monkie Posted July 1, 2021 Share Posted July 1, 2021 I've started to strip down the engine I got from @ianmayco68 at the weekend. Upon taking the cylinder head off I see some marks on the head and block that look like the head gasket had started to fail (Elring gasket) on cylinder #1. Other than this everything else looks to be in good shape head and block wise. What's the collective opinion on getting the head checked out to see if a skim is necessary? I did notice that some head bolts came undone very easy and others were in damn tight. A new set of head bolts in on my list from Turners. The pictures are of the head, gasket and block respectively. Quote Link to comment Share on other sites More sharing options...
Snagger Posted July 1, 2021 Share Posted July 1, 2021 That was blowing, but it doesn’t look eroded at all. Clean it up and check the face is flat it’s a straight edge. If it’s flat, then as long as there aren’t any hairline cracks near the valves or injectors, it should be good. 1 Quote Link to comment Share on other sites More sharing options...
Badger110 Posted July 1, 2021 Share Posted July 1, 2021 My answer would be why not? It’s not a huge expense and unless it’s been done before, I’d say go for it. Quote Link to comment Share on other sites More sharing options...
miketomcat Posted July 1, 2021 Share Posted July 1, 2021 Definitely looks like the head gasket was going. If the engine is a potential keeper then I'd get the head skimmed and checked. If it needs to be back on the road quick or you don't need the expense I'd clean it up new head gasket and off you go. I've cleaned up plenty worse than that and put them back together but I normally need them the next day and I can't afford the extra expense. Mike 2 Quote Link to comment Share on other sites More sharing options...
simonpelly Posted July 1, 2021 Share Posted July 1, 2021 Needless to say, when putting back together, vacuum/blow out the bolt holes clean 🙂 Quote Link to comment Share on other sites More sharing options...
Maverik Posted July 1, 2021 Share Posted July 1, 2021 If you have the time and inclination, getting the head skimmed would be the proper job, your peace of mind too. Quote Link to comment Share on other sites More sharing options...
monkie Posted July 1, 2021 Author Share Posted July 1, 2021 Thank you all. I took my 110 up to Stafford from Yeovil and back in a day and it performed really well (I did wonder if the 19J would give up and I'd be returning on a flatbed). So I am in no rush with this at all. The 200tdi seems to be in good condition, Ian replaced the pistons 5 or 6 years ago and the crowns look to be in excellent condition with no cracks and the bores aren't glazed or scored and have a good cross hatch pattern. I am renewing the oil pump internals plus all seals and gaskets and I'll inspect the bearings to decide if they're still good or could do with replacing so I will hopefully end up with a good reliable engine coupled to a nice R380 stumpy gearbox and rebuilt LT230. I have a tin of gold engine enamel so it will look as good as @western 200Tdi when I'm done Then my focus will have to be the back axle before it forces me to act! 2 Quote Link to comment Share on other sites More sharing options...
monkie Posted August 7, 2021 Author Share Posted August 7, 2021 (edited) Been busy at work so not had much chance to work on the 200Tdi rebuild until today. I have a snag regarding tightening down the cylinder head bolts (brand new from Turners). When I was stripping the engine down and undid the cylinder head bolts I noticed some were very tight and some were noticeably not so tight. When the block was bare I cleaned it up and ran a tap through all the threads to clean them up. Today I put a new (Elring) head gasket on, lightly oiled the new bolts and then tightened them down (in sequence) to 40Nm followed by 60'. All fine up to this point. Then the final tighten to another 60' and I noticed that 1 or 2 did not feel as tight as the others but I didn't want to go further than the 60' angle. Then on one of the bolts (near where the old gasket had been blowing) the 60' final angle was very much not tight at all. Obviously I'm frusted as I'm going to take the head off (wasted a new gasket, but oh well) and want to look at the threads and run a tap through them again. Before I do anything, does anyone have any thoughts or advice on what's happening? (I'm worried about a stripped thread in the block) EDIT: I'm looking on the brightside, at least I can now explain why the previous head gasket had failed. Edited August 7, 2021 by monkie Quote Link to comment Share on other sites More sharing options...
