Would you port/polish the head yourself if you had the tools?
- Thread starter tte
- Start date
No.
You have the tools already, sand paper and a drill..
Why I wouldn't attempt it myself?
FLOW.
Most of your high performance head companies FLOW PORT the heads, just not sit there and grind away.
FLOW BENCH IT.
You have the tools already, sand paper and a drill..
Why I wouldn't attempt it myself?
FLOW.
Most of your high performance head companies FLOW PORT the heads, just not sit there and grind away.
FLOW BENCH IT.
thats what I meant, if I had the ability to flow test it and such, I would go for it w/out thinking twice.
sometimes the flow bench can just tell you "oops, you fucked up" Tools are one thing but the ability is another. IMO if you have to ask the question, dont do it. You can safely portmatch it pretty easy, but if you have spent the dough to outflow the head and need a port job, then spend the dough on someone that knows the 7m head.
No I would not. I do not have the experience, flow tools etc to tell how the porting went; or even what in the world I'm doing anywho.
I would, but that's only because my dad has done porting and polishing before. He hasn't done it to a supra, but he's done it on heads to a 454 big block. 
Our heads have a great port design to start with so any port work is just cleaning up what's there and blending any sharp edges (Yamaha know what they're doing)
There are no glaringly bad areas so there's not a lot to be done.
Even the short turn radius is good so I'm confident I won't be making it flow worse than stock and I'll make a series of go/no go gauges to help keep it uniform from port to port.
There are no glaringly bad areas so there's not a lot to be done.
Even the short turn radius is good so I'm confident I won't be making it flow worse than stock and I'll make a series of go/no go gauges to help keep it uniform from port to port.
Good head porting guide here
http://www.sa-motorsports.com/diyport.shtm
You can buy tools on the same site
I would not do real porting myself, too easy to f~ck up the head
Vladimir, 89T
http://www.sa-motorsports.com/diyport.shtm
You can buy tools on the same site
I would not do real porting myself, too easy to f~ck up the head
Vladimir, 89T
Adjuster
Supramania Contributor
I ported my head, and ended up removing quite a bit of material around the valves, and the valve guides on the exhaust side.
On the intake side, it was mostly to clean up the machine work, and smooth out the casting marks as much as posible w/o changing the shape too much.
Seems to have worked as my tourqe numbers are better than ever.
Here is what I've done.
1MM over size stainless valves from enginebuilder on Ebay.
Had the valve seats cut, and then I went in and very carefully removed material to further open up the valve seats, and blend them into the runners. I also blended the combustion chambers, and removed sharp edges to help with flow in and out of the runners past the valves when they are open.
I left a 1mm lip on the exhaust to the gasket. I then opened up the exhaust manifold about 1mm more than the gasket opening to restore the "lip" that was designed into the 7M head, yet allow for more flow on top.
On the exhaust side, I removed the post around the valve guides. They are completely gone, it's basicly a flat area with just a hole now. The valves are under cut, so they help with flow too.
On the intake side, I just blended the valve guide posts since there is plenty of flow avialable on the intake side I think. (Especially under pressure.)
I used BBC inner valve springs, and stock hardware other than the valves.
So far I have much more tourqe than ever, and it runs great.
I'd do it again If I was building another 7M engine, and I'll do this on any engine I build in the future, (Even a lawn mower can benefit from better flow since really all engines are is glorified air pumps run on burning hydrocarbons.) The more air/fuel you can pump, the more power it's going to make.
On the intake side, it was mostly to clean up the machine work, and smooth out the casting marks as much as posible w/o changing the shape too much.
Seems to have worked as my tourqe numbers are better than ever.
Here is what I've done.
1MM over size stainless valves from enginebuilder on Ebay.
Had the valve seats cut, and then I went in and very carefully removed material to further open up the valve seats, and blend them into the runners. I also blended the combustion chambers, and removed sharp edges to help with flow in and out of the runners past the valves when they are open.
I left a 1mm lip on the exhaust to the gasket. I then opened up the exhaust manifold about 1mm more than the gasket opening to restore the "lip" that was designed into the 7M head, yet allow for more flow on top.
On the exhaust side, I removed the post around the valve guides. They are completely gone, it's basicly a flat area with just a hole now. The valves are under cut, so they help with flow too.
