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Wet Flow Head Porting: Intake ports Part 3 last part
Wet Flow Head Porting: Intake ports Part 3 last part
As I said the stock head (looks like rust & no paint) were ported pretty much until the casting line was gone, other than that it was just normal grinding away excess material, this is something anyone can do in a weekend easily and pickup 25-35Hp. Doing things like port matching the intake ports to the intake gasket and then on the intake manifold so everything lines up is a good boost to airflow and fuel mixture. So match the intake port to the gasket and then take it back into the runner right to the valve bowl, after you can do the valve bowl. Remember you can safely grind the walls until the cast parting line is gone,just keep the walls vertical, floors and roof horizontal. As for the valve bowl area, this is where you will pickup the most increase in airflow, a good valve job with bigger valves is second, and the port entrance & runner size are third but, the last 2 need to work together.
The picture below is a cutaway that Dave (67 Cutlass Freak) did and is a ported head. As you can see the intake runner angle is pretty good. On top fuel/alcohol hemi heads the angle is almost twice of what you see here and they are a straight shot to the valve. You can also see how flat the intake port is, this does not help, in fact it just makes things worse because it makes fixing the short turn radius a PITA. In fact this is why head porters are willing to give up cross sectional area and raise the floor by making a wedge that ramps down to the short turn radius and this is for iron or aluminum heads.
Fig. 7 This is what the overall port should be like. Fig. 8 On stock heads it is very safe to grind away until the parting line is gone. These are not Olds heads. Fig.7 .................................................. .................................................. ......................................Fig.8
BBC oval port heads, does anyone really think that raising the port floor this much is going to increase flow? These heads are now good for a stock truck engine or something like that.
Ok my wet flow is not like they use today but, most of us do not have the money to buy a liquid flow bench or even maybe a fluorescent wet flow add-on to a Sunflow bench but, my little demonstration will show where or where not the flow is. I find it takes a lot of guess work out of porting beyond the standard cleanup stuff. Unless you have a lot of experience it won’t help you get that last 5% of flow but, ask yourself do you really need that last 5%? Are you running competition eliminator or something where you need that last little bit? You can use what I have shown you here on any head including aluminum. When I reflow the heads I’ll post pics showing how easy it is to do and I’ll do the exhaust. I’m also going to see if I can simulate a valve opening and wave (ram air) tuning, well we’ll see. Damn dog leg.
74 Sprint, this is really good stuff. I applaud your thinking outside the box approach with your wet flow setup. I've read only a post so far but you have very good insight.
Have you ever experimented with dimpling the walls of the port or the combustion chamber itself?
Yes, back when I was young, around 77-78. What we found was that if the dimpling was not done right it actually caused less flow but, better mixing. When one makes a dimple it doesn't make a dent it instead makes a crater with a raised wall around it. So after the dimples are made you have to go back and sand down these raised walls. To get the benefits you have to make a lot of dimples and the depth of the dimples depends on the air speed. The faster the air speed the deeper the dimples have to be. The big thing is once the airspeed exceeds 350 fps the dimples are no different than leaving behind perpendicular grinding marks, so dimples are good for low air speeds/engine speeds. Dimples also are not worth the time it takes to make them, grinding marks are a hell-of-a lot faster, I guess that's why dimpling died out so quickly.
Originally Posted by 80 Rocket
74 Sprint, this is really good stuff. I applaud your thinking outside the box approach with your wet flow setup. I've read only a post so far but you have very good insight.
Keep up the great info!
Thank you and I'll try to keep the info coming as time permits.
Originally Posted by 80 Rocket
I'd really be curious to see the effect of dimpling the short turn to see if it can keep flow attached.
Dimpling has the opposite effect, it traps air and helps to expand the thickness of the boundary layer, this would have the net effect of pushing the airflow to the other side of the valve, where there is plenty of flow going on already.
Originally Posted by 83hurstguy
wow! Thanks for bringing back the tech. Neat stuff, I'll have read it all in detail when I have some time.
