Retroanaconda Posted August 2, 2012 Share Posted August 2, 2012 Stripped the front of the engine down yesterday and today in order to sort a few issues, and I'm come up against a few issues I'd like to put to the wider knowledge of the forum. First up is a classic issue, one water pump bolt sheared off many years ago and I managed to seal it since then without that one in place. But since the front of the engine is in bits it's probably worth sorting for good. This is what I'm left with: As you can see not much protrudes. There was a bit more but my usual method of welding a nut onto the stud just resulting in it shearing off again 1/4" further down! So now I'm left with about 1/4" protruding from the block. What are my options? I guess the answer is going to be to drill it out and helicoiling it, which I'm not too keen on as messing it up will end with a buggered engine block! If I do have to drill it out, I'd appreciate a pointer to those v. hard drill bits you can buy for this purpose! My second issue is an oil leak from the wading plug hole. Crankshaft seal, I figured. Will change it while the cover is off. It may well be leaking, but I think I've found another leak further up: On the above photo there are two plugs with screwdriver slots in. One just above the camshaft and one between it and the crankshaft. The oil appeared to be coming from these, or at least the upper one, before I wiped some of it off. Both of them turn freely in their holes up to point, and then go stiff. The upper one will come out of the block, but the lower one will not. They appear to have two punch marks each, at their edges. I assume this is to stop them undoing themselves? Doesn't appear to have worked if so. Looking at the parts information they are listed as a 'plug - oilway' so I guess they are a blanking plug for the open end of an oil passage that's drilled during the block manufacture. This would explain the leak. If I replace them, can I just threadlock them in to replace the function of the punch marks? Love/hate relationship at the moment...why is nothing easy? Quote Link to comment Share on other sites More sharing options...
Snagger Posted August 2, 2012 Share Posted August 2, 2012 For the broken bolt, I'd cut it as close to the block as possible and then drill down its centre in gradually increasing sizes until the threads can be tapped out at their standard size, only using helicoils if the threads got damaged. Don't use Ezi-outs as they will snap off in the bolt, leaving a hardened steel core that you won't be able to drill. As for the plug, I'd give the plug and its hole a good clean and then use red Locktite. Quote Link to comment Share on other sites More sharing options...
Maverik Posted August 2, 2012 Share Posted August 2, 2012 For the broken bolt, I'd cut it as close to the block as possible and then drill down its centre in gradually increasing sizes until the threads can be tapped out at their standard size, only using helicoils if the threads got damaged. Don't use Ezi-outs as they will snap off in the bolt, leaving a hardened steel core that you won't be able to drill. As for the plug, I'd give the plug and its hole a good clean and then use red Locktite. Sound advice^^^ - I think that's pretty much how I'd proceed... make sure you bung up the front of the sump of course you don;t want swarf going into the bottom of the sump. Good luck. Quote Link to comment Share on other sites More sharing options...
ejparrott Posted August 2, 2012 Share Posted August 2, 2012 You won't need any special drills to get the stud out. As Nick says, cut it off flush. We had the same fun and games last weekend, only to complicate matters, a PO has got the stud well and truely stuck in the timing case, Eventually after lots of wiggling the stud snapped off flush with the front of the block. We followed that with careful centrepunching and drilled it out...bang on as it happened, and a 6.8 drill left just the old stud thread which fell out. Start with small drills and carefully work your way up, and applying a blowtorch up the drilled hole may help loosen it. Quote Link to comment Share on other sites More sharing options...
Retroanaconda Posted August 2, 2012 Author Share Posted August 2, 2012 Thanks chaps. I will cut it off flush (ish) and give drilling a go. The minor diameter of an M8 bolt is 6.466mm, so I'll drill out to 6mm and see if I can tap the extra out. If not then I can go to 6.5mm, though I run the risk of losing some strength, depends how accurate I've been with the drill! The sump is plugged at the bottom, but the oil is drained anyway and I will be removing it to clean it out so it's not the end of the world. Will get some locktite on those plugs too, if I can find a way of cleaning the oil out of the threads in the block. Quote Link to comment Share on other sites More sharing options...
