Every 8-10 months, depending on use, I go through a waterpump via a head gasket failure.

The failure seems to be related to when I am using the 2step alot. My car is protuned and I do not experience knock events that otherwise point to excess cylinder pressures. I am using methanol and this I understand may cause excess cylinder pressure if missfires occur. I have removed the throttle body from the coolant loop in case there is an issue from there.

Basic stats: built 2.0, GT35R, methanol, aem ems, arp top to bottom (properly cycled and torqued), 1g coil on plug, and supporting mods

My question is, what success and failures have others experienced with a similar issue?

I know this is a common failure and there are alot of threads on the topic. I am seeking feedback from others who have had similar experiences.

 

Warped head

 

That would make sense if the block and head were not milled to better than 50rmr after the last failure.

 

I am going to step out on a limb and wait to be corrected by someone with more knowledge than I about the phenomina.

In my limited understanding it appears during the 2step engagement that methanol is present in the combustion chanber and since the 2step cuts the point of ignition there are multiple resulting misfires created by the motor hitting the limiter. As a result of the misfires excess methanol builds up inside the conbustion chamber and the subsequent firing of the motor occurs with a more than desired methanol content. This excess methanol creates cylinder pressures beyond that of the ring and head gasket capacity and the head lifts passing exhaust gasses into the coolant galley and either a freeze plug in the block or on the waterpump pops out, sometimes even the seal at the pump is compromised.

What have I done in an attempt to remedy the situation?

- I don't use the 2step to launch - I rev the motor to the desired RPM and disengage the 2step so it does not interfere

- I had my head and block macined to a tolerance indicated by my machinist to be a desired rmr to maintain the headgasket seal and keep some "friction" for the gasket seating

- I removed my throttle body from the coolant system just in case there is a seal that compromises the coolant system under boost

- I heat cycle and torque my headstuds to 120ft lbs. - when initially installing the head I torque the head studs in proper order at 20lb intervals to 100ft. lbs. then, afterheat cycling and allowing the car to sit overnight, I untorque one headstud at a time, in the order of proper installation, and retorque to 120ft lbs. (this approach to head stud torqing was presented to me by a very reputable engine builder and longtime enthusiast - in my observation it has helped the issue)

Through the above methods I have seen my headgasket last 8-10 months. Usually, the failure event comes after I decide to try and get the 2step to work again and ends in headgasket compromise. For this reason I am no longer going to use the 2step and see how long it will last this time. BTW - previous to the above measures I had mixed results with headgasket failure after 2step use that would sometimes last no more than 4-6 weeks. I also know that some stock cars that are completely unmodded experience this. (no meth)

I would like to have an open discussion with others who have had this issue. I know it is very common and this is an attempt to collect experiences on the matter for joint resolution.

I expect that some of my above assumptions are incorrect, with regard to the actual event that cases the failure. Will someone with more experience and knowledge chime in and add o the discussion?