Cracked piston
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Posting Guru
Joined: May 2015
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So I talked to Justin today, he told me he uses 7.3 gaskets on all his builds as they don't have the weak area where the coolant grommet goes.
Which makes sense because that's exactly where mine blew at, he also said the studs are supposed to be 6.125"
Which doesn't make any sense because most of mine were shorter, and the post I mentioned they were 5.9xx"
I'm pretty sure I got a set of bad studs, because when I got ready to pull the head I tried the torque wrench on a few just to see if they'd click at 100 and none of them did. One took a little over a turn and still didn't click....others got pretty close I guess in half a turn.
Something seems fishy here because I found several post last night of people running 20+ psi no problem on a studded 6.9. Justin also told me some guys with the rd-90 are hitting 25-27 and are having good luck so far. Although that high it's always a gamble.
If bolts would hold 15, and the studs wouldn't hold any more than that I would assume this set of studs isn't up to par...those bolts I had before were also only torqued to 80
I'm almost tempted to drop in a set of bolts and torque them to 115 and just run it....
Which makes sense because that's exactly where mine blew at, he also said the studs are supposed to be 6.125"
Which doesn't make any sense because most of mine were shorter, and the post I mentioned they were 5.9xx"
I'm pretty sure I got a set of bad studs, because when I got ready to pull the head I tried the torque wrench on a few just to see if they'd click at 100 and none of them did. One took a little over a turn and still didn't click....others got pretty close I guess in half a turn.
Something seems fishy here because I found several post last night of people running 20+ psi no problem on a studded 6.9. Justin also told me some guys with the rd-90 are hitting 25-27 and are having good luck so far. Although that high it's always a gamble.
If bolts would hold 15, and the studs wouldn't hold any more than that I would assume this set of studs isn't up to par...those bolts I had before were also only torqued to 80
I'm almost tempted to drop in a set of bolts and torque them to 115 and just run it....
Cargo Master
Joined: Oct 2012
Posts: 3,072
Likes: 48
From: California
Any chance you had a tiny HG leak that allowed a tiny drip of coolant to enter the cylinder? Then after enough fluid made it into the cylinder, the pressure of the water against the HG compression ring caused the ring to expand (no hydrolocking). As more fluid entered the cylinder, the greater the force on the compression ring and head studs, forcing more water incrementally into the cylinder with each stroke. It would exponentially expand the volume and exponentially increase the coolant flow. After a certain point, the cylinder would blow out the deformed HG since the deformed ring lost its circular integrity and the stretched studs at that area on the heads. Just a thought....
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Any chance you had a tiny HG leak that allowed a tiny drip of coolant to enter the cylinder? Then after enough fluid made it into the cylinder, the pressure of the water against the HG compression ring caused the ring to expand (no hydrolocking). As more fluid entered the cylinder, the greater the force on the compression ring and head studs, forcing more water incrementally into the cylinder with each stroke. It would exponentially expand the volume and exponentially increase the coolant flow. After a certain point, the cylinder would blow out the deformed HG since the deformed ring lost its circular integrity and the stretched studs at that area on the heads. Just a thought....
More Turbo
Joined: Oct 2014
Posts: 697
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From: Alberta Eh
That’s crazy about the studs not holding, quality control must be social distancing and working from home 
Just a random thought DOC, and I apologize if you mentioned it and I missed reading it, but did you clean the threads in the block before studding?
Just a random thought DOC, and I apologize if you mentioned it and I missed reading it, but did you clean the threads in the block before studding?
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Yes, and I plan on cleaning them again when it goes back together as well.
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After speaking to a few idi and other gurus these studs definitely should have held, so I either got a dud or Chinese carbon copy set.
Will be pulling the engine anyways to figure out the fourth gear problem, will update whenever I make some progress. Ordered some parts today, will order more next week. I'll have a surprise for yal if all goes well. We'll see... Stay tuned.
Will be pulling the engine anyways to figure out the fourth gear problem, will update whenever I make some progress. Ordered some parts today, will order more next week. I'll have a surprise for yal if all goes well. We'll see... Stay tuned.
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Pulled the engine today, got it out in two and a half hours this time instead of four like last time, guess I'm getting pretty good at this...
Driver's side head gasket looked great. Measured a few studs and they seem to be the right length so they didn't stretch.
Now I'm just waiting on parts. Hopefully they'll be here by Saturday and Sunday I can have some time to start back on getting it right.
