heres the previous thred, for anyone who's intrested in seeing my progress. http://thirdgen.org/techbb2/showthre...hreadid=323011 I took a real long break on these from being under the weather and loosing all motivation to complete this project. My funds are real low, i've been saving for machine work on the block and heads. These will be cut for 1.94 intakes before the valve job. I purchased SS undercut valves for these. they'll have comp 981 springs, that i have, with hardened retainers and locks. If i had the cash i'd go with better rockers, but im using the stock ones for now. Some work is still left here, i'm still needing to sqaure up the common wall some more and also needing to surface them. I'm also going to straighten the sweet spot on the combustion chamber wall's too and unshroud the intakes a bit more. The exhaust needs a little touhing up too. I hope i got this engine together by spring, it should be pretty sweet when its all done. here we are so far;

more;

more yet;

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last one

Nice work.

Make sure you read this thread as it has dyno results by Dewey316 on a set of ported 416 heads on a cammed 305.

Looks good so far. They should work well for ya.

Thanks you two

Id like to see how well Dewey316 ported his 416's. if i recall he said he worked mainly on the exhaust ports. theres a lot of potential in the intake ports and bowls too.


How do the bowls look, FBIRD? I've considered them done, but would like to here more opinions aswell.

Would it hurt anything to leave the carbide cutter surface in the intake ports and just finish and polish the exhaust and combustion chambers? My SA kit says to finish the intakes with 80, then 40 grit rolls. But the AFR heads ive seen have rougher finishes then the carbide cutter left, in the intakes.

Im still wanting to fill in those viods under the rockers, inside the intake runners, what type of epoxy should i use? jb weld?

Don't use JB Weld, use Devcon.

You've got the bowls above the valves opened nicely. From what I can see of the short radius in a couple of the photos, the intrusion of the castng has been knocked down enough to permit good flow. It's hard to see how much the port roof might be raised, but it looks uniform.

If you are asking about the holes in ther intake runners under the rocker studs, I'd be wary of any epoxy type fillers or plugs in there. Whatever you lay in could potentially end up dancing around in your chambers. I have no empirical evidence to support it, but my gut feeling is that the 3/8 hole is not going to impart enough turbulence to impede flow significantly. Many heads came with that hole, and perform well.

Using stamped rockers is not a problem so long as the stud slots are long enough to accomodate the valve lift without binding. It's a bit of a safety factor, since they will flex and limit some of the valve lift. Once it's up and runing, you may want to change to decent rockers to take full advantage of your cam's profile, but for break-in it's a little like using softer springs.

From what I can see in the pics, the bowls look good.
The 40grit work is just to get rid of any choppyness in your work. The appearance or smoothness is secondary.
I like using a rat tail file in a drill to straighten out the port wall and roof. And straighten out the ports corner radii. The more you raise the roof , the better. Within the limitiations of the intake manifold port opening you'll be using.
Obvoiusly a single plane manifold will like a raised port roof more than a dual plane.
Filling in the void in the roof of the port is worth about 6-8cfm
But like stated above you run the risk of haveing the epoxy come loose. Its critical to get the port clean of any carbon and grease and hot tank reside for the epoxy to stick. JB weld is not going to cut it. if you do want to fill the voids in the port roof use a quality A+B epoxy like sold by Edelbrock or Por15.
Ya get what you pay for.

Can you post some pics of the exhaust port and bowl?

It's a gratifying experience, isn't it?

looking great! I'm doing a set myself, yours look a little better so far.

I think you were a little more agressive at material removal than i was so far. Looks like i'm going to remove some more casting flaws and work on the common walls some more on the intake side.

Looks good so far. The bowl work is great. The next biggest gain to be had after a 3 angle valve job and bowl work is the area next to the push rod. Two things can be done here. First the common wall between the two adjacent intake runners can be thinned out to about .060" directly opposite the push rods. Second grind as much off of the push rod side of the port at the push rod as you dare without breaking through. On my stock car motor I actually epoxied brass tubes in the head where the push rods go then ground out the intake runner adjacent to the pushrod until i just touched the brass tubing. A bit extreme but that is where the power is.

Installing the brass tubes is quite involved but incase you are interested this is how I did it. assembled heads on motor and installed old cam and push rods. filled up pocket in heads where push rods go thru with JB Weld epoxy. Let it cure removed heads and removed push rods from epoxy. then I drilled out the epoxy using the hole left by the push rods as a guide. next I cut brass tubes to length and flared one end coated them with epoxy then inserted them in the head and flared the other end. After that was done I was able to port the head until I just touched the brass tubes with the die grinder.


Ric

Thanks for the tips and encouragement you all.



