Port and Polish for the Garage Guy

[JoeFin]

After years of doing this on my own cars, friends Hot Rods and still others by word of mouth. I’ve gotten to the point where I hate to see guys building engines and Not doing it. As any good Chevy SB builder will tell you its all in the heads.

Now before all the “Nay-Sayers” chime in with the “You’ll never pass smog again” or the “You’re ruining a perfectly good engine”, I’ll just say I’ve been doing this for over 10 years now, I’ve never had 1 of my jobs NOT pass Calif. Smog - years down the road (have the smog certs to prove it) and No I don’t lose all my low end torque or even an amount to effect the drivability of the car at low speeds/RPM

I do however gain 10-15% better gas milage (Freeway Driving) and lots of top end power, from just polishing the runners. In fact in 1 of my daily drivers (1993 Ford Excort with 1.9 lt eng.) where before I had to turn off the air conditioning and mash the peddle to the floor to try and maintain 70 mph climbing a steep hill before polishing, I was able to drive 75 mph, air conditioner on and some peddle left.

Furthermore – if you are worried about the engine’s ability to atomize fuel, given that just about every engine out there has EFI, I would be looking at my fuel injectors instead.

With that being said – here is an R22 head from friend building up an old Toyota 4WD for a rock crawler the way he brought in to me, with valves removed.

Same head, Decked .030” on a surface grinder and with the runners and bowls partially cleaned up.

Now it helps a lot I have a Valve and Seat machine because I wouldn’t want to be stuffing Cross-Buffs on a die grinder through valve seats I was going to use. But that doesn’t prevent the guy without them from first cleaning and polishing his chambers and runners prior to sending the head in to be surfaced with a fresh Triple Cut Seat Grinding and Valves Ground.

Personally it has gotten tough to find a shop that does good precision head work. Our disposable society has just about run them all out of business. The last set of heads I sent it (in 1993 - a 462 cu. in. Ford M Block) came back with seat heights varying .070" or better

And once again once those valves are back in the seat the customer isn't going to see what they have done. Personally I like to inspect the valves under a 30x tool scope to see how the grinder is cutting the face. With all the newer materials used to build valves you have to be careful to select the right stone.

This is a valve before lapping

Oh well that's my 2 cents
Peace out Hot Rodders

 

[theknurl]

JoeFin;
check out Mira Valve Seat Tools

http://www.miratool.ch/index.php?page_id=31

cuts a finished seat* in one pass and each is cut to exactly the same depth

* you pick the seat form

 

[crazy5]

I'd love to be able to do this sort of work, but wouldn't really know where to start. Have any links to good how-to articles?

 

[JoeFin]

I'd love to be able to do this sort of work, but wouldn't really know where to start. Have any links to good how-to articles?

One of the salesmen from Goodson had a blog article up years ago covering the subject pretty good - Can't seem to find it now that I go looking for it.

I'm not talking about hawging out metal by no means for the beginner. Guys who do this on the bracket circuit have Flow Benches and use patented, proven profiles to reshape valve pockets.

For a daily driver or even Street Legal Hot Rod there are 2 pretty simple steps that will help out a lot in the way of performance and economy.

Polishing the Runners.

You'll want to go in and remove any forge casting marks left over from the mold. If they are Aluminum Heads you won't need any thing stronger then the 80 grit sanding rolls, Iron Heads can use the cone grinding stones. After the ridges and excess metal has been removed from the casting marks, you'll start to take the rough texture out of the runners.

You'll then follow this with first Course, then Medium, then Fine Cross Buffs soaked with a good amount of WD40 to keep the grit flowing out of the Cross Buff. Leave no nooks for carbon to collect or airflow to ripple all the way up the runner, and through the valve bowl right into the chamber

That's it for the Runners

Port Matching

Apply Machinist Blue Die to your manifold and bolt it to your heads. Separate them once again and mark in black sharpie the areas where the surfaces did not mate around the port openings. That ridge will have a devastating effect on your airflow and you'll want to taper that ridge until both manifold and head mate perfectly.

