What Not To Do When Porting Heads Part2: The Numbers

[@Greybuiltracing]

The more I watch Eric’s videos the more I understand where I’m messing up at . For example, I thought the throat was the cross section area .. right before the valve boss going into the intake . It’s the valve seat area , right before it and after it . I’m fairly new at porting mini bike 4stroke engines and don’t really know the terminology and names of these ports .. some but not all . This helps a lot ! Ty🙏🏻

[@elmerfudpucker3204]

Experience is the best teacher. R&D on a cylinder head teaches you exactly what it takes to make HP for that head. Thanks for sharing and explaining so easily.

[@LOSTXPLAYGUN]

There are so many people around my area that use the bowl hawg. I have always been against it for the same fact you are describing as the venturi effect. I am by no means a guru but learned to do mild head work from a gentleman who worked for Audi's performance division and was kind enough to teach me. He always said less is more, mostly because most people do more and then end up with less as a result. Thank you for your informative videos, subscribed.

[@alejandro52612]

Would be great to have a series like this for 4 valve per cylinder heads

[@michaelblacktree]

I would love to see some 4-valve stuff.

[@servediocylinderheads]

Excellent video Eric, all good points. I was surprised when I flowed some of my 90's work that ran really well had swirl up to 4000! Sbc

[@goodfellasinc.5648]

Lol I knew the small block had a better swirl but the question is why I've been porting for 40 years maybe a little more And I've also done diesel Porting and two stroke porting I would love to show some top Secret stuff I've learned over the years see what you think about it

[@WeingartnerRacing]

I would be happy to see it just email it to me.

[@ameliachristian6099]

I have a lot of respect for you, and the things that you do. I appreciate your honesty, take care.

[@basketballcory2]

Thanks for all the great content

[@theshed8802]

Excellent video. Thanks Eric

[@markwallace5274]

Love your videos and the knowledge you share I would love to learn more about throat percentages with a 4 valve head if you could share that percentage ? I tend to work on and mess with overhead cam 4 valve per cylinder engines mostly Honda B Series

[@johnb7430]

The relationship between swirl and flame propagation / completeness of burn would be interesting.

[@TravosGarage]

hi Eric, great video! is there any chance you would be able to do a video on combustion chamber shape? especially on how to make a poor combustion chamber shape better? it would be excellent for us guys who have engines without aftermarket options for cylinder heads but still want to make the best out of our stock heads? and also how shaving the head to improve compression may effect how we need to go about shaping the chamber to improve flow?

[@alexsiurda6028]

Would love to hear more about 4 valve stuff or what the knowledge you have about porting them, I watch alot of your videos but I only deal with 4 valve heads so its hard for me to know if i can apply these methods to them, muchly appreciate if you could.

[@iceman9678]

Thank you for the explanation. It's too easy to screw up a port job. I might pass on the porting (minus removing of casting imperfections) of my Rover T16 head.

[@CherezianRacing]

Man i wish this video had come out before i butchered my first attempt at porting some old iron eagles. Took that throat right to the 45 cut :/

[@marklowe7431]

Such an art. Lot of people talk about flow but never air speed.

[@JohnClutch1]

My guess is GM had this as a consideration when designing the LS cathedral heads. Now onto the video.....

[@charliehupp5385]

Eric. I am glad you have so much work. The "Dog Leg" in the exhaust is a great idea but it belongs on the "No Flow side. Try it Sir.... It set many world speed records in 1985 or ask Bob Morgan

[@WeingartnerRacing]

Ok.

[@JS-ri2rx]

Glad you pointed out the throat and the 1" before and after the valve seat. Im still learning but good video. So many porters in videos. But how many show a throat percentage. Almost none.

[@YerkitRacingChannel]

I have always heard 90 to 91%. Good to see some numbers to back it up!

[@indyrock8148]

I wonder if they went such a big throat to try blend out the famous Pro Comp under seat ridge? The procomps I messed with for practice actually had been further ground in this area. Someone just wailed in there with a burr. A 2.08 valve and 90% throat didn't get it all out. Though I managed to blend seat with alli.

[@monadking2761]

Good information to know. I have a old 283 with P.P. heads and were told it's not worth porting and still had hardened seats installed on the exhaust side. My feeling is, if it's cleaned up even a little you should get better flow. I cleaned them up a little and trimed around the valve stem area and slightly under the seats just to smooth it out to the seats. Then cleaned up around the edge of the shroud area in the chamber area. Woukd that really helps or hinder flow? I know not seeing the heads makes it hard to say but I figure it doesn't hurt to ask.