On the intake side, I just blended the valve guide posts since there is plenty of flow avialable on the intake side I think. (Especially under pressure.)
I used BBC inner valve springs, and stock hardware other than the valves.
So far I have much more tourqe than ever, and it runs great.
I'd do it again If I was building another 7M engine, and I'll do this on any engine I build in the future, (Even a lawn mower can benefit from better flow since really all engines are is glorified air pumps run on burning hydrocarbons.) The more air/fuel you can pump, the more power it's going to make.
my 7m head has had a ton of material removed from the exhaust side. thats the side that need sthe most attn. the intake is almost gasket matched stock. just port match it and clean it up and unshroud the valves. then the exhaust, it has alot that can be removed to improve the flow. ill take plenty of pics of my 7m head when my friend dave is done with it. he did the 5m head im using on the carbed 3.1 im building. im also going with 1mm os ss valves and comp cams valve springs. havent decided on the lift of the cam yet. i have decided on a 264 deg duration though. im thinking 9mm might be pushing it for the shim over bucket setup. and have found reports that the hks 264 cams were ~8.1mm lift. anyhow. i say go for it. as long as you dont go crazy and keep them as even as possible itll help.
william
william
I would, but I would jus gasket match the intake and exhaust ports. As well as the intake and exhaust mani's to match.
In fact, Im prolly gonna do it here pretty soon.
Any major, or "real" porting, such as around the valve area, I would NOT do myself. Ive heard many stories about people doin it themselves and gettin WORSE flow. Not cool.
In fact, Im prolly gonna do it here pretty soon.
Any major, or "real" porting, such as around the valve area, I would NOT do myself. Ive heard many stories about people doin it themselves and gettin WORSE flow. Not cool.
Bigdough666 said:
Do not port match exhaust ports. Head port supposed to be smaller than manifold's. This is anti-reversion dam.
Vladimir, 89T
Yes you can port the head yourself. I bought the standard abrasives kit and read their website article several times. The main thing to remember in porting is that a tube (ie port) will flow faster if the exit is slightly smaller than the entrance. This will keep up velocity. So for the intake port the entrance at the intake manifold is larger than the exit at the intake valve. If you remove too much material around the valve (which is called the bowl area) you could slow down velocity and hurt flow. There is a lump under the valve seat that can be blended in the bowl and will really help low lift numbers. My low lift numbers nearly doubled with my port job and top flow increased a lot.
Also you need to make sure that all ports are the same size at the same distance into the port. You can measure the ports with T bar gauges at various depths. You also need to smooth out the intake before the injectors mirror smooth and after the injectors to about 80 grit as per the SA website. The exhaust ports can be 120 grit smooth.
The exhaust ports do NOT need to be port matched. The exit needs to be smaller than the entrance at the valve seat. One reason already stated is for a reversion dam which is important for a log manifold like our oem manifold. Also when the exit is smaller on the exhaust port this will keep velocity up. So if you open up the port so it does not reduce you will hurt velocity and flow.
I also polished the chambers smooth but i had my chambers and exhaust ports coated by swain tech. I had to make sure to match the volume in each chamber to be the same cc volume.
I will try to post some pics. One pic is the intake ports and you can see the step under the valve seat which is removed in one port. Another pic is the finished chamber and bowl. the last pic is the coated chambers and valves.
Also you need to make sure that all ports are the same size at the same distance into the port. You can measure the ports with T bar gauges at various depths. You also need to smooth out the intake before the injectors mirror smooth and after the injectors to about 80 grit as per the SA website. The exhaust ports can be 120 grit smooth.
The exhaust ports do NOT need to be port matched. The exit needs to be smaller than the entrance at the valve seat. One reason already stated is for a reversion dam which is important for a log manifold like our oem manifold. Also when the exit is smaller on the exhaust port this will keep velocity up. So if you open up the port so it does not reduce you will hurt velocity and flow.
I also polished the chambers smooth but i had my chambers and exhaust ports coated by swain tech. I had to make sure to match the volume in each chamber to be the same cc volume.
I will try to post some pics. One pic is the intake ports and you can see the step under the valve seat which is removed in one port. Another pic is the finished chamber and bowl. the last pic is the coated chambers and valves.
