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OK, now some fun MGB cylinder head pictures.

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Speedracer Avatar
Speedracer Platinum Member Hap Waldrop
Greenville, SC, USA   USA
1967 MG MGB Racecar "The Biscuit"
After the crack head thread, here's some more fun to look at MGB cylinder head pictures, this is going on a MGB vintage race engine. .



Hap Waldrop
Acme Speed Shop
864-370-3000
Website: www.acmespeedshop.com
hapwaldrop@acmespeedshop.com



Edited 1 time(s). Last edit at 2017-08-11 04:40 PM by Speedracer.


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Defender405 Avatar
Defender405 Silver Member Chris B.
Des Moines, Iowa, USA   USA
1975 MG MGB
That is ALMOST too pretty to mount on an oily stinky engine. Just spray it with a clear coat and mount it on the wall for decoration.



Chris AKA "Defender405"
1975 MGB
1979 Porsche 924
1999 Porsche 996
1987 Nissan 300ZX

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jimac Gold Member Jim Macaulay
Concord Ma., USA   USA
Wow ! What could be better than Friday evening 'B cylinder head porn? Hap I take it that when porting high
rpm race heads a smoother port wall,floor, and roof is the objective vs. a street engine which is better served
with rougher, or as cast port walls,floors, and roofs?
Thanks for the post/pics, Jim Macaulay

kmartin Avatar
kmartin Gold Member Ken Martin
Phoenix, AZ, USA   USA
1953 MG TD MkII "Baby"
1959 Austin-Healey 3000
1967 MG MGB GT "Blue Bell"
Yep, dang near orgasmic!!!smiling bouncing smiley

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Speedracer Avatar
Speedracer Platinum Member Hap Waldrop
Greenville, SC, USA   USA
1967 MG MGB Racecar "The Biscuit"
Jim, it is not as smooth in the ports as it looks, I finish with 60 grit cartridge rolls, then chase it with 100 grit flap wheel mandrel. Camera flash make it shine more than really does, look at the picture looking down into the intake bowl down at the bronze guide, that a better reflection of the texture of the ports Now the combustion chambers are a different story, they end up being finished with 240 grit, some folks go even smoother/slicker and use cratex rubber bits to polish even more, but I think it's more about being smoothed, and shaping up things, rather than shiny, as it all with will covered up soon enough with carbon burn, Now with this head, the goal is to make the chamber no bigger than possible when shaping and polishing, to be able to achieve the max CR we can with a flat top piston, which without going crazy, for me, is a little over 13.0 to 1, which with the pistons at zero deck height at TDC still takes a .100"+ cut from the head, early pre smog heads for this job is preferred, they are more trust-able, and thicker decks to work with and less likely to crack down the road.



Hap Waldrop
Acme Speed Shop
864-370-3000
Website: www.acmespeedshop.com
hapwaldrop@acmespeedshop.com



Edited 1 time(s). Last edit at 2017-08-12 08:36 AM by Speedracer.


Member Services:
MG/ Triumph Performance Street/Race Engines - Cylinder Head Porting - Modified SU HS Carbs - DIY Engine Rebuild Kits With Free Tech Advice - Alloy wheels for British Sport Cars,and others
Steve64B Avatar
Steve64B Steve Opitz
Phoenix, AZ, USA   USA
1966 MG MGB
Hap,

Talk about why you oblong the two intake ports. Is it just to keep from breaking into the pushrod holes or is there another method to your madness?

I was looking through Vizard's A-Series engine book (I know strange night stand reading). In the section on flow bias he shows an illustration of the high flow rates in the upper outside area of the port on the two outside exhaust ports and the alternating flow in the upper area of the center exhaust port. I've always wondered why the exhaust ports aren't cut in a D shape for the outside ports and more of a trapezoid shape for the center port?

Bruce Cunha Avatar
placerville, California, USA   USA
1950 MG TD
1967 MG MGB GT
1979 Triumph 1500 ~ For Sale ! ~
1986 Honda Street
Impressive work Hap. How much time did you put in that?



