Snapped bolts on ali outboard block

[9D280]

Couple of helicoil tips - if you are replacing an M6 be sure your tap for the coil thread is M8 fine - M6 has a 1mm pitch, M8 (standard) is 1.25..... Also get a bottoming tap for the final cut that you inevitably won't get in the kit - as it's a head bolt it will be going into a blind hole. Also use a stainless coil, then you end up with the thread against a similar material, so when it corrodes next time it just anchors the coil in place & the bolt / screw should release more easily, as opposed to 6 months later being doomed of ever getting it out again as the mild steel coil codrrodes.

Now for the warning, remember the stainless screw remains will not take kindly to a drill going too fast and will just surface harden if your drill is spinning too fast. So, make sure it's a sharp bit, and be very careful to make sure you get a constant stream of "chips" off it, otherwise your life will become very difficult very quickly as your snapped screw shank becomes an impenetrable shield.....

Good luck.

[doggypaddle]

a good unworn jacobs chuck can sometimes get into awkward places a molegrips wont too.

[Hightower]

OK, two options here.

Option one is the safest one. To leave the 4 bottom bolts in and to extract the upper ones. I would suggest a little drill guide to fit into the clearance hole of the lid. Then drill the bolt so that you can use an easy out. The heat from drilling coupled with the plus gas should break the corrosion sufficiently to enable extraction. You then screw in the easy out (a left hand helix tap) and hopefully should extract the stud. Easy out

The second is a little more risky as it involes removing the bottom bolts. First you must remove the bolts without snapping them. Plus gas is the first step the second would be heat but might I suggest doing the bolts up first. Yes really! The action of doing bolts up will make them shrink slightly and thus break the corrosion enough to be able to undo the screws normally. This might well be possible without the heat but you will have to have a steady hand and nerve Your experience from the other bolts snapping will help you here. Once the bolts are removed then you could try the hole grip method or the easy out method, it's up to you.

I have some easy out's but because of your location makes it difficult to get them over to you. Try tapping up some machine shops on the Island they might well lend you a set for the return of a holding deposit.....Tell em your a cash strapped Student

[Matt]

Listen to dirk!

A propane/butane flame is fairly cold, unlikely to cause collateral damage unless yer silly. Get the studs/bolts as hot as the propane torch will allow - should be at least straw coloured on the stainless. Get the remaining 4 out with heat, then heat on the studs to remove the remaining ones with mole grips.

Drill should be a last resort, as you need a kryptonite drill bit and drilling stainless is a pain. The chance of it wandering off centre into the soft ali is high. If you have to drill, start with a small size and work up slowly- if you can keep the drill centred, you have a fair chance of getting the studs out without needing to helicoil.

[Dirk Diggler]

Originally Posted by Hightower

You then screw in the easy out (a left hand helix tap)

If you decide to go the "easy out" route, then buy one from your local snap on man, otherwise you'll be starting the "How do I get an easy out out" thread pretty soon!

[Matt]

Yeh. I've never ever had an easy out work for me - but I've never had a snap-on one.

[Jono]

Originally Posted by Matt

....
Drill should be a last resort, as you need a kryptonite drill bit and drilling stainless is a pain. .....

.... If'n yer a Girlie.

[Matt]

Damn right!

[slimtim]

The bolts are not stainless if that makes any difference. Some of the snapped bolts are extremely corroded leaving hardly any material intact so I'm not holding out much hope in getting the remaining ones out.

Matt, am I not supposed to be heating the casting as opposed to the bolts? Heating the bolts would just expand them in the holes making it even more difficult to get them out wouldn't it? Or does the extreme expansion and contraction of the bolt tend to release it?

[Matt]

Oh shit! On the spot now.
The expansion rate of the ali is higher than the steel, that's the point of heating it. You do ideally want the bolt/stud cold, but it's generally not practical (cue sarcarstic remark from lofty ), and the colouration of the steel bit gives you an indication of the temperature.

[Hightower]

What you want to do is break the join between bolt and hole, two disimilar metals will expand at different rates at this will break joint.

As regards the easy out, I have a Kennedy set which is pretty good and never let me down, however we are talking of small bolts here and tricky with any method you use, you might well end up drilling them out and possibly either heli-coiling or tapping them to the next size of M8 if this is possible.

