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Discussion Starter #21
Liviu165 is right on the timesert but also it not only needs a chamfer but the surface of the thing you are doing needs to be countersunk with a special tool so the gasket will seal. For what you are doing I would stay with a helicoil. I am sure you have enough meat on the head to fix things. Keep us in the loop. Actually I think it was timesert that had the oversize insert, not helicoil.
I leave soon for a trip with my brother. That vehicle will now sit for a month.

I have enough time to investigate something I read about on my parts vehicle head. A saturated solution of Alum (ammonium aluminum sulfate) is supposed to dissolve ferrous bolts without damaging the aluminum head. I will try this on the same head bolt that also sheared on my parts vehicle. The head is sitting on my workbench so I only need to go to the grocery store to see if McCormick Alum has the correct chemical composition. If not then I will buy some off of eBay.

I still have M10 helicoil and the head from my parts vehicle as options for me.

I'll update the board sometime in June.
 

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Discussion Starter #23
I'm confused; if you're going oversized, why use a helicoil? Also, 3/8" is slightly smaller than M10.
John, I figure that I have only one shot at the helicoil in the vehicle. If I go with the 3/8" helicoil and it fails then the tap out from the 3/8" will prevent me from stepping up to M10 helicoil. At least that is my understanding.

I need to be educated! Thanks-Tom
 

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If you're cutting new threads, you won't need a helicoil. The only reasons to use the helicoil are to repair damaged threads, or to provide a better thread for a part that is regularly disassembled.

OBTW, I don't know how far off your drilling is, but, I will confess to having installed heli-coils in less than perfect holes, with acceptable results. I mean, it's not like the intake manifold is a high stress component... ;)
 

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I agree with John in that this area is not critical in getting it perfectly correct, but I also went into the garage and looked at the M-10 and M-8 helicoil. I found you can actually double them if you want to get back to the original thread size and need to drill out to a larger size. That is drill it out bigger then put the large helicoil in then an 8 in the same hole which the larger helicoil is in.. I confess I have not tried this for durability, but no reason why it would not work.
 

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I'm not sure how you determined that, but, absent data from Helicoil, I'd want to try it on a junk piece of aluminum first. I think it would be an incredible coincidence if the tap for an M8 Helicoil cut M10 threads (if I understand what you're saying.)
 

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If one thinks M8 helicoil could fit inside M10 helicoil then one should compare taps for those helicoils as helicoil taps have the same pitch as screws. Coarse m8 should have 1.25 mm pitch and coarse m10 should have 1.5 mm pitch. M10x 1.25 thread also exists.
 

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John, here is a picture of a M-10 x 125 helicoil and a M-8 x 125. The second picture show one being threaded into the larger one. Now I don’t know how strong it would be but if he is insistant on a standard size you could do this. Time sert also makes something called a large sert, which would work as well. When I did the heads I helicoiled all the bolt holes. The kit had lots in it and I figured I might as well when it was apart.
 

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Discussion Starter #29
John, here is a picture of a M-10 x 125 helicoil and a M-8 x 125. The second picture show one being threaded into the larger one. Now I don’t know how strong it would be but if he is insistant on a standard size you could do this. Time sert also makes something called a large sert, which would work as well. When I did the heads I helicoiled all the bolt holes. The kit had lots in it and I figured I might as well when it was apart.
I have ordered the M10-1.25 helicoil kit and a M10-1.25 40mm hex socket head stainless steel bolt. Also a 13/32" cobalt drill bit. The bit has arrived, the other parts are forthcoming. As mentioned earlier I will not get back to this project until late-June.

Inserting a M8-1.25 helicoil into a M10-1.25 helicoil should not be necessary for me since I intend to drill out the manifold bolt hole to M10 size.

I was not impressed with the Alum solution dissolving ferrous bolts. It takes way too long for that option to be seriously considered.

My parts vehicle right hand side head is sitting on my workbench and will be an option if the M10 helicoil fairs. If any of those bolts become problematic (as mentioned by Liviu165) then from my perspective it is game over.

I do have a question about that option. What would be needed to transfer my low mileage camshaft onto the high mileage head? Is there someplace that specializes in that task?
 

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What would be needed to transfer my low mileage camshaft onto the high mileage head?
To make that swap you need to remove all 5 towers (camshaft bearings) in order to extract the old camshaft. THen you install the new camshaft with either the old towers or the newer ones. However, be advised that each tower has one bolt that goes all the way into the block. If you strip the aluminum threads into the block, then you are in for a very costly repair (remove the head, use helicoils and the drilling jig). Question: Do you think is worth the risk?

In addition, by installing a different camshaft you'll have to adjust the valve pucks again, according to the new cam. Question: Are you willing to complicate your life with that operation? If in doubt, just ask Stutz.

So, isn't a better idea just to leave it the way it is?
 

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The helicoil changes size (gets smaller) when you thread it into the specially tapped hole. This is what helps keep them from unthreading when you remove the fastener. It is not reasonable to assume that, because one threads into the other on the bench that it will do the same thing in use. If that were the case, then the M8 helicoil tap would be exactly the same as a standard M10 tap, and it is not. If you don't believe me, screw the M8 helicoil onto an M8 bolt and you will see it is a very loose fit.

If you're planning to use M10 hardware, you can just drill and tap the original hole for M10; no need to go oversize then back to the M10 helicoil.
 

