porting and polishing
Discussion
two points.
1...the fact you are asking...makes me think you would be best to leave well alone, as you dont know how to.
2...either an electric die grinder or air powered with carbide bits first, then a finer wheel to finish.
A-series heads arent the easiest in the world to get results with.
1...the fact you are asking...makes me think you would be best to leave well alone, as you dont know how to.
2...either an electric die grinder or air powered with carbide bits first, then a finer wheel to finish.
A-series heads arent the easiest in the world to get results with.
It's fixable... said:
Gwiz, did you know that polishing inlet ports is generally thought to increase fuel puddling and dropout which will have a negative effect on power ?
I had that personally told to me by no less than David Vizard thst 60 grit was as smooth as you want to go.
just finished re reading his book. Mirror finish makes the surface "sticky" and reduces performance as you mentioned. I had that personally told to me by no less than David Vizard thst 60 grit was as smooth as you want to go.
TBH i have spent so long reading about cylinder heads on A+series engines and general builds i am a little over whelemed. I was a bit annoyed with the first response, presumptions and all that jazz. Thanks for the heads up though.
I am starting my mini build project with the cylinder head as i live in a flat and the missis will only let me have the 3rd bed room to play...... I fully intend to post pictures when completed. By my reckoning i will probably save my self 800-900 notes by spending time and effort porting a polishing out casting flaws. A really good head will cost about a grand, and that is purely down to the time involved....
Vizards book is brilliant, i have been collecting mini performance guides for 4-5 years now... i have what i would call a concise libary.....
Gwiz
GingerWizard said:
It's fixable... said:
Gwiz, did you know that polishing inlet ports is generally thought to increase fuel puddling and dropout which will have a negative effect on power ?
I had that personally told to me by no less than David Vizard thst 60 grit was as smooth as you want to go.
just finished re reading his book. Mirror finish makes the surface "sticky" and reduces performance as you mentioned. I had that personally told to me by no less than David Vizard thst 60 grit was as smooth as you want to go.
TBH i have spent so long reading about cylinder heads on A+series engines and general builds i am a little over whelemed. I was a bit annoyed with the first response, presumptions and all that jazz. Thanks for the heads up though.
I am starting my mini build project with the cylinder head as i live in a flat and the missis will only let me have the 3rd bed room to play...... I fully intend to post pictures when completed. By my reckoning i will probably save my self 800-900 notes by spending time and effort porting a polishing out casting flaws. A really good head will cost about a grand, and that is purely down to the time involved....
Vizards book is brilliant, i have been collecting mini performance guides for 4-5 years now... i have what i would call a concise libary.....
Gwiz
IMO, buying a ported head from someone with the experience and ability to do it right...is good value for money for peace of mind.
I know the notion of DIY is nice, but sometimes you just need to get real.
If you cant read where I told you what you need....did you just glance over the Yellow book the same ?
You need either an electric or air powered die grinder, various carbide bits and perhaps finer stone wheels for finishing. You need tools to cut out valve seats and install new hardened valve seats.
You need tools skim the head afterwards, and measure the combustion chamber volume.
And you need to supply new valves/springs/retainers as necessry. Oh, and a flow bench to mnake sure you are actually improving flow, instead of making it worse.
Good luck then.
You need either an electric or air powered die grinder, various carbide bits and perhaps finer stone wheels for finishing. You need tools to cut out valve seats and install new hardened valve seats.
You need tools skim the head afterwards, and measure the combustion chamber volume.
And you need to supply new valves/springs/retainers as necessry. Oh, and a flow bench to mnake sure you are actually improving flow, instead of making it worse.
Good luck then.
David Vizard did do a diy flow bench article on GFN (go fast news) but it seems to have been removed ..
but I did find this for you.
http://www.tonydrews.com/Flowbench/FlowBench.htm
Got to say I agree with Steve - sure you can have a go at a head and be proud of you work but there is no guarantee that you will have had it better and not worse.
I'm sure myself and others know when to stop diy and do some research and find the right expert to do work for us.
Edited to add - found a porting kit while I was looking for parts for my car:
http://www.v8tuner.co.uk/product.php?id=586
but I did find this for you.
http://www.tonydrews.com/Flowbench/FlowBench.htm
Got to say I agree with Steve - sure you can have a go at a head and be proud of you work but there is no guarantee that you will have had it better and not worse.
I'm sure myself and others know when to stop diy and do some research and find the right expert to do work for us.
Edited to add - found a porting kit while I was looking for parts for my car:
http://www.v8tuner.co.uk/product.php?id=586
Edited by rev-erend on Friday 16th April 10:09
I have been doing 2 stroke porting and polishing for a few years now, yes I know 2 and 4 are diffrent regarding the work that requres doing ( 2 strokes harder to get right lol)
I'm not gonna tell you to get a pro to do it ect, as I was told this when I started. I will say if you can get your hand on a friends ported head have a good look at it, see what work has been done and try and visualise what work has has been done to it, what tools were used ect...