And not to sound like I'm plugging one particular supplier but .... Goodson.com Not the cheapest but the best

 

[justanengineer]

JMHO but Ive been involved with designing intake ports and I wouldnt bother. Maximizing flow isnt really a consideration in port design, its more about getting the proper air/fuel motion going into the combustion chamber, and believe it or not we do take into account the casting roughness as it directly affects air motion/boundary layer. Not to be a naysayer, but theres a lot more to consider than most folks ever will and the "results" folks claim are usually hogwash. On a modern port/direct injected engine for example, porting alone without altering the fuel maps wont improve anything.

 

[JoeFin]

JMHO but Ive been involved with designing intake ports and I wouldnt bother.

Hey - are you one in the same "Justanengineer" that post over at Home shop Machinist? .. Small World Wide Web if you are.

Ya you would upset a lot of folks over here http://speedtalk.com/forum/index.php that use Calibrated Flow Benches that digitally plot the flow curve through the valve lift ranges and Dyno-Tune their engines to tell them all those proven results was just in their head and they were not really accomplishing any thing by going to all that trouble.

I can certainly understand why an Engine Manufacturer would not want to consider removing casting marks or create any thing resembling a polished surface given the highly labor intensive nature of the endeavor. Even with Liquid Hone Technology the time consumption involved to an industry absorbed with Machining Cells and per unit cost is out of the question.

Personally I wouldn't put the heads back on the engine without doing it - but that's just me.

 

[ADSR]

No more eye balling it for me. I send my heads out for CNC porting.

 

[rsanter]

The older heads can be improved a lot for performance and efficiency. You can get some performance and efficiency gains on the newer stuff but not as much.
I am a big fan of porting and do it to every engine I build including a mild port job on even stock engines just to remove and lumps or machine edges in the flow path

I have never heard of porting effecting the way a car smogs, all you are doing it making the flow more efficient

Bob

 

[justanengineer]

Hey - are you one in the same "Justanengineer" that post over at Home shop Machinist? .. Small World Wide Web if you are.

Ya you would upset a lot of folks over here http://speedtalk.com/forum/index.php that use Calibrated Flow Benches that digitally plot the flow curve through the valve lift ranges and Dyno-Tune their engines to tell them all those proven results was just in their head and they were not really accomplishing any thing by going to all that trouble.

Yessir, one and the same tho I do more reading than posting there nowadays as Im getting away from mostly machining/machine restos and more into garage/auto/antique hobbies while restoring an old house.

Im not out to upset anyone, just tossing out my $0.02 based off having a bit more experience/knowledge of combustion than those outside the profession. Compare homogenous charge combustion (well mixed air/fuel within cylinder) with stratified charge (serious separation in cylinder), and you get a big difference in performance bc the motion into the cylinder and consequently the burn is different. Hobbyists are welcome to call bs all they want but flow isnt really a big factor, its been well proven/documented that you can have plenty of flow but not enough/wrong type of motion and lose performance, and IME most heads flow plenty despite popular myths otherwise.

The interesting thing about "proven" results is that theyre usually not so well proven. Folks can point to a peak power or torque number and claim an improvement, but they usually dont consider peak vs net, nor do they realize the differences caused by operator or atmospheric (air) changes and numerous other factors. Simply stated - they see what they wanna see. When I run a test, most everything is automated regarding load and engine control and the air into the engine is conditioned regarding temperature and humidity to a very tight tolerance, good luck doing that without a few million bucks. Running unconditioned air alone, on a 300 hp engine Ive seen 30 hp differences in runs within an hour of each other, not to mention repeatability issues with a hobby operator running a manual throttle (wtf do ppl do this stupid ****?), manual dyno load control, and monitoring everything simultaneously.

 

[JoeFin]

Yessir, one and the same tho I do more reading than posting there nowadays as Im getting away from mostly machining/machine restos and more into garage/auto/antique hobbies while restoring an old house.

Well I'm more interested in when you graduated school

If I remember right you joined HSM about 3 years ago claiming to be a student enrolled in an engineering major and excited to be working with your hands.

I'm glad they crammed all that experience into a few short years so you could come here and tell all those professional race teams their full of Sh!!

