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Blew My Head Gasket On Built Engine


HeavyIron

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Damn dude...23 psi full time...spiking to 26psi...on pump gas? :huh:

.....:blink:

So?

And stock bolts and head gasket should be fine, and will be all I ever use on any of my cars.

One thing to consider with ARP studs is that the correct torquing procedure involves re-torquing after a couple of heat cycles. The same as any stretchless bolts. You may notice that on engines such as ours, this is hardly practical or convenient ;) I also suspect that nobody using ARP studs with whiteblocks actually does this.

OP, did you hear any detonation?

It's quite possible they torqued the bolts wrong... Do you know if flatness of the block and of the head was checked? I would personally insist that the head be resurfaced and if anything needs to be done with the block this time around, the block be resurfaced as well.

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With the number of people running 850 gaskets without problems that's what I chose for my rebuild too. Granted I'm still on a 15g, but it's held up. If you've got time, why not talk to cometic about a custom gasket? I'd be down for a group buy if they want to sell more than one.

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Motor has about 2500 miles on it right now. Spoke with Justin and a couple others - I will get pics tomorrow as I am going to see my tech. I want to measure the bolts to check for irregular stretching. I will be taking Justin's advice and putting on a HG from a S60R- it only needs a minor modification to work and is a lot stronger. Hopefully once the head is off no other problems I.E. burnt valve, cracked liner etc are discovered...

While in there I will do that as well.;) Hey, it's only money...

Hi H I

Sorry to here your problems there is nothing wrong with the standard headgasket so why change it ???? I run 2.5 bar with a standard gasket but arp stud and nut kit with no problems at all please post some pics what tune etc has the car got ? I would say your problem is det.

Russ

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Sorry to hear about the HG. A 22psi actuator and spiking to 1.6 bar sounds a bit iffy to me. Holding 1.5 bar also sounds quite high for a 19t. I run mine at 1.4 bar with a stock 16t actuator and it will hold 1.5 bar to 5000 rpm if I add an extra turn to it. I have been advised by my tuner that holding 1.5 bar is too much - even though it runs afr 10.7 to the redline at WOT and WI from 0.9 bar. The back pressure will be colossal at 7500 rpm with a 22 psi actuator - the wastegate needs to open at that engine speed if you are to flow enough exhaust gas safely. Boost will drop but it's well past efficient by then anyway. The turbine is saturated at around 1.0 bar at 7000 rpm. My next round of ecu fettling will see me asking for a peak of 1.3 bar. It's a 19t - if you want to hold a worthwhile free flowing 1.5 bar then something with a decent sized turbine is the way to go (td05/td06/garrett). Theres no meaningful torque above 6000 rpm with such a small turbo and you are out of the juicy midrange if you upshift at 7500 rpm. A decent tune will see good reliable power/torque with moderate boost from a 19t. Not a lecture but I can see another HG failure on the horizon with such optimistic boost/rpms - just some friendly banter from a fellow 19t owner. :)

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#1 cause of head gasket failure as reported by most HG manufacturers is detonation.

I have been playing over the cahins of events leading up to this again and again in my mind. I had made to runs to 120 prior to this but I had rolled into the boost rather than flooring it off the line, and no misfires occured. So on the third trip I brake torqued it and floored it after releasing the brake. What happened next took less than 5 seconds total. engine redlined, (no movement of car) rpms dropped, tires begged for mercy, rpms revved back up to redline and somewhere after 7k is where things got funny. My redline is 7500 but my 6AL did not come with an 8k chip so I am running a 7k until I get one. I thought it would just have a "soft" limiter not being sure what it would do past 7k. After 7k there was a brief hesitation and a slight misfire before it attempted to shift and blowup. I am not sure if the momentary hesitation was from the 6AL's limiter kicking in or not and I did not think the detonation was severe enough to do any damage. I will post up pics of the damaged HG tomorrow. pistons, valves, liners, all look ok. After much thought here is the course that I will be going down.

new head bolts- S60r

new head gasket- S60R

replace cam seals, intake mani gasket. ex mani, gasket, radiator, & expansion tank.

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I wouldn't use the special S60R gasket. If you notice, the S60R also has unique plugs due to the change in height.

diff. in plug length is 26.5mm to 19mm. 7.5mm difference is huge! Something other than the gasket is accounting for that....

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So?

OP, did you hear any detonation?

I'm just saying...ain't NO way he's getting full timing advance (more likely quite a bit of retard) on pump gas at 23-26psi unless he has meth injection running 100% of the time, or he only fills up with 100+ octane.

Car would probably be faster with less boost and more timing advance on pump gas.

...unless there's something magical about Motronic that I don't know about, anyway. heh.

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