Helicoil/Timesert

[midnight sun]

Is it feasible/smart to try and insert a Helicoil or Timesert in a cylinder head bolt hole with the engine still in the car?

Had a bad head gasket so changed it out and when torqueing the head back on the second to the last bolt stripped out the threads in the block. (1967 327)  

I would assume that drilling the hole would lead to having shavings fall into the water jacket.  (The offending hole is on the outside (bottom) so its one of the water jacket holes.

Any Ideas??

Thanks

[wayne petty]

yes... please create a drill guide.. if you don't have a LOT of experience doing it.  or screw long bolts into the other holes..  so its easier to keep the drill going straight..

helicoil 7/16-14 is 29/64ths.

you have 3 different lengths of heli coils available i tried to keep the versions just over 5/8 long to do head bolts.. check your length.. the short length will probably work.. i almost always doubled them up when only the short ones were available..

0.438"
0.656"
0.875"

http://www.grainger.com/category/thread-repair-inserts/thread-insert/fasteners/ecatalog/N-8o9?bc=y#nav=%2Fcategory%2Fthread-repair-inserts%2Fthread-insert%2Ffasteners%2Fecatalog%2FN-8o9Z1z0n51jZ1z0komwZ1z0o252Z1z0q79jZ1z0ha2v%3F_%3D1403395156964

making your own drill jig.. do you own a drill press and a welder..

got some angle iron..  and a chunk of steel about an  inch or inch and a quarter thick..   stick some 1/2" bolts between the flat sizes of the angles..  so you can weld the angle sections together.. you need probably 8 or 10 inch pieces.. weld the flat sides of the  to the  steel block.. everything clamped down..  weld something across the far ends..  now you can clamp it flat to your drill press to drill one of several holes. you will want to drill the 29/64 hole in 2 different spots but close to each other.  one is the drill hole.. use the drill press with the heli coil tap in the chuck to HAND START THE THREADING working it in and out a few turns..   you can cheat and counter bore the hole till you only have 5/8 of hole to tap.  but make sure the counter bore drill is the proper size to keep the tap aligned..   you can now use a different head bolt to clamp this into place.   you might want to drill an exact 7/16 hole so you can align it perfectly over the existing damaged hole.  you now have a drill and tap guide.  with enough room to drill for 1/2" heli coils to repair other engines .if you ever need it..

have  a drill press but no welder.. look around .. got an old harmonic damper.. you can remove the inertia ring and drill and tap that.. you can easily hold that down with something across the ring..

if you don't have a drill press.. have a machine shop drill the 2 holes you need thru an old inertia ring  perhaps counter bore one hole part way thru for the heli coil tap.. i don't recall what the OD is on the heli coil tap.. and mine are buried in my spare tool cabinet. with a bunch of stuff piled in front of them..

hint.. clean decks..  masking tape...  duct tape.. aluminum foil tape.. to seal off the top of the block completely..

you can use THICK axle grease on the drill bit.. wiping it off as you drill in and using fresh.. this traps the turning..  you can do the same on the helicoil tap..  thick grease in the flutes..   or pickup a magnet on an antenna wand..  please.. if you get it with the ORANGE handle.. please crimp the magnet into the end.. or try to pull it out and GLUE it in..  i have had the magnets come out of the end before.. it is small enough to stick thru a head bolt hole..

in the mid 90s i ran the head rebuilding department at an engine builder.. so i know heli coils. all too well.. i actually liked the self tapping thread inserts from silver seal products.. i have not tried them as a head bolt hole repair..  but intake or exhaust flange repairs.. even carb or thermostat housing thread repairs..  drill the hole.. thread a nut on a 3 or 4" long bolt.. then the thread insert till it is even with the end of the bolt .. then bring the jam nut down.. snug the two together..  then hold the long bolt as a guide.. and use an open end wrench to turn the JAM nut and the insert cuts its own threads..  some engine rebuilders will have them usually in 3/8-16 , 5/16-18 and 8x1.25 but that won't help you..


wow.. somebody with a pile of old harmonic dampers could really clean up at the swap meet after a a bunch of holes are drilled .. then some counter bored and tapped for heilicoil threads..

[midnight sun]

yes... please create a drill guide.. if you don't have a LOT of experience doing it.  or screw long bolts into the other holes..  so its easier to keep the drill going straight..

helicoil 7/16-14 is 29/64ths.

you have 3 different lengths of heli coils available i tried to keep the versions just over 5/8 long to do head bolts.. check your length.. the short length will probably work.. i almost always doubled them up when only the short ones were available..

