Head bolt shocker

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B

Big Jimbo

10 Year 15 Year
Joined
Mar 26, 2006
Threads
13
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42
Location
Rust Free Arizona
I have a 97 LX450 with 130,000 miles that finally blew the HG. I purchased it new and the motor has never been apart. I was putting it back together and was going to use the original head bolts when the machine shop who did the valve job told me I should replace all the head bolts because torque to yield bolts are one time use only. I then used a vernier caliper and checked them just like it shows in the shop manual, and all 14 were less than the specified minimum size! I thought maybe the gauge was off so I checked it against a micrometer and it was reading true. :eek:
After reading some of the threads it doesn't sound like everyone has had this problem with bad headbolts. I wonder if there were some bolts that didn't hold up as well as others?
Another call to Cruiser Dan and the new ones are on the way. :cheers:
 
Well, paranoia got the better of me and so I happily had all my bolts replaced with new OEM, glad I did although I think your experience is exceptionally rare; I do not think that "torque to yield" equals "one time use" if it did why would Mr. T recommend reusing them? Anyways, like I wrote, I had all my bolts replaced, "cause thats the way, ahaa, ahaa, I like it" :D :cheers:
 
Very strange. I'm assuming you did the measuring on the correct spot? Not by putting the calipers in the necked down area that's essentially the first thread, but on the flat section, right?

I used mine 3 times and the last time I had my measurements verified by the machinist in the shop while I looked over his shoulder. Not a single one even close, so I returned the head bolts.

DougM
 
really....Doug....

You went to all the trouble to not just do the HG job, but video it as well, and used the orig bolts? What would the engineers at Lexus think?:cool:

BTW, machine shop took .14 off my cylinder head today. I should have it back Monday for reassembly. I know...it's been apart a long time. I'm sure those cobwebs in the cylinders won't last long....

I'll send you some pics of how us over 6' guys work on a LC engine.

Dan:grinpimp: :banana: :banana:
 
Well, since the Lexus engineers are Japanese and their culture rewards frugality and efficiency I suspect they would say "Well done, Doug-san..."

I have a lot of faith in Japanese metallurgy and would have replaced them if it called for it. Can't believe how expensive the OEM head bolts are - nearly $140 for a set IIRC.

Looking forward to the pics, Dan. Hope you're riding safely and defensively on that organ-donor of yours...

DougM
 
DTAYLOR said:
BTW, machine shop took .14 off my cylinder head today.
Click to expand...

I hope that is either a typo or milimeters

.140" is a whole lot to take off a head
 
For the OE I work for we always recommend you change you head bolts after swapping heads. Even if there is little chance for damage, it is just cheap insurance. The OE I work for also happens to make the majority of all Toyota engines, so I would suspect it to be the same for them as well.

Just my nickel's.
 
Toyota makes Toyota engines. You must mean they SERVICE the majority of Toyota engines?? Also, what's OE - I only know it as Original Equipment?

DougM
 
IdahoDoug said:
Toyota makes Toyota engines. You must mean they SERVICE the majority of Toyota engines?? Also, what's OE - I only know it as Original Equipment?

DougM
Click to expand...

Maybe he's in Japan and works for Toyota ;p
 
whodat said:
OE= Omnipotent Emperor
Click to expand...

No, thats woody


Damn, maybe I should take my head apart so I can measure my bolts:confused:

I'll do that in another 200K miles or so.
 
Shirley, the fact that heads are seldom removed and the bolts are reusable means few are made; hence the astronomical price.
 
More than a couple bucks, and being wise implies making informed choices with your money.


DougM (with an extra $140 X two in his wallet...)
 
IdahoDoug said:
More than a couple bucks, and being wise implies making informed choices with your money.


DougM (with an extra $140 X two in his wallet...)
Click to expand...


Agreed, but that is interpreted in different ways; for me "wise" implied not taking any risk and replacing them. To each his own, me, I'd rather spend that 140 but be sure; its worth the peace of mind. YMMV. :cheers:
 
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