As for the drilling side of things then do as I suggested and try to use a guide bush for central drilling, a good quality drill and some cutting fluid will tackle the studs

[slimtim]

ok makes sense Matt, I was thinking of maybe heating everything and then squirting the bolt with that "cold stuff in a can" that someone posted a link to on page 1.

Andy, thanks for the tips. Really not sure about heli-coiling or re-tapping up to M8 as I can't see how much material I have to play with until the plate is off.

Plenty of advice for me to go on here, I just need to decide which approach to go with...

1. Do I leave the bottom bolts (and so the plate) intact and try and drill/"easy out" the broken studs (with heat and plusgas too) and replace with new bolts without ever removing the plate?

or

2. Do I attempted to remove the bottom bolts by using heat/plusgas/luck/power of the jedi but risk snapping those off too and thus ruling out option 1?

Having just looked at the engine, I'm not sure I will be able to take the block off as after initial inspection it seems I may have to remove the rear coolant ducting plate which may well lead to the same problem!

[codprawn]

Post a photo!!!

[slimtim]

here ya go codders...

You can see from the pics the 9 (not 10 as I had thought) holes and the 4 bolts at the bottom that I have not yet touched (and one further up).

I have also done a close up of the top corner to show the plate-gasket-spacer plate-gasket-block arrangement (or as far as I can tell this is what it is). All bolts appear to have sheared at the outer plate/outer gasket join so in theory there should be about 4mm of stud sticking out if I do ever get the plates and gaskets off.

[codprawn]

Typical the one thing we needed to see and you can't!!!

How much of the bolt would stick out if that cover was removed? The same amount as the thickness of the cover or will they be almost flush when the cover is removed?

[slimtim]

I reckon about 4mm should be sticking out assuming the spacer and gaskets come off easily.

I said in post one my outboard was a 4 stroke, why I said that I don't know but no one seemed to notice

[doggypaddle]

there's probably no easy short cut here! bite the bullet and take the powerhead off the leg so you can get at it properly, snap/undo the rest and remove the plate and then tackle the problem. It will be a lot easier if theres no restricted access and you can lay the powerhead down to drill the studs.
Make sure if you cant undo the studs and decide to drill them that you start and continue centrally.
The welding a nut on trick usually works well, if you can get a stut to start moving keep gently working at it until it frees with plenty of penetrating fluid.
Titaniun nitride coated drill keep their edge a bit longer too.
Or for really hard studs and drilling springs i use masonry drills sharpened on a white diamond stone to a suitable angle.
at least if you get them all out and remove the plate the finished jobs a good un.

[doggypaddle]

[quote=Hightower;283315]
you might well end up drilling them out and possibly either heli-coiling or tapping them to the next size of M8 if this is possible.[quote]


You can get M7 too.......peugeot use M7 not very common though. might be a possibility if there not suffecient meat for M8

[Nos4r2]

Originally Posted by doggypaddle

there's probably no easy short cut here! bite the bullet and take the powerhead off the leg so you can get at it properly, snap/undo the rest and remove the plate and then tackle the problem. It will be a lot easier if theres no restricted access and you can lay the powerhead down to drill the studs.
Make sure if you cant undo the studs and decide to drill them that you start and continue centrally.
The welding a nut on trick usually works well, if you can get a stut to start moving keep gently working at it until it frees with plenty of penetrating fluid.
Titaniun nitride coated drill keep their edge a bit longer too.
Or for really hard studs and drilling springs i use masonry drills sharpened on a white diamond stone to a suitable angle.
at least if you get them all out and remove the plate the finished jobs a good un.

Yep-with only 4mm of the bolt showing , this is probably the best suggestions. I thought the plate would be thicker-disregard my last post..

[jyasaki]

Originally Posted by slimtim

Considered the heat option, but not sure how far I can take it though before melting or distorting something.

Disclaimer: I haven't read more than first few posts. Sorry if I'm stepping on toes.

If the bolts go into the block, they'll withstand a good deal of heat. Drilling and an EZ-out after heating the block should do it (assuming they're large enough to work with.) I'd go with a heatgun, but I suppose careful application of a propane torch would work as well.

jky