ARP's are stronger than OEM, but not by much, then the next step up is A1, but i believe that good power can be made with OEM head bolts. Here in the UK we've had quite a few people lift heads in the 500- 600 range, with slightly lower grade petrol.
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read a while ago PRM uses different size head gaskets to fix head lift
Pit road M head gasket - 3000GT/Stealth International Message Center
http://www.pitroadm.com/public/ENGINE/PARTS/GASKET1.htm
If any part of the gasket hangs into the cylinder you are asking for trouble.
So I went to the shop today and grabbed a stock head bolt and washer..A1 washers are the same size.
There is a clear double indention in my head from a washer, one is stock level, 2nd is from a washer. I think the old ARP's I had a few years back, caused this. All good on the A1's. I am still going to see if I can find a slightly wider washer from maybe ARP, its not going to hurt things.
So heads up, not sure if anyone had old ARP's from maybe 2003-2005 era, but check your head washer area.
All the threads and fixes have left me somewhat baffled over the years. For every anecdotal citation of failure with A,B,C combination of hardware/installation process/tuning set up/power level there seems to be ten cases of just the opposite results from the same combination.................and vice-versa.
In my mind, coolant push is extremely simple..........yet amazingly complicated at the same time. The simple side is that each and every instance of coolant push into the overflow reservoir is caused by exactly one and only one thing: pressure in the coolant system exceeds the rated lift pressure of the pressure cap. The complicated side is: what is the source of the excessive pressure in the coolant system?? And how do I fix it?? For some people, simply jacking up the lift pressure from 13psi to 23psi is all that is needed. For others, some combination of fastener/gasket design/lift fix/etc/etc/etc was required to solve the problem. Some never find the right set of parts/installation/tuning that slays the evil Push Dragon. And for every ten vehicles with this problem, it seems there are 25-30 potential "fixes".
I think one underestimated factor is air pockets in the cooling system. These can be the result of lack of initial fill purging or small coolant leaks that draw in air instead of coolant from the overflow reservoir. Another issue I think is underestimated is the water pump itself. Certainly different non-oem units can more readily induce cavitation leading to hot spots, and system over pressure. And certainly the operating conditions in the environment influence things.
My conclusion? Every case has to be evaluated on its own merits. There is no single cure for the problem. Why do I say this? Because there are too many scenarios that will cause the observed symptoms and too many reports of different combinations that "fixed" the problem.
Just my 1.5 cents worth.
Quote:
Originally Posted by Streamln1
That's a lot of timing for that boost and octane. The head was compromised, but your tune is what popped it. Can you be more specific on the 100 octane you were running? Most 100 unleaded is only only 95-96 MON, and does not offer a huge increase in knock deterrence over 93, especially if its watered down with a little 93 left in the tank. Was it pure 100 or mixed in with some pump gas? Or did you dilute a higher octane and/or leaded fuel down to 100? There's a huge difference in MON depending on how you get to "100". What WTQ were you making?
Its probably a combination of things, cylinder pressure, non flat washer surface giving me innacruate torque readings on the head studs, etc. While not directly related to power, with my power goals in mind with my build in the process of changing, its actually a good thing it happened at 600awhp when I was about to pull the engine anyways for the new turbos. Even on e85 with my goal of 800-850awhp I bet they would have lifted, and been a lot bigger deal. I wasn't super pissed about it, it was just a learning experience for me.
Fuel was 95% Sunoco 100, we drained the tank down to next to nothing, maybe 1/2 gallon left and 10 gallons of 100. We backed the timing back down to about 16-17, closer to 18-19 was the knock threshold on that fuel though torque was still rising. 560ft lbs was the peak. We scooped the timing a bit in the peak tq area to keep it friendly. the HG was not really damaged much, you could see one spot on the gasket where it had pushed a little under boost, but it was very brief from the looks of it. And the heads are still strait so that's another good thing. The tuner I work with is damn good at keeping a close eye on things and when to abort and back it off. Compared to some I have seen over the years, hes probably the most careful and trustworthy.
Going e85 on much bigger injectors now, so that's going to significantly lower cylinder pressures, plus its cheaper. Doin a flex fuel sensor and map on the AEM as well. E85 was a little scary to me, not because of the tune but the variance in quality out there, but it seems doing a flex map will help keep everything in line with what the fuel will take safely.
Also, im looking into getting the PRM head gaskets, from what I have read they have a superior fire ring design, has to be much better than the cometic gaskets im running. Although there are a lot of success stories with cometic, infact I had run them for 10+ years, but again never at this power level, not saying they were the cause by any means but it cant hurt to step up in that area too.
So eliminating most of the probable causes, and back to it:)
They don't hang into the cylinder, they just offer various thickness like the cometic ones.Quote:
Originally Posted by donniekak
While I agree, this was clearly lift, the volume of push was definitely caused by overpressured coolant system...if it was just spitting out a little, I would prob up the cap to a 1.3 bar. It has a 1.1bar on it right now.
Quote:
Originally Posted by BaadVR4
Hopefully you guys back off the timing for e85. You don't need or want the timing at boost hit/peak tq. Up top may be fine at 18-19 depending on your setup.