Raising runner, not short turn?

[Rick Finsta]

Alright, I'm working with someone here on this, but to satisfy my curiosity I've got a question. If I take the floor of a port, and raise it 0.600" so that it is even with the short turn radius, does this help or is it a waste of time? Assume the port roof will be lifted and the proper CSA and shape will be achieved via porting.



The head is for an Oldsmobile with a stock 6* valve angle. On the left you can see an inside and outside port with the stock floor location, on the right I've welded them up to about even with the start of the SSR.

I'm going to defer to the porter's decision on if this is beneficial or not, but I can't quite get my head around whether or not this helps shape the SSR to avoid stall. I know stock Olds ports generally stall around 0.550-0.575" lift, but the Edelbrock port is a better design, especially in the bowl and SSR.

I am a complete novice, but I haven't found an in-depth discussion on this and I'm not sure if "raised runner" heads generally have a higher drop from the top of the short turn to the throat? I can weld up the short turn if necessary but if I don't have to touch this critical area I'd feel better!

[Erland Cox]

It does give a little more hp but the flow usually stays the same.
To get a real benefit from raising the port the radius of the turn to the valve must be made larger.
The crown of the short turn must be raised.

Erland

[Abbottracingheads]

The quantity of flow may not go up, but the quality of flow should increase. If you have room in the roof to the spring pocket you should be able to gain some flow as well. Remember you are dealing with fuel and air, not just air.

[mag2555]

I guess these are Edelbrock heads, not that it much matters, but out of the box they flow enough for making 525 hp in a race built motor, so is your customer looking for greater power then that?

With that being said the main issue that needs to first be addressed with these heads is the 15 odd Intake cfm difference between the left and right hand ports , not raising the floor!

This type of rework is not really something to be fooled around with with out a flow bench!

[GARY C]

To give you an idea of flow on a high port. http://www.musclecardiy.com/cylinder-he ... s-part-10/

[Rick Finsta]

Sorry, a few more details. Yes, Edelbrock 60529s. I'm not doing any porting work, only welding as necessary (including above the ports by the rockers pads if necessary). The porter is free to engage in any conversation about these, including telling me I'm an idiot, and he's free to share any pictures or technical details he wishes to. Application is for twin 66mm turbos on 362cid but I want to make 600hp normally aspirated at 6500-6800rpm. Cam will be <0.700" lift roller. Intake valve will be 2.125 or 2.150, both of which are doable with the stock seats and the meat in the bowl area. There is a head bolt issue in the inner runners as well, and I am assuming sleeves will be necessary. I don't care to move the pushrods but I will.

This isn't really intended to be a max effort deal, more than anything I wanted to learn more about how these things work, and the more I looked at it, the less I believed I could make a huge difference without raising the top of the SSR. I'll defer to the porter; I want to understand SSR height concerns versus "dead flow area" concerns. Even with a shop vac you can tell that the lower portion of the stock ports don't move any air, but I don't know if that translates to a flow bench, or more importantly, to a running engine with an intake bolted on.

[novadude]

Am I right in thinking that the low port, shallow valve angle, and small bore really limits the potential of the larger displacement Olds engines? Seems to be reasonable CSA, but small valve sizes and sharp turn into the valve seems like it really hurts. Just my uninformed observations in looking at a "Ga" casting on a friends workbench and comparing to a large oval BBC head. Wonder why the designers had to compromise like this?

[nickpohlaandp]

What are you using to weld in filler? Are you using TIG or MIG?

Oh, and Gary C, that's an awesome link. That book is supposed to be on my doorstep when I get home tonight.

[Rick Finsta]

Yeah I'm buying that book and a hard copy of Bette's airflow book (I have it on Kindle for light reading on airplanes LOL).

novadude, you're right on. All the aftermarket heads have the runners raised significantly. I think the OE design intent was really wide torque curves under 5500rpm. The Edelbrock casting has a taller SSR than stock heads, but not by a ton. Bore spacing is a limitation if you're looking to build gigantic motors, but it isn't an issue to get 4.185" out of most D/DX blocks. This particular engine will be 4.125"x3.385" BxS leaving me some room for an overbore or two if necessary.

nick I'm using TIG and the recommended filler which is plain ol' 4043.

[nickpohlaandp]

nick I'm using TIG and the recommended filler which is plain ol' 4043.