Kuddos

 

[jfdestree]

To get things back on track, I did try myself to port and polish the heads on my beetle engine. As mentioned in the beginning of the tread, power is in the heads. Especially true in the case of the aircooled flat4 VW.
They are some good how to's article online that explain the basic port and polish about those heads. And most point to the fact that you can gain both HP, torque and reliability, if done correctly.
If the engine "breaths" more easily, heads temp will drop ,which is a very good benefit on an aircooled engine, and allow you to rise CR.
They also insist that on a street engine, flow speed is more critical than volume because it improves drivability.
So, how I did it? Let's say it's a job to be tackle only if you really want to do it. It is both rewarding and frustrating...I've spend a goof amount of time to polish and port manifolds correctly but I did a mistake on the exhaust port because I increase them to much. (I have an VW head porter giving me advices).

 

[Lippyp]

I did a home port and polish job on a '76 Triumph 1500cc engine in my Dolomite back in the early 90's. Hard to say if it made a difference as I also rebuilt the engine at the same time with new rings, big ends, mains, oil pump, timing chain, vlave seats and guides etc etc. Its certainly went better afterwards though (once I'd ahem adjusted the valve timing so it was actually sucking in through the inlet valves rather than the exhaust valves I know, rookie mistake, valve timing 180 degrees out!)

 

[JonBoehman]

Done quite a few P&P jobs when I was racing motocross. On a single cylinder bike it really wakes it up with just opening up the holes. I always had to rejet and retune the carb afterwards. I tried chamber relieving however and didnt see much in the way of any power gains.

 

[justanengineer]

Well I'm more interested in when you graduated school

If I remember right you joined HSM about 3 years ago claiming to be a student enrolled in an engineering major and excited to be working with your hands.

I'm glad they crammed all that experience into a few short years so you could come here and tell all those professional race teams their full of Sh!!

Wrong, I graduated three years ago and was hired by my current employer prior to that. I started to list out my qualifications then realized its pretty irrelevent, I cannot possibly know what Im talking about bc Im justanengineer, and a young one at that. Nevermind patents and papers, almost a decade spent supporting myself as a tech/tradesman and a stack of certs/licenses, growing up wrenching in the family businesses or the equipment/dyno at home. Nevermind three years spent working for an OEM on alternative fuel projects focusing on combustion and performance, the master's Im currently pursuing specific to combustion, that race engines are only ~20 years behind the times, or that I have many friends/peers engineering them. Nope, I cant know jack, bc nobody knows anything until they reach age 50. Right....

Common sense would also ask the questions, on a public internet forum why would a "professional" race team be sharing their secrets? Beyond that, why would they be discussing flow benches and not an engineering CFD model/simulation as is much more common in engine development today? Even in the late 50s when my father started running SCCA the "pros" were altering jig grinders to do ports, now we run cnc, different control but same level of competition and not a hand grinder in sight.

 

[slickgt1]

Wrong, I graduated three years ago and was hired by my current employer prior to that. I started to list out my qualifications then realized its pretty irrelevent, I cannot possibly know what Im talking about bc Im justanengineer, and a young one at that. Nevermind patents and papers, almost a decade spent supporting myself as a tech/tradesman and a stack of certs/licenses, growing up wrenching in the family businesses or the equipment/dyno at home. Nevermind three years spent working for an OEM on alternative fuel projects focusing on combustion and performance, the master's Im currently pursuing specific to combustion, that race engines are only ~20 years behind the times, or that I have many friends/peers engineering them. Nope, I cant know jack, bc nobody knows anything until they reach age 50. Right....

Personally, I agree with you. I used to think this was the way to go, port polish, port match, all that ****. I did not notice much difference on any of my modern cars that I did this to. Plus attributing any gains to port and polish is also something that you cannot prove. You would have to assemble your engine with the original parts, including gaskets. It's all in the head, I have never had proven results doing this.

If you think about it, with fuel/power efficiency being the hot topic these days. Why would millions of dollars worth of engine R&D, a few hundred engineers, parts casters and manufacturers not look into flow dynamics of the heads, and figure out the best from the get go.

The guy with the dremmel must be onto something.

