I am planning on porting a set of e7 heads soon. I read the main problem with them is the thermactor bump in the exhaust. I am under the understanding that it is a ball of metal in the exhaust port. I was wondering if anyone had a pic of it and any more tips on porting the heads. Thanks for any help
you cant miss it. its on the roof of the port. dont remove material from the floor of the port. concentrate on port matching to your header or exhast manifold. use a gasket layed over the port and over the manifold to see what lines up and what doesnt.
Check out this site.I just got done porting my gt40's,using some tips/tricks from there.All kinds of good info. http://www.diyporting.com/
thanks a lot, it seems like I will be able to do a lot to these heads without spending a lot of money
I did mine, it gets pretty messy!! Standard Abrasives makes a good kit, and it comes with good instructions too.
Last pr.of e7's I did,I had roughly 27-28 hours in them.Lot of time,but worth the effort.With some work,the e7 isn't a bad flowing iron head.
I don't think it was 30 hours, I removed the bumps, cleaned up the exhaust ports, and slightly smoothed the intakes, and reshaped the bowls.
The most beneficial work can be done in a couple hours. Without a real expert or a flow bench you can hurt the flow.
Remove the bumps, open the roof and walls to match the header gasket, leave the floor alone, along with the short side radius. Bowl blend the area under the valves. Then polish all the surfaces. On the intake sides, just bowl blend the area under the valves and port match the ports to the intake gasket. Then polish the chambers, smoothing any sharp edges. When all is done, take em to a good machineshop and have a valve job done. My first set took a couple days, now i can do a set in a day. You'll need a good compressor and die grinder and a set of long carbide bits in addition to a port/polish kit
Yep, what he said. Done a few sets over the years. First set I did was under supervision of an old circle track racer around here by the name of Tom. Kind of like a giant Santa with hands as big as baseball mits. He had heads cut up to view the thin spots to avoid. Spent about a week of evenings at his place doing the porting and cutting for bigger valves. They went on my first Mav. Good times. I have a heavy duty electric Makita die grinder. Snapon carbides since he warrranties them for me if they chip. You can pick up porting kits with all the sanding goodies to polish for around 40 bucks up here. Carbides range in price. The cheap ones dont last long.
A note: Be very carefull porting GT40 P heads. They flow more air stock than the E7 do. You will find the exhaust ports are smaller but that dosn't mean they flow less. The exhaust port shape is different and is where the factory found the flow was improved as well as reshaping the combustion chamber. Porting these may screw them up of you don't know the background on them.. Also there is water jacket around the valve stem that is not present in an E7 head. You have to know not to cut metal away in these areas or you ruin a head. There is no air injection ports or humps to grind out. Also the spark plug type and angle changed and causes header issues. These heads were an attempt to improve the 5L motor just before they were phased out in 2002 in favor of the 4.6L DOHC motors.
The P heads are the ones that I spoke of. They have the reshaped chambers and exhaust ports and plug direction.. I have them on a 5L motor and done the research on their airflow and porting. The earlier 40s are not the same.
