blowing the head gasket

Teelo

Teelo

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Jun 10, 2007
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I have a set of a4000/s400 twins that I expect to make around 70lbs of boost once I get the head studded and valve springs in. this is on a stock gasket, should i have to worry about the gasket blowing?
 
No, if: your drive pressures are in check (should be), you wait till she's warm before you rail on it, get or make a coolant bypass, and torque em good. :Cheer:
 
Well just on studs and stock gasket I ran 98 pounds of boost when it went. I ran mid 80's just fine with my 66/80 combo. I have done no coolant mods at all. So just check drive pressure and and get that in a safe zone and all should be well at operating temps.
 
Should be ok at 70psi. What did you torque the studs to, and have they been retorqued?
 
Seems to be hit an miss. Mine lasted a few days after I did my twins and injectors. I was around 68 to 70 psi of boost. Some last longer though.
 
I plan on having the studs torqued to 140. that seems to be a good number
 
The biggest cause of gasket failure is the nuts get torqued once and thats it. You have to progressively torque them and then line torque them. The engine has to go through a few heat cycles while re-torqueing in between. As things expand and contract with the build up and loss of heat, the head settles and studs stretch, causing the need for re-torques. If you skip this step you will blow a head gasket, and if you didnt you are very lucky!
 
And some go through all that and still blow it. From my experience the MLS gaskets have a hard time living at or above 700 hp.
 
milldog said:
The biggest cause of gasket failure is the nuts get torqued once and thats it. You have to progressively torque them and then line torque them. The engine has to go through a few heat cycles while re-torqueing in between. As things expand and contract with the build up and loss of heat, the head settles and studs stretch, causing the need for re-torques. If you skip this step you will blow a head gasket, and if you didnt you are very lucky!
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This is new terminology for me! Could you please explain?
 
Mine held fine up to 80. Finally lifted the head at 90 but it re-sealed. I blew coolant out the radiator cap and lost the heater. I refilled the system and haven't had any issues since. (been 3 months) My studs were installed and re-torqued once. They need done again since it's been over a year.
 
im pretty sure ARP directions says three times,after heat cycles like stated above.i did mine 4 time"s to 140lbs.benn good for 20,000 and plenty of trac time
 
LReiff said:
This is new terminology for me! Could you please explain?
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To line torque head:
Make a mark with a magic marker, so you have a reference point on top of the bolthead or nut(studs).
Then start at the front(pass. side of head) bolt/stud-nut, loosen it up, then re-torque it to 125 ft.lbs.(studs) 90ft.lbs.(bolts.)
Proceed down that line of bolt/studs, doing same thing, one at a time.

*NOTE*
If you notice more than 1/8th inch rotation of the bolt while doing last step, then you may have a bolt that has 'stretched'
You need to pull that one out and measure it with a Cummins Bolt Guide, or Bolt Stretch Indicator.


The only thing I would differently is torque them to 140lbs instead of 125lbs
 
Maybe I just got lucky but the first time! I put studs in my motor at 42k and all I did was pull the head, clean the head and block surfaces and put it all back together with a new MLS gasket and studs...torqued to 130 in small increments then loosened them one at a time and retorqued to 130, never touch them after that...65 lb. boost and it's now at 96k without an issue...$.02
 
LReiff said:
Maybe I just got lucky but the first time! I put studs in my motor at 42k and all I did was pull the head, clean the head and block surfaces and put it all back together with a new MLS gasket and studs...torqued to 130 in small increments then loosened them one at a time and retorqued to 130, never touch them after that...65 lb. boost and it's now at 96k without an issue...$.02
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Thats a bada$$ avatar!!
 
i got a 96 dodge 3500 makin 65-68 lbs with stock turbo, stok head bolts, and stock gasket.. the head has never had any work done and mine lifts the head and blows water out the side but aint completely blew the gast yet. there is NO oil and water mixing anywhere
 
diesel_man_1231 said:
i got a 96 dodge 3500 makin 65-68 lbs with stock turbo, stok head bolts, and stock gasket.. the head has never had any work done and mine lifts the head and blows water out the side but aint completely blew the gast yet. there is NO oil and water mixing anywhere
Click to expand...

:umno:
 
diesel_man_1231 said:
i got a 96 dodge 3500 makin 65-68 lbs with stock turbo, stok head bolts, and stock gasket.. the head has never had any work done and mine lifts the head and blows water out the side but aint completely blew the gast yet. there is NO oil and water mixing anywhere
Click to expand...

:doh: And I thought I posted actual real to life data...WOW :bow:nothin speaks quite like bold :bow:
 
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