Recent Topics
Pecan Pie Cheesecake Recipe
by GumbyJarvis - 04/06/20 05:03 AM
Dewalt DXCM251 25-Gal Oiled Air Compressor
by The Critic - 04/06/20 03:40 AM
Windows File & Folder Fix Tool
by ZeeOSix - 04/06/20 01:53 AM
$.25 washer fluid at WM
by joel95ex - 04/06/20 12:13 AM
`16 Suburban OLM never tripped due to time
by zfasts03 - 04/05/20 11:26 PM
Straight 30W [Briggs & Stratton] @ Amazon
by SlavaB - 04/05/20 10:56 PM
Bosch 3323 Premium Filter Cut Open
by TrainingPolicy - 04/05/20 10:29 PM
CARQUEST Premium Oil filter 84341 Cut Open
by TrainingPolicy - 04/05/20 10:12 PM
C-1706 SAKURA Cut Open
by QuangTeo - 04/05/20 10:07 PM
Had to smile
by AZjeff - 04/05/20 10:04 PM
Childhood friend dies
by Marco620 - 04/05/20 10:00 PM
Leftover 100LL in vehicle
by PantherFan88 - 04/05/20 09:42 PM
The good old days.:)
by A310 - 04/05/20 09:04 PM
Harvest king switched suppliers confirmed.
by Micahmcmeen - 04/05/20 08:15 PM
Mobile 1 Synthetic 15w/50 - Not what it used to be?
by NorCalHD - 04/05/20 06:21 PM
Bad Rear Brakes- Not obvious
by ford46guy - 04/05/20 05:03 PM
Move car w/ NO coolant?
by SavagePatch - 04/05/20 04:39 PM
VIRGIN BOSCH 3400 CUT OPEN
by 53' Stude - 04/05/20 04:18 PM
First vehicle you ever purchased?
by 53' Stude - 04/05/20 03:56 PM
Newest Members
KebabDad69, KMoJo, F7daved, khouan, daniell
71108 Registered Users
Who's Online Now
79 registered members (4WD, Amkeer, alchargo, aquariuscsm, 77GrandPrix, 2015_PSD, 8 invisible), 1,609 guests, and 15 spiders.
Key: Admin, Global Mod, Mod
Forum Statistics
Forums67
Topics303,661
Posts5,239,368
Members71,106
Most Online4,538
Jan 20th, 2020
Donate to BITOG
Print Thread
Hop To
Page 2 of 3 1 2 3
Re: What happens if you reuse cylinder head bolts? [Re: Loobed] #2796008 11/07/12 08:57 PM
Joined: Sep 2006
Posts: 19,479
M
mechtech2 Offline
Offline
M
Joined: Sep 2006
Posts: 19,479
I have reused them with 'down and dirty' head jobs.
But there are too many variables to call this a correct procedure.
All sorts of things can stack up wrong.

TTY bolts are elastic, and are springs. They have limits.
I have had success with reusing them, but can not recommend it.

Re: What happens if you reuse cylinder head bolts? [Re: Loobed] #2796177 11/08/12 12:17 AM
Joined: Dec 2002
Posts: 43,557
S
Shannow Offline
Offline
S
Joined: Dec 2002
Posts: 43,557
They are actually operating in their plastic range, and when relaxed, follow an elastic line parallael to their original elastic line, but with the offset due to the permanenet elongation (that must exist, as they have yielded).

Depending on the material, the process can be repeated a number of times safely...some none, some a few.

Re: What happens if you reuse cylinder head bolts? [Re: Shannow] #4948819 12/11/18 09:10 AM
Joined: Jan 2013
Posts: 410
N
NGRhodes Offline
Offline
N
Joined: Jan 2013
Posts: 410
Stretch bolts are designed to be elastic, the closer they get to the limit of elastic stretch, gradually more permanent stretch occurs (I don't know the exact relationship); each time they permanently stretch they reduce the maximum clamping force possible (before failure) as the structure weakens each time permanent stretching occurs.
Also there can be issues with damaging threads on aluminium blocks.