monkie Posted August 8, 2021 Author Share Posted August 8, 2021 Been out this morning to discover it is indeed a stripped thread on bolt 17 on this picture below. 🤬 Atleast I know why the previous head gasket had failed as I remember this one seemed loose when I undid it. Quote Link to comment Share on other sites More sharing options...
cackshifter Posted August 8, 2021 Share Posted August 8, 2021 Oh dear. That is the problem with bolts over studs. So what now, helicolil or timesert? Quote Link to comment Share on other sites More sharing options...
western Posted August 8, 2021 Share Posted August 8, 2021 Replace with a helicoil that would be the quickest way, might be worth doing bolt 15 as well, 1 Quote Link to comment Share on other sites More sharing options...
monkie Posted August 8, 2021 Author Share Posted August 8, 2021 My thoughts are: Head off (obviously) Gaffa tap to mask off the rest of the block to stop metal shavings getting into the engine Use a drill guide (like the one below) to drill out the damaged thread insert a helicoil Run a tap through the remaining threads to be double sure and blow out with compressed air Refit with new gasket and re-use the new bolts (I think its okay to use them upto 5 times) Does this seem a sensible plan? I have an M12 Helicoil kit and I have ordered a new head gasket and this piece to drill straight: Quote Link to comment Share on other sites More sharing options...
western Posted August 8, 2021 Share Posted August 8, 2021 Sounds good to me 👍 Don't forget to use the m12 tap in the helicoil kit first before fitting the insert. Your 'new' bolts will be fine as they haven't seen any work yet. 1 Quote Link to comment Share on other sites More sharing options...
monkie Posted August 8, 2021 Author Share Posted August 8, 2021 10 minutes ago, western said: Replace with a helicoil that would be the quickest way, might be worth doing bolt 15 as well, Thanks Ralph. I just don't know what to expect with stretch bolts and angle tightening - I'm simply just used to having a torque figure. This morning (with all the bolts apparently tightened down as per the manual) I applied gentle pressure anti-clockwise (just using a 3/8" ratchet) to see if any were loose. 17 was properly loose. Most didn't budge (as I would expect) but a couple did seem to want to move a tiny fraction (nothing significant) - 3, 10 and 16 from memory. Is this normal for angle tighten or should none of them show any sign of budging at all with just gentle pressure? PS - I won't forget to use the tap for the helicoil 1 Quote Link to comment Share on other sites More sharing options...
cackshifter Posted August 8, 2021 Share Posted August 8, 2021 I have one of those drill stand things, and yeah they do work I suppose but I think the existing hole will guide you. Make sure it slides easily on the pillars if you do get one. What happens about the helicoil tang? Will you be able to get it out ok? Quote Link to comment Share on other sites More sharing options...
western Posted August 8, 2021 Share Posted August 8, 2021 I think my head bolts moved a bit after doing the 2nd angle stage, but its all good & no oil/coolant escaping or mixing. IIRC the tang only needs breaking off if the bolt goes all the way though. Quote Link to comment Share on other sites More sharing options...
reb78 Posted August 8, 2021 Share Posted August 8, 2021 Are helicoils really strong enough? I stripped a thread in an aluminium casting and put a helicoil in. I did it properly but it still feels like it is going to strip something if i torque to the massive 11nm torque the manual says! I use a small torque wrench on these delicate fastenings as I am conscious my monkey tight isn't that delicate! Quote Link to comment Share on other sites More sharing options...
monkie Posted August 8, 2021 Author Share Posted August 8, 2021 22 minutes ago, reb78 said: Are helicoils really strong enough? I stripped a thread in an aluminium casting and put a helicoil in. I did it properly but it still feels like it is going to strip something if i torque to the massive 11nm torque the manual says! I use a small torque wrench on these delicate fastenings as I am conscious my monkey tight isn't that delicate! I don't really know. I have put a couple into aluminium on the ladder frame and timing case and they seem much better than a tapped hole straight into aluminium (they are a dizzy 25Nm torque). The block is obviously cast iron so I would have thought they'd be even better into that... But I don't really know. Anyone have any experience of this? Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted August 8, 2021 Share Posted August 8, 2021 A good helicoil is stronger than the thread its replacing. When helicoiling a stripped thread, use the longest insert you can fit into the hole, I've seen multiple inserts go into a hole to get the length, but I've never tried it myself. Also, you can normally get the helicoil tap into the hole without using the drill beforehand. 1 Quote Link to comment Share on other sites More sharing options...
