10 replies to this topic

[Nikral]

hi all

 

is it possible to heli coil the sump plug in situation, as I am having a local garage do it I don't want them to blag me by saying they can only do it by dropping the engine out and it costing me more.

 

Tony

[cooperbloke]

You can do it in situ, and the easiest way I've found is to take the right hand tie bar off to gain full access.

 

Some will say the 'best' way to helicoil the sump plug is to remove the gearbox to be sure of all swarf removal, but if you're careful and allow some engine oil to run through the drain hole to flush as much out as possible, there shouldn't be a problem. 

[robminibcy]

probably could but i wouldn't advise it as bits of swarf will be left behind which could destroy the whole engine and gearbox. Would be best to take it out, split engine and box and then clean after

[robminibcy]

aha beaten to it!

[AVV IT]

I understand that whilst it's possible to do it in situ, it's preferable to do it with the engine out, in order for the casing to be drilled straight using a pillar drill. When I had mine done the guy said that he could do it using a pistol drill with the engine in situ, but that they hardly ever go in straight that way, which increases the risk of oil leaks. In the end it was done with the engine out, as the engine had to come out for a different reason anyway.

[Nikral]

thanks for the replies guys, if the engine comes out its a minimum of a days work and at local garage rates of £50 per hour plus vat I am looking at a bill of at least £500-£600 pounds for this work being done, my day just don't get any better.

[benjy_18]

Do it in situ yourself. Easy enough to do with the right drill, jus take it slow and then flush the box a few times with cheap oil to remove swarf. I've done a few this way and never had problems

[Stiggytoo]

I wouldn't worry about the swarf, just make sure the drill goes in straight.

[jcslocum]

Do it in place, Cover the end of the drill bit with chassis grease to capture and hold andy chips. Run a vacuum if you can.  Same with the tap. Clean as regrease as needed to get all bits. Then clean the newly special threaded helicoil hole with carb cleaner and dry. Put a small dab of loctite on the outside of the helicoil and insert. Leave loctite to dry if possible. Install new plug and fill with oil. Drive away smiling!!

 

I just did this yesterday on my Porsche 912 intake manifold. Had a stripped thread on the intake between tha valves. It was an M8 not a drain plug but you get the idea.

 

 

 

 

 

 

 

 

 

[tiger99]

It is UTTERLY POINTLESS to attempt this, or have a garage try it, unless there is a method of getting the drill and tap EXACTLY perpendicular to the sealing face of the gearbox, otherwise it is guaranteed to leak. This has been discussed many times previously.

 

One possible mitigation, if you can be very sure of getting it close to perpendicular, is to use a bonded rubber seal (Dowty seal) or a similar thing from a modern car (I think the readily available Ford Focus bonded rubber seal fits), because they are more tolerant of misalignment than the plain copper washer.

 

The other possibility, which surprisingly no-one seems to offer as a repair package, because it would be quick and easy, once the tooling had been made, involves Heli-coiling it, and then using a tool, basically a hollow milling cutter guided by a pin screwed into the Heli-coil, to skim the sealing face so it is perpendicular to the new thread.

 

But I would not do it that way. I would make up an ali top hat bush in the lathe, with accurately machined threaded bore and sealing face, and MIG or TIG weld it in. Even epoxy would probably suffice. Or, I would make a steel bush, with external thread too, bore and tap the hole oversize, and fit the bush permanently with Loctite. Either way, alignment of sealing face and thread is assured.

 

Oh, and when drilling in the car, why not put some Blu-tack, or even plasticene, behind the hole to contain drilling debris, and carefully fish it out afterwards? Again, professionals who were offering a service to repair this problem on a regular basis could devise a tool, possibly using an inflatable element, to do the job more effectively.

 

What you should not even think about doing is to use one of the bodger's delight taper drain plugs, available from the spivs and cowboys of the spares industry. Use of one of these is very likely to result in a scrapped transmission case.

 

Any garage worthy of the name ought to know how to do this PROPERLY.......

[Captain Mainwaring]

Personally I prefer to use an adjustable reamer to take the hole to diameter first where access allows - makes it much easier to keep things perpendicular.

 

Some people just can't drill a hole straight to save their lives and to be honest there can always be issues drilling out an existing hole in alloy when using a hand drill with limited access.

 

I suppose you could always pressurize the casing with compressed air through the breathers while drilling which would help blow swarf out.