stripped rocker arm bolt/chamber

[JaberCB7]

Few weeks ago as i was doing the timing and head gasket with 92smokeaccord while putting the rocker arm assembly back on two bolts and chambers got stripped, though i managed to rethread the bolts and tap one of the chambers the other one is pretty much done, there is no surface to tap. Wondering if i can JB weld the chamber and re-tap it, dont see any other solution besides getting new head or new motor witch i DONT want to do right now and winter is coming and i need my ride.... any alternatives?

ALSO if/after i JB weld the chamber what size drill bit do i use? the bolt is a M8x1.25
i got this from a chart but still dont get it

M8x1.25 0.3150 8.0000 ~21 1.250 6.8 mm

and id like to say thanks to 92smokeaccord for stripping my bolts ....btw bring me your spare bolt next time you come over

[batever]

I've never used JB in a critial application like this but I have read a bit about what others have accomplished and I see no reason why a well done JB fix wouldn't work well and fairly permanently. I believe the JB site has a case of a submarine crew JB welding a bearing end cap onto an engine with JB and that's a pretty critical app.

My thoughts: I would consider cleaning out the existing hole, putting petroleum jelly on the bolt you are going to use, then covering in JB weld and installing the bolt. Test this method first using just an oversized nut and a bolt outside of the car to make sure the bolt will release after 24 hrs of curing.

The petroleum jelly should allow you to effectively cast threads into the existing hole while allowing the bolt to be removed (because it will prevent bonding against the bolt and the JB will both bond against the uncoated metal and be mechanically reinforced/held in place by the irregular stripped surface of the existing hole.

Either that, or drill to the next size or two up, tap that, then fill the hole with JB, and either drill and tap it to the original size or do the petroleum jelly on the bolt thing as well.

The first set of threads will give an excellent bonding surface for the jb, and if you allow enough space then there will be plenty of space for a new JB plug and the original size fastener.

As for the stripped bolt, unless it's completely stripped, running a thread restoring file over it may make it functional again.

@"M8x1.25 0.3150 8.0000 ~21 1.250 6.8 mm "

You need to be aware of nominal vs actual diameter sizes:

I *think* this means use a 6.8 mm diameter drill bit to drill the hole to be tapped. You may want to read a more technical article about ASME (amern society of mechanical engineers) threading specs before going ahead. I think the 8mm in an 8x1.25 male or female thread represents the mean diameter (the diameter at 1/2 of the thread depth) This would mean that going to 6.8 mm actual diameter hole would mean you have slighltly more than 1.2 mm in diameter to play with (8-6.8+whatever half of the current thread depth is)while cutting threads, which allows 0.6 mm actual height or depth per cut or 0.3 mm mean height or depth per thread. That sounds about right to me.

It's possible that cut threads are specified nominally in mean figures and die and tap sizes are specced in actual diameter, I'm really not sure. If someone here doesn't know, you may need to look it up elsewhere but I hope that gives you some idea what may be going on and what to look out for.

[JaberCB7]

I've never used JB in a critial application like this but I have read a bit about what others have accomplished and I see no reason why a well done JB fix wouldn't work well and fairly permanently. I believe the JB site has a case of a submarine crew JB welding a bearing end cap onto an engine with JB and that's a pretty critical app.

My thoughts: I would consider cleaning out the existing hole, putting petroleum jelly on the bolt you are going to use, then covering in JB weld and installing the bolt. Test this method first using just an oversized nut and a bolt outside of the car to make sure the bolt will release after 24 hrs of curing.

The petroleum jelly should allow you to effectively cast threads into the existing hole while allowing the bolt to be removed (because it will prevent bonding against the bolt and the JB will both bond against the uncoated metal and be mechanically reinforced/held in place by the irregular stripped surface of the existing hole.

Either that, or drill to the next size or two up, tap that, then fill the hole with JB, and either drill and tap it to the original size or do the petroleum jelly on the bolt thing as well.

The first set of threads will give an excellent bonding surface for the jb, and if you allow enough space then there will be plenty of space for a new JB plug and the original size fastener.

As for the stripped bolt, unless it's completely stripped, running a thread restoring file over it may make it functional again.

@"M8x1.25 0.3150 8.0000 ~21 1.250 6.8 mm "

You need to be aware of nominal vs actual diameter sizes:

I *think* this means use a 6.8 mm diameter drill bit to drill the hole to be tapped. You may want to read a more technical article about ASME (amern society of mechanical engineers) threading specs before going ahead. I think the 8mm in an 8x1.25 male or female thread represents the mean diameter. Going to 6.8 mm mean diameter would mean you have 1.2 mm in diameter to play with while cutting threads, which allows 0.6 mm actual height or depth per cut thread. That sounds about right to me.

It's possible that cut threads are specified nominally in mean figures and die and tap sizes are specced in actual diameter as well, I'm really not sure. If someone here doesn't know, you may need to look it up elsewhere but I hope that gives you some idea what may be going on and what to look out for.

That makes a little more sense to me, i was gonna clean the hole and JB weld it but tapping it with a size or two bigger and Jb weld that wold give me more protection. I think i have enough JD weld to try both methods. Ill report back when im done

[batever]

A question: have you also considered a helicoil insert?

one thing I would be concerned with with the JB is what end temperature that part of the engine gets to during running. Compare against the temperature range for JB, which the J.B. box says is recommended up to 600F. My guess would be that you're probably be good with that a long as the coolant and oil is flowing in the engine, but if you had any doubts then a helicoil would be the more conservative way to go as that's made of metal (no epoxy) and doesn't have the same temperature restrictions.

good luck on your repair, i don't think you're going to have a problem with it whichever way you choose but I just throw those thoughts out there as things to be aware of.

