porting the a20a3 head

[resendez]

i no i probably sound stupid but what exatly is a port and polish and how would i go about doing this on my own?

[stephensimmons]

i no i probably sound stupid but what exatly is a port and polish and how would i go about doing this on my own?

Uummm.......... Naw i wouldnt say that. Porting is making the intake and exhaust holes bigger to get more air flow to the engine and polishing is making it smooth to help the flow. And as for doing your own if your not careful you could ruin you head.

[Nio]

Uummm.......... Naw i wouldnt say that. Porting is making the intake and exhaust holes bigger to get more air flow to the engine and polishing is making it smooth to help the flow. And as for doing your own if your not careful you could ruin you head.

Yea I'm still new to some of this stuff.

But I know it will help with power.


>.> especially since I plan to do the B16 intake swap...

[mushroom_toy]

So technically I just need to port match the exhaust and intake sides to the mani gaskets right? For a little bit anyway?

[stephensimmons]

Yea I'm still new to some of this stuff.

But I know it will help with power.


>.> especially since I plan to do the B16 intake swap...

Yes it will

[stephensimmons]

So technically I just need to port match the exhaust and intake sides to the mani gaskets right? For a little bit anyway?

Yes. And also clean up the bowl aria down in the valve pockets

[mushroom_toy]

^Yeah probably not gonna go down that far. Gonna be doing this on a head already on my other block, so only prob gonn go down about an inch from the inlets and just do the ends of the inlets.

[Nio]

Yes it will

I've been meaning to ask this.

Will the Venom Intake be to big for our engine bay....>.> cause I was actually wanting to get the black venom intake and install it...but I'm not certain if it would hit the firewall.

[stephensimmons]

I've been meaning to ask this.

Will the Venom Intake be to big for our engine bay....>.> cause I was actually wanting to get the black venom intake and install it...but I'm not certain if it would hit the firewall.

That im not sure of.

[whitekight]

Are you going to get the head flow benched to even out the flow ???

I never used to but after i had it done i havn't gone back

[Tomisimo]

when you send your head for 3 angle valve job, ask them before, what tool do they use for this job, if they use some kind of stone grinder tool, look somewhere else. look for a shop that has mill for this, real metal tooling. stone age technology will ruin your head. well it never will be as good as it can be.

you dont polish intake side because it will interrupt air turbulence, you can polish it first to mirror like finish, then go over by hand with grinding cloth P80 or P120, in cross directions. same goes for the pistons, smooth mat surface will gain power, sharp edges on pistons disturb velocity of detonation. but the dome chamber can be mirror polished.

Good luck, looks like you have some balls to do it your self!! respect

[stephensimmons]

Are you going to get the head flow benched to even out the flow ???

I never used to but after i had it done i havn't gone back

No I'm not. atleast not this one. Im just tryna see what i can get out of all ome parts before I build another one. Even though that would help but my money isnt plentyful right now and im just building me a toy for my spare time.

[stephensimmons]

when you send your head for 3 angle valve job, ask them before, what tool do they use for this job, if they use some kind of stone grinder tool, look somewhere else. look for a shop that has mill for this, real metal tooling. stone age technology will ruin your head. well it never will be as good as it can be.

you dont polish intake side because it will interrupt air turbulence, you can polish it first to mirror like finish, then go over by hand with grinding cloth P80 or P120, in cross directions. same goes for the pistons, smooth mat surface will gain power, sharp edges on pistons disturb velocity of detonation. but the dome chamber can be mirror polished.

Good luck, looks like you have some balls to do it your self!! respect

I've ported 2 valve ford and chevy heads before just not the import ones. Besides everyone laughs at my car because its a 3g and not a 4g or newer and calling it a throw away car (meaning when it breaks you junk it!) BUT ima show them!

[rjudgey]

You need to find a machine shop with Serdi Valve seat cutter and preferably get the valves backcut to match the new seats that are cut.

You should clean up the ports and blend the throats with the seats before getting the seats cut as you may mark the new seats doing it after.

Also opening up the areas in the cambers around the valves and blending the roof into the valve seats helps big time but requires steady hand and some skill as well as the right dremel tools and some spare valves to use and masking blanks so you don't grind out the seats and damage them too much.

Also worth getting some SI valves bronze guides fitted they are cheap and fitting doesn't cost much, if you plan on running uprated cam stock guides wear out quickly.

On the exhaust port I'd look at reshaping the area around the guide as this is quite restrictive can give you good gains if done properly.

[lostforawhile]

I've been meaning to ask this.

Will the Venom Intake be to big for our engine bay....>.> cause I was actually wanting to get the black venom intake and install it...but I'm not certain if it would hit the firewall.

can you get them to measure the length? If i can fit this long ass SU manifold in there with air cleaners on the end, I think pretty much anything will fit, remember the engine is tilted forward so the intake can be longer due to the angle. if the engine sat straight up, the intake tubes would have to be much shorter.

[stephensimmons]

Im still working on this and there will be updates soon. Cash flow was held up for a good bit but work is still in progress!

