Freshdot

I want to be as descriptive as possible so please bear with me.

So my freshly rebuilt motor has about 100 miles on it, I'm running a new OEM HG and new ARP studs TQ'd to 60ft lb as per ARP's instructions. The setup is a D16z6 fully built top to bottom on an 18G with stock sleeves.

**The block has a replaced stock sleeve in it**I also haven't checked or retorqued my studs as ARP doesn't specify to**also no overheating issues have been seen yet**


This is a motor that was experiencing headlift on my previous build. I was constantly getting coolant pushed in to my overflow tank. It should be noted that all the coolant hoses on the car with the exception of the upper and lower radiator are about 20 years of age and again were dealing with headlift previously. So I can understand how they would have become chaffed with all the expanding and contracting.


The current condition is that on the day of my dyno tuning, my mishimoto 1.3bar radiator cap failed. Which we attributed to the previous setup headlifting. On the dyno we replaced the mishi cap with a brand new OEM NSX cap. Whether or not this cap is appropriate is beyond me, however it seems to fit and function fine. I'll let you kind folks be the judge of that.

2 pulls later the coolant bypass hose failed where it meets the intake manifold at the hose clamp, a pin hole. The only option at the time was to repair the hose by cutting it after the pin hole and reinstalling it. That evening during WOT 3rd-4th gear pull on the highway that very same hose ruptured at the same location by the intake manifold, except this time it was more like a razor blade slice. Should I have probably replaced this hose completely before going driving?..of course. However who can resist cruising after being fresh off the dyno. Throughout all of this the coolant overflow hasn't been seeing much action, it's been seeing stock overflow with maybe a **** hair added than a normal car would have.

These symptoms have lead me to a few conclusions of which I would like to collectively chat about.

1. These lines are simply old, torn, and tattered and can't handle to output of a water pump being revved to ****. Failure should be expected given their history on a headlifted motor..?

2. The radiator cap isn't correct, which I don't really believe because the NSX cap is rated at 1.1 bar so is an OEM d16z6 cap. Maybe it isn't seating correctly in the mishimoto radiator and not functioning properly, however that would show in the form of a leak at the cap..amirite?

3. Mother F**king headlift..this one I don't want to believe..simply because I purposely went to a tuner with arguably one of the best reps on the east coast to avoid problems like preignition/detonation. The tune is also really conservative and Jeff told me straight up that the ignition timing is way too tame to have this problem.

4. and last conclusion..that replaced sleeve is ****, or could have slipped down in its bore.

The steps I'm looking to take are:

1. Replacing all these old *** coolant lines.

2. popping a mishimoto 1.3bar rad cap on the rad, mainly because I want to ensure a proper fit at the filler neck.

3. Checking the TQ on the studs.

4. If I'm still experiencing an issue such as a coolant overflow tank filling up, I'm going to perform a leak down test. the problem with this, is that I don't believe a leak down can simulate 18psi of boost pressure at 7,400rpm.


the last thing I really want to ask..is let's say everything is functioning properly, no headlift, and a properly functioning radiator cap...is it normal for coolant lines to experience higher pressures under boost than a stock car? Would we say it's probable that old shitty lines will pop on a properly functioning setup given what they went through?

I still consider myself a novice in the boost world and every day is a new learning experience. If you've stuck this thread out to the end then I seriously have to thank you

OneBadTurboCRV

I am just left scratching my head why you wouldn't have replaced maybe $50 in hoses to begin with? Why cheap out? In a normal operating coolant system the radiator cap is used to determine the pressure of the system. The amount in the overflow bottle is directly related to the coolant temperature and should go back to "normal" level after cool down.

You need to replace ALL the old hoses first and reevaluate the situation then.

mar778c

iTrader: (1)

Co signed everything stated.

OP, why did you not replace the hoses while your were rebuilding the engine? Fix this peddling stuff so you can enjoy your car. I saw your dyno thread, nice job.

Freshdot

thanx a lot guys, I will tackle this over the weekend. It wasn't so much as cheaped out rather than overlooked.

seriously thanx for taking the time to read all of that.