[@rocketsurgeon11]

So, you said that 4 valve heads have a slightly different set of "rules" when it comes to throat sizing and I am interested in what those differences are?

[@michaelblacktree]

Likewise.

[@BraapSupport]

me to please

[@danielesilvaggi]

Well in my opinion you don't need swirl to turn a fan, air just moving straight through will spin the fan. So, I don't see how you can tell if it is actually swirling. Great question. I would like to see a clear tube at the fan with smoke in the air to see if it is in fact swirling.

[@servediocylinderheads]

The blade is parallel to the flow. Only angular flow will produce torque to turn blades.

[@bdugle1]

Another video full of interesting info! Next time you’re flowing a BBC head, I want to see the swirl difference on good port vs bad port. They are oriented very differently to the cylinder and I’m guessing that makes a big difference. Another question, can you have too much swirl? Great stuff, thanks Eric!

[@jimmybare3026]

Speaking of 94%. You're probably getting near the actual numbers of people who have mistakenly hogged too much out of this area including myself. Common sense says the bigger the opening the more air can come through there. Like the saying goes just because it looks good on paper don't mean that it will in reality work. The bad part, once you remove this material, your street car's going to suck worse than it did with the stock heads and few will understand why.

[@stevenhobbs709]

When procomp first appeared years ago, I was curious, but the magazine ad had some typos, as a business owner I’ve had this happen, it leads to conversation about them fixing it and what compensation are you giving me. But the next month was the same…went on for at least six months as I recall. What I inferred is a lack of care for the details.

[@flflash4717]

Eric I can't seem to find the first video? Interesting content!

[@EamonnSeoigh]

I’d think it might be better to compare and predict flow with a complete view down the intake runner of both heads and a rotation of both with a view up the intake valve.

[@WeingartnerRacing]

I will work on that

[@MX-fo2nu]

Very good and clear detailed describtion, thanks i Do this next time better i still have Material to Do better undercut an improve top cut. at my 914 heads.

[@tomv7552]

The small block head. Believe it or not, OEM’s do a lot of R&D to get the most out of their engines while meeting performance goals. They quite often hold back the power so they can keep the same platform for many years while changing minor details for more power in the next vehicle model

[@faxxzc]

or emissions

[@BDauto86]

Thanks for sharing Eric.

[@rubbercitygarage2104]

Spring Inside Outside Divider Caliper Set Measures 8 inch Machinist Tools

[@Henily1]

Eric, 2 questions-How much bigger do you make the area directly under the throat? Is the throat measurement the same from the short side to the back wall?

[@seancollins9745]

There so much you can get in the chamber and piston design in regards to mixture homogenization

[@craigchiddo2794]

What would happen if you fill the port floor

[@DropcordKustoms]

Would having the throats to big cause or amplify idle/low speed drivability problems with a larger cam? (244@ .050")

[@rumblecanada]

Thank you for your knowledge! Have you done any ford 4.6 2v? I'm about to port some heads and could use some advise. Any info would be much appreciated. Cheers

[@infantryman7139]

The small block Chevy should have more swirl. Due to the port design

[@ankualex]

any advice for porting to get a better performance / torque on low rpm?

[@ts302]

Excellent content Eric! My hangup with flow bench testing is how does it translate to a running engine. To clarify, airflow in a running engine, starts & stops due to the valve opening & closing (one issue). On a flow bench, a port flows in one direction. With respect to swirl, is too much swirl detrimental? I visualize air/fuel separation with high swirl (centrifugal force?), especially with carbureted engines (bigger droplets of fuel) compared to FI. What say you Eric? Thank you Tony. Also, please explain your 4-valve theory.

[@stevenbelue5496]

One of Vizards videos he vaguely talks about the centrifuge effect causing loss of atomization and large droplets being slung out onto the walls if you have to much swirl. So I would guess your right. IMO

[@mikemcglothin9988]

Are percentages as important on the exhaust as they are the intake?

[@Bshiddy]

Pittsburgh and Harbor Freight?

[@finnroen2334]

I think the SBC has most swirl by a lot.