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Discussion Starter #32
To make that swap you need to remove all 5 towers (camshaft bearings) in order to extract the old camshaft. THen you install the new camshaft with either the old towers or the newer ones. However, be advised that each tower has one bolt that goes all the way into the block. If you strip the aluminum threads into the block, then you are in for a very costly repair (remove the head, use helicoils and the drilling jig). Question: Do you think is worth the risk?

In addition, by installing a different camshaft you'll have to adjust the valve pucks again, according to the new cam. Question: Are you willing to complicate your life with that operation? If in doubt, just ask Stutz.

So, isn't a better idea just to leave it the way it is?
It is my understanding that if the helicoil fails then I MUST remove the head. I would not be able to put the intake manifold back on the engine if that one bolt is absent. Is there another option available to me?

What would I have to lose by removing the head. I would have a non-functional vehicle without that intake manifold bolt. If the threads in the block strip then it would be game over for me.

I really am up against a wall.
 

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Discussion Starter #33
The helicoil changes size (gets smaller) when you thread it into the specially tapped hole. This is what helps keep them from unthreading when you remove the fastener. It is not reasonable to assume that, because one threads into the other on the bench that it will do the same thing in use. If that were the case, then the M8 helicoil tap would be exactly the same as a standard M10 tap, and it is not. If you don't believe me, screw the M8 helicoil onto an M8 bolt and you will see it is a very loose fit.

If you're planning to use M10 hardware, you can just drill and tap the original hole for M10; no need to go oversize then back to the M10 helicoil.
John, I thought the helicoil tap for the M8 insert that I already tried exceeded the limits for a straight M10 tap. I suppose I could try and if it fails then helicoil tap for M10 at that point.
 

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It is my understanding that if the helicoil fails then I MUST remove the head.
Correct.

I would not be able to put the intake manifold back on the engine if that one bolt is absent. Is there another option available to me?
Not really. That's why you have to make it work.

What would I have to lose by removing the head.
A lot if things don't come up right afterwards. It will also be a costly repair.

If the threads in the block strip then it would be game over for me.
Not really, you can still use your block but things will require much more work. Basically you will walk the same path that Stutz did.

I really am up against a wall.
You can put it that way, but the fact that you are aware of the challenge, its ramifications and your options, all together are to your advantage. I hope all that will help you in solving your problem.
 

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I hope you don't mind me asking, but can you please post few very close-up pictures (from different angles) and very clear of what you have right now? We've talking for over 30 posts, but none of us has seen what you actually have there. just saying.
 

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Discussion Starter #36
I hope you don't mind me asking, but can you please post few very close-up pictures (from different angles) and very clear of what you have right now? We've talking for over 30 posts, but none of us has seen what you actually have there. just saying.
Liviu165, I put all of the pieces back into place since I will be gone for a month. They are not torqued but just lightly bolted into place. My memory requires this unnecessary step along with lots of notes and plastic baggies marked with specifics. When I return next month then I will take it apart again and get close ups. I am also recruiting a person with better mechanic skills than my own to help when I get back.

I want to thank everyone on this board who has contributed to my education. Yes, I make mistakes. Without this board I would not even try these tasks. I will keep trying until I am completely out of affordable options. There is a finite limit on how much money I will pour down this hole.
 

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John, I thought the helicoil tap for the M8 insert that I already tried exceeded the limits for a straight M10 tap.
I'm confused. Are you saying you already installed an M8 helicoil and it failed?

The drill size for an M8x1.25 helicoil is 8.3mm. Drill size for a 3/8"-16 tap is 7.94mm. Drill size for a 3/8"-24 tap is 8.33mm. The drill size for an M10x1.25 tap is 8.9mm. The drill for an M10x1.25 helicoil is 10.3mm .

If you've already tapped the hole for the M8 helicoil you cannot go the the 3/8" bolt as the pitch is different. Next thing to try would be the M10x1.25 tap and bolt, not the M10 helicoil.

The M8 time-sert is also an option as it uses a larger hole than the helicoil (also 10.3mm) and would restore things back to standard size.

Last resort is to have someone silver solder the hole shut and start over. You could do that on the car, in fact, a skilled welder could TIG weld it, too.
 

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Discussion Starter #38
I hope you don't mind me asking, but can you please post few very close-up pictures (from different angles) and very clear of what you have right now? We've talking for over 30 posts, but none of us has seen what you actually have there. just saying.
I am back working on my intake manifold project. Here are two pictures of the hole before and after the M10-1.25 helicoil insert. All of the intake manifold bolts were torqued to 23Nm torque. Howerver, after sitting for a few hours I came back and checked them again. All of them needed some additional torque; some needed a lot. The helicoil insert M10 bolt required the least amount of re-torque. I read other threads where the user retorqued his intake manifold bolts for several days before everything stayed put.
 

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Discussion Starter #39
During reassembly of the lower and upper intake manifold pieces I decided to do the work in the engine bay. I loosened the EGR tube at the exhaust manifold connection and rotated the EGR tube upward in the engine bay while it pivoted at the EGR valve. I stuck a 2x4 block of wood under the bottom manifold piece for additional support. I hooked up the EGR tube to the bottom piece then attached the top manifold piece and bolted things together with three of the long bolts. This allowed me to check the eight gaskets for proper seal. The block of wood kept everything off of the new gaskets until I was ready to lower into place. A slight lift of the assembled intake manifold allowed me to easily remove the block of wood. It was easy to manage by myself.
 

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