Bruce E. Cunha

Speedracer Avatar
Speedracer Platinum Member Hap Waldrop
Greenville, SC, USA   USA
1967 MG MGB Racecar "The Biscuit"
Steve, this customer's head had this shape on the intake ports, which is even a further development from the Tabor D ports, bottom line it flowed a ton, but the head was cracked, so I made templates of this shape and re-created it on the new head, as it matches his intakes, he has both a Weber DCOE 45 and HS6 set up, we are going with the twin HS6s since they are proven to be better HP, so far it seem to be flowing more than I have seen on round ports. Yep you still got to respect the push rod bores. The original head was done by well known head porter, but not a LBC specific porter, sometime these guys more likely to find a new deal, because they are less influenced by the LBC community, some times they do as well, this time it appears it did. The idea of what works best is always a moving target.

Bruce too much time, but we got done rather quickly, Ben and I double teamed this head, and we got the porting work done in week's time, who knows, but lets say 12-15 hours of porting form tow guys that probably port faster than most because we do so much of this work. Then add another 10-15 hour of testing, and checking to it all and you in for a bunch of time.



Hap Waldrop
Acme Speed Shop
864-370-3000
Website: www.acmespeedshop.com
hapwaldrop@acmespeedshop.com



Edited 1 time(s). Last edit at 2017-08-12 08:39 AM by Speedracer.


Member Services:
MG/ Triumph Performance Street/Race Engines - Cylinder Head Porting - Modified SU HS Carbs - DIY Engine Rebuild Kits With Free Tech Advice - Alloy wheels for British Sport Cars,and others
glbishop Avatar
glbishop Gary Bishop
Spring Hill, FL, USA   USA
How do you know when to stop increasing CSA?

110 CID/7500 rpm and 100% VE is around 240 CFM

When does port velocity become more important than flow capacity?



Edited 1 time(s). Last edit at 2017-08-12 09:45 AM by glbishop.

glbishop Avatar
glbishop Gary Bishop
Spring Hill, FL, USA   USA
In reply to # 3571500 by glbishop How do you know when to stop increasing CSA?

110 CID/7500 rpm and 100% VE is around 240 CFM

When does port velocity become more important than flow capacity?

So I found the following 2 questions/answers in the transcript from a David Vizard interview by Stan Weiss.

Stan:-
The hottest topic next to low lift flow must be the importance, or not, whichever it may be, of port velocity. Want to start the ball rolling with your thoughts on that?

DV:-
I have to say there are plenty of highly successful pro head porters who talk about the importance of port velocity and make a real effort to inbuild it into what they do but, when cornered, and asked specifically to detail exactly how important it is they stall out for want of a good way to quantify things. The truth here is that all but a very few cylinder head designers pay little more than lip service to the importance of port velocity. The reason for this is that even most pro’s completely underestimate the weight of the air they are dealing with and it’s effect on the ports kinetic energy. At 10,000 rpm the kinetic energy in the intake port of a ProStocker, plenum to valve, is akin to that of the muzzle energy of a high powered air rifle pellet. That’s enough energy to put a pellet an inch deep into a 2 x 4. Let me hark back to the Cosworth Vs DV heads for the Avenger. The Avengers intake ports were round and my heads for this motor sported an intake port no less than a ¼ of an inch smaller in diameter than the Cosworth heads. The scariest comment I hear from novice engine builders failing to make output is, after asking them if the head has been re-worked they say ‘Yes – we have opened up the ports’. The novice assumption here

Stan:-
So how do you decide whether a port is too big or too small?

DV:- Well you have to understand that as a head porter you could be approaching this situation from two different vantage points. First the head porter may be called upon to produce a design for a spec of engine where certain aspects are already decided on. Let’s say we are going to do a hot street head design where the valve lift is limited by the need for long term reliability. Here the port should not be so big that it continues to deliver an increase in flow significantly past the point of maximum valve lift. If it does than you have just designed a port for a valve train which the engine is not using.
In the second situation the head porter could be called upon to port a head for the maximum power output possible. Here the head is made to flow, consistent with having good port velocity, as much as possible. When that’s done the engine builder then has to come up with the appropriate parts that compliment that cylinder heads characteristics. This is especially important in the cam department.
In the second instance it is really important to keep an eye on the flow increases made versus the port volume increases. When flow only goes up marginally for a given volume of material taken out then the port is probably already too big. However making that statement is close to oversimplifying the situation. At the end of the day it is vital that the port be velocity mapped to establish where the port is hyper active and where it is lazy. Again though this is simplified we can say that the lazy areas need to be filled in and the active areas need to be enlarged.
At the end of the day there is a certain port area that best suits a valve diameter and that this port area is dependent on the down draft angle of the port and just how good the porter is at getting air to go around a corner that normally, it has no desire to do.