[@HBJY-Cylinder-Head-Factory]

we're famous cylinder head block factory in China 🙂

[@johnginnitti4598]

I Believe it would be the SBC head with higher swirl

[@terryenyart5838]

I would be interested to know what amount of swirl a good 700-800 HP head has (RPM & direction of rotation) versus a lower performance head,say 500 HP. I assume every head has swirl, but is this something a head porter is attempting to change to extract more HP or better combustion? I know head designers have to consider this as the vortices in the wrong area can make a poorly combusting head.. Thanks for great info as always. Terry

[@cstavro]

how about testing swirl on a stock LS3 with the "swirl wing" still attached? I think you'd be interested in testing swirl on a gen V LT1 head to...

[@gavmorgan1846]

Hi Eric ,love you videos and appreciate your time to help us . What about throat percentage on smaller valves , the remaining 10% of say a 2 .25 inch valve is quite a bit bigger than 10% of a 1.8 . I've ported a head with 1.8 inlet valves and I'm not game to go bigger than 88.5%.. Dose this factor in the equation?

[@WeingartnerRacing]

I don’t port smaller than 1.94 so I don’t have experience with something that small.

[@robert2413]

Ok, I might be an idiot but I have an old 327 and have been thinking about those trick flow dhc heads. Heard there is a good amount of meat there to go bigger if you want to port. Like to hear if they are a possible starting place for a 500 horse 400 sbc

[@sethmiller9442]

I’d like to see what the swirl is on some Afr sbc heads.

[@johnnyboyssite]

Hi Eric so i picked up some 702 castings for my MarkIV 462 BBC . will be primarily street driven. i want to maximize the low lift flow but keep the stock valve sizes. I dont own a flow bench. for the intake side if i just do a 4 angle valve job, blend the bowls into the throat area and clean up the ports should do the trick? on the exhaust side again a valve job , blend the bowls on the long side, streamline around the valve guides then deshroud some around the quench side of the exhaust valve give me good results?

[@fukemallgarage]

I'd say the sbc, a brodix dragonslayer is a great head even unported and designed for a bit larger displacment

[@BDauto86]

They are, so is an LS3 head. They flow very well for a stock head and impressively well with good Port/valve work.

[@DURRIESVISION]

The 'Slayers' i think🤔

[@danmoffitt4521]

When you make the throat is it mostly contained in the seat? Trying to figure out how to word what I'm asking as in is the tightest cross section located on the pressed in seat and taper into the casting/bowl

[@johnnyboyssite]

Hi Eric ive got a pair of 702 BBC heads. car will be mainly street driven but looking for max low lift flow. if i keep stock valve sizes should i still go for 4 angle valve job with 30 degree back cut and just blend the pockets into the throat area ( intakes only ). for the exhaust side , clean up the ports, blend the bowls on the long side and deshroud at the quench area ? its a 462 with around 9.1 CR

[@darrellsomers5427]

LS would be my guess

[@nathanaelwarden]

Do you ever do any work with 4cyl engines? Is the principle the same?

[@shanerorko8076]

Hey Eric how much would you charge to buy a second hand set of late 2017+ gen 3 hemi heads and get them setup for a 224/232 cam on a 6.4l and send out to Australia? So new valves, seats and bowl blending ect.

[@patrickmoore1017]

More swirl goes to the Dragonslayers.

[@buchascii9]

Would. Like to know what you think about dart pro 1s older ones

[@RollingThunder85]

Do you have any bbf heads or recommend any brand in particular?

[@shanerorko8076]

The SBC head will have more swirl. I base this on LS heads in the cath ports having swirl features.

[@salvatorehayes2753]

Will New Cut Valve Seats And Valves Leak Air Under Extreme Pressure From A Blow Gun? I Filled The Chambers With Water And Blew Compressed Air Right Behind The Valve. At 80PSI They Didn't Leak. But At 120PSI I Started To See Bubbles Slowly Grow. Should I Lap The Valves Or This This Normal Given The Circumstances. I Also Noticed They Also Made The Throat Too Big. Waited 2 Years And $1,800 Kinda Disappointed. The CNC Looked Good But It Did Look Like They Ate Into The Under Cut Like This Video.

[@WeingartnerRacing]

It should remained sealed. The valve job isn't round.

[@firstworldboredom]

Would have been nice for you to explain the 90% in Part 1.