Your welcome, I hope everyone enjoys reading it as much as I enjoyed doing it, I just wish I could have done better.
There is a lot more I could talk about but, I was worried that I would get in trouble making long winded posts with the admins and it not being my thread. I did ask Dave if it was ok if I could post some stuff here before I did, after all he is the OP. I want to mention that there is a lot more detail I could go into about head porting but, how many people really want me to talk about gas laws and the mathematics on airflow. Take what you got, make it better and have fun.
I forgot to mention; for thou's who don't remember dimpling intakes, it all started as a way to push the limits of the rules where porting heads was limited to removing of protruding cast flashing but, it didn't mention dimpling. Dimpling isn't grinding or sanding of ports but, it is modifying them. LOL
Is it too late to fill crossovers on heads that already have liners installed and valve seats ground?
I picked up a set of C heads that have been ported and had the previously mentioned work done for the right price.
From my own experience, I would not recommend it. If you do the fill be prepared to touch up the valve job on the inner exhaust seats as a minimum. The heat will distort them.
Last edited by 67 Cutlass Freak; Dec 23, 2017 at 12:17 PM.
Is it too late to fill crossovers on heads that already have liners installed and valve seats ground?
I picked up a set of C heads that have been ported and had the previously mentioned work done for the right price.
I'm in the same boat sort of, I have the liners installed but, my seats only have had a plunge cut on the seats so that I would know how far I can go with the porting. I plan to preheat my heads before filling and welding up the center divider before having the final seat work done. As far as the seats go, my heads are 'G', so as long as I don't do any major damage the seats can be finished up, yours could be retouched, I imagine. Just be careful and take your time cleaning up the excess fill. You could always re-lap the valve seats to see if they are damaged and need re-cutting.
YOU all are missing one of the main advantages to filling the crossovers.
If fully filled it helps scavenging. Just pounding in the plugs or using block off plates doesn’t have the same effect.
Hi Mark.
We understand that the point is to increase exhaust port efficiency at the same time as keeping the intake charge as cool as possible.
The problem is the heads have already been machined.
So the risk vs reward is much higher than performing the fill on a bare core head.
Last edited by Bernhard; Dec 27, 2017 at 06:35 AM.
YOU all are missing one of the main advantages to filling the crossovers.
If fully filled it helps scavenging. Just pounding in the plugs or using block off plates doesn’t have the same effect.
I don't have plans for an engine powerful enough to take advantage of filled crossovers but I am curious what your preferred method of filling them is Mark? I have read several versions of the process and melting pistons and pouring them into the head cavities seems to be the most common but I have also read about a ceramic kit for filling the heads as well. What is your favorite?
Melting pistons is the cheapest.
And imo there is no hp threshold for this exercise. It’s a fairly cheap and easy way to add 10-15hp no matter what your hp goal is.
We tried melting pistons. Lots of impurities more work than its chalked up to be . Just buy an alloy ingot cheap enough and faster to do as the zinc alloy we used ( if I remember right ) . I ordered the ingot we used from smitty which I think he mentioned what it was somewhere in this thread.
Now another thought and I have never done this but JB weld has an extreme heat putty. You could buy a bunch of tubes and mix and press them into the port. I have used the regular JB steel sticks and once they set they grind like steel and sets up fairly solid. Much more so than the regular JB goop.
I'm in the same boat sort of, I have the liners installed but, my seats only have had a plunge cut on the seats so that I would know how far I can go with the porting. I plan to preheat my heads before filling and welding up the center divider before having the final seat work done. As far as the seats go, my heads are 'G', so as long as I don't do any major damage the seats can be finished up, yours could be retouched, I imagine. Just be careful and take your time cleaning up the excess fill. You could always re-lap the valve seats to see if they are damaged and need re-cutting.