 

[rsanter]

Fact is that thru OEMs do pay attention to flow dynamics. They pay more attesion than they did in past decades, however they also look at cost and manufacturability. Their OEM design is based on a need for the majority and not on the desire of a few hotrodders.
New engines will see less gains or none at all if it is only the porting being done. But if you were to change the cams, exhaust, and intake to now would have the need for better flow through the heads as well or they will be limiting then power output

The ford modular 4.6.....
The original version had heads that needed a great amount of improvement. Ford themselves came out with a police interceptor head that looks like the original but with improved ports. People bought the heads and saw more power. After a few years ford made them standard equip.
What was the improvement, better flow
The OEMs know what they are doing but they also limit things for the desirability and needs of the general public. Those guys building NASCAR engines cant all be wrong

Bob

 

[JoeFin]

The intake plenum was ported and polished for optimum airflow.
http://www.bankspower.com/magazines/show/653-banks-sidewinder-dragster-gets-more-power

 

[Kevin54]

Holy ****. A thread about porting and polishing has now turned into a bullying session? Instead of ones wanting to pick an argument, why not make it a civil conversation and ask the reason "why" for things instead of getting your damned feathers ruffled and strutting around like king **** of the roost?

And JoeFin.....nothing against you personally, but some won't take to kindly to a newbie making accusations whether right or wrong. That's the quickest way to get under other members skin. Then threaten to go dig up old posting to try and disprove something that is said?

Make it a civil conversation for all, and maybe compare knowledge instead of disproving knowledge and others may learn what to do and what not to do. But where this is going is doing nothing but getting closer to a thread being shut down because of internet bullyness.

 

[slickgt1]

Kevin how do you not have the word moderator by your user name? Seriously well put together post above. And 16k posts as well wow

 

[JoeFin]

Holy ****. A thread about porting and polishing has now turned into a bullying session? Instead of ones wanting to pick an argument, why not make it a civil conversation and ask the reason "why" for things instead of getting your damned feathers ruffled and strutting around like king **** of the roost?

And JoeFin.....nothing against you personally, but some won't take to kindly to a newbie making accusations whether right or wrong. That's the quickest way to get under other members skin. Then threaten to go dig up old posting to try and disprove something that is said?

Make it a civil conversation for all, and maybe compare knowledge instead of disproving knowledge and others may learn what to do and what not to do. But where this is going is doing nothing but getting closer to a thread being shut down because of internet bullyness.

I wasn't offered any opposing documentation, theory, or results to discuss. Merely boasting of $1Million Dollar equipment (unverified), accusations of "In their Head", "Hogwash" and innuendoes of inferior equipment, and a wealth of easily disproven statements. So where was the discussion?

Regardless I've edited my post

 

[iagsxr]

So you're arguing over the gains on some mythical/theoretical engine. Old SBC w/stock heads, huge improvements possible. Modern stuff less so.

Until you get your head around this you're an amateur; Low valve lift flow numbers are where it's at for street driven vehicles and most race motors. The port ends at the valve seat, a proper valve job is the foundation of a good head. The valve seat/bowl area is the last thing the air/fuel mixture sees before entering the chamber. Start with the bowls and work backwards if you're gonna grind.

If you're going to dyno; Unless the engine's going in a drag car with a super loose converter, area under the torque curve is a more accurate measure of the engine's ability to do work than peak HP numbers.

 

[crazy5]

Make it a civil conversation for all.. others may learn what to do and what not to do...

Thanks for that. I asked my question on page one because I wanted to learn, not watch an internet ******* match. I haven't learned much from this thread yet. I hope it can get back on track with some useful tech, even if it isn't universally agreed upon.

 

[crazy5]

...Old SBC w/stock heads, huge improvements possible. Modern stuff less so.

...Low valve lift flow numbers are where it's at for street driven vehicles and most race motors. The port ends at the valve seat, a proper valve job is the foundation of a good head. The valve seat/bowl area is the last thing the air/fuel mixture sees before entering the chamber. Start with the bowls and work backwards if you're gonna grind.

If you're going to dyno; Unless the engine's going in a drag car with a super loose converter, area under the torque curve is a more accurate measure of the engine's ability to do work than peak HP numbers.

Thanks for bringing some tech!

 

[iagsxr]

I'd love to be able to do this sort of work, but wouldn't really know where to start. Have any links to good how-to articles?

David Vizard How to Build Horsepower

It's a foundation, not cutting edge, the fundamentals apply to any engine.

 

[JoeFin]

Until you get your head around this you're an amateur; Low valve lift flow numbers are where it's at for street driven vehicles and most race motors. The port ends at the valve seat, a proper valve job is the foundation of a good head. The valve seat/bowl area is the last thing the air/fuel mixture sees before entering the chamber. Start with the bowls and work backwards if you're gonna grind.
.