Snagger Posted August 2, 2012 Share Posted August 2, 2012 Thanks chaps. I will cut it off flush (ish) and give drilling a go. The minor diameter of an M8 bolt is 6.466mm, so I'll drill out to 6mm and see if I can tap the extra out. If not then I can go to 6.5mm, though I run the risk of losing some strength, depends how accurate I've been with the drill! The sump is plugged at the bottom, but the oil is drained anyway and I will be removing it to clean it out so it's not the end of the world. Will get some locktite on those plugs too, if I can find a way of cleaning the oil out of the threads in the block. Brake cleaner soaked cotton tips, like you use for cleaning your ears, contrary to medical advice (the tips, not the brake cleaner - don't use that in your ears!)... Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted August 2, 2012 Share Posted August 2, 2012 Thanks chaps. I will cut it off flush (ish) and give drilling a go. The minor diameter of an M8 bolt is 6.466mm, so I'll drill out to 6mm and see if I can tap the extra out. If not then I can go to 6.5mm, though I run the risk of losing some strength, depends how accurate I've been with the drill! The sump is plugged at the bottom, but the oil is drained anyway and I will be removing it to clean it out so it's not the end of the world. Will get some locktite on those plugs too, if I can find a way of cleaning the oil out of the threads in the block. STOP! Core sizes of threads dont apply to a tapped hole, the holes are drilled larger, in this case 6.8mm. Dont try and run a tap down a hole any smaller than this as you run a very good risk of breaking a tap... Taps tend to need spark erroding out. Is the bolt in a blind hole? Quote Link to comment Share on other sites More sharing options...
Retroanaconda Posted August 2, 2012 Author Share Posted August 2, 2012 So if I drill it out as far as I dare, how do I remove the bits of bolt left in the thread? It's blind, though as a last resort I guess I could drill through to the back and profile the rear of the casting to allow a bolt/nut to be fitted. Though to be honest in this case I'd rather drill oversise and helicoil it. Quote Link to comment Share on other sites More sharing options...
Snagger Posted August 2, 2012 Share Posted August 2, 2012 That's true, but in this case, it's a pre-tapped hole which should have a thin shell of the old bolt left in it. With luck, the bolt wil quickly break up and come out. DOn't force the tap hard, though - use plenty of reversals and cutting fluid. Quote Link to comment Share on other sites More sharing options...
Tonks4x4 Posted August 2, 2012 Share Posted August 2, 2012 I have also found it useful to modify the drill bits I use for drilling out broken studs/bolts. I grind the end of the drill bit to put the cutting face on the opposite side. I then drill them out carefully in reverse. The reason for this is sometimes if the drill bit snaggs it will screw the broken stud further in. However when in reverse if it snaggs now and again it has heated from the drilling and begins to screw out, leaving more chance of not damaging the thread with a slightly off centre hole. The downside is that the drill but flutes will not be clearing away the swarf so you need to remove the drill bit often between drilling. Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted August 2, 2012 Share Posted August 2, 2012 I have also found it useful to modify the drill bits I use for drilling out broken studs/bolts. I grind the end of the drill bit to put the cutting face on the opposite side. I then drill them out carefully in reverse. The reason for this is sometimes if the drill bit snaggs it will screw the broken stud further in. However when in reverse if it snaggs now and again it has heated from the drilling and begins to screw out, leaving more chance of not damaging the thread with a slightly off centre hole. The downside is that the drill but flutes will not be clearing away the swarf so you need to remove the drill bit often between drilling. Just buy a left handed drill bit. Quote Link to comment Share on other sites More sharing options...
Tonks4x4 Posted August 2, 2012 Share Posted August 2, 2012 Just buy a left handed drill bit. Or yes just that.... lol. Never have one to hand when I need one. Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted August 2, 2012 Share Posted August 2, 2012 So if I drill it out as far as I dare, how do I remove the bits of bolt left in the thread? It's blind, though as a last resort I guess I could drill through to the back and profile the rear of the casting to allow a bolt/nut to be fitted. Though to be honest in this case I'd rather drill oversise and helicoil it. Drill it 6.8mm. If you do catch the side of a few threads it wont matter, you wont lose enough strength in the threads to cause an issue, you dont wang them bolts up. If the bolt hole was open at the back it would of been wise to drill from the back of the hole. Quote Link to comment Share on other sites More sharing options...
