[Spector]

I like everyone coming together to figure out the best possible solution to that cluster F. We all want to see success! Blue medium loctite is what I would recommend and would be pointless for the helicoil side.
Loctite needs to be without air to work properly I believe. Use it on the good bolt to avoid it from backing out.

 

[visionguru]

The hydraulic tensioner is constantly vibrating. I don't think any kind of chemical glue can survive in there. Also, there is no extra metal for drilling on a engine block, drilling else where don't seem a good idea either.

I think welding is the only and easiest way to go:

Weld a male stud in the hole. If that's not doable, just weld the tensioner on the mating edges, with the good and bad bolt threaded in.

 

[t-rd]

The hydraulic tensioner is constantly vibrating. I don't think any kind of chemical glue can survive in there. Also, there is no extra metal for drilling on a engine block, drilling else where don't seem a good idea either.

I think welding is the only and easiest way to go:

Weld a male stud in the hole. If that's not doable, just weld the tensioner on the mating edges, with the good and bad bolt threaded in.

That's why I said that I doubt it would hold at all with just cold weld. I've used JB cold weld on broken plastic intake box tabs on a Mercedes and even just that didn't hold. Need to weld a piece of aluminum block or drop a bunch of welds into that hole until you build up enough material to re-tap the hole, insert M4x1.25 stud maybe 20mm long with red loctite so it never moves again. But re-tapping that whole would be a huge pain because you need to go in straight and that area is almost right up against the frame. You will need a right angle drill with a small head.

 

[LondaTheHonda]

I’m almost leaning towards having a mobile welder come and putting some spot welds on the tensioner and engine block. Ie welding the tensioner to the block. It would be a permanent fix but would secure it for the life of the engine.

 

[NailGrease]

I thought this was interesting on the subject.

How To Weld A Cast Aluminum Bolt Hole Without Damaging Threads

Cast aluminum weld repairs are hard. Welding around a bolt hole w/o damaging threads is even more difficult. This trick may help your repair.

m.roadkillcustoms.com

 

[visionguru]

I’m almost leaning towards having a mobile welder come and putting some spot welds on the tensioner and engine block. Ie welding the tensioner to the block. It would be a permanent fix but would secure it for the life of the engine.

Yeah,if a welder can put some weld to the secured tensioner, the engine is totally salvageable.
Do the best job of installing the tensioner first, including the damaged bolt. Then weld to further secure the tensioner.

The only down side is: next time when you need to replace the tensioner again, you have to find someone with a blow torch to remove the weld first, and then a welder to put it on again. All those should be much cheaper than a new engine.

 

[LondaTheHonda]

Thought I would report back with what I did and the outcome. Once again, thank you all who have provided feedback.

I called a few mobile welders and one said he wouldn't do the work and the other said it would be incredibly difficult to weld an aluminum engine block. So no luck there.

Here is what I ended up doing.

Step 1: Helicoil

• I ended up getting a Helicoil to stick after retaping the previous hole.
• Yes, it's not straight but I didn't have much to work with since the old bolt remained in the engine block.

Step 2: JB Weld

• I ended up using normal JB Weld since it was rated up to 500 degrees.
• I roughed both the engine block and the hydraulic tensioner up with 36 grit sandpaper to give it a nice rough surface to bond the JB weld to.
• Then I cleaned the area really well and blew any dirt or metal shavings out with an air gun.
• I then applied a small layer of JB Weld to the tensioner and the engine block on the flat surface.
• Next, I went ahead and put some JB Weld on the bad bolt. I know that this probably wasn't the best idea but I would rather have this bolt stuck in there than coming loose again. I know that it'll be incredibly difficult to ever remove if I needed to replace the belt or tensioner but once again, this car has 258k on it. I don't intend to have to replace the belt ever again on this car. And if I do, then that's just the car gods telling me I needed to yank this engine in the first place.
• After applying JB Weld I went ahead and bolted the good bolt onto the block.
• Next I put the bad bolt in and got it snug. I made sure to not overtighten as I didn't want to strip or damage the threads. Snug was good enough and I let the JB Weld do the rest. I torqued the good bolt before the JB Weld cured.
• Lastly, I applied a layer of JB weld to the area where you could see the bad bolt (aluminum casing) and up on top of the hex bolt. My thought process was the more JB Weld in all places that used to have aluminum, the less chance this thing rattles free.

I let everything cure for 48 hours and now have my timing belt on the car and everything aligned to spec. Hopefully, this weekend I'll get the rest of it put together, turn the engine over and hope for the best.

Here are a few pictures of the process. I'm open to feedback so don't hold back. Hopefully, no one runs into this situation but if they do, this is a good forum with incredible information.

 

[Spector]

Hoping the best! Your attention to detail and prepping I think will be for a good outcome. That being a very permanent tensioner 🙃
Fortunately you can see the tensioner even with the belt covers back in place.

 

[NailGrease]

Really nice job on the Helicoil.

 

[LondaTheHonda]

Hoping the best! Your attention to detail and prepping I think will be for a good outcome. That being a very permanent tensioner 🙃
Fortunately you can see the tensioner even with the belt covers back in place.

Yes, frequent tensioner checks will be in my future lol

 

[visionguru]

Excellent work!

Think it this way: if the bad ass job of the previous mechanic had been working just fine, yours should be at least as good.

I would use thread locker to prevent the bolts from working loose.
Also, I would drill a hole on the timing belt cover, then cover with a piece of duct tape, so that I can monitor the situation more easily (either by a camera or bare eye).

 

[t-rd]

I am assuming you won't ever take that tensioner off and the car will be gone in the next 105k miles??!? 😂 now it's cold welded on there.

Good job and let us know if it holds.

You should give it a couple days for it to cure

 

[derass]

Nice job. That thing's not going anywhere.

I'm surprised how deep the damaged hole was. I though that broken bit of casting up high would make it impossible to get a Helicoil in there, but clearly that wasn't the case. It's in there very nicely.

 

[intelbot]

Good gracious.......! The proper way to fix that is to weld on a block of raw aluminum and re-tap, but it's real tough to do that in that area. I don't know if that cold weld is going to hold, you better let it completely cure over 24 hours before attempting to screw the bolt in. But I have my doubts it would hold. Time to find a new used engine or throw in the towel.

I agree. Not sure JB weld can survive the constant high frequency vibration and shear force from the tensioner.


Sent from my iPhone using Tapatalk

 

[qman]

One way to get the tap to go in straight is to use the tensioner as a guide for it.