I wasn't trying to get over technical on the subject and was merely trying to interject some thing the average Garage Guy could use. Not everyone has valve and seat machines or CNC mills in their garage. Let me preface the subject by saying I don't do this as a business but more for my own use and a few friends. But now that you brought up the point ....

Yes you are entirely correct and that a good triple cut valve job will increase flow and performance. One of the reasons I said "I wouldn't want to be running a cross buff through valve seats I was going to use" was because the sharp edges of the different angles increases fuel suspension.

Port cutting/grinding is some thing entirely different as it can radically alter the engine - for better or worse - so its best to have some expertise and a means to test the results. Pocket Porting for example, on an older SBC 283 along with a few other parts can see +420 ft lbs of torque. Works pretty nicely in the early 60s CrissCraft 17' with a 12x15 prop

 

[Squankum]

Observe my powers as I revive a dead thread!

I'd love to be able to do this sort of work, but wouldn't really know where to start. Have any links to good how-to articles?

This is the book to start with:

David Vizard's How to Port & Flow Test Cylinder Heads (S-A Design)
https://amzn.com/1934709646



_

 

[ADSR]

Observe my powers as I revive a dead thread!



This is the book to start with:

David Vizard's How to Port & Flow Test Cylinder Heads (S-A Design)
https://amzn.com/1934709646



_

If anyone cares, I didn't even get one comment. This offers a way to get all the ports the same.

http://www.garagejournal.com/forum/showthread.php?t=285000

 

[kerrynzl]

So you're arguing over the gains on some mythical/theoretical engine. Old SBC w/stock heads, huge improvements possible. Modern stuff less so.

Until you get your head around this you're an amateur; Low valve lift flow numbers are where it's at for street driven vehicles and most race motors. The port ends at the valve seat, a proper valve job is the foundation of a good head. The valve seat/bowl area is the last thing the air/fuel mixture sees before entering the chamber. Start with the bowls and work backwards if you're gonna grind.

If you're going to dyno; Unless the engine's going in a drag car with a super loose converter, area under the torque curve is a more accurate measure of the engine's ability to do work than peak HP numbers.

This ^^^^
Even cam grinders use .050" in their specs
I've got more gains from back cutting valves and a competition seat job ,than porting [and so called polishing, which is a joke]
I had a set of BBC ZL1 heads that some expert had hogged out in the'70's.
The flow numbers were terrible [the air was stalling].
After carefully welding up the floors in the ports etc etc, we managed to get some reasonable numbers out of it.

Another area where amateurs **** a good set of heads/manifold is gasket matching the ports. you end up with 2 trumpet shapes face to face which stalls the air [ the opposite of a venturi ]

Remember HP is the size of the bang x the number of bangs per minute. So unless you are prepared to rev the **** out of it, it is an exercise in futility.

On the drag strip $$ for $$ there is more gains in rear end gears and tyres

 

[JonnyMac]

Well quite a few intermingled opinions here!!
Ive spent the last 20 years working as an OEM calibration engineer both base engine/dyno and vehicle.
A couple of observations...
Modern engines are calibrated to primarily achieve smooth clean performance then once it gets placed into a vehicle its calibrated to meet emissions compliance unless its a vehicle that is heavily performance based (and im talking exotics not just a sports car). So once you understand this then you move onto the fact that the vehicle has so many machine tolerance variables that will affect the emissions and hence legal compliance you realize the dominant feature is the window of operation within the engine calibration.
So unless (in a modern ecu controlled vehicle) you tune the calibration on a dyno to specifically match the internal engine works that have previously been performed then you are not getting the best from the engine.
Now i say best rather than "anything more" because, for example, if your vehicle has a manifold pressure controlled fuel system and you improve the internal flow (however you decide) there will be an accompanying change in the fueling. But this translates more into efficiency rather than outright power improvements..
You also have to factor in the variations in fuel octane rating as there is almost always spark modifications and detonation limits included in the calibration which mean you really are not running at ideal spark at any time regardless of anything thats done to the internal hardware.. :-(

 

[kkroger]

Having dealt with this in detail many many times there are gains and modifications that can be measured on a Dyno and on the Track, generally when forced to use particular parts and the necessity to be "Stock" and in particular engines when trying to push the power and torque numbers up the curve... "Stock" street driven engines may have small gains by equalizing port volume and flow and port matching. Equalizing combustion chamber volume and smoothing the material and unshrouding valves for better flow. You can also screw up a perfectly good set of heads by going too far or doing the wrong thing.

