Perkins 4108- Heat exchanger stud sheered off

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blackdogsailing

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The heat exchanger on my 4108 is held on with 4 studs which are screwed into the side of the cylinder head. 1 of these has sheered off exactly flush with the face of the head. How can I get it out ? Best to get the head off ? Or will it be possible to drill it out. There is room (just !) to get an electric drill in there. Some ideas please before I start !

Chris
 
get a set of easy out's drill carefully re getting dead center. The easy out's are a left handed worm like tool that grip as you turn in, you may find it best to heat the area
 
mtb said:
get a set of easy out's drill carefully re getting dead center. The easy out's are a left handed worm like tool that grip as you turn in, you may find it best to heat the area
Click to expand...

Centre punch the stud before drilling and drill the largest hole you can without going near the thread. Easy Outs usually called stud extractors in the UK. You should go for a large hole because if you go too small the extractor might snap and that is not good! Heating is a great idea as well.

Richard
 
Initially you need to break any bonding of the thread I would heat with small lpg blowtorch and then give some judicious short taps with a hammer and suitable drift also penetrating oil may help.
 
If it's sheared off flush then its going to be corroded in there tight.
Hand drilling horizontally, straight down the middle of the bolt, is very difficult unless you are experienced in this tort of thing.
I would consider taking the head off and putting it under a pillar drill.

Plank
 
Thanks everyone. P.W.- Those were my concerns but I am tomorrow going to try the easy out method. Will apply some heat first. Another good idea me thinks. Will let you know the outcome. If the head does have to come off at least i can get the valves done....

Chris
 
blackdogsailing said:
The heat exchanger on my 4108 is held on with 4 studs which are screwed into the side of the cylinder head. 1 of these has sheered off exactly flush with the face of the head. How can I get it out ? Best to get the head off ? Or will it be possible to drill it out. There is room (just !) to get an electric drill in there. Some ideas please before I start !
Click to expand...

A good old-fashioned engine workshop should be able to do this for you ... if the head's off, I'd get outside help.
 
Usually the easiest way to extract such small studs is to use an arc-welder. Aim very carefully and then get the electrode stuck on the remnants of the stud. Release the electrode from the welding stick. The ensuing heat will break any rust bond and the stuck electrode will enable you to unscrew the stud.
 
blackdogsailing said:
The heat exchanger on my 4108 is held on with 4 studs which are screwed into the side of the cylinder head. 1 of these has sheered off exactly flush with the face of the head. How can I get it out ? Best to get the head off ? Or will it be possible to drill it out. There is room (just !) to get an electric drill in there. Some ideas please before I start !

Chris
Click to expand...

Lots good advice here, but I have a 4108, and would be difficult to apply heat to that area, certainly enough to make a difference. The stud is likely to be very well set in there, due to the circumstances is is in, it is a heat exchanger after all, getting hot then cold on each engine cycle, which is probably a lot.
My engineering practice and experience, and knowing a 4108, is to treat this as if it is a solid into which you wish to drill and tap a thread, rather than try to extract a broken stud wiich could cause you more problems.
Firstly, using a centre punch, get as close to the centre of the stud, as possible, make your centre for drilling, then use a small, repeat small HS drill, no more than 4mm, make your pilot hole in the stud to its full depth. then gradually open up the hole, make sure all drills are HS good quality ones, an intermediate between the final drill which must be the stud tapping size should be sufficient. I would use some drilling lubricant, it may surprise you but spit is very good. Do not over apply pressure when drilling. Once you have your tapping size hole, use a first tap, the one with lots of taper on it, they come in sets of three, starter or 1st tap, a middle and a bottom tap, then the middle, one, and finish off with the bottom tap. Always use a tapping grease, tallow was in vogue when I was doing this, but ordinary oil is ok. Take it slow and carefull, remove the tap frequently to remove swarf, clean and oil and continue.
If your 4108 is like mine access is not to good, when tapping it may be an idea to press a suitable size nut on the the square end of the tap, nice and tight, then you can use and extension on it with bar on it, more 'feel' than with a rachet. Done that many times with a nut, east to remove later.
Once hole is tapped, either use a bolt when refitting the heat exchanger, or a piece of stud to replace the original. An hours work, no head removal, Good luck
 