Make sure you have everything you need to do a proper job before atempting it
Oh and get a few heads off a scrappy to practice on, no matter how good the 'pro' is they will have definately ruined plenty of heads before they got things right. And you don't want your only head to turn into a misshapen paper weight
Btw, please excuse any grammer mistakes, posting off my mobile lol
I'm not gonna tell you to get a pro to do it ect, as I was told this when I started. I will say if you can get your hand on a friends ported head have a good look at it, see what work has been done and try and visualise what work has has been done to it, what tools were used ect...
Make sure you have everything you need to do a proper job before atempting it
Oh and get a few heads off a scrappy to practice on, no matter how good the 'pro' is they will have definately ruined plenty of heads before they got things right. And you don't want your only head to turn into a misshapen paper weight
Btw, please excuse any grammer mistakes, posting off my mobile lol
stevieturbo said:
And to add.....no, a Dremel wont cut it
My brother cut an A series head to DV's specs with a 100 Watt Minidrill (early kind of Dremel, but better). Was a bit slow going but got there in the end and the engine made quite decent power (on a par with ready built engines of similar spec).If you follow Dave Vizards instructions to the letter you won't go wrong. Do the ports first. As you say, inlets should br left rough and exhaust ports smooth (helps to stop the soot stick as well as improving flow.
When I have done mine in the past (on 5 different ocassions, and 2 'B' heads also) I roughed out the combustion chambers then got the head skimmed at a machine shop (very cheap) and new valve seats cut with hardened inserts fitted for unleaded. Then I finished off the combustion chambers taking great care not to damage the valve seats or leave any dust in them!. take them out to the recommended size, polish them a little then measure and match their volumes using thin oil in a burette. Polish and measure until they are all equal and shiny!
Dont forget to 'reshape' the portion of the valve guides which protrude into the ports and get some nice slim valves too!
Doing it this way you take on the labour intensive part of the job without the large outlay for specialised euipment, plus you get a great deal of satisfaction from doing it yourself!
Happy grinding!
ETA I may have an unused set of high-lift rockers if you're interested!
When I have done mine in the past (on 5 different ocassions, and 2 'B' heads also) I roughed out the combustion chambers then got the head skimmed at a machine shop (very cheap) and new valve seats cut with hardened inserts fitted for unleaded. Then I finished off the combustion chambers taking great care not to damage the valve seats or leave any dust in them!. take them out to the recommended size, polish them a little then measure and match their volumes using thin oil in a burette. Polish and measure until they are all equal and shiny!
Dont forget to 'reshape' the portion of the valve guides which protrude into the ports and get some nice slim valves too!
Doing it this way you take on the labour intensive part of the job without the large outlay for specialised euipment, plus you get a great deal of satisfaction from doing it yourself!
Happy grinding!
ETA I may have an unused set of high-lift rockers if you're interested!
Edited by Poledriver on Tuesday 20th April 01:33
30 years ago when I was just a kid and cars were just a hobby I ported my first cylinder head. It was a 1275 A series head for my Morris Marina and I sat outside in the sun working at it for hours and hours with a Black and Decker drill, a flexible drive shaft and some stones I'd got from Halfords or wherever. Running porting stones at only a couple of thousand rpm is pretty much a waste of time but time was the one thing I had lots of for free and I also had a copy of David Vizards first Mini book to follow. I had the seats cut by a very experienced professional who many years later actually taught me a lot about porting when I started doing it professionally.
Anyway 10 years or so later, for reasons which still escape me I gave up a lucrative career in accountancy and went into engines full time. One of the first things I did was put that old Mini head on a colleague's flowbench and then we reworked it properly to see what we could get. My home porting efforts, even with the DV book to follow, had only achieved about 50% of the gains over stock we eventually ended up with and most of that was probably from the valve seats rather than my porting.
Without a flowbench, proper porting gear and lots of experience I'd say you just can't get anywhere near what it's possible to achieve. In many cases ill judged porting attempts will actually make things worse. Some heads are easy to do and what looks right tends to work ok and others need shapes you'd never think of without a flowbench to guide you. Heads with horizontal ports and vertical valves like the Mini, B Series and Ford Pinto are the hardest to get optimised. In any case it's the valve seats and areas within about half an inch of them that give the most gains and you aren't going to be able to cut seats yourself and most so called pros can't cut decent seats either.
You can't do porting properly by following drawings in a book, no matter how good the book is. You need the experience to know what shapes to aim for and whether you're achieving them or not. Without long reach carbide cutters you can't even get to the parts of the port that really matter. Most of my work is done with carbide burrs on shanks 4" to 6" long. With a 2" long porting stone all you'll reach is the bit of the port near the gasket face and that part does bugger all to influence flow anyway unless it's far too small. If I'm using stones, which is rarely and only on cast iron heads of course, I fit them into extension holders so they have a similar 4" reach. Without that you can't even see what you're doing because a drill chuck will be in the way.