Re: What happens if you reuse cylinder head bolts? [Re: Loobed] #4948904 12/11/18 11:36 AM
Joined: Nov 2004
Posts: 8,180
G
GMBoy Offline
Offline
G
Joined: Nov 2004
Posts: 8,180
You will be doing the job over

Re: What happens if you reuse cylinder head bolts? [Re: Loobed] #4948961 12/11/18 12:56 PM
Joined: Feb 2005
Posts: 3,296
E
Eric Smith Offline
Offline
E
Joined: Feb 2005
Posts: 3,296
Don't know about GM but I'm reusing the ones on the Focus. Granted they were new and only used for a couple hours runtime before it sucked in another piece of valve seat. Used some copper gasket coating on the headgasket. We'll see what happens... I didn't reuse the factory bolts the replacements was cheap.


05 Chevy 3500 (Class C RV) 71k
04 Escape 170k
02 Focus 152k
00 Dakota 95k
Re: What happens if you reuse cylinder head bolts? [Re: Loobed] #4949630 12/12/18 04:32 AM
Joined: Dec 2011
Posts: 319
E
Exhaustgases Offline
Offline
E
Joined: Dec 2011
Posts: 319
In the old days things were done correctly, no need for TTY bolts. Things done cheapy now and TTY is a great way for the dealer to make more $ on the repairs, it helps pad the parts bill. Car things are not better now just cheaper to build, there is no money in making it last forever.

Re: What happens if you reuse cylinder head bolts? [Re: Exhaustgases] #4949633 12/12/18 04:37 AM
Joined: Dec 2011
Posts: 6,976
rooflessVW Offline
Offline
Joined: Dec 2011
Posts: 6,976
Originally Posted by Exhaustgases
In the old days things were done correctly, no need for TTY bolts. Things done cheapy now and TTY is a great way for the dealer to make more $ on the repairs, it helps pad the parts bill. Car things are not better now just cheaper to build, there is no money in making it last forever.

Seems like we're doing fewer head gaskets now...


"Zed's dead baby, Zed's dead."
Re: What happens if you reuse cylinder head bolts? [Re: Loobed] #4949655 12/12/18 05:55 AM
Joined: Oct 2008
Posts: 19,640
SteveSRT8 Offline
Offline
Joined: Oct 2008
Posts: 19,640
I cannot imagine doing major work like a head gasket and cheaping out on parts!

Crazytown...


"In a democracy, dissent is an act of faith."
J. William Fulbright
Best ET-12.79 @ 111 mph
4340 pounds, Street tires
Just like we go to Publix
Re: What happens if you reuse cylinder head bolts? [Re: rooflessVW] #4949685 12/12/18 07:20 AM
Joined: Jan 2013
Posts: 410
N
NGRhodes Offline
Offline
N
Joined: Jan 2013
Posts: 410
Originally Posted by rooflessVW
Originally Posted by Exhaustgases
In the old days things were done correctly, no need for TTY bolts. Things done cheapy now and TTY is a great way for the dealer to make more $ on the repairs, it helps pad the parts bill. Car things are not better now just cheaper to build, there is no money in making it last forever.

Seems like we're doing fewer head gaskets now...


TTY bolts hold their clamping force for longer, they have less mechanical strain and fatigue less than regular bolts (of same size, similar cost target) when used correctly.

One workaround for regular bolts is to use more or oversize. Compression washers can also help with regular bolts (they add a bit of elasticity to the clamping force), but are not economically reliable under the high forces required for clamping a cylinder head down.

Re: What happens if you reuse cylinder head bolts? [Re: Exhaustgases] #4949701 12/12/18 07:50 AM
Joined: Dec 2005
Posts: 13,882
K
kschachn Online Content
Online Content
K
Joined: Dec 2005
Posts: 13,882
Originally Posted by Exhaustgases
In the old days things were done correctly, no need for TTY bolts. Things done cheapy now and TTY is a great way for the dealer to make more $ on the repairs, it helps pad the parts bill. Car things are not better now just cheaper to build, there is no money in making it last forever.

People who have no clue as to a valid engineering reason for something should not fabricate one in their own head and post it to the Internet.

Where did you get your engineering degree?


