I blew my head gasket on my 12V'er over a month ago, and have been shaving away at the head since.  I'm not going to pretend like I know what I'm doing, I just want to document what I've done.  Some of these pictures arn't up to date, I'll update them as I get new ones.  Taking pictures of this stuff have proved to be challenging.

 

First things first.

 

Now, here's a look at the factories handy work.  Notice the difference between these two cylinders.  I can't do any worse than that!  Also note the horrendous lip around the inside of the valve seat blocking much needed air flow.  Plus there is an excess of material around the valve guide.

 

 

And a stock exhaust port.  In stock form they really arn't that bad, a slight lip around the inside of the valve seat, and the large area around the valve guide.

 

Here you can see the floor of the stock intake runner.

 

And then after some massaging.

 

And then for the actual port work, of which I'm not completely done..

Intake:

Exhaust:

I also did a number on the valves, including giving them some shine and grinding the seat width back to spec (1.5-2mm) mine were 2.5-3mm.

 

 

Edited December 3, 20159 yr by Cowboy

9 hours ago, Cowboy said:

Close, but this time he was under the hood 

Well hope the loose nut is easily fixed.

This loose nut will never be fixed, he will continue to do crazy stuff causing more carnage.  I'll just try to keep him occupied with something else for a while.

Well it's about time I updated this.  I said I would when it pans out, while it hasn't quite come together yet, it's getting pretty close.

The Story:

On the 15th I was going to retorque the head bolts, but I didn't like how little thread engagement the long bolts had. Seeing as we're putting 20% more torque on the same bolt minus the thickness of the washer (SHCS). I had a couple options but I figured the best/fastest one was to get the rockers machined down a smidgen. The 16th I bring them to a local machine shop which I've never used before, the owner who would normally do these things wasn't there. An employee hooks me up on the phone with him, I explain what I'm wanting and all is good, he says he'll look at them and call me before he does anything. I left the rockers there along with a crude sketch of what I'm wanting done to them along with the different measurements.

On the 17th he calls but leaves a message stating that he did one already and it will be $100. Me not being familiar with general machining costs I decide that's a little much. I call him back saying for that price I'll pass, but I'll pay him for the one he did. So I get a call from him the 18th saying that they're all done ready to pick up.... WTH? So I headed over there not sure what to expect. Turns out I had the wrong number, I figured this out later due to a call back from the local 'Chamber of Commerce'. 

Got there and everything looked really good. The finish left looked much better than any other pictures I've seen, so figured he went a little overboard not knowing what the application was for... Fine, for the sake of just being done, I'm cool about everything and give him his $100. All is great, I go on my way. Then doing what I should have done while I was there, I inspected everything. First thing I noticed was one of the bosses was damaged where something was clamped up against it... Then looking at it with a naked eye the steps didn't look square......... Pull out a caliper and sure enough. Some are off .010". So I call him back with my displeasure, but left a message. It was short and sweet, just saying I had a couple questions, if he could call me back, and if I'm not there leave a message stating when would be a good time to call back... I called 2 or 3 times a day except sunday (with the correct number this time), plus left another message with no response from him. Finally the 23rd I stopped by, but no one was there, I left a note asking him to call. Which he did the 24ths morning. So I head over there again (it's almost 20 miles one way), show him the problems, he blames the bad cuts from taking off all the material in one pass... I'm not a machinist so whatever, sounds plausible but isn't my problem. He's cool about it, but says he's not going to be able to take care of it right away, and may be a couple days.

On the damaged boss, I basically gave him 3 options. 1) Fix it. 2)give me back $15 and I'll buy another used one for him to machine. 3)leave it and guarantee no damage will result because of it (I explained it was in the oil path). Said he'd try out #1, but may go with #2 depending.

He got back to me the 29th saying everything was good to go, I picked them up and everything seems like it will work.  Hopefully I can get them all installed in the next couple days.

I hope it all works out. Taking a chance on a shop you've never used before is always unnerving. 

9 hours ago, The_Hammer said:

I hope it all works out. Taking a chance on a shop you've never used before is always unnerving. 

I hope so too!  I'll keep ya updated.  

One thing I noticed while I had it all apart is #5 exhaust seal popped up.  Who knows how long it would have been before I noticed.  All the others appear fine.  I was able to re-seat it with a couple screw drivers.

 

Edited December 31, 20159 yr by Cowboy

On 12/16/2015 at 3:47 PM, Mopar1973Man said:

I'm waiting to see it start up with it fresh head and gasket...

Just for you.  

http://www.youtube.com/watch?v=8wUnBDOv_4Y&feature=youtu.be

Funny... Typical P7100 cold start. Low and lopey. Once they warm up a bit they are an animal.

In it's defense, it was running on 3 cylinders. haha

To sum this all up.  I'm happy with how it all turned out.  There are two main changes.  

EGT's are down.  Before the head porting they peaked at 1325°, now they peak at 1250°, but it runs stronger as it took .75 seconds off my 20-80 times.

It also spools faster, before it would make 10 psi at around 1400 RPM.  Now it makes 10psi at 1310 RPM.  Stock 20psi would come around 1580, now it's 1520. 30psi would hit at 1860, now it's 1790.

Another interesting thing I found,  I took the 99 up a certain hill maintaining 40mph, boost stayed right around 20 psi.  Doing the same with the 96 (the one with a head job) gave a reading of 11 psi.  Same gear, same tire size.  This test is somewhat like comparing apples and oldsmobiles, but I found it interesting.

I believe what's currently holding me back is the tremendous amount of drive pressure!  Making 35psi (33 in the manifold) drive pressure goes above 60 psi!  I need to find a replacement turbo and fast!

Between the combination of a cam and head porting, I also noticed a drastic drop in drive and boost pressure at a given load and RPM.... When the truck was in pretty much stock form it took about 15 PSI boost to maintain 65mph on level ground, after the improved head flow it dropped down to about 6-8 psi.. Mileage improved especially at highway speeds as well