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Dryflycaster Avatar
Dryflycaster Bill K
Caroga Lake, New York, USA   USA
1978 MG MGB
HAP,

Terrific work.

Many, many moons ago I built and drove my own modified racecars (everything from SB Chevys to BB FE Fords). At the time (even at 16 years of age) I was more than aware of the importance of a good set of heads. Unfortunately I had neither the Equipment, Skill or the Cash to have a good competition set of heads. I instead selected the best cam I could afford and scrounged up the best stock heads available (usually from a engine that had puked) with a regrind, new valves, smoothed chambers and upgraded springs and rockers. It would have been great to have a set of heads that had been worked like the one you have here. I can see HP oozing out all over the place.

If not for the distance, I would love to drop in and see your operation and chat for just a minute or two.

Those Were the Days !



Ever Wonder ?

_bill

Currently Running: 78 B Roadster

Needs Help: 54 Healey100-4

Speedracer Avatar
Speedracer Platinum Member Hap Waldrop
Greenville, SC, USA   USA
1967 MG MGB Racecar "The Biscuit"
Gary we can't any where near perfect VE with a MGB head, and even then, at what inch of testing are talking about, I have a Superflow 110, I flow at 15" then covert that data to the commonly used 28". VE also depends on the use of the engine, on the street engine, a larger port like the ones shown here would be counterproductive, as they just can't shove enough air into them to be efficient. So for street head it is more about getting the bowl and short radius in good working order, and not really enlarging the port runners much. Now on a race engine , that's a different story, it is gonna live it's life on road course, if the driver is doing it job, then it only operates at 5500-7500 rpm when it matters, so no one care about efficiency at low rpm, so we shoot for the stars. A good 28" flow number at say .500" lift on a MGB head would be 160 cfm on a intake.

Head porting is the most nerdy topic you'll get into in engine performance, lots of egg heads have comments, on what is best, but at the end the day a human has to sit down with die grinder and get the job done, most guys I know that talk the science, can't do the walk the work. Years ago when I got busted old V8 heads to practice on, it was different world, guys did things by the seat of their pants, and learned on the race track if they did good. A very well thought of head porter in NASCAR at the time, gave me the best advice I think I ever got, "son you have to look at the hole and imagine how air can move thru it better" . While that advice sounds too simple by today's standards, think about this, when all those egg heads talk the science, do they ever tell you how to accomplish it? Yeah that's what I thought smiling smiley The above conversation with DV is typical, nothing to sink your teeth in. I had a chance to have dinner with DV and David Anton in Charlotte earlier this year, but didn't get the voice mail in time, it would have been fun to chat with them. Keep in mind at the end neither one of those guys ever dabbled into top level road racing these cars. So these days at the level of what we do with these cars, it is little science, a lot of experience, and still finding out at the race track if we did good, since I am pretty fast, and win races, I guess I do OK. I do use math formulas to help me here. Bottom line for racing, we can't make the ports as wide as we would like, the push rod bores being our biggest hurdle. If the sky was the limit, and resources unlimited, then I am sure we could find more, but this isn't NASCAR, and those resource don't exist. Even when I saw top level consultants help with these :LBC efforts, , and test everything out the yen-yang, they did so with store bought ported head. Think about this, the 1000cc speed record was broke a few years ago with a Longman ported head, a head any of you can buy for not big money, you think there could be some improvements made there, yeah I do. So in closing there's talk and then there is walk, I can't say I know everything for damn sure, but I do walk the walk to find out smiling smiley

Gary, Bill you are welcome to stop by anytime



Hap Waldrop
Acme Speed Shop
864-370-3000
Website: www.acmespeedshop.com
hapwaldrop@acmespeedshop.com



Edited 2 time(s). Last edit at 2017-08-14 06:36 AM by Speedracer.


