I stripped one of the middle intake manifold bolts while redoing my gasket. I don't trust myself to do the helicoil so want to have a shop do it. If the other 7 are torqued down and the last one is a little more than finger tight with some rtv on it would it be okay to drive it to the shop or do I need to have it towed

 

I would say have the vehicle flat-bedded in. First, check with the shop that's doing the work. Many shops will not charge you for a tow in if they are doing the work.

 

If you have a "Dewalt" type electric drill and some basic hand-tools installing a Heli-Coil is really not that hard. In my garage I have several sizes of both Metric and SAE Heli-coils as I grew up on Volkswagen Air-cooled engines and when you modified one you would start installing Heli-Coils right away to hold it "together", ( Literally). I have put in so many heli-coils that it would take literally minutes once you have the parts ready. Your local auto parts might not have all the sizes but they have a lot of them. Most of the nicer ones come with a Drill bit and the Installation "Tool" along with 8-10 heli-coils all that particular size. The one last thing is some Lock Tight "Red" to lock the heli-coil into it's new home.

Come on you are able to do this, I have seen your posts and I suspect it is withing your abilities versus paying/letting somebody else fix it. Corvettes were not made to be "Towed", they were made to DRIVE...

I hope what ever you do that it works out for you!

Best regards,
Chris

 

I talked to a buddy who works at a body shop and he said he would just retap the hole, what are the benefits to one vs another?

 

A re-tap would use a larger bolt, a helicoil uses the same bolt. If you retap adding the helicoil is only one more step... quite literally inserting the helicoil. I'd use a helicoil personally...

 

I wouldn't hesitate to do the same, but the OP said he didn't trust himself inserting a heli-coil. Easy? Yes. But not everybody has the same comfort levels with some jobs as others.

Hence, my response.

 

I'm going to ask around and see if I can't find a friend who has used them before to come help me, so in the future I know how to do it.

 

All good. It was more geared toward asking on if one was better than the other more so than doing it is all..

 

So, just my two cents here - don't use a heli-coil in that application. Use a Time-sert instead.

The hole in the head that you'll be tapping and repairing has no bottom, and the heli-coil would be open to spinning down below the ideal position flush with the head sealing face. The Time-sert kit comes with a solid insert rather than coils, and it bottoms out and locks at the sealing face level. Not only is it more stable, but repaired this way I think it's probably stronger than the original threads in the aluminum head.


Worth a look if you intend to keep the car and fix it right; that area is a critical sealing surface for the intake to heads joint. The L98 uses a 3/8" x 16tpi thread pattern like this, but please confirm that's the same for your LT1.

Cheers.

 

Just ordered the kit, gonna give it a shot this weekend and will update back here after. Is this something you've done before? Did you use the .750 or 1.00 inserts?

 

Do the time sert or heli if you do anything. Dont tap it bigger. If those threads weaken now you have to weld it up and start over.
big difference in strength between the two processes

 

Going to be doing a time sert

 

I have not but I have been all over that area of my heads lately. The kit I mentioned uses a .520" length Time-sert, and that's long enough for the head threaded area. The .750 or 1.00 are too long and would accomplish nothing more.

Cover those intake ports with tape to seal them, make sure to have a really good set of rags or plastic barrier underneath where you're going to be drilling / tapping, and go real slow. You don't want metal shards flying around the inside of your engine while it's opened up.

 

Have a conversation with a local shop(s) regarding the 'time-sert', some might offer a mobile service! Have your conversation before your attempt. You want keep the purchase returnable. Do nothing until you have a conversation with a 'local/competent' shop.

 

I know the shop I normally use doesn't have this, I have seen some ads for mobile mechanics, I suppose I could ask around and get some quotes

 

Would it be worth it to order a thread chaser for the right size and try that first? Or should I just go ahead and do the time sert

 

Only you know how those threads look; i.e. how bad are they stripped? But I can tell you, if the manifold bolt torque is 35lbs like it is on the L98, that's pretty good torque on an aluminum hole that doesn't have that much thread depth to begin with. If I remember correctly, that part of the head isn't much thicker than 1/2" worth of depth in that hole before you hit air again on the bottom side of the hole? I wouldn't mess around with the chaser. But that's just me.

 

Using the 'Torque Sequence' diagram in the FSM which position is it? Middle I'd think doesn't work. Specifying which someone can actually determine thread count/depth and post very useful information. You 'noticed' stripped it when? First pass or final pass?

***OR 1 - 6 (front to rear left/driver) 7 - 12 (front to rear right/passenger)

***I didn't intend to suggest a 'mobile mechanic' but needing only one many shops have the tools, 'serts and might consider a rental of them or knowing the need might consider a mobile repair OR actually might suggest one.

 

-----12---11---4---1---5---6
Back--------------------------Front of intake/Motor
-----10----9---3---2---7---8

It would be 11 from this, I noticed it stripped when I went to torque it and it stopped getting tighter

 

Try the thread Chaser before drilling or modifying anything. It can't hurt and it might help you. I agree with the above Poster who said not to drill it larger and thread it.

I saw the information regarding the Time-Sert and it is a bit "different". I am not sure I would want a flange on the surface and the kit for just one size has four tools to enable you to put 1 insert "in" successfully. I have used literally Hundreds of Heli-coils and NEVER had one "wind" down the threads. This is why I mentioned the RED "Lock Tight" as it will lock or glue the heli-coil in place when you install it. I am not so sure that the Time-Sert's are an "improvement" over Heli-Coils but they are WAY more expensive for the kit to fix one hole. I have already invested in the Heli-coil kits so I will stay with them. I hope to learn more about the Time-Sert as you install one in your engine! Sometimes newer is better and sometimes it is clearly not better or easier, this is how we all learn.

Be sure to vacuum any aluminum flakes out of the hole before putting the new bolt into it.

Having a Tap and Die set is something very handy to have in my garage. I went and bought myself a Metric set a while ago from Harbor Freight so now I have both SAE and Metric taps for "chasing" threads. Chasing threads is always important on engines to clear any residual material from hole and if done carefully it might restore minor thread damage. When building an engine I check every hole with a thread chaser (Tap) for that particular size. When putting a Tap or thread chaser in the hole be sure it is perpendicular to the surface it is threading into as this is critical. A tap can easily destroy the existing threads if it is put in at a slight angle.

I wish you the very best in your project!