Has Anybody Atempted To Port/polish Thier 1.9 Head Themselves

[Peetypug 5]

as above

i've got a spare head so it doesnt matter if i mess one up

 

i was going to mark the inlet ports in the same shape as the bogg bros manifold then workmy way down inside to get a nice smooth finish

 

is there any point doing the exhaust ports as well?

 

basically i was thinking of getting rid of all the little imperfections

[Batfink 201]

what are you trying to achieve?

Personally I would match the inlet manifold and head but leave the rest to the experts.

 

When you say smooth, what do you mean by that. I dont know where the word "polishing" ever came into head modification but its most certainly the wrong thing to do.

[VisaGTi16v 1]

You mean like those polished throttle bodies that people pay £50 for on ebay thinking they will give power

[kyepan 291]

power.. as in " the power of greyskull", standing around in furry yfronts, flexing muscles, and riding a green and blue tiger.. that kind of power polished throttle bodies definitly give.

 

If you want a good reference, check out david vizards "how to tune your A series engine" its got some good general advice on porting of heads.

[VisaGTi16v 1]

Are you telling me that doesnt work? I have been doing that religiously every night for 4 months!

[christopher 5 1 Cars]

There is nothing wrong with removing casting marks and sharp edges if you have some manual dexterity but don't polish. This results in a loss of flow. You need to finish with a slightly rough surface. I would use 80 to finish.

 

As for choping into the start of the inlet port to match your manifold... Well this could loose you power as well because you are affecting the designed flow of the port.

 

 

As far as the exhaust ports go don't bother. They will get covered with carbon deposits anyway. If you have nothing to do you can remove inperfections very carefully and then polish to shine as you like to try to prevent carbon adhesion.

 

Definately do no match the exhaust port to the manifold. This will most definatley loose you power.

[DamirGTI 342]

Hello !

 

I did and I'm very pleased with result :

http://forum.205gtidrivers.com/index.php?s...l=inlet+porting

 

If you have some further questions regarding this job please feel free to ask

 

Have fun !

Damir

[carbers205 1]

Yeah, check Damir's work out and the links in that article are excellent. Thats what encouraged me to do some work on mine.

As already said, 80 grit is all you need to go to on inlet side but shiny is good for exhaust to minimise carbon.

You can feel imperfections and sharp changes of radius using your finger. Whatever you do dont go taking random chunks out of it, the 1.9 head is already flowed pretty well but nevertheless there are still a few improvements can be made!

 

Andy

[DamirGTI 342]

I can also recommend visiting Guy Croft's website , as he helped me a lot with this job , he's very kind man with NO secrets - what you wish to know he will tell you and explain how to do the job properly .

 

http://www.guy-croft.com/phpBB3/viewtopic.php?f=2&t=45

http://www.guy-croft.com/phpBB3/viewtopic....ugeot+205#p3614

 

Regards !

Damir

[VisaGTi16v 1]

christopher, why does matching the exhaust manifold lose you power?

 

cheers

[DamirGTI 342]

...some more to help you out :

 

 

 

 

 

 

(this is professionally ported head by Guy Croft)

 

[NColl 0]

Christopher

polishing ports does not loose flow. I have found in some cases it can give a 1-2% increase in flow. Polishing exhaust ports is a waste of time. If you run the engine for a few minutes, remove the exhaust manifold, you would see the shine had gone. As though acid had been tipped down it, a matt finish and all the colours of the rainbow. I finish all my ports inlet and exhaust with strips of 120grit aluminium oxide cloth. You can alter the finish by altering the speed of the tool. Any body who is interested in modifying cylinder heads could build themselves a flow bench cheaply, by using a vacuum cleaner and manometer and an adapter to sit the head on. You will not be able to measure the cfm, but you will be able to measure an improvement. And just to get you started, the most important parts on a fast road head are the valve seats and the short side radius. Basically building your own flowbench would teach you more about head modifying than reading all the books that's published.