0.438"
0.656"
0.875"

http://www.grainger.com/category/thread-repair-inserts/thread-insert/fasteners/ecatalog/N-8o9?bc=y#nav=%2Fcategory%2Fthread-repair-inserts%2Fthread-insert%2Ffasteners%2Fecatalog%2FN-8o9Z1z0n51jZ1z0komwZ1z0o252Z1z0q79jZ1z0ha2v%3F_%3D1403395156964

making your own drill jig.. do you own a drill press and a welder..

got some angle iron..  and a chunk of steel about an  inch or inch and a quarter thick..   stick some 1/2" bolts between the flat sizes of the angles..  so you can weld the angle sections together.. you need probably 8 or 10 inch pieces.. weld the flat sides of the  to the  steel block.. everything clamped down..  weld something across the far ends..  now you can clamp it flat to your drill press to drill one of several holes. you will want to drill the 29/64 hole in 2 different spots but close to each other.  one is the drill hole.. use the drill press with the heli coil tap in the chuck to HAND START THE THREADING working it in and out a few turns..   you can cheat and counter bore the hole till you only have 5/8 of hole to tap.  but make sure the counter bore drill is the proper size to keep the tap aligned..   you can now use a different head bolt to clamp this into place.   you might want to drill an exact 7/16 hole so you can align it perfectly over the existing damaged hole.  you now have a drill and tap guide.  with enough room to drill for 1/2" heli coils to repair other engines .if you ever need it..

have  a drill press but no welder.. look around .. got an old harmonic damper.. you can remove the inertia ring and drill and tap that.. you can easily hold that down with something across the ring..

if you don't have a drill press.. have a machine shop drill the 2 holes you need thru an old inertia ring  perhaps counter bore one hole part way thru for the heli coil tap.. i don't recall what the OD is on the heli coil tap.. and mine are buried in my spare tool cabinet. with a bunch of stuff piled in front of them..

hint.. clean decks..  masking tape...  duct tape.. aluminum foil tape.. to seal off the top of the block completely..

you can use THICK axle grease on the drill bit.. wiping it off as you drill in and using fresh.. this traps the turning..  you can do the same on the helicoil tap..  thick grease in the flutes..   or pickup a magnet on an antenna wand..  please.. if you get it with the ORANGE handle.. please crimp the magnet into the end.. or try to pull it out and GLUE it in..  i have had the magnets come out of the end before.. it is small enough to stick thru a head bolt hole..

in the mid 90s i ran the head rebuilding department at an engine builder.. so i know heli coils. all too well.. i actually liked the self tapping thread inserts from silver seal products.. i have not tried them as a head bolt hole repair..  but intake or exhaust flange repairs.. even carb or thermostat housing thread repairs..  drill the hole.. thread a nut on a 3 or 4" long bolt.. then the thread insert till it is even with the end of the bolt .. then bring the jam nut down.. snug the two together..  then hold the long bolt as a guide.. and use an open end wrench to turn the JAM nut and the insert cuts its own threads..  some engine rebuilders will have them usually in 3/8-16 , 5/16-18 and 8x1.25 but that won't help you..


wow.. somebody with a pile of old harmonic dampers could really clean up at the swap meet after a a bunch of holes are drilled .. then some counter bored and tapped for heilicoil threads..

Thanks Wayne.  A friend of mine who used to own a filling station/towing outfit had alsmost the exact setup you described.  Worked great.

[wayne petty]

I am glad that it worked..   straight is so much better than crooked..


back in the early 90s.. a shop sent over some 450SL heads.. every valve was bent..  valves.. guides, gaskets, oil squirters, timing chains..  when he reassembled his torque wrench was out of calibration as some of the head bolt holes stripped..  i offered to loan him the rebuilding shops drill and tap guide.. he said he could drill and tap them for the inserts freehand..  i told him that they are at an angle.. he said.. yea he knows ..  he has done it many many times..  3 days later.. he called.. said the head bolts won't go in..  i went over.. he had drilled and tapped them into the aluminum benz V8 block perfectly straight.. 90 degrees to the deck.. not 80 degrees like the holes in the heads are drilled..  he ask me if the shop could fix it.. i looked at him and said.. i don't think so..  i don't know what he did with it..  

another shop pulled all the main caps off to do a crank swap.. in chassis..  and tossed them all in the solvent tank to wash them.. and mixed the order up..  took my boss hours to figure out which one fit which position ..

glad you got it fixed..  if you have an old beam type torque wrench laying around.. please make a mark or place some masking tape at the 70 pound mark.. so its easy to see..   use a 15mm 12 point socket on the end and turn your click type torque wrench up to 70 foot pounds and see where it clicks at..   this is to verify the calibration.. NOT TO RECALIBRATE your click type torque wrench..   if you drag race and have your racecar at an NHRA national event..  the ARP Fasteners trailer has a torque wrench tester..  so  they can verify the proper torque setting on your wrench for the ARP fasteners you use.  something else i got done for everybody..