I blew something due to overheat. - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members

Engine Performance This section is for discussion on all engine building related questions.
Sponsored by:
Sponsored by:

LinkBack Thread Tools Search this Thread
Old 06-18-2010, 04:45 PM   #1
Junior Member
Thread Starter
iTrader: (4)
Join Date: Mar 2007
Location: Greece
Posts: 290
Total Cats: 4
Default I blew something due to overheat.

I am afraid I have some bad news.
My car overheated while a pipe of the coolant reroute slipped and lost all of my water in a matter of a second.

I didn't realise it because in tunerstudio,which I am monitoring via a carpc all the time, didn't show any overheat. I had 80-90oC when it happened. I the sensor was actually measuring the air in the pipes.

The only sign I had was heavy knocking when I was in boost. So I stopped thinking I was out of methanol/water and the realised that I had a water pipe off the system.

I rejoined the pipe and filled the system with water. The start was quiet hard. It didn't want to start. The engine was flooded. It started when I unflood the engine with 100% tps but it was running rough in idle.
The car in low throttle and boost was running fine. I boosted after this up to 28 psi without any problem. No smoke, no detection that the car has a fault. Just rough idle and couldn't start easily.

The next day I measured the compression. Now are the bad news.
A week before I measured 165 165 170 165. Quiet good number.
Now it was 140-90-90-120. SHIIIIT. I didn't know how deep was the ****...

So I took the car to a friends garage. We took the head out and we found a blown headgasket and the head was not straight underneath( I don't know the word in english) It had to be resurfaced.
The pistons were clean and so does the cylinder walls.The block was straight also. (good news)

So we resurfaced the head on a machine shop and replaced the headgasket.
New compression numbers : dry 140-115-115-130. **** TWICE.
wet: The same numbers

The problems remained the same. Rough idle , couldn't start easily and the engine was flooded all the time.

So we performed a leakdown test. We performed it where the valves were fully closed. We opened the cover to be sure.
The results in all cylinders was that air escaped from the other 3 cylinders. You could feel and hear huge amounts of air passsing through. We also heared good amounts of air through intake side and the exhaust muffler. (valves?)

There was a very tiny leak from the oil dipstick but not something serious.
We will take the head again on Monday and measure it at a machine shop.

Sorry for the long post. I need your opinion on this.

Last edited by gianic; 06-18-2010 at 05:19 PM.
gianic is offline   Reply With Quote
Old 06-18-2010, 05:04 PM   #2
Senior Member
iTrader: (8)
Join Date: Feb 2009
Location: Jax, Fl
Posts: 907
Total Cats: 0

Block deck might not be even
johnmatt is offline   Reply With Quote
Old 06-18-2010, 05:06 PM   #3
Junior Member
iTrader: (3)
Join Date: Mar 2010
Location: Culpeper Va
Posts: 264
Total Cats: 0

Originally Posted by gianic View Post
28 psi

bojanglincraig is offline   Reply With Quote
Old 06-18-2010, 05:25 PM   #4
Elite Member
iTrader: (11)
chicksdigmiatas's Avatar
Join Date: Apr 2008
Location: Texas, 'Murica
Posts: 2,505
Total Cats: 7

A warped head could cause sticky valves, If you have extremely loud HLA noise, that would be the problem. Head bolts could have stretched. Block or head could be cracked, also there could be damage to the rings.
chicksdigmiatas is offline   Reply With Quote
Old 06-18-2010, 05:41 PM   #5
Elite Member
iTrader: (2)
fooger03's Avatar
Join Date: Jan 2009
Location: Columbus, OH
Posts: 4,133
Total Cats: 188

you will resurface the block and the head and put a new HG in

you will never be happy with how it runs again

get a new long block
fooger03 is offline   Reply With Quote
Old 06-18-2010, 07:07 PM   #6
Elite Member
iTrader: (12)
Join Date: Jan 2007
Location: Hermosa Beach, CA
Posts: 2,575
Total Cats: 11

Just as a reference, when we overheated our CBR600RR engine for FSAE, we spun a crank bearing. So I hope for your sake its just a warped deck.
cardriverx is offline   Reply With Quote

Related Topics
Thread Thread Starter Forum Replies Last Post
Bad head gasket or ? shooterschmidty Engine Performance 8 09-30-2015 11:28 PM
Low oil pressure after 1.8 swap and new turbo setup JesseTheNoob DIY Turbo Discussion 15 09-30-2015 03:44 PM
Koni 1150 Coilover Kit drumman83 Suspension, Brakes, Drivetrain 2 09-25-2015 08:03 PM
Advanced Engine Dynamix Review (dead oil pump content) itsMikey Insert BS here 0 09-05-2015 03:56 PM

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

All times are GMT -4. The time now is 11:18 AM.