Drill & Tap Vs Helicoil?

I have a 1952 Ford Flathead 8RT. One of the bolt holes in the head for one of the thermostat housings have been stripped (prior owner - I'm sure you know how that is). What's the best fix, drill & tap or helicoil? Thanks in advance.

 

If you have enugh metal to drill and tap, do it. I helicoiled a head bolt on my flat head 40 years ago and it never gave me any trouble

 

If you want to keep the same size bolt, then heli coil, If you don't care about using different size bolts then drill and tap. You pays your money and takes your choice.

 

Years ago I purchased a Time-Sert kit at the Pomona swap meet. I consists of steel threaded inserts and special taps with the same thread pitch for repairing stripped threads. I stripped the the hole for the distributor hold down on a SBC aluminum intake manifold. It was a easy fix with the manifold on the car. Now it's a hardened steel insert for either a stud or bolt.

 

Another trade name for these is "Keen-sert" if your looking for them in Mcmaster or grainger. Great fix

 

Heli Coil is an easy fix so are the others

Tig

 

Cheapest, most direct way is to go oversize. As long as it dosn't look ugly with one big bolt head.

 

I've used "keyserts" in alloy bodied tools where a steel base is bolted on. Very high compression forces, these things stand up. Now if only I can buy a bolt wher the head doesn't bust off.

http://www.efunda.com/eds/company_details.cfm/id2/5359/pv/NO/cp/Helicoil%20Singapore%20Thor%20International/

I use these in pneumatic over hydraulic powered hi tensile steel strapping tools BTW

 

A "Time-Sert" or the larger version "Big-Sert" are good for fixing bolt holes that have been too far oversized (or a pulled Heli Coil) for a standard thread replacement. Normally a Helicoil insert is stronger than the threads it replaces as the insert is stainless steel.

 

There is also a Keen-Sert available to use when the helicoil repair goes bad. Of course more expensive and they are available with the over-size tap.

Bob

 

Oversize usually works out, or do both the holes so they match.

Bob

 

It's only a 5/16" bolt with no real pressure on it. I'd use what ever brand of helicoil type kit that you can find at the parts store. Being right up in your face, an oversize bolt will look stupid to my eye. It's very easy.

 

Keep it at 516" make it rite its a easy cheap repair

Tig

 

I'd go with the heil coil....that or drill both bolts out so they're both bigger bolts.

 

Thanks for the feedback guys.

The reason I asked about the helicoil is because years ago I worked at a plastic extrusion plant and the maintenance men were always putting helicoils in the extruders' die bolts. They would usually have to try a couple of times to get one installed properly. Then some young punk like me would come along and torque them back down with a five foot pipe, and the maintenance man would be back out at the line with a few more inserts the next week.

In this case, as someone mentioned, the torque required in the thermostat housing is almost negligible. I'll put a helicoil in...

 

Helicoil it , if its worth doing do it right.

 

i used to be one of those maintenance guys cussing your ass for using a 5' bar! they have limited life in them under those conditions, 700 ton extruders can blow dies apart with ease and the bosses cry when their is too much rework!

 

Ive been working on vintage to modern European bikes for fifteen years. I've also been building and maintaining cars for longer. When I first discovered the "heli-coil", I was amazed. When A co-worker turned me on to the "time-sert", I never went back. I use them almost daily for over a decade, and have never had to re-dux the repair after using a "time-sert". The heli-coil is fine, but seemingly require somewhat frequent replacement on constantly maintained holes I.e. Caliper bolts, drain plugs, pressure switches, spark plugs etc. Anything that gets frequent use, gets a time sert in my world.
Just my two cents.

 

Sometimes helicoils are the best or only way to go. If the tapped hole is in a "boss" then the larger, thicker walled inserts may reduce the boss' wall thickness too much, or require drilling and tapping a much deeper hole than original, which may turn a blind hole into a thru hole, and create sealing difficulties. The helicoil is considered preferable for frequently "maintained" threads in aluminum parts on some aircraft. If a helicoil insert is long enough ( 1.5 diameters in iron or steel, maybe 2.0 diameters in aluminum) then even a grade 8 bolt can be torqued fully. Be sure to install with the helicoil well below the surface.

 

We use them both to repair damaged holes at the shop I work at, Helicoils for most lighter duty stuff, but the time-serts for use on spark plug holes in O/T Ford engines that seem to love blowing the plugs out of the heads, and for repairing head bolt holes in Northstar engine blocks that you are stupid enough to do head gaskets on . They both perform pretty well, but the time-serts do look a little more trustworthy if you have enough metal in the boss to use it.