Fuel distribution issues

After a spirited first test ride of this year I had some oil leaks in the valley tray, so I remove the intake to fix and notice I have 2 intake ports in the heads soaking wet with fuel. The wet ports have no staining from the red fuel I used, but all the others are dry and stained. I use the Indy 400-3 intake and can only figure I have a distribution issue here. Cylinder intake ports #6 and #7. How to fix?

What do the plugs look like?

They burn darker than the others. #7 has always been a problem.

Anyone every see anything like this before?

I can tell you from running 10 o2 sensors, fuel distribution moves around alot, based on RPM and load. I would look at the plugs and see if they are the same, if they are i wouldn't worry about it.



Joe

If its a carb and the plugs are not real dark like black , and if the oil dosnt smell badly of gas I wouldn't be too concerned. Judging by the heads you are using this is a hot rod , not a mild build. If its a carb its just not a perfect system . If you smell the gas in the oil quickly after an oil change you should be concerned about cylinder wash down .

Just my experience and observation.

I have dealt with this on 6bbl intakes.
Not going to be WOT fuel issue.
Idle/ part throttle and coasting.
Fuel puddling on floor and running in wet.
Small dam on runner floor fixed it for me.
Didn't effect WOT in my experience.

You need to run 1 or 2 heat ranges hotter in the 2 cyls that are running fat.. just the
cyls that are fat

ok, I can run a different plug I the rich cylinders. Dom suggested same thing. I could mount a turtle in the bottom of the intake as well I guess. It may be just an issue at idle, but if it was seems like all the ports would be stained red.

Dont start adding things.. one step at a time

Which version is your intake, early 440-3 (round individual injector bungs,, late 440-3 or 440-3X?
They are all different under the carbs.

fuel pressure above 5psi floates set too high

I believe its a later version cab because I bought it new 4 years ago. Looks a little different now that I removed the clover leaf.

I run my pressure at 5.5psi and floats just below middle of site glass.

This video might make things a little more helpful. https://youtu.be/CBqd4WO9BzQ

That is the later 440-3, not the early one with the cast in round bungs for tapping for EFI injectors. I'm sure it is not the taller bigger plenum 440-3X either.

No, it’s not the 3x. It is a 400-3. For now I just removed the 1” 4 hole tapered and used a 1/2” wood straight 4 hole. I keep an eye on it. Never used red fuel before, so it’s working for my like a figure print.

Do you run a spacer that is modified to match the top of the manifold? Or are you putting the carb directly on whats in that picture?

The wilsons tapered 4 hole matched fairly well to the carb pad opening and I was following their direction with the removal of the clover leaf and putting their spacer on top. The straight 4 hole obviously covers more of the carb pad, so will see how this works out. May just be a common issue with this intake and I found it with the red dye in the fuel. Gonna call Brodix Monday and see what they say about a turtle in this intake just for curiosity.

I don't like the idea of a 4 hole on that just my gut reaction, that there would be reversion with 4 holes dumping into a plenum that wide open. I would run an open spacer (a cheapie) of 1"-2" inches.

On some of these BIG manifolds like Bret Miller makes, most guys run at least a 1" open under a 4-hole tapered for best results and Jeff Saucier on here just made 817 hp and 500 something tq w/his little 418 w/this combo iirc with one of my 1150ish blp billet Dommy's and many others run similar spacer combos some up to 4"......

I may have an open spacer in the garage for this. I'll have to check.

I am not an expert, but have done a little work on manifolds, what I would do is pull off the intake clean it good and have somebody with an aluminum spool gun put a dam about 1/8 high in front of runners 6 and 7 then dimple the floor of the intake and runners with a course carbide bit to help break up puddles of fuel. I don't think any kind of spacer will fix your issue. If you have access to a flow bench try setting the manifold up and using a wand with a string attached, may help decide exactly how to place the dams, and see how much turbulence is in the plenum. I like a lot of turbulence in the plenum and then the flow should straighten in the runners, if that makes sense.

Not doubting any of that, but an open spacer would be quickie. I have a flow bench but I'm not sure how you would set up a manifold to pull from all 8 at the same time.

I understand perfectly and had something like that in mind, but wasn't sure exactly what to do. I know years ago guys used popsicle sticks. If I keep the intake long term I will get more interested in your suggestion. Going tunnel ram at end of season to see how I like that first. I'll throw a open spacer on it for now. Thanks guy, great ideas.

[quote=B1MAXX]Not doubting any of that, but an open spacer would be quickie. I have a flow bench but I'm not sure how you would set up a manifold to pull from all 8 at the same time

Most v-8 manifolds I set up pulling out of the two intake runners that set side by side, and use duct tape to block off all the other runners. It is not perfect, but after you do all of them and document flow and velocities, it gives you a better idea of what is going on. I did a couple cast iron dual plane intakes for a pulling truck class that required the OEM manifold, no welding, just work on a milling machine and carbides, they turned out very good. both my buddies had their engines torn down by competitors, who had to post money to have it performed.

Doesn't take much of a dam.
16th" high, use epoxy.
Can be removed easily if not satisfied with the results.

Got ya!, thanks

I've used the Wilson reversion 1.5 inch spacer on all my stroker 400 motors with both the Indy 400-3 early and late intakes, none of them had the interior work done like yours is now.
I have seen 150 degree difference in the EGT on #2 and #7 cylinder on several Indy 440-3 and maybe one stock late model 400-3 with no spacer on two different brand engine dynos
I had Bob George racing modified one 400-3 intake for me but I don't remember now if it was a early or late model casting or not now