Driver's side head gasket looked great. Measured a few studs and they seem to be the right length so they didn't stretch.
Now I'm just waiting on parts. Hopefully they'll be here by Saturday and Sunday I can have some time to start back on getting it right.
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Scope Wizard
Joined: May 2019
Posts: 6,530
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well the COVID police will destroy any accomplishments
check the heads for warpage clean the deck and nail it down and do a retorque after first run
on NA engines I do a retorque 2 times before I release it as job done...... just saying.... now I don't use studs and I don't reuse head bolts either.
check the heads for warpage clean the deck and nail it down and do a retorque after first run
on NA engines I do a retorque 2 times before I release it as job done...... just saying.... now I don't use studs and I don't reuse head bolts either.
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Posting Guru
Joined: May 2015
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well the COVID police will destroy any accomplishments
check the heads for warpage clean the deck and nail it down and do a retorque after first run
on NA engines I do a retorque 2 times before I release it as job done...... just saying.... now I don't use studs and I don't reuse head bolts either.
check the heads for warpage clean the deck and nail it down and do a retorque after first run
on NA engines I do a retorque 2 times before I release it as job done...... just saying.... now I don't use studs and I don't reuse head bolts either.
Now that we're over that political rant I like that method of doing two retorques. Although it's rather inconvenient to do them in my truck. Would probably take a few hours each retorque. But before I pulled the passenger side head I retorqued a few and they took an extra 1/4 turn! So it's definitely worth doing imo, although arp says it's not needed, Justin told me he doesn't retorque.
It looks like almost all the parts will be here today, still got one mia, fingers crossed it comes in tomorrow.
Scope Wizard
Joined: May 2019
Posts: 6,530
Likes: 25
yeah retorque can be a PIA for sure especially with turbo in some cases... it may have a lot to do with gasket quality... this method was the way I was taught when working on aircraft engines so it just became habit for me.
I didn't mean to skew this thread to politics with my Covid comment it was really just made in Jest... but I do understand the feelings and I'll leave it at that as I know we are not allowed to talk about it here.
BUT stay Safe my Friend and hope you get yer parts.
I didn't mean to skew this thread to politics with my Covid comment it was really just made in Jest... but I do understand the feelings and I'll leave it at that as I know we are not allowed to talk about it here.
BUT stay Safe my Friend and hope you get yer parts.
Cargo Master
Joined: Oct 2012
Posts: 3,072
Likes: 48
From: California
The last two times I torqued my head studs, I just went to 140 or 150 ftlbs for the final pass. Justin said he does 150 all the time, so I just copied his technique.
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So I think I figured out the fourth gear problem
Once at a junkyard I came across a 2wd t19 (out of 86 f350) and took the input shaft, bearing retainer and 4th gear synchro and a non cracked forward bell housing. I swapped it all over but it would throw it out of fourth harder than I could hold it in. The clutch showed slippage and minor heat spots on the flywheel upon pulling that this time too. I'm hoping it was just from the sudden engagement/disengagement and not slipping under the new found power.
Low and behold the bearing retainer is different (even though it should be the same) it has a deeper lip that is letting the input shaft walk forward towards the engine more. Thus making the space between the shift collar and synchro further apart. Which is exactly what it felt like.
Tomorrow I'll get that buttoned up so the motors ready to go back in when it's ready.
Still hopefully have a surprise coming for you guys, wish me luck, I'll need every ounce of it.
Once at a junkyard I came across a 2wd t19 (out of 86 f350) and took the input shaft, bearing retainer and 4th gear synchro and a non cracked forward bell housing. I swapped it all over but it would throw it out of fourth harder than I could hold it in. The clutch showed slippage and minor heat spots on the flywheel upon pulling that this time too. I'm hoping it was just from the sudden engagement/disengagement and not slipping under the new found power.
Low and behold the bearing retainer is different (even though it should be the same) it has a deeper lip that is letting the input shaft walk forward towards the engine more. Thus making the space between the shift collar and synchro further apart. Which is exactly what it felt like.
Tomorrow I'll get that buttoned up so the motors ready to go back in when it's ready.
Still hopefully have a surprise coming for you guys, wish me luck, I'll need every ounce of it.
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I got the trans reassembled today and the input shaft no longer has end to end play. So fingers crossed it fixes that problem. Also used the old synchro just to be safe.
Yeah I can't wait, I miss the whistle but the 89's straight piped so she still talks
