Polish and port, take 2

[John]

Flash, sounds like you did what too many of us do on our first porting, most don't know they lost ground, or admit it. The first head I did, I ended up tossing. It also made power on top and I needed it down low. Most people should not redesign a heads flow path. Significant improvements can be made by proper gasket matching, cleaning up the castings rough areas, removing the ridge in the pocket and cleaning the bowl, after that find someone with a flow bench. Rule of thumb for stage 1 and 2 porting, if you are getting much cuttings, you have goofed up.
John

[Flash]

this is how much filing i colected from my Renix 4.0L porting, and that was with a lot of grinding in the bowl area due to a BAD Core shift smack dab in the middle of the bowl.

NOTE: this would be way over board porting for the first timer and would cause pore flow!!!!!!........even with a bad core shift as mine was.!!!!

head porting and push rod inlargeing003.JPG

MOST OF THIS WAS FROM INLARGEING THE PUSH ROD HOLES SO THE LIFTER COULD BE REMOVE WITH OUT REMOVEING THE HEAD
Flash

[SilverXJ]

And that is why I am asking so many questions, so I don't screw up!

[John]

You are doing far better than I did. Make haste slowly.
John

[gradon]

I got rid of all casting flash(except right around the seats, as I didn't want to damage them), edges, and seams. I have to put another 2-3 hours into the head's intake ports to match the gasket and intake. I am tempted to polish the outside of the IM(like the one Mark just got), but I bet it'd take another 8 hours to do it.

[SilverXJ]

Made some more progress today. I got rid of the remaining casting form the valve guides on the exhausts and feathered the intakes some more. I'm down to the 80 grit rolls on the exhaust side. What grit should I stop at on the intakes? Some people have told me 40 grit, others 80. I've been pretty careful not to touch the valve seats, but I did hit them a few times.. not too deep, but I will be getting a valve job anyhow. As for the casting that went up to the machining under the valve seat I flattened that out a bit. I figured that it was only on 3 of the intakes and the others weren't that way.. just made them all match.

Oh yeah, and Flash, I took a look at the push rod holes in the head, and i really didn't see any coolant passaged that close to them. It seems that you just have to be careful not to go into the vertical portion of the head that borders them. Was that what you found?

[Flash]

Made some more progress today. I got rid of the remaining casting form the valve guides on the exhausts and feathered the intakes some more. I'm down to the 80 grit rolls on the exhaust side. What grit should I stop at on the intakes? Some people have told me 40 grit, others 80. I've been pretty careful not to touch the valve seats, but I did hit them a few times.. not too deep, but I will be getting a valve job anyhow. As for the casting that went up to the machining under the valve seat I flattened that out a bit. I figured that it was only on 3 of the intakes and the others weren't that way.. just made them all match.

Oh yeah, and Flash, I took a look at the push rod holes in the head, and i really didn't see any coolant passaged that close to them. It seems that you just have to be careful not to go into the vertical portion of the head that borders them. Was that what you found?

You need to take a real good look at them, you are going to more then double the diameter of it, and the hole MUST be ground off set to stay out of the water jacket.........take another look at the pic i put up, if you are going to do this.

If you do find a water jacket, the head is now JUNK. It can be done but slow and carefully.


flash

[SilverXJ]

After about 32 hours I have the intake and exhaust are done. The exhaust was polished and the intake was stopped at 80 grit. I think the results are pretty good. The cross buffs that came with the kit are pretty useless as they are too larger for the Jeep's exhaust ports. I ordered some 3/4" ones and they are a perfect size.

I still need to do the 5 remaining combustion chambers. I decided I won't be de-shrouding the exhaust valve as after tracing the gasket onto the head I really don't have that much room for de-shrouding before I hit the gasket. You can some what see the scribed line in the first image below.

Any tips for getting into the light space in the combustion chamber? The rolls seem to what to disintegrate when they hit the base casting.

Anyhow, let me know what you think. Some pics below and the rest are here: http://jeep.blackonyx.net/forum/pnp3/










Oh yeah... about my combustion chamber measuring episode... paint thinker and acrylic don't mix well.. one dead buret and no measurement.. long story short: started with some tranny fluid and alcohol.. they didn't mix very well... so I used some tranny fluid and paint thinner... but didn't think ahead to realize that the paint thinner was going to melt the acyrilic buret. In goes the fluid... some drips down the side.. interesting... the graduations are moving down.. and its fogging.. oops. Oh well

Two questions on that.. 1) what size should the hole in the plexi be and 2) what do you use for the fluid?