Ray
My other option is to fill some bone-stock big valve GA heads that are good enough to run as-is. This would take the liners out of the equation, but I still might chicken-out because I don’t want to mess up the valve seats and set back the completion date of my engine and disturb the factory induction hardening of the seats. I really want to drive my car this spring.
T311
Posts 129
06 May 2014, 20:07 #19
At the same time you were doing this, I was putting the same product in my heads. After a season of racing, I can say that mine isn't holding up. It seems to be mechanically breaking down.
I pulled the intake and everything seemed intact, but I noticed on the head side of the intake gasket on one side was a build up of very fine ceramic powder - felt about like ash. I put new intake gaskets on and reinstalled the manifold. Went to the track and made 1 pass, and ended up needing to pull the intake again (unrelated issue).
Well, after just one additional pass, this time it burned right through the intake gasket. A small chunk of the Resbond fell out of the heat riser in the intake. Additionally, more of the very fine ceramic powder was being blasted into the heat riser. Well even that fine, ceramic is still abrasive and not something I want swirling around the exhaust ports, potentially ending up on exhaust seats.
It was nice to be able to work it cold, but it doesn't seem to be holding up. It didn't break up into chunks or anything, but seems to be eroding away, and I don't want an abrasive powder flying around my engine. I'm going to pull the heads and break it up and remove it.
Just thought I'd share my experience with it for those who read this thread.
I havent looked back but what was the heat rating on the resbond ?
The one member used 3000 F Resbond
I don't know what the person that had the failure used?
If you go to their website they list many types of epoxy some with aluminum and other compounds.
They also listed some that could resist temps above 3000 F.
I think Dave's method along with well executed fill and good prep will yield the best result.
Its just not for heads that have had final machine work in my opinion.
Last edited by Bernhard; Dec 30, 2017 at 09:59 AM.
Like with any failure one has to look at the procedure that was used.
Was the mixture instructions followed exactly ?
Was the fill complete as in no air pockets ?
What was the prep of the port like ?
Was the right product used ?
Was the working time exceeded?
If I were to use a product like this I would go with a short fill on the exhaust side of the port,
about 3/8 back, into the port for maximum support and no clean up.
From what I have read this will not hurt performance.
I just question the risk reward V a stainless steel block off plate.
Is it worth the 10 to 15 HP on a non stock class type build.
Last edited by Bernhard; Dec 30, 2017 at 10:21 AM.
I may have to try it. Dave's way is the way to go he did my heads which are set up for my new engine ., the engine thats in the car now has non ported big valved #6 heads with out the heat risers filler. I dont want to remachine anything but my old (current) engine can be a test mule
67 Cutlass Freak: after sifting through this thread I lost track....whens these heads going to the track?
Which set are you referring to? I showed like 5 different sets throughout this thread. At least two sets are going down the track. One set made 527 HP, at least two others are in cars running. I haven't heard if they hit the track. I don't know what Ulises is waiting for. He's had those ported heads for three years sitting on a shelf.
They sat on the engine for 2 years lol. No need to swap engines just yet. But once i hash my suspension out the swap will happen. Good things take time im patient. Should be some time this summer. Only been building that engine for 5 years lol. It takes time to build a 3k $ sbo that will run 11's lol.
Which set are you referring to? I showed like 5 different sets throughout this thread. At least two sets are going down the track. One set made 527 HP, at least two others are in cars running. I haven't heard if they hit the track. I don't know what Ulises is waiting for. He's had those ported heads for three years sitting on a shelf.
Tell me about the 527 HP build, what did it run at what weight, thanks.
Tell me about the 527 HP build, what did it run at what weight, thanks.
That engine was sold and delivered to a young man from St Louis. Never heard if he made it to the track. My race car with a crappier bottom end went 10.64 @ 125 MPH and it weighs 3250 lb with me in it.
That engine was sold and delivered to a young man from St Louis. Never heard if he made it to the track. My race car with a crappier bottom end went 10.64 @ 125 MPH and it weighs 3250 lb with me in it.