Retroanaconda Posted August 2, 2012 Author Share Posted August 2, 2012 I will see if the motor factors has a 6.8mm drill bit and go from there. Obviously I will need to start off with something smaller (4mm or so) and then go up to 6.8mm. Just hope I can drill the hole straight! Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted August 2, 2012 Share Posted August 2, 2012 Just hope I can drill the hole straight! Dont get upset if you cant, drilling broken bolts out on a Milling machine is hard work, with a pistol drill its 100 times harder. Quote Link to comment Share on other sites More sharing options...
reb78 Posted August 2, 2012 Share Posted August 2, 2012 with a pistol drill its 100 times harder. = impossible in my hands!! Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted August 3, 2012 Share Posted August 3, 2012 ....... Just hope I can drill the hole straight! The magnetic drill we were using on the trailer is still at mine if you think there is enough of a flat on the front of the block to mount it. That will at least keep the hole straight .... there will be a 6.8mm drill kicking about here somewhere if you need it along with the m8 taps. Let me know if you want to borrow them. Quote Link to comment Share on other sites More sharing options...
oneandtwo Posted August 3, 2012 Share Posted August 3, 2012 Weld another nut on the 1/4" left protruding. Let it cool down. Heat the casting up with oxy acet or possibly a blow torch but may not produce enough heat, it will come out. I have to do it day in day out with iron and alloy castings on marine engines and very rarely do I ever resort to a drill Quote Link to comment Share on other sites More sharing options...
Maverik Posted August 3, 2012 Share Posted August 3, 2012 Weld another nut on the 1/4" left protruding. Let it cool down. Heat the casting up with oxy acet or possibly a blow torch but may not produce enough heat, it will come out. I have to do it day in day out with iron and alloy castings on marine engines and very rarely do I ever resort to a drill I would be a little nervous taking any type of substantial heat to that area, there are a lot of perishables around there and oilyness which could catch quite easily... Quote Link to comment Share on other sites More sharing options...
Retroanaconda Posted August 3, 2012 Author Share Posted August 3, 2012 Cheers all. Ok, so all I could get was a 6.5mm drill bit so got that. Started off small (3-4mm or so) and worked slowly up to 6.5mm. Got the tap going but found that it was up against a great deal of resistance. Far more force to turn than I was prepared to apply for fear of snapping the thing. So I drilled it out to 8mm: Plan is now to drill out further and Helicoil it back to M8, will do so when I can get my hands on a kit. Local factors out of stock at the moment annoyingly. The plug things I've also sorted I think. Top one I was able to get out, so did so and cleaned up and reinserted it with some Loctite. Bottom one wasn't coming out and I was only chewing up the slot in trying so I though sod it and left it as is. Put a smear of RTV over both of them to help stop any seepage. Not that it's the end of the world if there is any, as it would only end up back in the sump anyway. So there we go. Will report back when I've attempted the thread repair. I've also got to do one of the tapped threads in the timing chest, on the underside of the water pump, as the thread has pretty much pulled out. Quote Link to comment Share on other sites More sharing options...
Julian Posted August 4, 2012 Share Posted August 4, 2012 Cheers all. Plan is now to drill out further and Helicoil it back to M8, will do so when I can get my hands on a kit. Local factors out of stock at the moment annoyingly. I'd not bother with helicoiling unless you have a strong urge. There looks to be plenty of meat there so just open it up to the next size and use a bigger stud - in these instances I normally find that there's a UNC size that's marginally bigger and will do very nicely! PS A copy of ''Engineers Black Book'' is a good additon to any book shelf! Julian. Quote Link to comment Share on other sites More sharing options...
Retroanaconda Posted August 4, 2012 Author Share Posted August 4, 2012 In that case I will obviously have to drill out the holes in the water pump and timing chest, that isn't an issue is it? Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted August 4, 2012 Share Posted August 4, 2012 the next imperial size is 3/8ths which is basicly 10mm. I'd helicoil or better still timesert the hole. At work, when we helicoil holes, we dont tend to drill the hole, we just bung the tap straight in. Quote Link to comment Share on other sites More sharing options...
ejparrott Posted August 4, 2012 Share Posted August 4, 2012 Having had the one apart last week, I'd say there isn't enough meat to drill it out to 10mm, helicoiling is a good option. You would also have to drill out the holes in the waterpump don't forget, and that bit of the timing case cover which is so stupidly fragile, then I think an M10 nut would be too large to clear the waterpump casting so you need special shouldered washers....... Helicoil. Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted August 5, 2012 Share Posted August 5, 2012 James, I have an m8 recoil kit here with the correct drill if you want to borrow it. Pm your address here or on fb. Mo Quote Link to comment Share on other sites More sharing options...
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