1994 BMW 530i, 252K
1996 Honda Accord, 288K
1999 Toyota Sienna, 434K
2000 Toyota ECHO, 284K
Re: What happens if you reuse cylinder head bolts? [Re: Loobed] #4949717 12/12/18 08:29 AM
Joined: Nov 2006
Posts: 23,196
T
Trav Offline
Offline
T
Joined: Nov 2006
Posts: 23,196
MB used to publish a max length spec for stretch bolts so those could be reused with no problem if it was under the max. If there is no spec I don't reuse them.


ASE L1, Master. Deutsch Meisterbrief.
Re: What happens if you reuse cylinder head bolts? [Re: Loobed] #4949970 12/12/18 12:43 PM
Joined: Jan 2013
Posts: 3,837
W
WyrTwister Offline
Offline
W
Joined: Jan 2013
Posts: 3,837
I was a High School Senior 69 - 70 . Went to school 1/2 day .Worked 1/2 day at the dodge dealer as a shop flunky / go-fer .

At that time it was SOP to re-use head and all the other bolts , as long as they were not damaged .

Only in the last 5 years have I heard of TTY bolts .

Anyone wish to enlighten me why the change ? Does it have anything to do do with aluminum heads and / or blocks ?

Thanks , :-)


Wyr
God bless
Re: What happens if you reuse cylinder head bolts? [Re: WyrTwister] #4949987 12/12/18 01:03 PM
Joined: Dec 2005
Posts: 13,882
K
kschachn Online Content
Online Content
K
Joined: Dec 2005
Posts: 13,882
Yes, it can be related to the use of aluminum cylinder heads but it is also related to the specific type of head gasket being used. Overall it provides a much more consistent clamping force over the expected operating temperatures.

I tried to find a good reference and this seems about as good as any other:

https://www.felpro.com/technical/tecblogs/proper-installation-use-t-t-y-bolts.html

You can still generally reuse TTY bolts as long as you know what is a maximum permitted length (or sometimes a diameter) for the bolt.


1994 BMW 530i, 252K
1996 Honda Accord, 288K
1999 Toyota Sienna, 434K
2000 Toyota ECHO, 284K
Re: What happens if you reuse cylinder head bolts? [Re: kschachn] #4950029 12/12/18 01:55 PM
Joined: Dec 2006
Posts: 9,324
K
KrisZ Offline
Offline
K
Joined: Dec 2006
Posts: 9,324
Originally Posted by kschachn
Originally Posted by Exhaustgases
In the old days things were done correctly, no need for TTY bolts. Things done cheapy now and TTY is a great way for the dealer to make more $ on the repairs, it helps pad the parts bill. Car things are not better now just cheaper to build, there is no money in making it last forever.

People who have no clue as to a valid engineering reason for something should not fabricate one in their own head and post it to the Internet.

Where did you get your engineering degree?


Yup, the use of TTY bolt has nothing to do with cheapining out or padding the repair bills for the dealerships.

For cylinder heads, TTY bolts have a very good advantage. Since they are in the elastic range, they can elongate and shrink with the head and gasket as the temperatures changes and keep a more consistent clamping force on the whole assembly.

It is not a coincidence head gasket problems are occuring much less and at much higher odometer readings. TTY bolts are part of that.


2015 Grand Caravan 3.6L - 35k miles.
2006 Mazda 3 2.0L - 186k miles
Re: What happens if you reuse cylinder head bolts? [Re: Trav] #4950432 12/12/18 10:09 PM
Joined: Dec 2013
Posts: 4,296
C
clinebarger Offline
Offline
C
Joined: Dec 2013
Posts: 4,296
If the OP is asking about his GM LM7.....No such spec exist for reusing them & the FSM specifically states to use new head bolts.

Most head gasket failures these days NOT caused by overheating or thread pull-out can be traced back to "scrubbing" of the head gasket from different expansion rates between the block & cylinder head. The LLY Duramax is a perfect example of this phenomenon.


2001 Chevy Camaro L92/4L80E
2006 Chevy 2500HD LBZ/Allison 1000
2010 Toyota Corolla 2ZR-FE/U341E
2000 Toyota Avalon 1MZ-FE/A541E
Page 2 of 3 1 2 3
Previous Thread
Index
Next Thread

BOB IS THE OIL GUY® Powered by UBB.threads™