Intake ports skewed off center to head?

[olddog]

Edelbrock Performer RPM heads
Edelbrock Victor Jr single plane intake
5.0 Ford block
Victor Rienz intake gaskets.

With the intake setting on the heads and studs screwed into the heads (where intake bolts normally go), the bolt holes in the intake match up to the bolt holes in the head very well. I started with the intake setting with the studs centered in the holes. When looking into the #3 & #4 ports, through the open carb flange you see the edge of the front of the ports flanges. If you slide the intake back as far as it will go (against the studs), the passenger side looked ok, but then the back edge of the ports flanges shows on the drivers side #6 & #7.

Centering the intake gaskets to the bolt holes in the heads, the head ports match up to the gasket fairly well, with the exception of the head ports having been opened up about 0.010" bigger than the gaskets (by feel - I didn't measure this).

When centering the intake gaskets to the bolt holes, on the drivers side of the intake manifold flange, the drivers side ports are centered with the gasket, with the exception of #7. The #7 is out of center to the rear by 0.020".

When centering the intake gaskets to the bolt holes, on the passenger side of the intake manifold flange, all ports are off center with gasket. All ports are off center to the front of the engine. Each port gets progressively worse, with #4 being 0.065" off and #1 being 0.090" off. So there is flange showing on one side of the port and on the other side of that port the gasket is into the port opening (covering part of the port).

If I were to grind the ports out to match the gasket, then those ports will be wider than the rest and the gasket will hang into the flow on the other side. I am concerned about getting flows screwed up, as this intake was modified by Mass Flow and now has fuel injectors at each port. So equal flow is important with EFI.

This truely sucks! How much Hp will it cost to leave it as is? What would you do?

[vettestr]

Dog,
I have seen some pretty bad misalignments on stock engines that ran without issues. No way of telling how much better they would have run but your options are limited. Short of pulling the heads off so they can be cleaned up after Gasket Matching it is what it is.You can still do any blending that is needed on the intake to get a little closer to ideal but 1/2 is better than nothing. I think you will be fine but only you know how much this will bug ya thinking about it latter. Is a couple HP worth pulling the heads.

[olddog]

Here is a picture. After looking at the picture, the ports are scewed off more as you go toward the front. I stated it backward in the first post.

[olddog]

delete this

[olddog]

Originally Posted by vettestr

Dog,
I have seen some pretty bad misalignments on stock engines that ran without issues. No way of telling how much better they would have run but your options are limited. Short of pulling the heads off so they can be cleaned up after Gasket Matching it is what it is.You can still do any blending that is needed on the intake to get a little closer to ideal but 1/2 is better than nothing. I think you will be fine but only you know how much this will bug ya thinking about it latter. Is a couple HP worth pulling the heads.

I think the heads are Ok. If anything they were opened up too much. I sure don't want to remove any more on the head ports. The problem is the intake. Man 0.090" seems a lot to me to be off.

[vettestr]

I hear ya. I will also bet 1/2 the production cars on the road have the same issue. What ya gunna do?

[DAVID GAGNARD]

Unless you are using your car for all out racing, don't worry about it....You will never "feel" or be able to notice the loss of HP because of this......and it will be a small hp loss.....nothing to worry about.....

David

[olddog]

After spending a couple hrs getting detailed measurements, it will come pretty close to matching up once I open up the manifold to the gasket. The manifold port widths are on average about 0.040" +/- 0.012" narrower than the gasket. Only one port will end up with 0.010" of gasket hanging into the port. The head port is 0.010" wider than the gasket so that endge will only be 0.005" mismatch, and I will trim the gasket to the manifold on that port.

It may not make a big power differance, but since it is multi port EFI, I think it will buy me peace of mind. If different ports are getting more or less air, then the mixture is different in those cylinders. A little rich on the cylinder with the O2 sensor and the rest could end up lean. So I will port match the intake to the gaskets and see what it looks like.

[Rick Parker]

Olddog your split'n hairs.....save your time & $$.

[olddog]

Well some times I wish I wasn't such a perfectionist. Maybe it is a good thing I didn't build one from a kit.

Not only was the intake ports narrow and miss-aligned, they were a good 1/8" short on the height. While grinding the ports out (which is quite easy) I noticed the fuel injector bungs were sticking into the air flow. They were all different lengths the worst was 1/4" into the air flow and two were flush. Since the bungs are all straight and level on top, I guess the manifold port heights are all different. So while I was at it I ground them all flush to the port wall. Then I noticed that where the fuel injector bungs were welded, the metal swelled in blocking the path of the fuel flow. A couple ports were nearly 1/3 blocked. So I rounded the diameters out. That wasn't too bad to do either.

While smoothing out the grinding with a small wheel of sand paper flaps in the die grinder, I was amazed at how easy it was to polish away the rough casting. After getting the center four ports done, I realized I couldn't reach all the way through the 4 end ports. It's always a dad time to figure this out - after you are committed. Well 8 hrs later after using a dial rod and sand paper I had the entire inside of the manifold polished. And the bad thing is I fully understood that this polishing would do next to nothing at the rpms I run in, but I just couldn't stop my self. The cleaning was a horrible job. Even mildly polished this thing is porous. Another 2 hr job. All in all I must have 20-30 hours in intake.

I do feel that matching the intake ports to the gaskets and getting the bungs out of the air flow has to help on the power. Rounding out the bung holes may have helped on atomizing fuel better, at least it should have.

While I had the oil pan off I put in a windage tray, so it would be impossible to separate out what did what in terms of Hp gains. It definitely has more torque down low and I haven’t a clue how this work would have done that. The intake was leaking vacuum when cold before maybe some hot too. The idle speed is same as before with out any adjustments, so I don’t think is was leaking much vacuum when hot. Power wise it is too loose in 1st gear to tell anything, but second gear seems to wind out much quicker. It’s been seven months since I drove it, so how can I say for sure. I want to believe it did something for top end Hp, but honestly I cannot say for sure.

The one thing all this work definitely did was help fifth gear a bunch. Before I had to stay above 1800 rpm to keep it from surging and it didn’t have much guts down there. Now, I can drop it down to 1400 rpm in fifth, and it pulls much stronger. Before, the torque didn’t come in strong until 3500 rpm and now its pulling pretty hard bellow 3000 rpm.

In the end I’m not sorry I did all this, but I sure would like to understand how this helped the low end torque so much. That was the last thing I expected. Makes no sense to me.

[Gaz64]

Originally Posted by Rick Parker

Olddog your split'n hairs.....save your time & $$.

If the heads match the gasket and the intakes are smaller, a mismatch as a step is what you want to help mimimize reversion.