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Sarnia said:
Lots good advice here, but I have a 4108, and would be difficult to apply heat to that area, certainly enough to make a difference. The stud is likely to be very well set in there, due to the circumstances is is in, it is a heat exchanger after all, getting hot then cold on each engine cycle, which is probably a lot.
My engineering practice and experience, and knowing a 4108, is to treat this as if it is a solid into which you wish to drill and tap a thread, rather than try to extract a broken stud wiich could cause you more problems.
Firstly, using a centre punch, get as close to the centre of the stud, as possible, make your centre for drilling, then use a small, repeat small HS drill, no more than 4mm, make your pilot hole in the stud to its full depth. then gradually open up the hole, make sure all drills are HS good quality ones, an intermediate between the final drill which must be the stud tapping size should be sufficient. I would use some drilling lubricant, it may surprise you but spit is very good. Do not over apply pressure when drilling. Once you have your tapping size hole, use a first tap, the one with lots of taper on it, they come in sets of three, starter or 1st tap, a middle and a bottom tap, then the middle, one, and finish off with the bottom tap. Always use a tapping grease, tallow was in vogue when I was doing this, but ordinary oil is ok. Take it slow and carefull, remove the tap frequently to remove swarf, clean and oil and continue.
If your 4108 is like mine access is not to good, when tapping it may be an idea to press a suitable size nut on the the square end of the tap, nice and tight, then you can use and extension on it with bar on it, more 'feel' than with a rachet. Done that many times with a nut, east to remove later.
Once hole is tapped, either use a bolt when refitting the heat exchanger, or a piece of stud to replace the original. An hours work, no head removal, Good luck
Click to expand...
I read your post with great interest but you did not fully convince me. Are you going to tap the newly made bore so that it will fit a bolt of the same original size? If yes I foresee possible problems, while a larger threaded bore/bolt might be ok. In case of same size I would trust more an operation similar to the one you describe but involving helicoils, i.e. a larger bore here too.

Daniel
 
danielefua said:
I read your post with great interest but you did not fully convince me. Are you going to tap the newly made bore so that it will fit a bolt of the same original size? If yes I foresee possible problems, while a larger threaded bore/bolt might be ok. In case of same size I would trust more an operation similar to the one you describe but involving helicoils, i.e. a larger bore here too.

Daniel
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I understand your concerns, but I have done this previously elswhere, I find the new tap will often 'find' the original thread and follow it, cutting out the shell left of the broken stud. One further tip I forgot to mention, is to counterbore the new hole drilled, with a clearance of no more than 0.010, and no deeper than 0.125, this ensures the surface around the newly tapped hole is free from any swellings often as a result of tapping, always a good toolroom parctice.
 
ghostlymoron said:
How do you counter bore like that? Drills aren't available in .01mm steps.
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Obviously I am talking imperial, drills are available in steps of 0.15625 ("1/64) but the point I am trying to make which was common toolroom practice is to counterbore slightly with a drill just over clearance of the external bolt diameter prior to tapping the threads for the reasons previously explained. It was the custom to measure a drill with a micrometer to determine its size, rather than depend on the size engraved on it. A drill can be made to drill (not counterbore) a slightly larger hole than its actual size, simply by regrinding its centre off centre, having a trepanning effect to make a hole a few 'thou' larger. This was in the days when toolmakers did all the procedures required, milling, shaping, grinding, turning, heat treatments etc. On many tools using a jig borer tapping holes were piloted then bored to size, the counter bore simply followed by 0.010. It wouldn't matter if the counterbore was 1mm (0.039) clearance, would have the same effect. Hope that explains your query.
 
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Sarnia said:
Obviously I am talking imperial, drills are available in steps of 0.15625 ("1/64) but the point I am trying to make which was common toolroom practice is to counterbore slightly with a drill just over clearance of the external bolt diameter prior to tapping the threads for the reasons previously explained. It was the custom to measure a drill with a micrometer to determine its size, rather than depend on the size engraved on it. A drill can be made to drill (not counterbore) a slightly larger hole than its actual size, simply by regrinding its centre off centre, having a trepanning effect to make a hole a few 'thou' larger. This was in the days when toolmakers did all the procedures required, milling, shaping, grinding, turning, heat treatments etc. On many tools using a jig borer tapping holes were piloted then bored to size, the counter bore simply followed by 0.010. It wouldn't matter if the counterbore was 1mm (0.039) clearance, would have the same effect. Hope that explains your query.
Click to expand...
Proper way of working!
S
 
danielefua said:
I give up! maybe units in km... :)

Daniel
Click to expand...

Hello Daniel hope all well with you and your enjoying your retirement, remember me you helped me install a Simrad autopilot with a Neco drive motor, in a Nic 38. I even got a mention on the 'how to' sheet posted on the net. I was in Sardinia at the time, now moved to Greece. Best wishe . Mike
 
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