Please Explain how i blew 2 heads in a year?

[SpeedAintFree]

The first was last november when my mods were only intake, catback, 190 walbro, & a t28; So pretty stock. Still dont know how that head got a crack in it. Probably age, but it was replaced at 78k in Nov 05 and in Aug 06 at 89k this new one blows as well. With mods of 550s, MBC at 15psi, & a AFC all installed and tuned at RRE in June 06 untill three weeks ago i raised it to 17psi. I use the car to deliver pizzas, so iyeah its my DD. She is ATM and never sees that hi boost (maybe 5-8 on the street/freeway tops) I always thought that was babying her enough, but maybe I'm totally wrong? Any suggestions?

 

[dsm4fun]

I had a problem like that but i had mine replaced and its fine now. Is it just the head is cracking or have you bent valves, broke belts etc. I replaced mine because my timing belt stretched out and bent stuff. Also my mechanics daughter has one she had the same problem you are ill ask for you to see what it was. I would check the timing first though.

 

[formulav893]

the first could have been due to high milage, overheating, maintainence etc. the second, could have been from installation, im guessing anyways im not familiar with dsm's. could have been incorrect torque pattern used when installing, or even wrong torque numbers for the head.

 

[Blackmitzu]

Where exactly is the head cracked? Did both of them crack in the same spot?

 

[SpeedAintFree]

i haven't had the mechanic pull the head yet. they told me water was in one of the cylinders though. also what prices should i be expecting, SBR has OEMs for $750 and stage 1s for $950, but how much would labor be on these heads? i last paid $1100 for the first head gasket total.

 

[jumpfroggy]

Can you clear up your description a bit? It seems like you had it tuned at 15psi at RRE, turned up the boost yourself without retuning, then turned the boost down to 5-8? Just need a clearer idea of the history of the car and where it stands now. Also, you have water in the cylinder... what were the symptoms that caused you to believe the head's blown? Have you ruled out things like pitson rings and head gaskets?

 

[95talon_in_ma]

I have only heard of heads cracking from overheating. I am unaware of any other way that it could happen except through excessive heat.
Outside of a piston letting go or some kind of obvious abuse.
When you put the new ones on did you have them hot tanked and magnafluxed? The cracks are so small sometimes you can't see them with naked eye.

 

[Merkles]

i haven't had the mechanic pull the head yet. they told me water was in one of the cylinders though. also what prices should i be expecting, SBR has OEMs for $750 and stage 1s for $950, but how much would labor be on these heads? i last paid $1100 for the first head gasket total.

learn how to do it yourself, and use all that labor money to get better parts.... just an idea though

 

[talonproject]

i d get a used one for 200 $ ... searcha bit and you will find used ones that are clean