Tst=blown Head Gasket

[Digger]

I recently installed the TST Pomermax CR on my truck. Before I put the box on I would get 40lbs of boost. After the TST (no boost elbow) I was seeing 48lbs. After a day of driving the head gasket is now toast. This box makes a lot of power, but doesn't seem to be real smooth. Has anyone else had any problems with smoothness? Has anyone blown a head gasket? I new the gasket would go sooner or later but just one day of driving was a little soon for me.



digger

 

[Jeff Clark]

I would have thought that the stock head gasket would be good for more than 48 lbs of boost. That has me a little concerned. I want to upgrade the turbo, but I really don't want to do head work. Let us know what you find out.

 

[hotram03]

what level did you run your TST on to do that with

 

[Vaughn MacKenzie]

From what I understand anything much above 40-45 pounds of boost and you are treading on thin ice with a stock headgasket. Usually guys are blowing turbos instead of headgaskets though

 

[Loaded 45]

Most times that I have seen problems with the TST is when injectors are involved. Maybe Im wrong but tst + injectors seem to be a bad combo.

I drive my truck hard TST + fueling box seems to be a good combo. Power is not as aggressive as tst alone.



Watching the boost gauge is hard to do when you got her to the floor .

 

[Digger]

When the gasket actually gave up. the TST was on level 5/5. I was not getting on it hard just normal at first I thought it was another turbo. I had ran the box at all levels to see the power, smoke and how the turbo would handle it but 5/5 is the highest I could go without the egt's getting to hot to fast. Have not tore into it yet. The next step would be to O-ring the block.



digger

 

[Bertram65]

Not doubting it's the head gasket but how can you tell? what indications does it show?

 

[jsimpson]

Digger, are you the same Digger as on the Cub Cadet forum?

 

[robertyoke]

do you have other gauges or are you going of what the tst box saw as boost?

the boost senser is only good to 45 psi reading.

 

[KYLE4]

48 lbs of boost definitely pushing it just fire ring it this time probably hold. Best is o ring of course that involves downtime and $$$ If your gonna be pushing your luck running those kind of boost levels you should be retorqing cylinder head occassionly that will help gasket last longer

 

[jwilliams3]

If your not running an aftermarket wastegated turbo you might just have too much back pressure!

 

[BCarmicle]

I blew my head gasket over a month ago. When I opened up the wastegate controller all the way I saw boost get to 80lbs. , on a 80lb. boost gauge, and I let out of it. The truck didn't show any signs of but I was curious if the head gasket may have been partially blown, if thats possible.



Then I clamped off my BOVs and had the wastegate set at 60lbs. and blew the head gasket. Boost came on faster with the BOVs clamped off but the head gasket coudn't handle it.



I am also using ARP studs. Head gasket blew between cylinder #1 and #2.



Brandon

 

[jwilliams3]

What did you replace it with?

 

[BCarmicle]

There wasn't many options. Could have used a copper one but was told they leak alot. You can't o-ring or fire ring these gaskets either. To do that I would have had to went with a second gen gasket which isn't as strong as the 3rd gen gasket.



So I just replaced it with a stock gasket and am going to torque the studs tighter and try to keep boost under 60lbs.



Brandon

 

[Fred Swanson]

48 is low for a 3rd gen. I run DD2's and TST, and with a Jammer have seen 53. Now with the twins, keeping it under 60 so far with no issues.



Even with just the TST, DD2's and Jammer 45 all the time, no issues. 58K miles on the motor so far.



80 without rings seems a bit high.

 

[jwilliams3]

Good idea.

And you bring up a good point.

The 2nd gen gaskets are not as strong as the 3rd gen.

I think Piers can prep you a 2nd gen gasket for your 3rd gen surface

(for O ring purposes).

What kind of stud torque are you going after this time?

 

[BCarmicle]

I'm not for sure just yet, truck still isn't together. I think maybe 105ft/lbs. and then tighten them again to around 115. I'm going to ask around to find out for sure at what torque they need to be.



Brandon

 

[Vaughn MacKenzie]

What turbo you're running makes a BIG difference. 48lbs of boost with a stock turbo is much harder on the engine than 53 lbs with a Jammer. Think drive pressure.



Taking a stock turbo past about 40psi sends drive pressures to the stratosphere, and if you're doing that on a regular basis the stock turbo needed to go a long time ago. The stock turbo isn't too restrictive because of the large wastegate, if you let the wastegate open normally (keep it under about 35psi). Keep it closed and the turbo becomes a huge restriction.



Vaughn

 

[Fred Swanson]

So True Vaughn. But I know another 3rd gen on these boards running a Piers modified HY hitting 40psi with no issues with about 25K miles on the turbo.

But the drive pressure issue is the main possible culprit.

Seem to recall 125 for the studs.

 

[BCarmicle]

I don't completely understand drive pressure yet but I do think its what made my gasket blow since none of the pressure was let out through the BOVs. The gauge only read 60lbs. and I had been there many of times with the BOVs open with no issues. I'm running BOVs and an external wastegate.