I spent a good 3 hours working on them today and i think that one of the intake ports is completely finished. I'll get some photos of it soon.

I took a rat-tail file to the corners and worked it by hand to square them up (thx for the idea FBIRD). It works great if you dont mind some manual labor. Once it got a rough finish in the corners, i took 40 grit cartridge rolls to the corner surface, then the carbide cutter, followed by the 40 grit again. This system leaves you with a really nice, smooth, corner radi.

The exhaust still need some work, next i'll be streamlining their valve guides more and opening up the area around them some. Do the exhaust ports benefit from port bais like the intakes do? The seem offset slightly from the factory. i'll get photos of them soon.

I'm trying to hurry and finishes these so that i can get to the track when it opens this year. I have everything for the engine except the heads complete. Its hard going right now, though, because i dont have a garage to work on them in and the weather hasnt been very cooperative.

ok heres some photos of the "finsihed" intake port. After blowing all the metal shaving out i can see some spots that need to be shaved with cartridge rolls. its about a whole 5 mins of work so probably not even worth mentioning.

I took some more photos of the bowl, because i got the common wall pushed back even more, after straightening it up to the runner. But the photos didnt turn out too well.

anyhow, here you go.. sorry for the crazy lighting

another

I actually snap the end off the rat tail file and put it in an electric drill. Just not that much into "manual labour" I guess.

Any tips on doing the exhaust?

They look pretty straight-forward, but i dont like working off assumptions when i dont have to. From what i can see the valve guide needs worked heavily and the short side radi need a lot of smoothing, a lot so where the crease of it meets the walls in the bowls.

Am i on the right track here?


I wish i had an electric drill, FBIRD, all i have is a battery powered semi-worthless one. The file i found really useful for doing the corners by hand, though, was a thin trianglular shaped one chucked in a interchangable head screw driver. I actaully ran this in the die-grinder for a while (on lowest RPM) before i got impatient and put to much pressure on it and broke it.

Ive pulled all but 1 rocker stud so far (stripped bad) and i'm tapping for mr gasket collarless screw-in studs. I was thinking of not fooling with the rocker studs, but the xe268 cam may have its way with them if i dont. better safe then sorry the way i see it.

The most important thing when doing the exhaust port is the venturi directly under the exhaust valve. You want the small/choke diameter to be about 90percent of the valve seat diameter. Then a nice smooth radius that goes from the valve seat to the choke diameter and back out to the port walls. It is tempting to make this too big and loose the venturi effect. But all past wisdom says that the venturi is critical to optimum flow.

Ric

ok need some advice on the combustion chamber work.

heres how this 305 head's combustion chambers looks compared to the 350 bore head gasket. It looks way too small to me. I was starting to bend and blend the last arch in the wall before the sparkplug hole, on the intake side. how close to the head gasket can/should i get? am i on the right track here?

the pistons are slightly dished w/ 4 valve reliefs, i'd like to have decent compression, but i also dont want to have to use premium either. around what it was with the 305 would be great, i think they were 9:3 my year.

What gasket is that? It's a rotten fit.

my machinist told me to bolt my heads onto the block, and stick my hands up the bore, and scribe the bore onto the heads. (rather then using the head gasket).

I think you want to remove the the cast iron roughness, and open it up around the intake and spark plug side. Fbird posted a nice paint modified picture in sitting bulls thread I think...

its an enginetech gasket kit, head gasket. I got to looking into it, and at http://www.enginetech.com/pr_gasket.php , it says its made with oversized bores.

my GM head gasket fits much better then this one does. This ones noticeably thinner so i was planning to use it though (the engine tech one).


Sonix i was checking out sittingbulls thread again and couldnt find those pics. he has 601 heads, and his chambers are a bit different then mine anyhow.

yea, neither could I....

well, I have seen a pic that f-bird drew, posted on a head porting thread, try searching for it. It's a certain spot that you want to open up to unshroud your intake valve. The opposite side is thin and weak, and not a good place to open up...

DOOOOOO NOOOT use a composite gasket as a guide to deshroud the combistion chamber. It is way too big. it is about 4.166" +++. The new larger vavles are only .050" larger in radius compared to the stock valve. So you only need to remove about .050" from any point of the chamber wall to deshroud. Don;t get carried away here. Only a small amount of metal needs to be removed.
Put the stock 1.84" valve in the head. Watch the flow window around the valve near the chamber wall as you work the valve open by hand. See the closest points. Now put a 1.94" valve in the same head and see the flow window.
The flow window at the closest point is only decreased by .050". If you get crazy and open up a 305 chamber to match the gasket bore , you will gain nothing and weaken the head. its not nessessary.

