• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

1994 K3500 extended cab dually

n8in8or said:
Yep, I did do that. It isn’t any closer to the channel than the sides so I figured I’d give it a try. Maybe it will be less of a heatsink? Maybe smoothing it will help? Maybe I effed up? I’m going to try it and find out.

This is the casting mark that’s on the heads that came off the Hoe’s Optimizer and the one I got from the junkyard this winter.

View attachment 61687

Not “GMD” like the GM heads and no Navistar mark.
Click to expand...


I'm 99% sure that is a "Cleveland foundry" castings.... they also do a lot of ford's....
 
Husker6.5 said:
Am I seeing things right, Nate? You took metal off in the crack-prone area between the valves when you unshrouded them? I know these have the brass tubes installed, but isn't this tempting fate in a failure-prone area? Also, forgive my ignorance, CF heads?
Click to expand...

The primary reason for the cracking found on ANY head without seats is the induction hardening process done to this type of head, when cast iron is hardened it makes it very brittle, the constant heat cycles along with cylinder pressures does them in... fact...

Even new GEP/AMG heads are induction hardened to this day, the exception is the P400 heads, and now China is installing seats not hardening the seat area... does that mean the China heads will last longer... who knows but I bet they will fare better in the seat area, that is if the seats are installed right and they don't fall out during use...

I always suggest P400 heads if someone has plans to invest a lot in a build they plan to keep for many years, it's all part of the investment...
 
I've been busy with some house projects lately, so I haven't made a ton of progress on this truck in a while. Sunday I did get a few hours to work on it and I ended up with the long block pretty much assembled.

I got the heads installed using +.010 head gaskets. I cc'd all of the pieces-parts and decided the +.010 gaskets were where I wanted my compression ratio to end up:

Combustion Chamber: 7.7cc
Pre-combustion Chamber: 22cc (using my custom machined precups that are a little larger than Diamonds)
Piston Dish: 3.5cc
Piston-to-Deck: .85cc (.004" below deck since this short block has -.010 pistons)

With that data, as well as the known volume of the cylinder being 810.34cc I worked up the compression ratio with the 2 gasket options.

With the standard thickness gasket (9.31cc) I got 18.76:1 for the CR.

With the +.010 gasket (11.53cc) I got 19.67:1 for the CR.

And then, just for funsies, I ran what the CR was before with the -.010 pistons and +.010 gaskets, but the stock combustion chamber volume (5.8cc). That calculated out to 19.53:1 for the CR. So I had somewhat of a baseline.

I decided that I would go the 18.76:1 route. This gives me a little more volume for pushing it in the future as well as a little more clearance for carbon build up.

In the same vein of preparing for pushing it in the future, I got some Comp Cams pushrods to complement the valve springs from Chris. I used checking pushrods to check for optimal length at .050 preload. Perfect would have been 8.7625 for the Intake and 8.775 for the Exhaust (stock pushrods are 8.8215", but this is checking using the Harland Sharp roller rockers....). I looked in Summit's catalog and found they had some beefy .135" wall ball-end pushrods in 8.78" length with just a couple day lead-time, so I ordered those. The beefier wall of these pushrods and the better springs from Chris should really improve valvetrain stability/accuracy.

6.5 Push rod.jpg6.5 Rockers.jpg

I still had some time after torqueing the rockers down so I worked on cleaning up some covers. I got the valve covers, oil pan and front cover installed. Hopefully in the next few days I can get some more stuff installed and then slap paint on it.

6.5 Long Block.jpg
 
I noticed that, too. I figured (pun intended) that it was either a math error or a typo. Thicker head gasket will always equal lower Compression Ratio all other things being equal.
 
ak diesel driver said:
So I guess I'm confused. With stock gasket you get 18.76 but with a thicker gasket you get 19.53?
Click to expand...
Husker6.5 said:
I noticed that, too. I figured (pun intended) that it was either a math error or a typo. Thicker head gasket will always equal lower Compression Ratio all other things being equal.
Click to expand...
DAMMIT!! That's what I get for working and posting.

.010 gasket = 18.76
stock gasket = 19.53

So much for multi-tasking. Sorry about the confusion.
 
Question, in the pic of the rockers, it looks like 2 different rockers, noted in the shape on the pushrod end... the HS rockers have a different shape on that end between 1.6 & 1.7 ratio... are you going to run split rockers or is that just the pic that makes it look that way ?
 
I just copied the pic and zoomed in on it, you have 2 different ratio rockers and they are mis matched on valves.. might want to check that unless it's just the pic... You could use different ratios but the rockers need to be on the same valves, IF that is the case you better make sure you have valve clearance and I'd suggest the 1.7's on the exhaust valves...
 
I ended up with the different shape rockers when some of them got roached from fitting incorrectly. I just assumed they had updated the design when they sent me the replacements. I’ll remove a set and look at them more closely to make sure they’re the same. Thanks for the info.
 
It will be noticeable in the cup position location... but with talking with HS years ago they have visible differences in the ratios and that is one of them, I have both ratios here from a couple years ago and that is one way to note it...
 
I remembered this morning that I had pictures from when I was working with Randy Becker Jr at Harland Sharp to get my defective rockers taken care of. I found some pictures from the first replacements he sent me. I had forgotten that he accidentally sent me 1.5 rockers instead of the 1.6 rockers the first go around and I noticed the difference. These are the pictures I sent him and you can clearly see the different location of the push rod cups. The original 1.6 ratio rocker has the square corners and the replacement 1.5 ratio rocker is the one with the rounded corners.

1.5 1.JPG1.5 2.JPG1.5 3.JPG1.5 4.JPG

Right away he acknowledged that he sent 1.5s instead of 1.6s. Then he sent me the correct 1.6 rockers. This is the only picture I have of them, but you can make out that the cup is closer to the fulcrum. I know I inspected them closer than that at the time, this is just the only picture I have.

1.6.JPG

So in my case, I had both 1.5 and 1.6 rockers that both had the rounded profile. The square corner rockers are old - I think I was one of the first 5 customers that bought them through Leroy so I'm attributing the difference to that. I still appreciate you raising the red flag and keeping me honest though! I'm just glad I don't have to pop the valve covers back off - that Right Stuff is a PIA every. single. time.
 
You must log in or register to reply here.
Back
Top