Example of a good port job!

[killercolt]

The porting is very good. The combustion chamber could use a little more time.

I would not recommend cutting down the guide bossings or guides to much. Although the gain might be there, it is not worth that extra power. I have seen the head cracked under the spring seats from chopping out to much of the guide bossing. There is a lot of lateral movement in the valve stem during its travel. You can see the burnt mark on the stem on your old valves that indicate this lateral movement. I believe it is this lateral movement that can cause the head to crack or the valve to be unstable at high rpm. Thin out the area underneath the spring seat might cause the crack too.

When I see people cut the intake valve guides flush, they have major smoking issue upon deceleration at high rpm. I think the high vacuum at high rpm deceleration sucks in a bunch of oil through the valve stem seals. This problem might be cause by poor valve stability at high rpm. This might even cause boost leak through the valve stem seals too.

I can see where the exhaust guides were not cut down evenly. Next times ask for two sets of intake guides and use one set for the exhaust. The exhuast guides are longer than the intake guides. Using the intake guides on the exhaust side means you will get good valve stability with having to cut anything on the exhaust side.

See if he would debur the guides too. The pics above show overhang into the guides.

With higher lift cams now day, make sure to check spring retainer to valve stem seal clearance to. Don't trust the machine shop to drive the guides in deep enough. Failure to do so will result in torn valve stem seals or worst.

The tools to drive the valve guides are pretty cheap. You can do it your self. Air valve guides driver is 20 bux plug shipping from Goodson tool. The air hammer to be use with the tool is 35 bux from harbor freight. Heat the head in the pre-heat oven at 250-300 for 20-30min and the guides glide right out. You can relief drill it guides ease removal if you like. Going back in is a breeze. Measure and drive to the depth that you like and then take the head to the machine shop.

 

[keltalon]

The porting is very good. The combustion chamber could use a little more time.

I would not recommend cutting down the guide bossings or guides to much. Although the gain might be there, it is not worth that extra power. I have seen the head cracked under the spring seats from chopping out to much of the guide bossing. There is a lot of lateral movement in the valve stem during its travel. You can see the burnt mark on the stem on your old valves that indicate this lateral movement. I believe it is this lateral movement that can cause the head to crack or the valve to be unstable at high rpm. Thin out the area underneath the spring seat might cause the crack too.

When I see people cut the intake valve guides flush, they have major smoking issue upon deceleration at high rpm. I think the high vacuum at high rpm deceleration sucks in a bunch of oil through the valve stem seals. This problem might be cause by poor valve stability at high rpm. This might even cause boost leak through the valve stem seals too.

I can see where the exhaust guides were not cut down evenly. Next times ask for two sets of intake guides and use one set for the exhaust. The exhuast guides are longer than the intake guides. Using the intake guides on the exhaust side means you will get good valve stability with having to cut anything on the exhaust side. As far as the valve guides

See if he would debur the guides too. The pics above show overhang into the guides.

With higher lift cams now day, make sure to check spring retainer to valve stem seal clearance to. Don't trust the machine shop to drive the guides in deep enough. Failure to do so will result in torn valve stem seals or worst.

The tools to drive the valve guides are pretty cheap. You can do it your self. Air valve guides driver is 20 bux plug shipping from Goodson tool. The air hammer to be use with the tool is 35 bux from harbor freight. Heat the head in the pre-heat oven at 250-300 for 20-30min and the guides glide right out. You can relief drill it guides ease removal if you like. Going back in is a breeze. Measure and drive to the depth that you like and then take the head to the machine shop.

Stage 1 port job. Jerry wanted to get really wild on this head I would not let him because the setup isn't wild. I requested casting clean up , gasket match and valve pocket blend only on the intake side. Overall we ended up with improvement on a head that already flow exceptionally well from the factory which was the objective I am not a big fan of using the shorter intake guides on the exhaust side IMO they are made longer for a reason therefore I just leave them as be.

 

[keltalon]

Here's preliminary result of the head. also an updated link to the video

http://www.dsmtuners.com/threads/new-dyno-numbers-697whp-591wtq-bc272-pte6266.481097/

You must be logged in to view this image or video.

 

[92AWDHX40]

Big us had uncles fixing the jets, born 15 miles from warner robins good work, nice write up.

 

[JacksonAuto]

Whats the issue with cutting them down on these heads?

The shorter guide does not support the valve as well. The result will be accelerated wear of the guides and valve seats.

 

[keltalon]

The shorter guide does not support the valve as well. The result will be accelerated wear of the guides and valve seats.

Yeah he cut them down just for the porting purposes I replace them with standard length guides.

 

[keltalon]

Big us had uncles fixing the jets, born 15 miles from warner robins good work, nice write up.

wow! took me almost 3hrs to get to him. He live across from the big air force base.