Drilled out exhaust manifold bolt: Helicoil or Tap it?
#1
Drilled out exhaust manifold bolt: Helicoil or Tap it?
My new to me motor (2004 5.3) had a head bolt broken off. I couldn't get it out so I had to drill it out. The bit sticking out is the same depth as the other manifold bolt holes. Would it be better to helicoil this or drill and tap it?
#2
TECH Senior Member
Doing a HeliCoil involves drilling and tapping anyway. You drill out the original hole, tap it a size up from original, then thread the HeliCoil into it.
#4
TECH Senior Member
iTrader: (25)
As mentioned in the other thread, welding is the preferred way. But drilling oversize and tapping is fine--I've done that when the original thread were stripped.
Helicoil or keensert would probably make a stronger thread but those bolts don't go very tight--like 25ft/lb or so.
Worse comes to worst, dorman makes a decent kludge fix. 917-107 is the part number.
Helicoil or keensert would probably make a stronger thread but those bolts don't go very tight--like 25ft/lb or so.
Worse comes to worst, dorman makes a decent kludge fix. 917-107 is the part number.
#5
Heli-Coil it.
They will hold FAR more torque than the original aluminum threads, and don't require the use of a "special" size bolt that's different from everything else. Just altogether the ONLY RIGHT way to fix that sort of thing.
Drill the hole to the correct size tor that Heli-Coil to the FULL depth of the hole. (don't go an farther though, you might do something stooopid, like, hit water) Install the insert with the last thread about ½ turn below the surface, use a punch to break off the tang, blow the remains out with compressed air, use a normal bolt. 25 ft-lbs is about right for those, or for any other bolt of that size (since torque generally goes with hardware size, not anything about the application itself).
In fact it wouldn't be a bad idea to do all 12. I usually do.
They will hold FAR more torque than the original aluminum threads, and don't require the use of a "special" size bolt that's different from everything else. Just altogether the ONLY RIGHT way to fix that sort of thing.
Drill the hole to the correct size tor that Heli-Coil to the FULL depth of the hole. (don't go an farther though, you might do something stooopid, like, hit water) Install the insert with the last thread about ½ turn below the surface, use a punch to break off the tang, blow the remains out with compressed air, use a normal bolt. 25 ft-lbs is about right for those, or for any other bolt of that size (since torque generally goes with hardware size, not anything about the application itself).
In fact it wouldn't be a bad idea to do all 12. I usually do.
#6
TECH Veteran
iTrader: (40)
The answer depends on what you did to get it out and what you have left
Did you drill and ease out the old bolt? Did it unthread out? If so just stick a new bolt in.
Or did you have to completely drill the bolt and hole. If you had to completely drill it then you've now enlarged the hole and you'll have to heli coil it. Other wise you would have to tap the hole to a larger size then you would have an oddball sized bolt in that one hole and you'd have to drill your header/manifold hole out larger too.
heli coils work just fine for exh bolts
Did you drill and ease out the old bolt? Did it unthread out? If so just stick a new bolt in.
Or did you have to completely drill the bolt and hole. If you had to completely drill it then you've now enlarged the hole and you'll have to heli coil it. Other wise you would have to tap the hole to a larger size then you would have an oddball sized bolt in that one hole and you'd have to drill your header/manifold hole out larger too.
heli coils work just fine for exh bolts
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#10
TECH Senior Member
Did the kit include re-usable tools? So next time all you need are the Heli-coils themselves?
#13
TECH Senior Member
I would say a good part of the $38 was a good investment in tools you can use from now on...