If I'm not mistaken, Barney sucessfully contained 21 PSI, but instead of finding the lift point for the gasket, he found the crush point for the wrist pin.
HYPERMAX HEAD GASKETS
- Thread starter tknomaj
- Start date
If I'm not mistaken, Barney sucessfully contained 21 PSI, but instead of finding the lift point for the gasket, he found the crush point for the wrist pin.
Dsl_Dog_Treat
I lost my face to the jaws of a poodle
If I'm not mistaken, Barney sucessfully contained 21 PSI, but instead of finding the lift point for the gasket, he found the crush point for the wrist pin.
Yup, he hit 21psi, but looking up the skirt on the culprit piston it's still up in the air.
One hole had been bored and sleeved and that too may be a determining factor. The jury is still out.
tknomaj
Registered User
If I'm not mistaken, Barney sucessfully contained 21 PSI, but instead of finding the lift point for the gasket, he found the crush point for the wrist pin.
Does anyone know if Barney running Turbo rods and pistons or stock? And what gaskets did he run?
rhkcommander
Full Access Member
Anyone recall his CR? I'm no rich kid, I just want my truck to perform as good as it safely can 
. If I'm gonna spend time rebuilding the motor then why not take extra precautions if the options exist (or could exist)?
Price vs performance matters too, I cant afford 1000$ head gaskets from Hypermax if they did exist, but if I could get some for 3-500$ that's more choke-able
.
I've seen other people claim to push 15psi no problem, I do realize each PSI jump is considerably more air, and psi /= air volume... but how high have you guys or others gone without breaking something
. If I'm gonna spend time rebuilding the motor then why not take extra precautions if the options exist (or could exist)?Price vs performance matters too, I cant afford 1000$ head gaskets from Hypermax if they did exist, but if I could get some for 3-500$ that's more choke-able
. I've seen other people claim to push 15psi no problem, I do realize each PSI jump is considerably more air, and psi /= air volume... but how high have you guys or others gone without breaking something
redneckaggie
rebel w/o a cause
You are speaking in opposing terms, what someone has hit a few times and the motor is still together and what someone has consistently run for hundreds of thousands of miles and everything still works properly are two completely different things. My point is not to bash you just to point out something that needs to be considered. Most people that want to push a motor will at least check everything out before trying to push it. I guess what im trying to say is no matter how you look at it any boost strains the motor, however minimal it may be. The higher you go with it the more you strain the motor. If you start with a perfect motor than obviously you can strain it a little harder than a used motor and get good results for more miles. I am not trying to tell anyone you cant push these motors because I bashed mine hard for the first few years(gotta love that first truck feeling) but just trying to throw a little common sense reason into things because you can set a limit and there is pretty much always someone who has exceded with fine results. But fine to them may be a reliability of 50-100 thousand miles where as fine to me would be closer to 300 thousand.
tknomaj
Registered User
The Engine in question is MAX a Brand New Ford Factory REMAN 7.3IDIT Never Ran or Fired except by ford for testing purposes. It is coming apart and MODS are being done. I have all the parts except some and they are being done as we speak. Head gaskets are the only open item the rest has been or is being nailed down
PwrSmoke
Full Access Member
To me the issue is combining boost with a 21:1 CR. If you don't have the high CR, then the engine is a bear to start in cold weather. If you have the CR, then adding boost is putting so much more stress and strain on all the parts. It's the IDI dilemma and why DI was taken over. I'm just about convinced now that I will install 0.010 destroked pistons, with will drop me about one ratio with the stock bore and adding about 3ccs.
Speaking of which, has anyone measured the volume of the prechamber and piston notches, not to mention deck clearance? I just thought about this now. I ought to do that and will try to remember before I get to that point. The engine is all apart now.
And what's the difference in volume between the 7.3L precups and the 6.9L? I understand the 6.9L version are NLA.
Speaking of which, has anyone measured the volume of the prechamber and piston notches, not to mention deck clearance? I just thought about this now. I ought to do that and will try to remember before I get to that point. The engine is all apart now.
And what's the difference in volume between the 7.3L precups and the 6.9L? I understand the 6.9L version are NLA.
That CR is what gets me. On some European diesels they have similar compression and run 15-18 lbs and better boost. and these are high rpm diesels. Big difference is they have some wicked TTY head bolts on those things ( it'll scare you half to death the noises they make when torquing and removing the things
When they first came out they had composition gaskets and would run about 120-150k miles ( sometimes more, but they also failed to mention SCA usage and gaskets would erode )befoer a head gasket change was in order , then the factory switched to MLS gaskets and they can go indefinitely on a head gasket, in fact many folks even re-use the head gaskets when they have the things apart ( saves a $285 gasket , but the fact remains that the things will hold together fine with composition gaskets, just for not as long , which leads me to believe that with studs and good factory gaskets ( i.E. Victor Reinz ) these things should be capable of running about the same amount of time at that kind of boost without having to resort to custom gaskets. While it would be REAL nice to get some MLS gaskets, the cost and extra machine work involved is going to be prohibitive.Diesel JD
Full Access Member
I've also thought of custom builds, and I'd have to say I think head gaskets would be low on my priority list. Bill has logged a lot of hard miles on an IDI and he's not the only person to complain of the piston pin issue. From what I remember the issue usually manifests itself as the engine having that piston pin slap sound and eventually getting weaker and weaker power wise until you have to fix it. I wonder if this wasn't the reason for the bigger piston pins and bosses in the factory turbo and later PSD engines. I've always said if I go to the expense of a high output build I want to do factory turbo rods even if that means custom pistons, should eliminate the issue at least unless the HP levels get insane. I was hoping for 300 HP at the crank, maybe low to mid 200s at he wheels and be able to hit 15 or 20 psi without breaking stuff or wasting most of the energy as heat.
icanfixall
Official GMM hand model
JD... Mahle... The oem maker of the idi pistons makes both types of turbo pistons. They make a low comp and a standard height piston for the turbo motors. They are all hard anadoized tops too with the 33 mm pins. NA pistons have a 28 mm pin. I'm running a set of the low comp with 14 thousands cut off the tops. Then ceramic coated with CBX from Tech Line coatings here in Ca.
Diesel JD
Full Access Member
I had heard that no 6.9 turbo pistons were available anymore....am I wrong(I would really like to be!) ? I'd be happy with a CR in the neighborhood of what you have. I agree with Russ if you need more than 13 psi (intercooled) you probably need a bigger truck. If we were just going for high HP I'd still get the custom slugs and the turbo rods though because I think for reliable high boost we need a much lower CR maybe 18 or 19:1.
Black dawg
Registered User
how many have had head gasket failures, 6.9 or 7.3? I took apart a turbo 6.9 years ago to do gaskets as preventative maintenance, it had 2 broke bolts on 1 side and 3 on the other and the fire rings were not leaking. While Ive seen 6.9s have blown gaskets (leaking combustion into coolant) Ive never seen a 7.3 blow one.
dyoung14
Is getting worn out
Knock on wood but so far i havent failed a wristpin, and i see 4500 rpm and 15psi of boost
rhkcommander
Full Access Member
What neighborhood does that throw your CR into?
PwrSmoke
Full Access Member
Not putting words into his mouth, but my guesstimate would be about 18.5. I don't know what the Mahle low comps are, though but 0.014" is about 1.25:1 of the ratio.
I'd ask again:
A) volume of the prechamber and piston notches
B) deck clearance
C) difference in volume between the 7.3L precups and the 6.9L? I understand the 6.9L version are NLA.
