Porting. Break it down for me and ???
Thread Starter
Le Mans Master
Joined: Dec 2002
Posts: 5,270
Likes: 3
From: Seattle Area WA
Porting. Break it down for me and ???
Ok, so when someone says, you should get these heads ported.
What EXACTLY does it entail.
The reason why I ask is, I am looking at Dart Iron Eagle Platinum heads, they flow great out of the box. When I asked about porting he said most of the things you do when porting had been done so there is really no point. Now, if I eventually move to a 406cid I would like to keep the same heads and I figured that I could port them out and when the 200cc runners are more like 215cc or so, it wouldn't be a problem. So clarify what exactly porting is and how wrong/right I am about the intake runner size.
Thanks in advance!
What EXACTLY does it entail.
The reason why I ask is, I am looking at Dart Iron Eagle Platinum heads, they flow great out of the box. When I asked about porting he said most of the things you do when porting had been done so there is really no point. Now, if I eventually move to a 406cid I would like to keep the same heads and I figured that I could port them out and when the 200cc runners are more like 215cc or so, it wouldn't be a problem. So clarify what exactly porting is and how wrong/right I am about the intake runner size.
Thanks in advance!
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,444
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Porting - It is often broken down into parts. Bench flow testing with either hand or CNC porting can add up to $1000's.
The simple job done right from the Dart factory includes bowl blending and the ports are matched to a intake gasket size. That's what this person was refering too.
It's not like the stock head with ruff casting and casting flash in the mass produced stock heads anymore.
I would not buy iron heads ever again. I've put money into them in the past and they failed. They just can't handle overheating or the valves impacting pistons and getting wedged sideways in the port. You just kind of walk away and cry when they tell you at the machine shop that they have a crack radiating out from the exhaust seat.
Now with aluminum - Walk in with multiple broken valves and the seats ripped out of the heads and they say pick them up next week.
The simple job done right from the Dart factory includes bowl blending and the ports are matched to a intake gasket size. That's what this person was refering too.
It's not like the stock head with ruff casting and casting flash in the mass produced stock heads anymore.
I would not buy iron heads ever again. I've put money into them in the past and they failed. They just can't handle overheating or the valves impacting pistons and getting wedged sideways in the port. You just kind of walk away and cry when they tell you at the machine shop that they have a crack radiating out from the exhaust seat.
Now with aluminum - Walk in with multiple broken valves and the seats ripped out of the heads and they say pick them up next week.
Thread Starter
Le Mans Master
Joined: Dec 2002
Posts: 5,270
Likes: 3
From: Seattle Area WA
Ok, I totally hear you on the iron head thing. But the only other heads basically in my price range are Pro Toplines, and I would prefer to stay far away from them.
I completely hear you on the aluminium being repairable, but let me tell you, this is a street stroker. It will probably see a drag strip once and a few autocrosses every year, and probably rarely even get over 6000rpm. If I was building a serious motor, it would aluminiums all the way, however for this street machine, I think irons should be just fine. And for the price, I can't beat those platinum flow numbers.
As for the porting issue, I take it then I should be able to get more out these things besides their factory job?
I completely hear you on the aluminium being repairable, but let me tell you, this is a street stroker. It will probably see a drag strip once and a few autocrosses every year, and probably rarely even get over 6000rpm. If I was building a serious motor, it would aluminiums all the way, however for this street machine, I think irons should be just fine. And for the price, I can't beat those platinum flow numbers.
As for the porting issue, I take it then I should be able to get more out these things besides their factory job?
Cruising
Joined: Jan 2005
Posts: 11
Likes: 0
Simple porting you can do!
Take the intake manifold gasket and line it to the bolt holes. The intake can be slightly smaller than the head opening, (same is best, matched Porting). If the heads are smaller it will cause the flow to be disrupted or not flow smoothly. Look in the intake carb. or fuel injection for blunt obstructions and round them off.
Don't forget about the exhaust. It must get out! The exhaust manifold can be slightly larger than the head opening. You want Smooth and no obstructions.
On an emission car, some EGR valves require some back-pressure to function correctly.
Catalytic Converters can only remove so must NOx. The only reason you have an EGR is to remove the NOx.
Don't get crazy!
Take the intake manifold gasket and line it to the bolt holes. The intake can be slightly smaller than the head opening, (same is best, matched Porting). If the heads are smaller it will cause the flow to be disrupted or not flow smoothly. Look in the intake carb. or fuel injection for blunt obstructions and round them off.
Don't forget about the exhaust. It must get out! The exhaust manifold can be slightly larger than the head opening. You want Smooth and no obstructions.
On an emission car, some EGR valves require some back-pressure to function correctly.
Catalytic Converters can only remove so must NOx. The only reason you have an EGR is to remove the NOx.
Don't get crazy!
