear the results Josh wish they would have been better 'cause now I really want to talk my dad out of porting his

James Thomas · Oct 3, 2007

Re: Lower intake swap / Vortec head & cam install on stock bottom end

Don't miss the boat here fellas! Porting and proper valve jobs are with it for sure! Tooky at least do the valve job and I would try to verify the flow bench results cause they sound like Dig says, "off".

__________
James

Tooky · Oct 5, 2007

Lifter Preload

Lifter Preload

(Regarding head porting, I know guys can get 260-270cfm out of a good fully ported set, but it'll take some bucks and finding the right person to do it. I'm just gonna see what I get out of my "stock" vortecs (can I call them that?) as they sit right now.)

I threw one of the heads on the deck to check out my luck on the (nonadjustable) vortec roller-shaft valvetrain.

Here's how the valve stem wear came out. It looks pretty good to me, doesn't touch the edge on either side.

I tested the lifter preload by simply fastening the aluminum rocker "rail" to the head and tightening the rocker arm bolts. Comp said to make a mark even with the valve cover surface, and then release the rocker bolts and compare the distance between the two, to let you know how much the lifters are getting preloaded when you assemble the nonadjustable valvetrain.

Here's with the hardened 1pc Manley pushrods I'm upgrading to:

Here's with the stock pushrods:

They say you want .020-.040 preload. I'm getting about .100" with the Manleys! I found out they are 7.250" and stock is 7.200". The stock ones are much closer to where they should be (they give ~.050" preload) so I'm getting some Manleys in the 7.200" size.

Goes to show how worth-while these kind of "blueprinting" assembly checks can be. If I had never checked, my preload would be .100" and who knows what would happen (All Hell Would Break Loose, obviously!! :silly: ) The same goes for degreeing the cam.

Project Status
I just finished bending the upper-outmost 2 corners of the stock metal valve covers so they would fit on the Vortec heads properly. Thanks to TurboTony for that tip! They really fit like shit until you give a good bend to those corners. The valve cover gasket couldn't possibly seat all the way around the head if you left it alone. I also finished the exhaust manifold port matching today. (hopefully it doesn't HURT the flow like my heads

) It will certainly be a nightmare reinstalling those because all the outside ports' bolt holes aren't even close to lining up with the manifold holes.

Next I have to fully assemble the heads, clean the deck one final time, and install the heads. Then things will start moving fast. I feel like this project has been taking freakin' forever!

Tydriver · Oct 6, 2007

Re: Lower intake swap / Vortec head & cam install on stock bottom end

Since Tooky is talking about valve train here, I'd just like to submit this link of a Nascar motor at 7000 RPMs.. I think its kind of a neat video taken with a high speed camera. Turn your sound down before opening tho.....

http://www.youtube.com/watch?v=i_Np...nything-goes/59232-valve-spring-7000-rpm.html

Quickstop [UK] · Oct 6, 2007

Re: Lower intake swap / Vortec head & cam install on stock bottom end

opcorn:

It's just a six · Oct 6, 2007

Re: Lower intake swap / Vortec head & cam install on stock bottom end

It's just a six said:
On another note,
on your pics of your cylinder heads, it looks like you really did not take away too much material.

Did you perform a stock intake/exhaust port cc volume & after you ported them?

TYHOGG · Oct 8, 2007

Re: Lower intake swap / Vortec head & cam install on stock bottom end

Tooky
It might sound like a silly question at this point, but i noticed you used the .040 Cosmetic head gaskets. Do the stock style Victor gaskets also work or is there something different between the 2? I have tried tracking down the Fel-pro 1203 intake gaskets, Autozone was worthless. I noticed Jegs has them in stock. I was wondering if there is somewhere that normaly stocks them so i can walk in and pick them up. I'm dropping off my Vortec's and stock heads this Thursday to have them drilled/tapped.

Did you just add weld on your manifold or weld on a piece of plate?

Thanks for the help,
Adam

Quickstop [UK] · Oct 10, 2007

Re: Lower intake swap / Vortec head & cam install on stock bottom end

Tooky - are you getting the job done professionally now? I really hope you do so you get some gains outta this!

When are you re assembling it?

Mark

Lower intake swap / Vortec head & cam install on stock bottom end

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