Peaklander Posted January 17, 2020 Author Share Posted January 17, 2020 Got some (good) family distractions preventing me commenting in detail to all this good advice. I really appreciate it. Just to clear up a comment or two, whatever has happened to this engine like overheating or water, has happened before I bought it. That was five years ago and something like 30-40K miles. I’ve driven it all over Europe, up to 2,400m and some long distances. It has never missed a beat. The first ever problem really has been the white smoke a couple of weeks ago. So I trust it and I now have a fully checked out head as it passed all the tests. The question about block out is really not what I want to do. I replaced the clutch etc last year at chassis swap and did the timing belt not long before that The engineering shop say it’s absolutely not necessary to rebore as it will not need it and that’s after looking at the pistons and my pics and description of the bores. I will measure it though and try to get solid data. For that I’d like to thank @nickwilliams who has lent me the measuring kit to do this. The pistons by the way are +20 and the crank is at original size. Quote Link to comment Share on other sites More sharing options...
blowmeover Posted January 17, 2020 Share Posted January 17, 2020 An old engine of mine was smoking white, it was a hole in the inlet manifold where the turbo heat shield bolted to, Quote Link to comment Share on other sites More sharing options...
monkie Posted January 17, 2020 Share Posted January 17, 2020 Wow, I thought they were good from what you said before, but if they can measure cylinder wear from a photo... I'm impressed! Quote Link to comment Share on other sites More sharing options...
Peaklander Posted January 18, 2020 Author Share Posted January 18, 2020 I’m trying to soak up all this advice and determine what the next action should be. The machine shop has been there for years and has a big turnover of work. When they say “measure if you want but the bores won’t be warn” then I have to take that as reliable. I was interested to hear that they rebuild Land Rover engines that the army send from Devon. I said I will measure so I will. I hope I do it accurately enough to make a decision. 1 Quote Link to comment Share on other sites More sharing options...
monkie Posted January 18, 2020 Share Posted January 18, 2020 Now you have the right tools, take your time and measure the bores carefully. When you've done all 4, repeat to see how precise you are. If your measurements are within the tolerance for the +20 pistons, then you are working from a known point and not just taking someone's word for it, no matter what their experience maybe (they and you don't know what's gone on internally to the bores since the last rebuild). I made an excel spreadsheet with the workshop tollerences and a space to add my measurements (3 replicates to test my precision). I can send you it if it would be helpful. If so, PM me your email address. Quote Link to comment Share on other sites More sharing options...
Peaklander Posted January 18, 2020 Author Share Posted January 18, 2020 Thanks @monkie I will. I have some experience with gauge R & R but not measuring bores. That was weighing of full drinks cartons. Quote Link to comment Share on other sites More sharing options...
monkie Posted January 18, 2020 Share Posted January 18, 2020 4 hours ago, Peaklander said: Thanks @monkie I will. I have some experience with gauge R & R but not measuring bores. That was weighing of full drinks cartons. Email sent Quote Link to comment Share on other sites More sharing options...
cackshifter Posted January 18, 2020 Share Posted January 18, 2020 Hi, Apologies if I misled re the bore size; I was basing it on the 300tdi Overhaul Manual, one of your pics shows 90.903 stamped on a piston which I took to be its diameter, but at the end of the day measurement is king. Quote Link to comment Share on other sites More sharing options...
Peaklander Posted January 18, 2020 Author Share Posted January 18, 2020 Well it looks plausible! I’m not having a garage day but can’t wait to get back out and check. I spend so much time in there as it is, it’s referred to as Grampy’s house. Quote Link to comment Share on other sites More sharing options...
monkie Posted January 18, 2020 Share Posted January 18, 2020 10 minutes ago, cackshifter said: Hi, Apologies if I misled re the bore size; I was basing it on the 300tdi Overhaul Manual, one of your pics shows 90.903 stamped on a piston which I took to be its diameter, but at the end of the day measurement is king. I noticed this and it's why I hate measuring things using inches. 20 thou is 0.508mm which added to the standard size is the max shown above of 90.903mm. I thought you could also get 40 thou oversize but that would take you way over. Quote Link to comment Share on other sites More sharing options...
Peaklander Posted January 18, 2020 Author Share Posted January 18, 2020 I have had time to check this. Standard bore diameter is 90.47mm from the above, a piston size of 90.395 gives a clearance of 0.075 or 3 thou of an inch and using that: an oversize piston of 90.649 would give a bore of 90.724 which is +10 thou and oversize piston of 90.903 would give a bore of 90.978 which is +20 thou and +40 thou would mean piston size of 91.411 and a bore of 91.486. Turners show this size on their website as @western showed earlier. In fact they list a +40 and a +40 replacement. These two have different prices so I don't know whats happening there but it does appear that there is are two oversizes at 20 and 40 not the 10 and 20 that the manual shows. My piston does indeed measure at 90.903 so @cackshifter is correct and I am happier as there is another size to go if I need it (cough). Quote Link to comment Share on other sites More sharing options...
western Posted January 18, 2020 Share Posted January 18, 2020 If rehoning on the bores cleans them up, with out a full rebore to .040 then you may get away with rehoning & new piston ring set of .020 there are mobile companies that can rebore engines in situ, they should be able to carryout a rehoning of the bores https://www.google.com/search?q=mobile+engine+rebores&oq=mobile+engine+rebore&aqs=chrome.0.0j69i57.7012j0j7&sourceid=chrome&ie=UTF-8 Quote Link to comment Share on other sites More sharing options...
