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Guest Message by DevFuse

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Ea81 and Ea82 head porting.

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13 replies to this topic

#1 Jerry DeMoss

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Posted 14 December 2005 - 09:15 AM

I would like to know if someone knows how important that little runner is on the intake side of the ea81 and ea82 heads.I have taken that out when porting a ea81 engine that I had in a hatch I used to own, and it ran like a monster.I just wondered how much that would decrease my port efficiency if at all.I just thought I would see if anyone has experience with that.Also I have no way of testing it as I don't have a flow bench to test it on.But my overall thought is that the effiency shouldn't be hurt that much as there is a great increase in volume of air with making the ports larger.Someone let me know what you think. Thanks for reading my post.:)

#2 soobscript


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Posted 14 December 2005 - 12:03 PM

Are you talking about the cast line in the intake area that runs with the flow?

I guess I can't really help, since I have no experience in the matter. But... I would grind it down.

Hmmm... someone with a flow bench and spare parts (and spare time) should test out the best porting method for our heads.

#3 Jerry DeMoss

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Posted 14 December 2005 - 12:08 PM

Are you talking about the cast line in the intake area that runs with the flow?

Yes that is the one that I am refering to.I guess I should be a little more specific.

#4 Jerry DeMoss

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Posted 14 December 2005 - 02:14 PM


#5 Ross


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Posted 14 December 2005 - 03:32 PM

I doubt it would be doing much, as far as i can remember the ports are symmetrical? If so, the flow should split properly without it.

Just remember - when it comes to porting, bigger is definitely not always better!

#6 BoostedBalls


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Posted 14 December 2005 - 06:53 PM

I just ported the heads on my EA82T and I know the ports are not symetrical.

Unless you are turning insane RPMs, I would remove only small amounts of material in areas that protrude into the direct flow. I grinded down the areas under the intake mounting holes. I took a course sanding wheel to just knock off the casting flash and give a smooth transition. I also matched the intake and gaskets also. The key factor to remember is that VELOCITY makes power. That mixture needs to blast into the chamber with some serious motion. Too large of port will only slow this down. Your cam needs to match your ports, you will throw away power if they don't match. I'm running stage 3 cams and I'm still on the conservative side with my porting. Seen too many people open ports up wide only to find out that their engine doesn't do crap until the RPM comes up; by then the race is already over.
Usually. people do more harm than good when porting heads. A good 3 angle valve job can give you excellent results with a stock port.

Rule of thumb- remove material only in the narrow areas, and only remove a small ammount if you have no flow measuring equipment.

#7 coronan


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Posted 29 October 2014 - 08:40 AM

Have before and After pics of your port job?

#8 coronan


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Posted 08 December 2014 - 09:05 PM

I've been searching but unable to find pictures of port jobs before and after.  

It must be a well guarded secret.  


Any one got a pictoral?  

How to?



Its not hard just time consuming.  Anyone wiling to share their mistakes????

#9 ferp420


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Posted 09 December 2014 - 09:02 AM

im woundering about that to i just took the ruff edges off the it because it sticks in to the intake and leaves a big sharp edge i dont know about taking it out completely im in the preping stage for a full reseal of my motor and am practicing my porting of the heads and intake manifold in also fabing up some intake spacers and a throtle body spacer in hopes of geting to the torque sooner

#10 coxy


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Posted 27 December 2014 - 06:06 PM

Look up Pocket porting namely the area just before the valve seat that is where you pay the most attention as it will give about 80 percent of the benefits power wise, with such a long and not very efficient intake runner actually opening up the throat of the port will likely be of academic benefit unless like some of the Airplane or Gyro people you make a totally new intake manifold and run twin carbs above the heads.


As for flow benches they can trap people very easily as you can port to get better numbers and lose real power because of poor mixture mixing and fuel dropping out of suspension, The real standard these days is what is known as a "Wet" flow bench look it up and see what I mean, An older dry flow bench is only as good as the person using it who has decades of real world knowledge.

#11 hatchsub


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Posted 28 December 2014 - 01:58 PM

My former ride had ported heads that i had a local shop do for me.  If i remember right he did not remove too much material.  HIs goal was to smooth any transition area such as under the valves and any corner and smooth the walls everywhere.  He also did a 5 angle valve job and shaved .030 off each head to up the compression.  That motor moved out pretty well for itself even without a aftermarket cam grind.  I did however have a tuned weber for that combo as well as a true 2" exhaust the whole way back.


As for that rib i think he removed most of it if not all of it.   

Edited by hatchsub, 28 December 2014 - 02:01 PM.

#12 ferp420


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Posted 29 December 2014 - 06:05 PM

the intake has a swirlie type thing in it im removing that also im thinking the swirlie thing and the big fin thingie would contradict each other why swirl the air right befor the head only to use the fin to redirect the air im leaving the short side of the manifold ruff to get a tumble affect befor the head im only guessing though it would be nice to see some pics and something more than a guess as to how they work or not

#13 scubaroo84


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Posted 30 December 2014 - 03:11 PM

I ported and polished my heads on my turbo ea81 build. I just smoothed any casting flash in the intake runners I did the majority of the work in the exhaust. I opened the exhaust ports a ton and gasket matched them. With a stock rhb5 turbo and a weber it would spin the stock tires in second gear if you punched it around 25mph. That was also before tuning and not havin enough fuel. Haven't driven it in awhile with the 235's on it as I've been doing wiring. even before the turbo was installed it had more balls than stock.

#14 nncoolg


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Posted 31 December 2014 - 03:37 AM

this thread covers EA82T or MPFI heads, but it may help...





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