[Flash]

After about 32 hours I have the intake and exhaust are done. The exhaust was polished and the intake was stopped at 80 grit. I think the results are pretty good. The cross buffs that came with the kit are pretty useless as they are too larger for the Jeep's exhaust ports. I ordered some 3/4" ones and they are a perfect size.

I still need to do the 5 remaining combustion chambers. I decided I won't be de-shrouding the exhaust valve as after tracing the gasket onto the head I really don't have that much room for de-shrouding before I hit the gasket. You can some what see the scribed line in the first image below.

Any tips for getting into the light space in the combustion chamber? The rolls seem to what to disintegrate when they hit the base casting.

Anyhow, let me know what you think. Some pics below and the rest are here: http://jeep.blackonyx.net/forum/pnp3/










Oh yeah... about my combustion chamber measuring episode... paint thinker and acrylic don't mix well.. one dead buret and no measurement.. long story short: started with some tranny fluid and alcohol.. they didn't mix very well... so I used some tranny fluid and paint thinner... but didn't think ahead to realize that the paint thinner was going to melt the acyrilic buret. In goes the fluid... some drips down the side.. interesting... the graduations are moving down.. and its fogging.. oops. Oh well

Two questions on that.. 1) what size should the hole in the plexi be and 2) what do you use for the fluid?

Lookin pretty
I used plain old water. If you add a touch of red food dye would help to be able to see it better.
the entrance hole should be the just large enough that the tip of the buret will fit in it. the air exit hole could be the same or slight larger.

If you put a small layer of grease on the valve/ seat surface you can do your testing with out installing the valve spring.
One note of caution, look inside the port before you right you cc down for that cylinder or combustion chamber.

Flash

[John]

Good work!!!!! I use the tapered rolls for the transitions of the walls to the valve seat area, slow light touch, don't run your rpm as fast. And yes as flash commented water works about the best for cc'ing. Food coloring is about a necessity. Definately use Vaseline or grease under the valves and the glass cover to help keep the water where you want it.
John

[SilverXJ]

More progress. I have 5 of the 6 combustion chambers done in 80 grit. One polished up (seen above) I saved the last one for when I cc for a base line. One thing that has been bothering me... do other head gaskets have different "bores"? I have the Mopar performance one and I don't see how anyone could unshroud an exhaust valve... there is just not enough room.

-Chris

[Flash]

More progress. I have 5 of the 6 combustion chambers done in 80 grit. One polished up (seen above) I saved the last one for when I cc for a base line. One thing that has been bothering me... do other head gaskets have different "bores"? I have the Mopar performance one and I don't see how anyone could unshroud an exhaust valve... there is just not enough room.

-Chris

It would be nice to know if there was...........But i would bet that there all the same.
Would probably have to go to a custom soft copper one to accomplish that.

The issue with the exh valve and the combustion chamber, is one of the reason why its been said, that the flow drop off a lot after .500 lift...........the other problem, you have already fixed.

The newer head must of address the shroud issue better because, my Renix head had........probably around a 1/32 to 1/16" before the head gasket suffice.

I thing Your head is going to flow well.

Flash

[gradon]

Yeah, I unshrouded my exhaust valves a little too much so I'll have to remove a little (like 1/16") from the head gasket so that it won't be the hot spot in the CC. That was the part where I feel I effed up on my first port and polish job. Compared to yours, my exhaust ports are larger and more round and my intakes are a little larger as well. You might have removed a little bit more of the casting flash right around the valves in the cc, but hopefully didn't hit the seats as much(why I held back a lil).

[SilverXJ]

A nice fellow forum member sent me some junk valves to protect the valve seats while working on the chamber. I have however lightly hit the seats with the sanding rolls like 3 times.

[John]

Duct tape can be used to advantage while working in that area, a single layer is not a cure all, but it is surprising how often the tape will peel up or off and protect the surface below. Those heads should do you well.
John