Peaklander Posted January 18, 2020 Author Share Posted January 18, 2020 (edited) Yes that’s what I’m hoping will happen. New 20 thou rings and a hone then away we go, but I will measure first anyway. Mobile re-honing isn’t something I thought to Google. This is a surprise as I seem to Google everything else. So thank you again @western. Edit: The people at Sheffield Engineering Services said that a hand held honer would be fine to use. They said that it should only need twenty up/downs to sufficiently hone each bore. Any more than that would remove too much metal and create a taper or whatever. By the way I hadn’t realised that the Overhaul manual is different to the Workshop manual. I have a pdf copy of both but have never looked at the Overhaul manual. What a twit. Edited January 18, 2020 by Peaklander Quote Link to comment Share on other sites More sharing options...
cackshifter Posted January 18, 2020 Share Posted January 18, 2020 It looks to me like Overhaul Manual may not be correct or maybe the oversize bore sizes have changed. I have never seen +10 as an option before, only +20 and +40.. I am really sorry if it has caused a problem. 1 Quote Link to comment Share on other sites More sharing options...
Peaklander Posted January 19, 2020 Author Share Posted January 19, 2020 Absolutely no need to apologise. It’s a good news story that there’s a rebore size available. I hope I don’t need it. Will find out on Monday when I measure. Quote Link to comment Share on other sites More sharing options...
Peaklander Posted January 19, 2020 Author Share Posted January 19, 2020 (edited) I'm thinking ahead to tomorrow when the measurements are done and there's confirmation that the bores are OK 😉. What are your recommendations regarding DIY honing? I have approached a mobile company, who are fairly local, following the Google suggestion from @western but I think that honing is straightforward and I should consider doing it myself. The engineering shop said a flexi-hone is fine and I should be careful to only do about twenty passes up and down each cylinder. So it doesn't look like a big job. There are plenty of tools around for ~£20. Also they said to keep the cylinders lubricated with paraffin and soak it up at the bottom, above the crank, with plenty of rags. So how to choose a tool and is there any advice on how to do it please? TIA Edited January 19, 2020 by Peaklander Quote Link to comment Share on other sites More sharing options...
cackshifter Posted January 19, 2020 Share Posted January 19, 2020 I have used a flex hone successfully, but you have to pull it up and down quite quickly to get a decent cross hatch finish. Do you plan to do all cylinders or just no.2? I'd budget for a set of big ends as well, maybe also a rocker shaft. 1 Quote Link to comment Share on other sites More sharing options...
monkie Posted January 19, 2020 Share Posted January 19, 2020 I used a flexihone on a two stroke engine. I found it harder to use than the normal 3 legged type. Use plenty of lubrication when you do it. Have you got anything to practice on first? I wonder if you went to a local scrap yard and could find some steel pipe roughly the same bore size to have a go on so you know what you have to do to get a good cross hatch pattern. 1 Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted January 19, 2020 Share Posted January 19, 2020 Flex hone and very slow drill speed and you will be fine. Have done so very effectively a number of times. 1 Quote Link to comment Share on other sites More sharing options...
Peaklander Posted January 20, 2020 Author Share Posted January 20, 2020 Mrs Peaklander and I have had an interesting day measuring our bores. We are using a telescopic (snap) gauge and a vernier both from Mitutoyo. There is definitely a lot of care needed to ensure repeatability in the measurements and I worked hard to try to ensure that every one was made using exactly the same method. Measurements were taken within the swept area just down from the top, the middle and a little up from the bottom and for those, front to back and side to side. There are three data points for each one. The results are good. Then I started to measure the pistons but there was a sound of glass from the other side of the house and we found a Velux window where the unit has exploded. The inner pane was all over the kitchen floor with a still intact outer sheet. We contacted Velux who told us that there was a problem with that age of unit (about 19 years) and even a recall in the press which we didn't see. They are sorting it pronto. Measurement of pistons continues later! Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted January 20, 2020 Share Posted January 20, 2020 Looking good Quote Link to comment Share on other sites More sharing options...
cackshifter Posted January 20, 2020 Share Posted January 20, 2020 Considering the mileage, a remarkably good set of measurements. And a good job no-one was under that window. Quote Link to comment Share on other sites More sharing options...
Peaklander Posted January 20, 2020 Author Share Posted January 20, 2020 Yes the measurements are good. TBH I did redo ones that were clearly outliers. This was mainly down to method. I used the gauge as a snap meaning put it in on an angle, fully open as it is only marginally wider than the bore, with the clamp tight. Then carefully moved it through the perpendicular, to then withdraw on the other angle. Sometimes I didn't tighten the clamp enough and it sprang open but other times it felt too tight. If it looked a but questionable we actually took a lot more of one measurement until I felt that the method was back in repeatable mode. I think that's OK. The kitchen table is right under that window. Quote Link to comment Share on other sites More sharing options...
cackshifter Posted January 20, 2020 Share Posted January 20, 2020 Assuming you will hone no.2 but in the light of that do you plan to hone & re-ring the others or just put the other pistons back? Quote Link to comment Share on other sites More sharing options...
Peaklander Posted January 20, 2020 Author Share Posted January 20, 2020 Yes hone #2 probably not the others but I will practice first and see. If a little fettle is possible then I might. Certainly I’ll change all the rings. It won’t break the bank. As for the bid end shells, none are showing wear (colour change through to base) so I’m thinking not necessary? Tomorrow I will check the pistons especially #2. Also I will perhaps text the oil jets but I think they need to be removed for that. Should I change the core plugs? There are six but I don’t know if they can be accessed. Do I lever out and then smoothly tap new ones in? New ground. Plenty of questions!!! Quote Link to comment Share on other sites More sharing options...
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