Blew a HG on the dyno...

[yellow1995Cobra]

Ok heres it went it down..

Had the car on the dyno, he burnt a quick chip, real conservative. He ran it up to 3k a couple times, it was making 360 rwtq at that point, exhaust was starting to get black as he got on it (rich), the air/fuel was at 10-1.

So everthing looked great at that point, he went ahead and ran it up to 5k, air/fuel was right at 10-1, still real rich, and boom, the upper rad hose goes flying the **** off, drenching us in antifreeze, luckily it was only at 135 degrees or so. He shut it down immediatly.

At first glance, we thought it was just the upper rad hose, so we threw a new clamp on there, leaving the rad cap off. He went to start the car, and the coolant shot out the rad about 3 feet. Blown HG!!

So wtf is going on here, we took out the 5 plugs that are easy to get too, and they all looked good, none ghost white like last time.

We really are at a loss to what the problem could be. I torqued the heads correctly both times. My thoughts so far are: 1) One bad injector? Would the air/fuel still be THAT rich though? 2) block warped somehow? 3) heads warped some how? 4) junk arp bolts?

Im kinda loosing my interest in boost now, two HG's in 1 week is crap. I figure ill give it ONE more shot with some of those ROL gaskets and see what happens. IF i pop another for no f'ing reason, im doing like vib and going with a fuelie 408.

Well im pretty pissed to say the least after the 240 towing bill lol. Thankfulling the dyno shop owner(mike dez) was nice enough to only charge me 100 even though we were there for 4 hours.

Any ideas guys?

 

[Rootus]

DAMN! That sucks!!

... I have dibs on the PTK kit! ...

(sorry, had to...)

I'd say it's time to check the deck for square as well as the heads, maybe when it was running lean before it warped something. That's the only explanation I can think of, short of a defect in the HG. Which gaskets were these?

Dave

 

[RIO5.0]

What a drag....

 

[S/CBlack95GT]

What was the timing at? Did you clean the block really well each time? What did you torque the head bolts to? What PSI of boost are you running? Next time take the heads somewhere to be checked for flatness, check the injectors, and BTM. I know that is all costly but something is wrong if you are blowing them this easy at only 5K with a 10:1 AF/R.

 

[5.0 from 95]

I am about to be at that point on my install. I hope it goes better than that for me. I also hope it was just the head gasket and not something out of square. I will keep my fingers crossed for you.


Paul

 

[VibrantRedGT]

I feel ya Jesse. Been there and done that. Hopefully it's just the gasket. I thought so too until the leakdown test. I would suggest you do one too.

 

[S/CBlack95GT]

I have had great luck so far with my graphite Fel-Pros torqued to 85ft-lbs(65 with the moly lube and thread sealer).

 

[yellow1995Cobra]

Thanks for the responses.

Well the heads were torqued to 80 on the top, 70 on the bottom...

I poped the pass side head off, and yet another 3 cyls fire rings are screwed. It actually cracked the fire ring in one spot, yet the plugs look perfect.

So it leads me to believe that either the block on that side is outa wack, or that head is warped.

We are gonna check the block tomorrow..If its the block, i really cant see pulling it and repairing it. Maybe ill just go the expensive route and grab a dart block with forged internals.... Who knows

 

[SN95_XB331]

How much boost are you running?

Definitely sounds like you're blowing boost into the cooling system. That's why the plugs look good, no leakage into the cylinders or steaming--either the head is lifting from boost or you got warpage somewhere. If this is the 2nd HG blown, I say it's the latter (sorry). Also, are you using a stock PCV setup? If everything checks out, reassemble, run it lightly a few times and do a leakdown--if 100%, then take it to the dyno.

As for having a 10:1 A/F... if you're under 500whp, turn off the inline pump and make cautious pulls from there (i.e. dyno operator should know this). I run a 255 (GSS340) intank and 255 inline, could not get the A/F above 10:1, so I took power off the inline and now runs smoother (11.5:1).

 

[yellow1995Cobra]

How much boost are you running?

Definitely sounds like you're blowing boost into the cooling system. That's why the plugs look good, no leakage into the cylinders or steaming--either the head is lifting from boost or you got warpage somewhere. If this is the 2nd HG blown, I say it's the latter (sorry). Also, are you using a stock PCV setup? If everything checks out, reassemble, run it lightly a few times and do a leakdown--if 100%, then take it to the dyno.

As for having a 10:1 A/F... if you're under 500whp, turn off the inline pump and make cautious pulls from there (i.e. dyno operator should know this). I run a 255 (GSS340) intank and 255 inline, could not get the A/F above 10:1, so I took power off the inline and now runs smoother (11.5:1).

I was running off just the wastegate (8lb's). He had purposely made the car run very rich, as he knew i just blew a HG and didnt wanna lean it out and pop another. The base timing was at 10 degrees, and pulled out a bunch more to be safe.

The header on the passide was coated in antifreeze, and cyl's were filled up as well.

I know that tomorrow im gonna find that the block is warped...

 

[95GTvert[bv12]]

DUDE get a new tuner...if you anything over 12:1

 

[95GTvert[bv12]]

DUDE get a new tuner...if you anything over 12:1 and your tuner is useing the fule to cool the air....get a water injection set up and tune out some fuel you will kill your piston rings at 10:1.....i give your rings 20,000miles if you run at 10:1.

 

[yellow1995Cobra]

You obviously dont read anything i write. Thanks for the useless post

 

[stang_gt_1994]

You obviously dont read anything i write. Thanks for the useless post

Between me and you this is why I am on turbomustangs.com more now. Maybe after you get your block and heads checked out you can try out some cometic gaskets. Good luck and see you on tm.

 

[Rootus]

Three more rings, eh? Really sounds like something's warped. I'm going to bet it's the head. Good luck, hopefully you'll get it back together soon.

Dave

 

[OrangeMustangGt]

damn man sucks. Where did you bring your car to get tuned? my buddy needs his car to be done soon

 

[Grn92LX]

I agree with checking the heads and block for warpage. If thats not it, consider upgrading to heads Studs..

 

[95snoozer]

Can I suggest a pair of dart juniors or senoirs ovver the AFRS?

something iron

definitely sounds like the heads warped. My friend went through 5 in 3 weeks on his plymouth laser (Trapped mid 120s). he had a BIG turbo running mid 20s in boost. after the 5th went while running my roomate at the street races, I asked him if they milled the head for flatness. No, they didnt check.

me-you have the block and heads O-ringed?
him- would that help?

 

[stang_gt_1994]

Sometimes o ringed head gaskets will not be a good idea. A head gasket works as insurence. Thare are plenty of gaskets out thare that are not o ringed that will hold pleny of boost. Also iron heads tend to detonate alittle more due to the heat exchange between iron and aluminum, and he doesent want that on a stock bottom end. Something had to happen with you cooling "yellow". Did at any time you run way up in temp?

 

[Joes95GT]

I know next to nothing about boost (especially a turbo), so I'm learning with everyone else on this one. The first thing that would lead me to believe that the deck is out of square is WHERE the headgaskets are blowing. Are they in the same spots everytime? If so, that is where I would really focus on. I know there are many other factors that could be causing the headgaskets to blow in the same spot, but just look for obvious clues. It's always the obvious stuff that gets over looked. I would also suggest trying a Cometic (sp) headgasket. I've heard that they are the best when it comes to boost - bar-none.

When I read your very first post, the very first thought that came to my mind was "bolts or studs?" Like Grn92LX said, you may want to look into studs if you don't have them already.

Good luck. I'm interested in seeing what comes out of this...

Joe