[Sickest3G]

Thanks for those tips rjudgey i needed that cause i blew my head gasket a few weeks ago and since i have to take the head off i decieded to put in some work by adding some HP to the the new a20. I sent my camshaft to colt cams for a stage 2 triflow grind and i already customized the b16 manifold i had laying around waiting for an occassion like this. I'll be port matching the head and mani and port and polishing the intake mani and exhaust side of the head cause the intake is already done. I'll also be getting a 3 angle valve job and new "bronze" valve guides instead of stock ones thanks to your wise advice. So thanks again rjudgey...if you have any other tips on porting and polishing share it with me. BTW can you let me know where i can get these broze guides?
Here is the work I did to the head the first time around...starting at #17 https://www.3geez.com/forum/showthrea...ight=sickest3g

You need to find a machine shop with Serdi Valve seat cutter and preferably get the valves backcut to match the new seats that are cut.

You should clean up the ports and blend the throats with the seats before getting the seats cut as you may mark the new seats doing it after.

Also opening up the areas in the cambers around the valves and blending the roof into the valve seats helps big time but requires steady hand and some skill as well as the right dremel tools and some spare valves to use and masking blanks so you don't grind out the seats and damage them too much.

Also worth getting some SI valves bronze guides fitted they are cheap and fitting doesn't cost much, if you plan on running uprated cam stock guides wear out quickly.

On the exhaust port I'd look at reshaping the area around the guide as this is quite restrictive can give you good gains if done properly.

[rjudgey]

Ok I've read the thread, what pistons did you use when you rebuilt the A20A1 you do know they have a lower compression as std? the inlet ports are ok you've done the basics, clean up and blend throats to the seats, but the seats themselves they are way too big! there is barely a 60 degree cut on the seats from the width of those, their worse than stock seats which are quite nicely cut in the first place. I'd have them redone preferably by someone who knows there stuff as clearly last place didn't! Max seat width should be 1.5mm but 1mm is better for performance but you'll only get say 50-60k miles out of em, 1.5mm will last 100k miles or more. The valves also need to be backcut to match the new seat width if you leave them stock you are just robbing the engine of a extra untapped power. Where you can try and unshround the chambers around the valves, and blend the roof down to the same level as the seats so there's a smooth transition from seat to roof with no edges. Also get the head skimmed a little could be a bit warped hence the blown gasket and check the deck for flatness as well. If you take off 1mm from the head will increase your CR ratio.
The bronze guides you can get really cheap from SI valves and it's worth reshaping the exhast ones and reducing the size of the guide ramp in the exhaust ports too.
I bet you gained a lot of power when you changed out that exhaust from rusty old stock pipe to 2.25" all the way through!!

[Sickest3G]

The pistons are stock. got new rings and bearings. I'll be taking care of the wide seat with a basic 3 angle valve job. I reseated the valves myself due to a shortish in funds and time but will be done right this time by a shop that knows their stuff. The head was shimmed last time too but i'll be getting another .5 or so taken off along with the rest of the work to the head at the shop. But i'll be porting and polishing before i send it in. In order to reduce the size of the guide ramps, I would have to have them taken out first right or wrong? Yeah the engine breaths much better now with those pipes and sounds so mean. I intimidate others just by reving it. I cant wait for all these new mods to come together.

[rjudgey]

Will sound even better if you stick in some bigger valves and get those exhaust ports sorted out! :0)
You need to have the old guides taken out, and the new ones fitted then do the work, you could do most of it then have the new guides fitted but you'll have to grind them down afterwards still as they'll be sticking out loads! Definately worth having them put in though, as for the camshaft choice not sure if it's best with colt think the Bisi grinds are better for performance, but the colt ones are best if you want good fuel and nice streetability. Might be worth having another one done and you can see what the differences are like.
I run a 272 degree with just 10mm lift and the engine really likes this runs smooth at idle and lots of low end and midrange top end power peeks at around 7000rpm but pulls cleanly to 7500rpm, the 285 degree with 10mm lift idles a bit lumpy but not that bad, looses a bit of low end and hit's 4k and pulls like a train to 7500rpm peak and goes to 8krpm easily after that!!
At the moment running big valves, custom downpipe with ported cast manifold, and need some more work around the exhaust ports as I had to rush it to get the engine running again, so I think I still have room for improvement on this setup, I also have a A18 head with bigger better shaped valves and better exhaust port setup this for sure would be giving me good numbers too. But what I'd really like is to get a ET1 head and block up and running again as this is the best head for our cars as it combines high compression with ideal port size and shape. For me this is more feasable but for you your kinda limited to A20. Also worth ditching your flywheel for something lighter like Prelude A18/ET flywheel machined down to 10lb and clutchnet clutch with a nice disk and red pressure plate. Or maybe look at clutchnet ally flywheel for A20 and clutch kit too. not sure howmuch that weighs in at, if you do a lot of traffic driving then having a slightly heavier clutch is a good thing.