X2
When I installed my back pressure gauge I got a lot of ticking noises at first. Had to change the line routing and install a needle valve. After that things were a lot better.
Yellowchevy
Injector hold down bolts stretch?
- Thread starter thunder550
- Start date
X2
When I installed my back pressure gauge I got a lot of ticking noises at first. Had to change the line routing and install a needle valve. After that things were a lot better.
Yellowchevy
Mine stretched after one re-torque. Pushed the injector out on the highway. Sounded like a steam engine for the next 40 miles. lol
It got a little better after I put some more torque into the bolts, so I'm pretty confident this is the problem. I just don't feel comfortable putting any more into them, they are pretty tight.
I know that the heads are aluminium n all, and it's not advisable, but I torqued my hold down bolts to 36ft lbs this last time before they sealed under pressure...
I did this very slowly and using ARP thread lube...but again it's not advisable and I'm not advising you to do so, just sayin that's what I had to do at the time to get a few of the injectors to seal...
I did this very slowly and using ARP thread lube...but again it's not advisable and I'm not advising you to do so, just sayin that's what I had to do at the time to get a few of the injectors to seal...
I ordered new bolts last night, hopefully that will fix it. If not, I'll start looking at other options. Good idea on the ARP lube, I have lots of extra.
Good thread, :thumb: something I never thought of when thinking about boosting to higher pressures. Just remember lube on the threads and under the head of the cap screw on any fastener.
22 ft-lb with arp lube.
Stock bolts and hold downs is all that's ever held my injectors in... As much as 85 psi on twins, and I'm making over 60 psi on my current 3.0 turbo...
For future reference, I would advise NOT using ARP's lube on the bolts. We had a mechanic at our shop use them on some bolts, and it caused them to not be able to be torqued properly because it sealed and pressurized under the bolt. Started the truck and 4 injectors backed out and leaked.
I would advise also spraying out the injector bolt hole if any fuel or liquids leak in it.
IMO it's not like headstuds where you only finger tighten them, and then torque them on the other end of the stud where the ARP lube can escape.
I would advise also spraying out the injector bolt hole if any fuel or liquids leak in it.
IMO it's not like headstuds where you only finger tighten them, and then torque them on the other end of the stud where the ARP lube can escape.
I would be inclined to believe that the mechanic didn't clean the holes out in the first place or used too much lube. You don't need very much. If it's dripping off the end, you have too much on there. I've never encountered this problem except for where there was too much lube/loctite used or water/oil already in the hole.
Same could be said for putting loctite on converter bolts or used in other blind holes which gets done millions of times a year. More isn't necessarily better. There just needs to be enough to fill the void between the threads. If it is coming out the hole and running everywhere as you thread it in, you used too much. If you look at for instance new U-joint bolts, there is very little thread lock on them.
This makes no sense, maybe that's why people call mechanics ''parts changers'' and not engineers.
You SHOULDN'T use ARP lube on anything that wasn't designed for ARP bolts, UNLESS you know what you're doing. You over stretch the fastener, it loses it's memory and doesn't return from the stretch, and thus a failure to seal and then you blame the product.
All I know is we torqued it, and the hold down was loose like the bolt bottomed out. We took the bolt out, and there was excess arp lube in the bottom. Cleaned it out and the bolt secured right.
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Exactly. Too much lube used is all. Seen it happen before in other applications. One being with loctite which is why I brought up that example.
One company I worked for it was so bad they switched to loctite paste because we had too many dummies working there that used to hose the bolt down like they were trying to clean it!!
It doesn't mean it's okay to.
A person researching will see this and may think ''oh, it's okay" and want to hear that side, and not the latter.
Unless advised, only 30wt oil should be used. Using ARP lubricants will end up over torquing fasteners and if it something that needs 50 + ft lbs you can break the fastener inside the threads (crank, flywheel bolts etc).
Not only that, bolt stretch is inproportionate unless you have 3k sonic bolt tester stay away from that stuff, you can have high bolt torque on one and low on the other.
A person researching will see this and may think ''oh, it's okay" and want to hear that side, and not the latter.
Unless advised, only 30wt oil should be used. Using ARP lubricants will end up over torquing fasteners and if it something that needs 50 + ft lbs you can break the fastener inside the threads (crank, flywheel bolts etc).
Not only that, bolt stretch is inproportionate unless you have 3k sonic bolt tester stay away from that stuff, you can have high bolt torque on one and low on the other.
When it is dripping off the end of the bolt and displacing the air in the cavity with a non-compressible fluid, that is when you have used too much.
As far as how it alters friction levels, you are correct. Which is why I said more isn't necessarily better. It is entirely possible to achieve positive thread engagement before achieving proper hold down torque if there is fluid trapped in the bottom of a blind hole. Your torque wrench may read it is torqued, but the force on the surface area the bolt is holding down may not reach spec.
Unless it's advised, don't use ANY loctite, anti-seize or fluid on the bolts for the exact reasons stated above regarding thread stretch. In many cases torque to yield fasteners are the only ones that require the use of a lubricant. That said however, Loctite normally is approved for use in most applications but as I said it is to be used sparingly.