Stripped bolt hole
 

Thought I was just about done with mounting my expansion tank. Tested thermostat, applied the gasket maker yesterday so it would cure. Both bolts were going in fine and things didn't feel right for one. I made sure not to over tighten. I think it was already stripped. Now the question. What is the best and easiest way to repair this stripped bolt hole. Thanks!

Drill, tap, and helicoil.

Another option is after repairing the manifold hole ( might as well do both ) with a Helicoil ( make sure you break off the and remove the instalation tang on the coil after its' in place) and install ARP SS studs. Alluminum has a problem that helicoils and studs help with greatly.

Could a self tapping bolt be used?

Self tapping bolt? You mean like one of these? :D

http://myword.info/images/l_screw_1a.jpg

Maybe, but if it failed, you might be so oversized a helicoil wouldn't fix it without going to the next size up. That might be pushing the limits on both the manifold and the expansion tank flange. The expansion tank puts more strain on that connection than a simple water neck.
A helicoil kit is cheaper than a towtruck charge. I would fix it right the first time.

Also, you might consider a Keensert-style insert. You don't need a special tap for them so if you have a set of standard taps, you save a few bucks.

Visit mcmaster.com and search for "key locking insert".

Timeserts or keenserts
 

psychoSEAL Helicoils are good for a quick fix with a LOW torque setting for that bolt, under 50 lbs. in Aluminium. Any thing over I go with a timesert or Keenserts. They are a solid insert with a locking pin that pushes into the edge of the threads and keeps the insert from coming out of the hole when removing a bolt. You should use a touch of high strenght loc-tite (RED) to help with keeping the insert from twisting also. Timeserts come in a kit with drill bits, installers, flat surface face installers, and the correct tap. A master kit is about $300.00. Expensive yes, but you will only need to buy this kit once. I just replaced all the helicoils in my shelby heads because they keep loosening up after racing. I broke a heavyduty rocker shaft and ripped half the threads out of the head. Installed 8 new timeserts, no problem yet with rocker assemblies coming loose. Make sure you allow the loc-tite 24 hours to cure if you can. There is a little more work with timeserts. This is the only differents. You can repair the hole on the car as long as you can get a straight shot to the hole. If you go through the manifold into the water jacket, make sure you add pipedope to the threads on the bolt. The surface must be dry for it to work and last. Rick L. Ps. Do you know Jim Watson? either JR or SR.

Those resemble lag screws for wood. I have seen self tapping bolts very similar to the ones that can be used on an oil pan.

You are talking About a 5/16" bolt or stud. . If you take full advantage of the depth of the original hole, drill it out and tap it corectly and straight for the Heli-Coil. It will take more than the load needed to hold and seal your surge tank. The ARP SS carbruetor stud Have a rounded ball end for starting the nut. You can slide the surge tank over the studs with gasket applied, and everything will stay inline.

You know, my lag bolt suggestion was a joke... :LOL:

I have used the Timeserts on Headbolts with 100% success. A little beter than Helicoils IMO.

Excaliber, I know it was a joke. My computer died on me before I could send another response. I will be picking up the helicoil or keensert on Monday. I'll let you guys know how it works out. I know one thing, this hole was stripped before I started tinkering with it. Thanks to everyone who has replied.

Genuine Helicoil are used as original equipment part by industry such as Aerospace, Aeronautics, Avionics, Defense, Automotive, Heavy Engineering, Power Generation, Electronics & Telecommunication, Electrical & Light Engineering.
Hmmmm sounds like they'll work! If you can use needle nose to break the tang off you'll be able to hang onto it and pull it out. Greasing the tap will stick the chips to it instead of dropping them in which may help also.

They split apart in the thread hole
 

Mick mate I have used helicoils over the years. On some repairs helicoils work great. I think they work best on steel or iron stripped holes. The first 3-4 threads do all the holding of a bolt. With Aluminium and GM we have gone to timeserts. The 2 master kits are almost $1,000.00 dollars. The kits can fix every hole in LS2 and Northstar motors. I would think that there is a reason for GM to use timecerts and not helicoils. I have had to repair the 8 wholes on my shelby heads because of helicoils not holding to the aluminium. I now have 8 timeserts with special studs that are 3/8 into the serts and 5/16" shaft through the rocker assemblies. Helicoils IMO are good for low torque applications. I think under high torque requirements that helicoils wiggle loose in the hole, ( aluminium ) and back out. They where installed properly and given 24 hours to dry. Helicoils are good for a quick repair but, I will stay with a solid metal tube with threads when there is room to install IMO . Rick L.

Bought a HeliCoil kit today at a local NAPA store. Only cost $29! Took my time and rethreaded the stripped hole. Worked like a charm. Thanks to everybody's input! Now for some nice weather.

I saw a real nice kit at Harbour freight $19.00. A clone of Helicoil. Drill, tap. instalation too and about 6 inserts.

Correction: I think the bit was included?

I just might have to visit our local Harbour Freight. Fastenal wanted $65 for the kit. The NAPA kit came with the tap, insert tool and 10 inserts.

Pick up some nice Chinese tools while your there, I hear there really cheap (in more ways than one). :LOL: Actually HF aint 'that bad', like Walmart and a 'Dollar Store' you just have to shop careful, there are some deals to be had!

:) Glad it worked out Dave. I saw your tank up at Mark's a couple weeks ago. It looked like he did a really good job on it.
steve