heat + plastic dipstick = engine fire! - Page 2 - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Race Prep Miata race-only chat.
Sponsored by:
Sponsored by:

Reply
 
 
 
LinkBack Thread Tools Search this Thread
Old 08-22-2012, 06:33 PM   #21
Junior Member
Thread Starter
 
Join Date: Apr 2011
Location: Oregon
Posts: 278
Total Cats: 7
Default

I took this apart last night and noted that all of the studs were also backing out; and noticed that the threads were damaged due to the flange vibration. I checked my build notes and it shows that I torqued the studs in at 30#, dry; and then torqued the crimp nuts in at 35#. I couldn't reach the bottom 2 with a socket, so these were tightened with an end wrench, "tight".

The car was not street tested, and I figure that the two events that I attended prior to the failure consisted of an accumulated 4 1//2 to 5 hours of on track time.

The downpipe is quite heavy and is unsupported until the first OEM exhaust hanger prior to the rear axel. The suggestion of an exhaust brace at the forward section of the downpipe looks to be a very good solution.

I will also replace the steel studs, crimp nuts and also use nord lock washers.

What is the concensus for stud material? steel, stainless; I'd rather not buy the expensive Inconel unless it's necissary.

What do you think of Handyman's suggestion of resbond to lock the studs? (I worry about dis-assembly at later date). Sorry Hus, I don't know what a CHRA is or how to saftey wire it.

Sav: I will take off the heat shield... and replace it with a nomex jock strap? like Hus suggested.

Thx for your help and solutions. cj
gtred is offline   Reply With Quote
Old 08-22-2012, 09:41 PM   #22
Cpt. Slow
iTrader: (25)
 
curly's Avatar
 
Join Date: Oct 2005
Location: Oregon City, OR
Posts: 12,107
Total Cats: 518
Default

The CHRA is your Center House Rotating Assembly. From front to back on your turbo you have your compressor housing, CHRA, and Turbine housing.

The compressor housing is what the hot side intercooler pipe and air filter bolt to.

The CHRA is what the oil feed/drain and water feed/drain bolt to, and both ends have wheels on the end that stick into the two housings.

Turbine housing is what bolts to your manifold and downpipe.

The CHRA is held to the turbine housing and compressor housing with 4-6 bolts depending on turbo size. With Hustler's V-bands on the manifold and downpipe, he destroyed a CHRA by having these bolts back out/stretch. He bought inconel bolts to stop the stretching, and safety wired them to stop them from backing out.

This is certainly a "buy it and leave it" solution, probably the best you can do.

The exhaust clamp will go a long way to reduce your failures, along with placing inconel and locking hardware everywhere you can.
curly is offline   Reply With Quote
Old 08-23-2012, 10:26 AM   #23
Elite Member
iTrader: (9)
 
TurboTim's Avatar
 
Join Date: Jun 2006
Location: Chesterfield, NJ
Posts: 6,484
Total Cats: 248
Default

Quote:
Originally Posted by Savington View Post
Find me a race car with heat shields, please.
Depending on your definition of race car and heat shield:



But certainly different heat management & durability requirements compared to a turbocharged track miata.

Different budgets too.
Attached Thumbnails
heat + plastic dipstick = engine fire!-bonnevillerod-9366.jpg   heat + plastic dipstick = engine fire!-engine%2520speed%2520demon.jpg  
TurboTim is offline   Reply With Quote
Old 08-24-2012, 01:22 PM   #24
Supporting Vendor
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 14,363
Total Cats: 1,323
Default

Tim, those are a hair more extensive than the piece of sheetmetal that everyone else passes off as a heat shield.
Savington is offline   Reply With Quote
Old 08-24-2012, 02:14 PM   #25
Elite Member
iTrader: (3)
 
Join Date: Mar 2008
Location: Granbury, TX
Posts: 6,009
Total Cats: 583
Default

In the pictured cases, the components are better described as insulators rather than shields. Rather than trying to protect external items from frying, the intent is to retain as much heat energy as possible for use in the turbine. I think Andrew's point is that extra stuff (such a shields) = weight = bad. In addition, shields make inspection harder. In many cases, you are better off moving heat sensitve components away from heat sources rather than shielding the heat source.

But, we digress.

To OP, if you want to know why you should look into Inconel, Google "Creep" or "Thermal Creep."
hornetball is offline   Reply With Quote
Old 08-24-2012, 03:03 PM   #26
Supporting Vendor
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 14,363
Total Cats: 1,323
Default

I'm just saying that I don't think they do nearly as good a job as individually wrapping each line in Firesleeve or reflective heat sleeve. If you want to effectively keep specific items cool (heater hoses, lower coolant hose, oil/water lines, brake MC reservoir), then wrap those specific items.
Savington is offline   Reply With Quote
Old 08-24-2012, 03:40 PM   #27
Junior Member
Thread Starter
 
Join Date: Apr 2011
Location: Oregon
Posts: 278
Total Cats: 7
Default

Those are some well insulated pipes!

Guys, I wonder if it is more the vibration rather than the heat that rattled these bolts loose.

The nord lock washers aren't going to fit onto the flange as they are too large in diameter.

As suggested, I think that safety wire is the fix. The nuts are too small for me to drill out a corner, but I can replace the stud/nut assy with hex head bolts; drill and then tie the wire... then also weld up a DP brace.