Member Services:
MG/ Triumph Performance Street/Race Engines - Cylinder Head Porting - Modified SU HS Carbs - DIY Engine Rebuild Kits With Free Tech Advice - Alloy wheels for British Sport Cars,and others
glbishop Avatar
glbishop Gary Bishop
Spring Hill, FL, USA   USA
In reply to # 3572100 by Speedracer Gary we can't any where near perfect VE with a MGB head, ....

smiling smiley
Making a point with hyper exaggeration.

You can tell VE is pretty low on these engines based on the HP figures people get even when they build the heck out of them.

I guess my point was really more of knowing when to stop based on the cam's characteristics.

Paraphrasing Vizard (hope he chimes in if I characterized it incorrectly), when increasing port volume no longer increases flow, they're probably too big.


And what is "flow:"?
The opening and closing intake valve on a running engine must create a very different flow situation than a flow bench.

Somewhere else in that article Vizard likens the energy of the moving air stream to an air rifle driving a BB into wood.

A slower moving air steam will produce a lower VE.

Too much port for the cam and high speed VE won't be as high as it could be.

Short of breaking into push rod or water cavities, have you ever gone too far and seen reduced numbers on a dyno?

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Speedracer Avatar
Speedracer Platinum Member Hap Waldrop
Greenville, SC, USA   USA
1967 MG MGB Racecar "The Biscuit"
Gary, I had not been making my port throats square like this head, and I still have data to collect to see how good it is, but is was about 6 cfm better than the two round port race heads I flowed recently, and it really wasn't never a thought not to do this, since I have to match the intake the customer already owed with this shape.

No doubt that a flow bench is not the real word, but it is still the best tool we have.

David Tabor, a well known engine builder, head porter for our cars, who passed away 20 years ago now, who's engines have racked more championships than the rest combined, used to port until he broke thru every intake port at the push rod bores he did, then sleeve it. As far numbers dropping, no not really, we are still finding more. Now mind you a vintage engine is a different animal, we do less CR, and less RPM than the SCCA race engine did, and no one wants to build their engine every three races like we did back then. Now days we mostly run flat top pistons in vintage, but that does allow the ability to run more lift, as dome pistons limited our lift. Also in vintage we can run larger valves, longer rods, shorter pistons, so we are getting closer to the numbers of the high CR SCCA days. Also no one likes to hear this, well drivers anyway, but the biggest deciding factor in our racing is the guy behind the wheel, lots of guys in our racing who spend huge money for HP, and still get beat.



Hap Waldrop
Acme Speed Shop
864-370-3000
Website: www.acmespeedshop.com
hapwaldrop@acmespeedshop.com



Edited 1 time(s). Last edit at 2017-08-14 06:39 AM by Speedracer.


Member Services:
MG/ Triumph Performance Street/Race Engines - Cylinder Head Porting - Modified SU HS Carbs - DIY Engine Rebuild Kits With Free Tech Advice - Alloy wheels for British Sport Cars,and others
Bruce Cunha Avatar
placerville, California, USA   USA
1950 MG TD
1967 MG MGB GT
1979 Triumph 1500 ~ For Sale ! ~
1986 Honda Street
Hap. I grew up in my uncles machine shop. he started out building charter midgets, moved up to sprint cars. Even built a few I e.g. engines (in 1955, Bardahl sent him and a few other car guys to Indy to get the Ferrari competitive, unfortunately, the Ferrari folks could not accept their input and Ferrari never returned to Indy,)

He built his sprint cars using his garage floor as his drawing board. Built good cars, but no where near the cost of some of the other racers. He, like you, believed a well built car with a good driver could win enough to give the money folks a lot of headaches.

www.velocetoday.com/ferrari-at-indy-part-2

My uncle is Al Hinds. behind the driver in the jacket second from the last picture.

You remind me a lot of him.



Bruce E. Cunha

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