steve b Posted August 8, 2021 Share Posted August 8, 2021 3 hours ago, monkie said: My thoughts are: Head off (obviously) Gaffa tap to mask off the rest of the block to stop metal shavings getting into the engine Use a drill guide (like the one below) to drill out the damaged thread insert a helicoil Run a tap through the remaining threads to be double sure and blow out with compressed air Refit with new gasket and re-use the new bolts (I think its okay to use them upto 5 times) Does this seem a sensible plan? I have an M12 Helicoil kit and I have ordered a new head gasket and this piece to drill straight: What pitch is your kit ? It needs to be M12 fine , not sure what the number is -1.25mm maybe ? Steve Quote Link to comment Share on other sites More sharing options...
cackshifter Posted August 8, 2021 Share Posted August 8, 2021 I think your comments about one or two bolts feeling a little loose when you tried with a 3/8 drive ratchet can be explained as follows. When you tighten the bolt it is both being stretched and is in torsion, effectively a torsion bar as well as a spring. So as the bolt tightens, the thread will lag the head end by the torsional deflection. Once the bolt is still, ie you finish tightening, the head will either spring back to relive the torsional stress or if the static friction under the flange of the bolt is too much for that it will stay as it is - at least it will till you come along with your 3/8 ratchet and give it a helping hand. I would consider putting a smear of molygrease under the flanges of the heads before fitting so that the bolt will turn as easily as possible. Either way as the thread hasn't moved the linear tension in the bolt will stay (almost) the same. But they do feel absolutely terrible to tighten even when OK, it's a horrible job. 1 Quote Link to comment Share on other sites More sharing options...
monkie Posted August 8, 2021 Author Share Posted August 8, 2021 1 hour ago, steve b said: What pitch is your kit ? It needs to be M12 fine , not sure what the number is -1.25mm maybe ? Steve I have the kit from screw fix. https://www.screwfix.com/p/helicoil-eco-thread-repair-kit-m12-x-1-5mm-13-pieces/798FR?tc=YS1&ds_kid=92700048793290424&ds_rl=1249413&gclid=CjwKCAjwgb6IBhAREiwAgMYKRvWWmgd7cpu9n1wsxhn6tvkD85MrzVrBASfjfDPS49GJ9_SbdtwQ7xoCM_sQAvD_BwE&gclsrc=aw.ds Quote Link to comment Share on other sites More sharing options...
monkie Posted August 8, 2021 Author Share Posted August 8, 2021 39 minutes ago, cackshifter said: I think your comments about one or two bolts feeling a little loose when you tried with a 3/8 drive ratchet can be explained as follows. When you tighten the bolt it is both being stretched and is in torsion, effectively a torsion bar as well as a spring. So as the bolt tightens, the thread will lag the head end by the torsional deflection. Once the bolt is still, ie you finish tightening, the head will either spring back to relive the torsional stress or if the static friction under the flange of the bolt is too much for that it will stay as it is - at least it will till you come along with your 3/8 ratchet and give it a helping hand. I would consider putting a smear of molygrease under the flanges of the heads before fitting so that the bolt will turn as easily as possible. Either way as the thread hasn't moved the linear tension in the bolt will stay (almost) the same. But they do feel absolutely terrible to tighten even when OK, it's a horrible job. This is very interesting and sounds plausible, I tried to get a video clip of the movement I'm talking about but the movement is so slight you couldn't tell on the video so I didn't bother posting up on here. Quote Link to comment Share on other sites More sharing options...
cackshifter Posted August 8, 2021 Share Posted August 8, 2021 Looks like the thread pitch is 1.5mm Link, we have been here before. 1 Quote Link to comment Share on other sites More sharing options...
monkie Posted August 8, 2021 Author Share Posted August 8, 2021 Thank you for that Link. You had me worried for a minute but luckily these are the inserts I have: Quote Link to comment Share on other sites More sharing options...
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