Aluminum head steel bushings at header screws

[LodiWino]

When I unscrewed two header bolts, the threaded steel bushing in the aluminum head unscrewed and came out with the header bolt.

I can re-install the threaded steel bushing by making a shoulder screw to re-install them. Is this the correct procedure?

Should high temp Lock Tight be used to prevent the bushing from unscrewing again?

[Rick Parker]

Is this a Helicoil that has come out (?) or a legitimate threaded bushing?

[LodiWino]

This is a threaded bushing

[RICK LAKE]

LodiWino BOY you are having alot of problems. First name would be nice. Here's the thing, you can reinstall the helicoil back in the hole. You need the red threaded loc-tite and give it 8 hours to cure before trying to install a bolt
The problem I have found is there is no pin, or spreader to lock the threads into the bolt hole. Over heat cycles they will loosen again. I have converted my blocks over to timecerts in aluminum blocks. When installed they lock into the hole and don't come loose. They are steel sleeves and can work in any hole, wet or dry. They set below the surface of the block or heads. They come in a 4 piece kit or get a master kit. Fine and Course threads. I have not had one fail in 7 years on 482 motor. I have had helicoils fail in my heads, reason for switch. Think about the cost of replacing the motor, helicoils are cheaper and in MOST cases work just fine for LAWN MOWER MOTORS. For a 15-40k motor is going cheap worth it??? Good luck Rick L. Ps we repair blocks ands heads with timeserts for GM and have not had any failures from this repair. 140 pounds on head bolts torque in diesels. This is alot cheaper than replacement of main parts.

[vector1]

Originally Posted by RICK LAKE

LodiWino BOY you are having alot of problems. First name would be nice. Here's the thing, you can reinstall the helicoil back in the hole. You need the red threaded loc-tite and give it 8 hours to cure before trying to install a bolt
The problem I have found is there is no pin, or spreader to lock the threads into the bolt hole. Over heat cycles they will loosen again. I have converted my blocks over to timecerts in aluminum blocks. When installed they lock into the hole and don't come loose. They are steel sleeves and can work in any hole, wet or dry. They set below the surface of the block or heads. They come in a 4 piece kit or get a master kit. Fine and Course threads. I have not had one fail in 7 years on 482 motor. I have had helicoils fail in my heads, reason for switch. Think about the cost of replacing the motor, helicoils are cheaper and in MOST cases work just fine for LAWN MOWER MOTORS. For a 15-40k motor is going cheap worth it??? Good luck Rick L. Ps we repair blocks ands heads with timeserts for GM and have not had any failures from this repair. 140 pounds on head bolts torque in diesels. This is alot cheaper than replacement of main parts.

rick, do you have a link to what you use?

[mickmate]

++ TIME-SERT Threaded inserts for stripped threads, threaded inserts, thread repair stripped sparkplug's, Ford sparkplug blowouts, threaded inserts threaded, repair stripped threads, stripped threads, inserts threaded inserts, Ford spark plug repair,

[mickmate]

Another option is the locking (screwlock) helicoils Helicoil - Helicoil Screw Thread Inserts, Helicoil Free Running Inserts, Helicoil Screw Lock Inserts, Helicoil Metric, Helicoil BSW, BSF, BSPF, BA, UNC, UNF, Helicoil Spark Plug Inserts, Emhart Technologies

[vector1]

i like the timesert idea. i have tried the helicoils in an aluminum block and wasn't impressed.

do the timeserts require thread lock to hold them or just screw them in, someone with experience?

[mickmate]

TIME-SERT® is self locking. On installation the bottom internal threads of the insert are cold rolled to expand the mating external threads into the base material locking the insert in place. Locking mechanism is at the bottom of insert.

[Jerry Clayton]

I have to disagree with Rick's lawnmower comment--Heli coils were designed and used for aircraft and are very reliable--of course the installation process is important and a sloppy install can/will maybe result in a failure---but probably the same reason the first thread failed is why the second failed

[HI Cobra]

I recently used a "Big Sert" also from Time Serts. Same bushing type except
it has a locking tab. I used one on a head where the heli-coil pulled out to
replace the heli-coil but needed the 3/8" threads so I could use the same stud
when I replaced a broken rocker arm shaft. So far has worked great.
Just another option. Took me a while to find it.

[tboneheller]

Use studs instead of bolts for any fasteners threaded into aluminum.

[Rick Parker]

If this will thread back into the head I would do so and use Hi Temp thread locker or stake it in place.

[RICK LAKE]

Jerry Clayton Hey Jerry Helicoils are a cheap repair for a damaged hole. Over time they rust out, break down or just come loose.
Helicoils are best with LOW torque and LOW load carrying factors.
The top 3-5 threads hold 80% of the load, The rest is along for the ride and over time start to also hold a torque reading too. Heat cycles kill helicoils. IMO they are a quick and cheap repair at the track for making 1-2 more runs. After that, I wouldn't take a chance on them. The threads in the hole loosen and loc-tite doesn't hold them from coming loose. Helicoils strip out high torque holes over time. Been there, had this problem.
Timeserts IMO are alot better than coils. You tap into virgin metal with course threads, countersink them into the surface, they lock in the hole, and in 20+ years of using them I have not had on come out of a block or head yet. This includes alot of your LS motors. They timeserts cost double to three times the cost of a helicoil set or repair kit. I think it's great if you can get by with helicoils. The better product is still a timesert. As far Lawnmowwers and airplane motors both ran for a couple of thousand hours and got a rebuild or replaced. You race on a budget and squeeze every penny. Some motors cost 2-3 times the cost of what you are running. You are a SEMI PRO or PRO racer, Pass on the best info you have or say nothing. If you think helicoils are better than timeserts, then why are timeserts in new motors and not helicoils??? Helicoils are cheaper??? The repair kits are timeserts, not helicoils. I guess the Engineers for GM, Ford, and other companies have a different opinion about the better repair and how to do it and have it last for more than a year or a season. Rick L. Ps I have blown helicoils out of a 3.5 lawn motor engines. It came loose over time due to heat cycles and the breaking down of the material around the hole. Guess I will have to wait 20-30 years my first timesert to give out. If I was to repair airplane motors and the FAA allowed a choice, and have enough material to drill tap and install a timesert, this would be the only way I would gamble with someones life.

[Jerry Clayton]

Rick--I did not state anything comparing helicoils to timeserts--I simply pointed out that they originally were standard in aircraft engines and that the install process was critical--

However to your last post I will comment/correct a couple of things---They are made of high quality stainless, they will not rust . also, the first thru the last thread all pull the same load--if heat cycles effect anything around a heli coil, it will be the heli coil that lasts longest--

However---If you have a severely damaged, stripped out hole, the timesert will probably be the best for the job as it will remove a larger amount of parent material and is usually used with a larger size tap , where as the helicoil uses a special tap made for the specific size used. A helicoil should never be used for a sloppily drilled hole--and this is what usually happens when someone has a broken bolt/stud--drilled off center,oversized,etc

[LodiWino]

Rick;

Can the existing threaded steel bushings be removed with an Easy Out?

[Jerry Clayton]

http://www.helicoil.in/pdf/HeliCoil%20Catalogue.pdf

has a lot of info on heli coils and uses /proper installation