[YK86]

I would highly reccomend helicoil. I was rebuilding a K24 in a Nissan Stanza and almost every single rocker bolt hole stripped (apparently a common problem). I used helicoil as advised and it was good as new and much more durable.

[myblk92ex]

I would also use helicoil, I have had to repair spark plug holes in everything from hondas to ford trucks. They are under much more compression than a rocker bolt.

[JaberCB7]

A question: have you also considered a helicoil insert?

one thing I would be concerned with with the JB is what end temperature that part of the engine gets to during running. Compare against the temperature range for JB, which the J.B. box says is recommended up to 600F. My guess would be that you're probably be good with that a long as the coolant and oil is flowing in the engine, but if you had any doubts then a helicoil would be the more conservative way to go as that's made of metal (no epoxy) and doesn't have the same temperature restrictions.

good luck on your repair, i don't think you're going to have a problem with it whichever way you choose but I just throw those thoughts out there as things to be aware of.

Sure hope so, i have a similar set to helicoil but doesnt have the tread inserts. Im going to try the JB weld since ive already put it in the hole, tomorrow ill check it out and see if bolt is still loose, if it is im just going to get a slightly bigger bolt and use that....think a M8x1.50 should do the trick worse case

[wed3k]

lol, JB weld...and you dont need to take the rocker arm assembly in order to do a timing belt correctly.

helicoil the hole.

[JaberCB7]

lol, JB weld...and you dont need to take the rocker arm assembly in order to do a timing belt correctly.

helicoil the hole.

sorry i was brief. i was doing timing belt, headgasket and reason i took rocker arm off was to replace the the spark plug well seals, mine were dried up and was flooding the spark plug chamber with oil.

[JDMDriver]

If you haven't been using a torque wrench i suggest you do.

If you are using a torque wrench make sure its correctly calibrated.

A properly set and calibrated torque wrench should not let you strip a bolt as the hole should be strong enough to hold that bolt to factory specs (with some more force).

A Torque wrench assists in

1) maintaining factory tightness (so it doesnt work its way loose)

2) maintain even thightness (so pressure is evenly applied)

3) may prevent stripping of bolts (as it regulates the force applied).
Unlike hand lightening which is subject to judgement it can be succeptible to error especially when in a hurry, frustrated or just not concentrating (tired, late).

[JDMDriver]

Word of advice from my experience.

In using torque wrenches you should still use judgement and feel the force applied.

I was using a torque wrench and my judgment kicked in telling me the force I was applying seemed too much for the bolt (yet the wrench hasn't alerted me the desired force has been reached).

I checked the equipment and turns out the thing was out of calibration. I could have easily ruined my work.

Note:

Click type torque wrenches (calibrated clutch mechanism type) which are really common should not be moved beyond its lowest setting. Moving the dial (on the handle) beyond the lowest setting automatically means the calibration is out (even if you tighten it again).

Problem with borrowed tools is this error is caused by the novice mechanic, overlooked when returned and the tool is out of calibration for the succeeding people to borrow (resulting in stripped threads and snapped bolts).

[92smokeaccord]

ay mang i didnnt mean to strip ur shit it just happend...it did the same to me on mine.but well fix it tomarrow.ill be there all day..

[batever]

Click type torque wrenches (calibrated clutch mechanism type) which are really common should not be moved beyond its lowest setting. Moving the dial (on the handle) beyond the lowest setting automatically means the calibration is out (even if you tighten it again).

Problem with borrowed tools is this error is caused by the novice mechanic, overlooked when returned and the tool is out of calibration for the succeeding people to borrow (resulting in stripped threads and snapped bolts).

Wow, I never realized this. Could you explain further? So if the bottom of the range is zero and you dial it back to below zero it will bring the wrench out of calibration? Can you explain this as my instruction manual didn't say this or I don't recall it saying this?

[JaberCB7]

Word of advice from my experience.

In using torque wrenches you should still use judgement and feel the force applied.

I was using a torque wrench and my judgment kicked in telling me the force I was applying seemed too much for the bolt (yet the wrench hasn't alerted me the desired force has been reached).

I checked the equipment and turns out the thing was out of calibration. I could have easily ruined my work.

Note:

Click type torque wrenches (calibrated clutch mechanism type) which are really common should not be moved beyond its lowest setting. Moving the dial (on the handle) beyond the lowest setting automatically means the calibration is out (even if you tighten it again).

Problem with borrowed tools is this error is caused by the novice mechanic, overlooked when returned and the tool is out of calibration for the succeeding people to borrow (resulting in stripped threads and snapped bolts).

ay mang i didnnt mean to strip ur shit it just happend...it did the same to me on mine.but well fix it tomarrow.ill be there all day..

Wow, I never realized this. Could you explain further? So if the bottom of the range is zero and you dial it back to below zero it will bring the wrench out of calibration? Can you explain this as my instruction manual didn't say this or I don't recall it saying this?

i know all too well about calibrated wrenchs, my mothers husband had loaned his torch wrench to a friend and he got it out of calibration, we were doing the same thing i did to my motor (timing, head gaskets valve adjust the works) but on a saturn twin cam motor and snapped two bolts in the head.

and dont worry jeremy, worse case ill just take ur f22b

[92smokeaccord]

i know all too well about calibrated wrenchs, my mothers husband had loaned his torch wrench to a friend and he got it out of calibration, we were doing the same thing i did to my motor (timing, head gaskets valve adjust the works) but on a saturn twin cam motor and snapped two bolts in the head.

and dont worry jeremy, worse case ill just take ur f22b

over my cold dead body......then u have to go threw my wife......goooood luck..