I think that's what I'll try... and of course I'll leave the heat shield off so that I can inspect on a regular basis.
gtred is offline   Reply With Quote
Old 08-25-2012, 09:26 AM   #28
Cpt. Slow
iTrader: (25)
 
curly's Avatar
 
Join Date: Oct 2005
Location: Oregon City, OR
Posts: 12,107
Total Cats: 518
Default

Quote:
Originally Posted by gtred View Post
...but I can replace the stud/nut assy with hex head.
Can you? Can you really?
curly is offline   Reply With Quote
Old 08-25-2012, 09:48 AM   #29
Senior Member
iTrader: (14)
 
Join Date: Jan 2007
Location: Murfreesboro,TN
Posts: 1,277
Total Cats: 53
Default

I know the exhaust manifold studs on a Supra Turbo have a small hex on their ends. Many MR2 Turbo people swap them in and stay they hold better.
Midtenn is offline   Reply With Quote
Old 08-25-2012, 08:14 PM   #30
Junior Member
 
Join Date: Jun 2011
Location: Houston
Posts: 409
Total Cats: 17
Default

Quote:
Originally Posted by curly View Post
Can you? Can you really?
Handy Man is offline   Reply With Quote
Old 08-26-2012, 12:42 AM   #31
Elite Member
iTrader: (3)
 
Join Date: Mar 2008
Location: Granbury, TX
Posts: 6,009
Total Cats: 583
Default

Quote:
Originally Posted by curly View Post
Can you? Can you really?
Actually, it depends.

OP didn't give us any information on his setup. If he's running a TD04, there's actually plenty of room to use safety-wired bolts.
hornetball is offline   Reply With Quote
Old 08-27-2012, 09:33 PM   #32
Elite Member
 
Join Date: Jul 2007
Location: Little Rock, AR
Posts: 3,110
Total Cats: 127
Default

because dipstick?
jacob300zx is offline   Reply With Quote
Old 08-27-2012, 09:39 PM   #33
Elite Member
iTrader: (24)
 
kotomile's Avatar
 
Join Date: Oct 2006
Location: Monterey, CA
Posts: 7,578
Total Cats: 40
Default

This reminds me that I need to take pics of the engine from my daily. Overheated so spectacularly that the plastic timing belt cover melted onto the belt and dripped down the oil pan.
kotomile is offline   Reply With Quote
Old 08-27-2012, 09:57 PM   #34
Junior Member
Thread Starter
 
Join Date: Apr 2011
Location: Oregon
Posts: 278
Total Cats: 7
Default

Quote:
Originally Posted by curly View Post
Can you? Can you really?
I have given so much latitude for lewd innuendo in this post...

It might not matter now, but I did mean to say a "hex head bolt"; ARP 8m 24mm x 1.25 black oxide with an expanded shoulder and a 10mm head... I think it's a better way than a stud + nut as it can be easily drilled and wired.

... it's a lot of work to keep your dipstick from getting flamed.
gtred is offline   Reply With Quote
Old 08-27-2012, 10:12 PM   #35
Cpt. Slow
iTrader: (25)
 
curly's Avatar
 
Join Date: Oct 2005
Location: Oregon City, OR
Posts: 12,107
Total Cats: 518
Default

My point was you most likely can't get a bolt into all those holes. That's why the studs come in from the back.

A lot of us have studs that protrude exactly 0mm past the nuts.

Put that in your sig and smoke it.
curly is offline   Reply With Quote
Old 08-27-2012, 11:40 PM   #36
Elite Member
iTrader: (3)
 
Join Date: Mar 2008
Location: Granbury, TX
Posts: 6,009
Total Cats: 583
Default

Quote:
Originally Posted by kotomile View Post
This reminds me that I need to POST pics of the engine from my daily. Overheated so spectacularly that the plastic timing belt cover melted onto the belt and dripped down the oil pan.
Fixed. Sounds really cool. Fire! Fire! Heh, Heh!
hornetball is offline   Reply With Quote
Old 08-28-2012, 02:30 AM   #37
Moderator
iTrader: (11)
 
sixshooter's Avatar
 
Join Date: Nov 2008
Location: Tampa, Florida
Posts: 15,669
Total Cats: 1,560
Default





No exhaust leaks but cast FM mani was unshielded for trackday. Lesson learned. Now mani and dipstick tube have protection. And a new dipstick.
Attached Thumbnails
heat + plastic dipstick = engine fire!-dsc_0001.jpg   heat + plastic dipstick = engine fire!-dsc_0007.jpg  
sixshooter is offline   Reply With Quote
Old 08-28-2012, 09:32 AM   #38
Junior Member
 
Join Date: Jun 2011
Location: Houston
Posts: 409
Total Cats: 17
Default

Yep. Mine looked exactly like that, and I didn't have any exhaust leaks either.
Handy Man is offline   Reply With Quote
Old 08-28-2012, 10:38 AM   #39
Tour de Franzia
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,114
Total Cats: 351
Default

So this is now a Nordlock thread? We've done that before.
hustler is offline   Reply With Quote
Old 09-09-2012, 01:13 PM   #40
Elite Member
iTrader: (24)
 
kotomile's Avatar
 
Join Date: Oct 2006
Location: Monterey, CA
Posts: 7,578
Total Cats: 40
Default

Quote:
Originally Posted by hornetball View Post
Fixed. Sounds really cool. Fire! Fire! Heh, Heh!
Attached Thumbnails
heat + plastic dipstick = engine fire!-photo-2-.jpg  
kotomile is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Project Gemini - Turbo Civic on the Cheap Full_Tilt_Boogie Build Threads 58 Yesterday 10:04 PM
Changing from 460cc to flow force 610cc in diypnp 90 Turbo MEGAsquirt 19 10-19-2015 04:23 PM
Expected intake temps on the track? tazswing Race Prep 20 10-03-2015 12:04 PM
Leaky Wilwoods mx592 Suspension, Brakes, Drivetrain 1 10-01-2015 01:45 AM


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 04:14 AM.