5 replies to this topic

[GeezRX]

OK all you racers and general engine rebuilders, help me out here. I am trying to put this '86 3G Si engine back together and several of the head bolts were difficult to get out on disassembly and won't easily thread back in. I don't believe anything is actually stripped, just gunked up. I have been searching for hours on the web for a "deep reach" thread chaser for these 10 x 1.25 bolts with no luck. The thread chasers and kits that I can find look to me like they would be to short to reach all the way in to the bottom of these internal threads. Putting a head bolt through the head leaves me with 2-1/2" of exposed bolt and none of the chasers I found appear to be this long. Also as I see it the two bolt holes with the dowel pins will require at least another 1/2" of length to reach bottom. Someone who has been here before tell me how you conquered this? Thanks in advance for any help!

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[chedda_j]

You need a long shank straight flute, you can also try finding some really good cleaner and dumping it in their, let it soak for a few days, and use an air tool to blow it out if you can.

http://www.fish4part...ap.100876.html' class='bbc_url' title='External link' rel='nofollow external'> http://www.fish4parts.co.uk/Tools.1099/Thread+Insert+Systems+%252526+Cutting+%25252F+Tapping+Tools.10930252/Thread+Cutting+Taps.10930332/Metric+Standard.10930334/M10+x+1.5mm+Pitch+Long+Shank+Straight+Flute+Tap.100876.html

[GeezRX]

Thanks Chedda, I will most likely just use some cleaner and one of the head bolts to try and clean this out. After reading up on this on the web I decided NOT to simply use a standard tap to restore existing threads. Consensus seems to be that using a tap intended for cutting new threads could lead to overcutting and weakening the existing threads leading to failure when I go to retorque them to specs.

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[Bubba]

I have used a long grade 8.8 bolt with a vertical slot cut up the threads (use a dremmel for cutting the slot)- not as good as a tap but cheap and it can remove some of the crud.

Edited by Bubba, 22 March 2012 - 06:24 AM.

[Rampage]

^ Agreed.

Whenever i'm faced with a unique setup where a thread chaser won't reach, up to four vertical slots cut into the proper bolt converts it into a tap allowing you to chase the threads.

Soaking it with brake cleaner over night is a good idea too.

[GeezRX]

Well, I thank you all for your responses! I had read about the DIY chaser on some of the web sites discussing using thread chasers in general. Unfortunately I don't have a dremel at the moment and couldn't afford to get one so...I soaked the head bolt holes with citrus based paint stripper overnight (stuff is amazing at removing crud,safe for metals and biodegradeable!)and then just used a head bolt to clean them out. Followed this with an overnight soaking of alcohol and the bolt again and they seem to be as good as new. I can run the bolt all the way in to bottoming with just normal resistance. Thanks again for the input!

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