I figured as much. The welds didn't look porous at all. I imagine you could obtain similar results with a good 220 MIG and a good purge, but TIG is always the best way to go. I was just thinking it had to be a mother to get the torch that deep in the ports and still have room to get filler rod in at the same time. Are you using a special torch?

[Rick Finsta]

17 Air cooled but I've got a 20 on the bench now, waiting for the cooler. Everyone told me if I did aluminum I'd eventually go water cooled... and they were right! I use a stubby gas lens on the 17 making it slightly bigger than the 20 but what I ended up doing is sticking a purge line into the valve guide and plugging the throat with aluminum foil, with about 5CFH going in, and around 3/4"-1" stickout and 25CFH on the torch. Getting around the pushrod pinch is a gigantic pain, especially since these are used castings so I'm having to constantly clean my tungsten when I hit a pocket of crap. It takes several cleaning passes with the EN cranked and the carbide burr before I can even start adding filler and floating crap out of the puddle. Then a few times cleaning like that, and I can start laying down beads. Clean I've heard these Edelbrock castings are a dream to weld on. I'm trying to get a hold of a 25/75 He/Ar mix but so far I've been okay using 200A wide open on my little Lincoln and a MAPP gas preheat of only around 150-200*F. It takes so long to get everything clean that by the time I'm really puddling and adding filler it is melting just fine. Helium sure would make it easier, though.

[groberts101]

Erland nailed it.

And @ Rick. Do yourself a favor and spend the extra coin for pure helium. Pricy but you won't regret it. Also allows turning down the amperage to ease life on the equipment. Less time preheating or even eliminates it altogether. Running allthread through bolt holes to pin both heads together helps keep the firedecks stabilized and adds more heat sink mayerial too. Hope that helps.

[nickpohlaandp]

Everyone told me if I did aluminum I'd eventually go water cooled... and they were right!...

Yup, water cooled make a HUGE difference when it comes to comfort level, but then again so do a nice pair of gel filled welding gloves. I used to have a ThermalArc 185 true square wave Inverter that I would do all my TIG work with. One day it seems it grew a pair of legs because it just up and left, never to be seen again. That pissed me off. For $2600 you'd think that if the company knew that the machine had a tendency to do that they would've provided me with a leash or something, lol!

Seriously though, that ThermalArc was the best machine I've ever used. I could go from steel, to stainless, to aluminum without ever changing tungsten, simply push a button on the control panel to switch outputs. That coupled with the fact that it was about the same size as my Lincoln SP125, only a little narrower, and it made for an awesome machine. The first time I tried to TIG on an old-school machine with lift-to-start I quickly realized that I suck at TIG, and the ThermalArc just made me look good because it was so user friendly. I want to replace it so bad, but it's hard to justify that kind of $ on something that I really don't have a lot of use for anymore, maybe every now and again. I've looked at other inverters, but nothing seems to come close to the ThermalArc. I even toyed with the idea of getting a Chinese made unit.... until I started reading reviews. Looks like when the day comes for me to get another TIG I'm just going to have to bite the bullet and spend the $.

[Rick Finsta]

This is the $1400 SW TIG 200 and so far I've gone balls out all day on aluminum at 160-200A and I burn my hands but have never hit the thermal cutoff on the machine! 20% duty cycle my ass! Mexican made, but backed with the thousands of Lincoln services centers across the country - that is what steered me towards it versus the Chicom stuff is the support structure. Doesn't have all the bells and whistles but it does what I need and never complains. This is one of the first 500 units sold based on the serial number (I pre-ordered when they were announced).

As for the Helium, the issue is reportedly inverter machines really don't like anything more than a 50% mix. 25-35% seems to be a sweet spot based on guys I've spoken with. I just don't want to have to get a 300CF cylinder of premix since I have no way to get it home LOL. The 80-125s that I own/use are easy to handle. I'm just a hobbyist!

When I get the 20 torch hooked up I'll take a look and see what it would take to get the short turn higher. How high are we talking? 0.100" seems doable.

[nickpohlaandp]

Well Lincoln is a great brand and I'm not a master TIG welder, so that machine would probably work just fine for what I want to do. I'm going to look into that one. The Chinese ones are just too much of a gamble. You get what you pay for isn't always true. Sometimes you don't even get that much, especially if you try to cheap out on an inverter TIG.