Without all the right gear, and by that I mean professional high speed flexible shaft equipment, long reach carbides, a mill to skim the head, a valve refacing machine, a flowbench, equipment to remove and replace valve guides and ream them out and proper seat cutting gear even I wouldn't bother doing it myself. You can't really finish a head until the seats are cut and if you then hit any seats with the cutter you need to get them recut again or if you skip the cutter out onto the gasket face it'll need skimming again. Even if you have all the right gear you still need to know how to use it and I've seen plenty of so called "pro" heads that were either worse than standard or not much better.
So in summary DIY porting is pretty much a waste of time. Unfortunately so is most "professional" work but that's another story.
Anyway 10 years or so later, for reasons which still escape me I gave up a lucrative career in accountancy and went into engines full time. One of the first things I did was put that old Mini head on a colleague's flowbench and then we reworked it properly to see what we could get. My home porting efforts, even with the DV book to follow, had only achieved about 50% of the gains over stock we eventually ended up with and most of that was probably from the valve seats rather than my porting.
Without a flowbench, proper porting gear and lots of experience I'd say you just can't get anywhere near what it's possible to achieve. In many cases ill judged porting attempts will actually make things worse. Some heads are easy to do and what looks right tends to work ok and others need shapes you'd never think of without a flowbench to guide you. Heads with horizontal ports and vertical valves like the Mini, B Series and Ford Pinto are the hardest to get optimised. In any case it's the valve seats and areas within about half an inch of them that give the most gains and you aren't going to be able to cut seats yourself and most so called pros can't cut decent seats either.
You can't do porting properly by following drawings in a book, no matter how good the book is. You need the experience to know what shapes to aim for and whether you're achieving them or not. Without long reach carbide cutters you can't even get to the parts of the port that really matter. Most of my work is done with carbide burrs on shanks 4" to 6" long. With a 2" long porting stone all you'll reach is the bit of the port near the gasket face and that part does bugger all to influence flow anyway unless it's far too small. If I'm using stones, which is rarely and only on cast iron heads of course, I fit them into extension holders so they have a similar 4" reach. Without that you can't even see what you're doing because a drill chuck will be in the way.
Without all the right gear, and by that I mean professional high speed flexible shaft equipment, long reach carbides, a mill to skim the head, a valve refacing machine, a flowbench, equipment to remove and replace valve guides and ream them out and proper seat cutting gear even I wouldn't bother doing it myself. You can't really finish a head until the seats are cut and if you then hit any seats with the cutter you need to get them recut again or if you skip the cutter out onto the gasket face it'll need skimming again. Even if you have all the right gear you still need to know how to use it and I've seen plenty of so called "pro" heads that were either worse than standard or not much better.
So in summary DIY porting is pretty much a waste of time. Unfortunately so is most "professional" work but that's another story.
good lord the four horsemen have just turned up at my front door with death as a groupie...
Thankyou all for input on this topic, i am however going to give it a go, it will cost me what it costs and on the bright side i will be able to add to my tool collection (never a bad thing in the world of "man")
I will in months to come start another topic and let everyone know how i got on, even if it turns out i would have been better spending my time rolling around in turds. Its clear it won't be easy and i am likly to f*** it up but hey i am sure i will have a modicum of fun, and when i have my garage/house etc i can just buy parts and do it properly if needed.....
fingers crossed ehe!?
Rob
Thankyou all for input on this topic, i am however going to give it a go, it will cost me what it costs and on the bright side i will be able to add to my tool collection (never a bad thing in the world of "man")
I will in months to come start another topic and let everyone know how i got on, even if it turns out i would have been better spending my time rolling around in turds. Its clear it won't be easy and i am likly to f*** it up but hey i am sure i will have a modicum of fun, and when i have my garage/house etc i can just buy parts and do it properly if needed.....
fingers crossed ehe!?
Rob
There are always a bunch of folks just waiting to tell you it can't be done/your not good enough/you need to pay someone else/it won't work/they know it all and you know nothing.
The truth is if you have a few brain cells to rub together you will probably do a perfectly acceptable job and learn something along the way and have a bit of fun. It's grinding metal out of a hole to make it flow better, sure there are finer points to it that a very experienced person with a sqillion quids worth of equipment and years of practice will be able to do better but there are also plenty of people out there with or without a squillion quids worth of kit who will do a worse job. If you make a total balls of it what have you lost, an A series head.
Good luck and enjoy
The truth is if you have a few brain cells to rub together you will probably do a perfectly acceptable job and learn something along the way and have a bit of fun. It's grinding metal out of a hole to make it flow better, sure there are finer points to it that a very experienced person with a sqillion quids worth of equipment and years of practice will be able to do better but there are also plenty of people out there with or without a squillion quids worth of kit who will do a worse job. If you make a total balls of it what have you lost, an A series head.
Good luck and enjoy
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