This is a tiny bit of the information that i have gained in 20 years developing heads with the help of a superflow 110 flowbench.

ncoll

[Peetypug 5]

Ncoll

would you recommend me giving it to somebody that knows what they are doing?

or should i just have a play and see what i can make of it?

 

thanks damir

those pics are just what i wanted

i was going to do the same as the first pic of the inlet

then just remove any casting marks/sharp edges

 

thanks everybody

[NColl 0]

Ncoll

would you recommend me giving it to somebody that knows what they are doing?

or should i just have a play and see what i can make of it?

 

thanks damir

those pics are just what i wanted

i was going to do the same as the first pic of the inlet

then just remove any casting marks/sharp edges

 

thanks everybody

sorrentopete,

It depends what you want out of the cylinder head but, by all means do it yourself, because at the end of the day it can be very rewarding especially if you have got a few more break horse power.

ncoll

[joni 0]

sorrentopete,

It depends what you want out of the cylinder head but, by all means do it yourself, because at the end of the day it can be very rewarding especially if you have got a few more break horse power.

ncoll

 

I'm going to have a go at this tomorrow under the watchful eye of a master head tuner! I'm putting a Piper 270 in a 1.9 head. Removing casting imperfections from the head, removing the valve guides that are in the ports and radiusing off any sharp angles. The head is for a road rally car.

Was also going to play around with the valves too and get rid of any sharp angles depending on which way the air is flowing. Has anybody done any work on their standard valves?

[bales 1]

christopher, why does matching the exhaust manifold lose you power?

 

cheers

 

It helps to stop the exhaust gas being sucked back into the cylinder under vacuum during any overlap period. You are ideally supposed to match either the top or the bottom of the port to one another but leave a step at the opposite side.

[carbers205 1]

Yeah I forgot to mention about the short side radius (SSR) in my previous post. I found in one of my old 1.9 heads there is quite a sharp transition between the inlet and the throat so smoothing the radius there should see a reasonable effect.

I know Damir has 5 angle valves but dont know if he DIYd them. I got 3 angle valves and seats done but by a pro so they could be pressure tested afterwards. This seems to be a very important area to work on according to the various sites ive read.

I think it really comes down to how much you're looking to gain in terms of personal knowledge. I know these mods wont make a groundbreaking difference to power/torque/delivery but if you DIY you get the satisfaction of knowing you manipulated the engine yourself.

 

Andy

[DamirGTI 342]

Yeah I forgot to mention about the short side radius (SSR) in my previous post. I found in one of my old 1.9 heads there is quite a sharp transition between the inlet and the throat so smoothing the radius there should see a reasonable effect.

I know Damir has 5 angle valves but dont know if he DIYd them. I got 3 angle valves and seats done but by a pro so they could be pressure tested afterwards. This seems to be a very important area to work on according to the various sites ive read.

I think it really comes down to how much you're looking to gain in terms of personal knowledge. I know these mods wont make a groundbreaking difference to power/torque/delivery but if you DIY you get the satisfaction of knowing you manipulated the engine yourself.

 

Andy

 

Hi !

 

True , the short side radius is awful shaped on these heads - too sharp bend ...

 

We made the seats with an Neway tool (well my mate did this cos i don't have this seat cutting tool...) and he maid :

inlet - 15, 30, 45, 60, 75 deg.

exhaust - 15, 45, 60, 75 deg.

 

And yes , it's very important to do multi angle seats afterwards cos if not it'll spoil all (well not all but most ..) the work which you have done in the ports - if you want the proper job do the ports , chambers , remove the valve guides and fit new ones , do the valves (reshape and made a back cut) and on the end cut 3 angle seats (or more if you wish 4 or 5 angle ..)

 

Cheers !

Damir

 

Edited February 15, 2008 by DamirGTI

[brianthemagical 1]

just curious about these muilti-angle valve seats. as far as iw as aware, the idea of 3 angles is to optimise the seat width. add the extra cuts and not just round the rest of the seat (after the three cuts if needed), just ensuring the valve seat is left flat.