Hi,

I build a b20vtec about 2 years ago, I only bring it out during summer. Here is the setup.

- 2000 GS-R Head
- Skunk2 Tuner Stage 2 vavletrain (0 degrees IN/EX)
- ARP Head studs
- JDM B20b Block
- CP Pisons 84.5mm 11.5:cr
- Eagle Rods
- ACL main and rod bearings
- KMS Block girdle
- KMS Blockgard
- Cometic B20vtec 84.5mm head gasket
- Block breather kit

Lately, I was missing coolant every once in a while (Thought I had a slow leak from a hose). When I checked my oil, I noticed that it was mixed up with coolant. I brought my car in, and the mechanics told me my head gasket was shot. He said the it screwed up because a bad tuning. He mentioned that my coolant sensor (the one for the ECU, not the dash) was defective (always sent signal that the engine was cold). It makes sense, my car had difficulty starting when it was hot (after a 20 - 25 minute ride). My question is, since the faulty sensor indicated my ECU that the engine was cold, my ECU sent too much fuel in (like a bad tune) and THAT is what screwed up my head gasket, does this make sense? Should I consider checking other things as well when I change the gasket (other possible failures)? Also, the car was tuned with eCTune, shouldn't a check engine light up with that faulty sensor?

Thanks,

 

I'm leaning towards that cosmetic gasket. Do a leakdown test.

 

yeah that doesnt sound right with a bad tune, sounds mostly like what the above said, bad head gasket. i never really heard a bad tune would do that, unless you drive extremely aggressive with a bad tune to cause your gasket to blow.

 

I had a ton of problems seating my Cometic HG in my 84.5 mm B20V. Both decks were machined also. I switched to an OEM B20 gasket and machined it to fit, worked fine after that.

 

Happy to hear that, I ordered a OEM B20 gasket at Honda today. It should arrive tomorrow. Basically, I just swap the gasket (make sure head and block is OK before setting everything back in place) and I can continue running on the same chip. I don't drive like a maniac, it's a daily driven car. I like to pop it from time to time, but I'm mostly relax with it. I switch gears from 3.5k - 4k RPM.


When you say machined, what do you have to do? Isn't is supposed to be a direct fit (84.5mm isn't big enough to make a difference)?

 

i forget to ask, what vtec conversion kit did you go with? You might know this, but there is more than just a head gasket. Unfortunately the b20 block doesn't have the same oil feed lines like the vtec b series. i'm pretty sure if you search you'll find a lot of b20 vtec conversion kit. The one i have is the Speedfactoryracing kit.

 

It's a 3000lbs truck brake line. You can see it well here....

 

If the coolant temp sensor was bad and indicated a cold temp from coolant. You will run super rich, which had nothing to do with your tune but with the sensor.

That will not cause a blown headgasket.

 

I have been running OEM B20 HG on an 85mm for a few years now with no issues, would never spend the extra $$ to have it machined. FWIW

 

Thanks, that's what I wanted to read!

 

what happens if u don't have the oil feed line in? because i don't have it in, i think my car was vtec but previous owner got it removed. it was also turbo because i have gauges and apexi controller still in and they light up. I'm interested in converting back to both and my car has the b16 ecu

 

Head warped - use a good HG next time around.

 

Nothing wrong with Cometic gaskets. I have used them on all my Honda/Ford/Chevy builds and never had issues.

 

Holy old thread!

While it's up, what was the problem? Just a bad headgasket? worse?

Reading the whole thread I wouldnt have blamed the coolant sensor either. If anything it will lessen the chance of the typical head gasket lean failure.