[@WeingartnerRacing]

Back then nobody was really watching.

[@timothybayliss6680]

Eric, have you ever tried a lower valve seat angle for mild street stuff? I remember a decade ago guys were using a 30 degree seat for flat tappet big block stuff. They were picking up flow under .400.

[@ericbrandt829]

Pontiac used 30 degree seats on many motors....But, the loss after 0.400 if your using a decent performance cam....Your better off with the 45 degree seats from what I have seen.

[@WeingartnerRacing]

No I would never use a 30degree valve job in anything I do.

[@timothybayliss6680]

@@ericbrandt829 ya, it didnt really make sense to me. Go through a set of heads with a valvejob and a set of springs only to put a hydraulic flat tappet with .450 lift in it.

[@bigredracer7848]

29👍's up EW thanks for sharing

[@bigredracer7848]

between cast iron big black Chevy heads aftermarket in aluminum big black Chevy aftermarket heads if you had them both ported and they both had the same flow numbers is it only the weight difference is why people choose aluminum over the cast iron one

[@peteJoseph-x3h]

Insizers…….you’re welcome

[@4speed3pedals]

Are the ProComp reliability issues found in all their heads or just big block Chevy? How about the age? Wondering if issues have been address with more recent casting? Thanks.

[@WeingartnerRacing]

Don’t know I stopped selling them years ago.

[@stevehammel2939]

I'm curious about the difference in flow numbers between aspirated and supercharged applications, are the throat diameters larger for supercharged engines?

[@WeingartnerRacing]

I will try to do a video about that later.

[@tonyavila5556]

Do the LSA heads show better swirl?

[@gjponsford4892]

The dragon slayer is my guess.

[@charliehupp5385]

hahahahaha The quotes about ' Restricted Area" on the small block head was MY Article in 1998 in Car Craft hahahahahha

[@WeingartnerRacing]

I have heard it many times but I don't remember it in car craft.

[@chucksmith7166]

It’s a spring calipers

[@tomkelly9206]

Dividers

[@xlr8r3VA]

I think it is the SBC head.

[@davidreed6070]

That would be the small block Chevy

[@chucksmith7166]

Sbc has mor swirl

[@cliftonsnider5776]

not promoting procomp but we have seen american heads chunk out seat pieces..

[@JC-gw3yo]

Apparently, swirl is not all that important in making power as the LS engines are superior power producers

[@WeingartnerRacing]

I don't know about superior power producers but they make good power.

[@claas90017]

Eric, Have you ever flowed or ported coyote heads?

[@WeingartnerRacing]

No

[@claas90017]

I was just curious, I know in some or your videos you mention that a 4 valve head some things would be different. Like throat area ratio

[@arturozarate1752]

The Brodix SBC Dragon slayer

[@johnkries8189]

Small block

[@cameronsmith8730]

What not to do.If you're Tube guru with NO experience at all in porting heads......don't touch them.

[@chucksmith7166]

And has more swirl

[@bobbyborba6460]

Small Block

[@michaelblacktree]

Here's a link to the first video: kzbin.info/www/bejne/d3ndiJxmepeHmq8

[@deerslayer5863]

Flotec

[@brucefulper2433]

These are just flow numbers. How does the head work on the car??? Without that test you know nothing,

[@WeingartnerRacing]

This is one piece to the puzzle.

[@RogerMoore-ne6hu]

Sbc head

[@eewheeler29]

Sbc head

[@jacksonbermingham2168]

sbc

[@bassettraceengines]

Brodix 23

[@goodfellasinc.5648]

Sbc head duh

[@johnmorris5834]

Brodix

[@jameslaurinitis7580]

sbc head

[@chevyrc3623]

Ls3

[@chevyrc3623]

I was wrong lol

[@juanf4739]

Stop promoting harbor freight junk tools.

[@thorout8377]

It would be a very huge help if you showed us all how to port a V twin m8 heads 😉

[@FACEBOOKS-WBDS]

I have been watching all your vids, and I have a few questions but can't find a vid close to my questions. so, here it goes....i have been told you can put a rectangle port bbc intake on oval port heads? Also I have tall deck engines and they use 1/2 spacers to fit intakes too......is it possible to machine 1/2 spacers with oval on one side and rectangle on the other is it worth the work? ( none of these are in a full race application)

[@petergehle4222]

Yep I always kept at 90 to 91%