In the pic:

The purple arrows show the intake fow pattern into the combustion chamber towards the sparkplug.

The green area show the spots that need a small amount of metal removed to make room for the larger valves and improve flow near the chamber walls. Only a little bit of metal needs to be removed. the valve to wall clearance is only decreased by .050" with larger 1.94x 1.60" valves. Don;t get crazy.

Red arrow.... do not grind out the raised spark plug boss in the chamber. All you'll do is create hot exposed sparkplug threads and increase priignition.
Polish the reast of the chamber to your hearts content.

For the exhaust port you need to open up the bowl under the valve. the short side radius is a very sharp edge angle.
Needs to be made smooth and rounded. The guide boss is a significant blockage to air flow. Contour the vave guide boss, creating two flow pathes around the guide. The air flow is mostly concentrated on the roof and walls of the exhaust port. Do not make the port opening larger than your headers are. I use a 1.5" round header gasket as a guide for 1/5/8" headers. Do not make the opening round thou.

many thanks FBIRD, as always, you're the man.

i think i didnt explain my self well enough when i said i was going to "use" this gasket. I meant i was going to use it when i put the engine together, not for marking guide lines.

After seeing the photo of a cut 305 head's exhaust port, on standard abraisives website, i became weary of removing too much metal in the bowls. It looks to be quiet thin from the photo. What i'm gathering, is the exhaust just needs a "basic" port job anyhow, compared to the intakes? remove flaws and smooth the radi's. thanks again FBIRD, and Ratchet.

I find doing the exhaust to be a real pain. The ports are so tiny its hard to get the grinder in there and still be able to see what you're doing.

Now all i need is some decent weather, doing this work outdoors isnt an ideal way to tackle this project. Im doing what i can indoors, but anyone whos done this will tell you its messy and very loud. Not something you want to do when you'r kids are running around the house

Thanks again you all. I cant wait to get this car together and to the track.

Here is a pic of what I meant by creating a venturi.

Ric

I love threads like this !Looks great for a home porting job but Im a porting noob, what do I know.

Question....When working the bowls over, what method do you prefer to avoid dinging the valve seats? Seems like a pretty crucial step. Thanks

A steady hand

Additionally you need to know that you are going to damage at least one of the vavle seats so plan on it. When it happens you just go ... Hmm .....I was wondering when that was going to happen...... then carry on.

Ric

my machinist told me that the nut on the end of your die grinder is usually what dings the valve seat, as you're grinding. Wrap some duct tape around the nut, so that when you hit it, you'll feel it before you mash it up.

Is that like the loose nut behind the steering wheel????

Reshaping the short side radius is critical. you don't want to remove the arch in the port floor, just smooth and round out any sharp change in angle. Do not lower the floor of the port. Concentrate the metal removal to the roof and walls. Create a nice flow path around the valveguide boss in the port. Raise the roof to the gasket edge. make sure the gasket matches or is slightly smaller than your headers opening at the flange. DO not lower the floor opening to match the gasket. You want to leave a small step there.
Anti-reversion.

So your saying its best to grind off the edge from where the valve goes in, thats what i see in the green right?

FBIRD'88 nice save. I was focusing on the creation of the venturi at the base of the valve and got a little careless with where the port transitions to the floor.

The venturi creation is difficult but very worth while. Just like in a carburator when the air passes through a venturi it accelerates due to pressure differentials. This creates higher exhaust gas velocities and improves scavenging. I agree though don't lower the floor do raise the roof all the way to the header and leave the step between the floor of the port and the header.

this is the way the transition should have been if you are going to create a venturi.

Ric

im really bummed out about these heads. I think i may scrap them and use the 083 heads that i have. When i was pulling the very last rocker stud it cracked the damn casting, not broken, but hairline cracked. That compound with the hole i made in the intake bowl months ago it just really makes me not want to use these. im sure its all repairable but i dont want to risk it. I take mini road trips in this car and dont want some pacthed up cylinder head leaving me on the side of the road at 3 am.

the intresting thing is that i've read on TGO another person cracking the casting pulling the studs out of the 416 casting heads (his completely broke though). The studs were in there so tight it was unreal. My 083 casting heads stud's slid right out with VERY little effort. It took a total of 2 nuts to get the 083's finished and i honestly probably used 15-20 on the 416's.

that Really Sucks

I scrapped one of my heads by grinding through the port also. I thought about JB Weld and for the same reasons you suggested (Road Trips) I opted to get another head and do it again. Hopefully the one you ground through the port on and the one the cracked is the same one and you will only have to port one more to match.

Ric