Stripped cylinder head bolt in aluminum block

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As the title suggests, my engine build has come to a screeching halt when the very last head bolt yanked the threads out of the block. Vehicle is a 2004 Honda Odyssey with 3.5L V6, all aluminum. The torque sequence on this cylinder head is 23-51-73 -- start at the lower value, torque each bolt twice, then move to the next, etc.. The threads in question failed when I was trying to apply the 51 lb-ft, so they were likely garbage to begin with.

This engine is apart because I discovered a bad cylinder head gasket shortly after buying the vehicle. Interestingly enough, the failed threads are in the same location that the head gasket failed-- coincidence?

All that said, what are my options for repair? This is a daily driver, not a boosted track vehicle or hot-rod, so I need a general purpose repair that will last and nothing more.

The repair has me a bit frightened, because the block is in the vehicle and I certainly don't want to go through all the work of removing it again-- that would be a royal pain in the arse. There is plenty of space to work around this particular bolt hole, however. Is it possible to tap to an oversize thread size (stock bolts are 12mm-1.50)? Helicoil? Tap the upper portion of the bolt hole, and use a new bolt that doesn't go so far in the block?

Need help from someone who's done this before-- I came across this link and it seems like this would be right up my alley, but not sure if this is a valid repair option:

http://southeastcylinderhead.com/aluminum-block-head-bolt-thread-repair/

Any help, info, suggestions, etc. on how to go about fixing this would be much appreciated. I need to get this vehicle back on the road, and this is the only thing holding me up. Thanks in advance!
 
I've fixed a couple stripped cylinder head bolts with Helicoils or "thread repair inserts".

Thread inserts at Autozone?

Use a vacuum cleaner and a bunch of rags to keep chips out of the engine and you should be fine. I haven't ever used them on a torque-turn bolt, however. Good luck.
 
Threads are threads, I'll bet that would work fine, the hard part would be getting gasket clamping load right, as torque ro yeald bolts have weird properties, butI'm not an engineer so I don't really have a say in that.

I'll bet it has been done a hundred times and there hasn't ever been problems
 
I'd look to see if there's a head stud for that app, so you can feel good about it being in the helicoil, then torque its nut up top without disturbing things.
 
So...if I understand you right, the head of the bolt is stripped correct?
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That is enough to make anyones blood boil.

I did this recently as well. The solution is the use of turbo sockets. Made by a number of different manufacturers. Craftsman, Snap-On, Matco etc. They work by creating a new bite on the stripped head. Just bang in place with a mallet/hammer/sledge/other weighted object and remove. Very easy.
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Check them out, this was the only way I was able to remove a stripped recessed bolt head of my tensioner assembly.
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http://www.sears.com/search=turbo sockets
 
Ditto for helicoils. The difficult part is to keep the tools perfectly lined up, since you can't place the setup on a mill.
 
An application like this would be just right for Keenserts. They're stronger than Helicoils, but they require more meat around the hole than Helicoils do. If you got the meat, go Keenserts.

Keensert.gif


LINK showing installation.

LINK showing installation.

For a head bolt hole, you're going to recess the Keensert a little bit further than what those people did.
 
Originally Posted By: eljefino
I'd look to see if there's a head stud for that app, so you can feel good about it being in the helicoil, then torque its nut up top without disturbing things.

Exactly my thought as well-if you can do it, a nutted stud is best in these situations-good luck.
 
Torque is an approximation to get the correct bolt stretch. The stretch in the bolt itself provides the clamping force. You want even, and specified, clamping force, across the head. Change bolt length, or diameter, and you throw off the stretch, and therefore the amount of clamping force across the engine's operating temperature range. So...

As long as the stud has the same diameter, and length, as the other bolts - that would work.

Changing the bolt length, as the guy in the link does, will work, IF you replace/tap ALL the bolts...thus keeping the stretch consistent over those shorter bolts.

As expensive as the TimeSert is, that replaces the original threads, and allows the original head bolt to be used. That ensures proper stretch.

A good thread insert, cleanly threaded and held in place with Loctite would be my first choice. But shop around, that $400 price tag is just wrong...
 
Toyota had this issue on the 2AZ engines & the fix was to use a TIME-SERT insert. I've had several repairs using this method working at Toyota & it's worked great. Add a tiny bit of red loctite. Very small amount, or the loctite will get on the threads of the headbolt side & give you a false torque reading since the threads of the inset is caked with loctite
 
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The folks over at Toyota Nation have a lot of experience with repairing Camry I4 engines vintage 02/06 that experience head gasket failure due to thread failure.
 
You can go this route. Its a 12mm x 1.5 thread. This kit gives you the drill, tap, counter bore, install tool and some inserts.
The second link is for the inserts that are included in the Head bolt kit. The third link is to a tap guide (highly recommended) it has to be straight.

http://www.amazon.com/TIME-SERT-Metric-T...viglink20245-20

http://www.amazon.com/1-50-30-0mm-Time-S...=timesert+12159

http://www.amazon.com/TIME-SERT-Guide-M12X1-5-Part-32155/dp/B003WRDRSA/ref=pd_bxgy_263_text_y

https://www.threadkits.com/catalog/Time-Sert.pdf
 
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