 

[raddksn]

Kevin how do you not have the word moderator by your user name? Seriously well put together post above. And 16k posts as well wow

I've wondered the same thing for some time now!

 

[FunkyfullWidth]

Since this thread was brought back....

porting alone without altering the fuel maps wont improve anything.

I always had to rejet and retune the carb afterwards..

I think these two about sum it up. to really maximize the benefits ... On older cars, you remap it manually by changing jets, turning the dizzy, adjusting fuel pressure, changing spark plugs. Newer computer controlled cars, you remap with a computer. Same thing only different.

I think it was an apples to oranges debate going on. Even in the 90's you could change things, and the computer would throw you back into the stock parameters. Pre obd1 vehicles didn't have a computer adjusting things for you, So if you did a valve job, or p&p you're way more likely to feel or see a difference. Throttle response may not always increase HP, but it's certainly an improvement worth going after.

 

[dffay]

All well and good for the top end. That stuff really matters and it's worthwhile time spent. If it's a complete engine teardown, one of the often overlooked things for the machinist's list is to balance the rotating assembly. Even one or two con rods or crank counterweights out out can really effect the free revving capability. It's time and labor well spent to have it balanced to the smallest practical margin. That way, the engine is not fighting itself.

 

[66fl]

I hope this thread goes back on track. I am a lurker and rarely post in any forums but gain a lot of knowledge.
I think for many with hobbies forums are great. Lots of people with different engines and vehicles. Also lots of different experience and education levels here.
This is a deep subject but many can benefit from even a basic understanding of flow and velocity. I've had heads done that required adding material to increase velocity at an rpm that was usable. I have cleaned and polished and enjoyed the process bonding with the machine.
To much motivation not enough knowledge and a Dremel or grinder can make many things worse. We all have learned from those mistakes.
My hobbies are to avoid drama of humanity . And there are generations that have never seen points or a magneto.they still may want to bond with a machine.
Looking back on the subject of head work over 25 years ago I had a bike engine build and the heads were a done by a companies that flowed and added material as the deemed important. I did the rest of the build. I was connected to the machine. I had no Dino results or drag strip times just horsing around with friends. But I have memories of how it felt the whole package and the knowledge I did it.it felt awesome
I was very young and had help from great mentors. And I appreciate their knowledge and help. And even the work I had sent out I understood why and what was done. This is a chance to help others gain understanding and learn or spend time and teach there kids. It should not be a competition of who posts more or who has what degree or job. I respect the time and energy of those that post a lot I read this forum to decompress and get to sleep most nights. Most other forms of media just irritate me. Please don't screw this up

 

[66fl]

I hope this thread goes back on track. I am a lurker and rarely post in any forums but gain a lot of knowledge.
I think for many with hobbies forums are great. Lots of people with different engines and vehicles. Also lots of different experience and education levels here.
This is a deep subject but many can benefit from even a basic understanding of flow and velocity. I've had heads done that required adding material to increase velocity at an rpm that was usable. I have cleaned and polished and enjoyed the process bonding with the machine.
To much motivation not enough knowledge and a Dremel or grinder can make many things worse. We all have learned from those mistakes.
My hobbies are to avoid drama of humanity . And there are generations that have never seen points or a magneto.they still may want to bond with a machine.
Looking back on the subject of head work over 25 years ago I had a bike engine build and the heads were a done by a companies that flowed and added material as the deemed important. I did the rest of the build. I was connected to the machine. I had no Dino results or drag strip times just horsing around with friends. But I have memories of how it felt the whole package and the knowledge I did it.it felt awesome
I was very young and had help from great mentors. And I appreciate their knowledge and help. And even the work I had sent out I understood why and what was done. This is a chance to help others gain understanding and learn or spend time and teach there kids. It should not be a competition of who posts more or who has what degree or job. I respect the time and energy of those that post a lot I read this forum to decompress and get to sleep most nights. Most other forms of media just irritate me. Please don't screw this up