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Steve4012

Engine's out - which way to go?

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My dry sump engine is now out and on a stand. Removed to fix a blowing manifold gasket as well as all the other associated jobs of fuel tanks etc. I'm not sure which way to go with the engine though. I have to take the crank out to rebore, to fix the common problem of the clutch shaft pushing into the crank so I believe that means taking the sump off. Should I be looking to take advantage of this and do some engine work while I'm there? The car was owned for 28 years by a Lotus specialist who used it as his own personal car and it now has 114000 miles on it. He only sold due to ill health but unfortunately I can't get any history of engine rebuild work for the same reason. It was running before engine removal but after spotting splits in the cambelt, this meant I couldn't crank it again for a compression test. What do you guys think? General service of fluids, belts etc and back in and see or a partial/ full diy rebuild and if I go this way, is this doable for an engine novice?

Thoughts appreciated!

Thanks, Steve.

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Once the crank is out you can inspect the bearing surfaces and measure them for circularity. New bearings on reassembly, use the graphite grease...new liners/pistons if needed. All of this stuff can be done by a neophyte, as long as you are careful, keep thinking, read the service notes and have the right tools....torque wrench etc.

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Steve

Don't overlook the matter of thrust bearings as Lotus circulated a Technical Bulletin specifying a minor mod to one of the rearmost main bearing shells for the purpose of improved oiling at the thrust flange of the crank.

Cheers

Steve

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59 minutes ago, Steve4012 said:

My dry sump engine is now out and on a stand. Removed to fix a blowing manifold gasket as well as all the other associated jobs of fuel tanks etc. I'm not sure which way to go with the engine though. I have to take the crank out to rebore, to fix the common problem of the clutch shaft pushing into the crank so I believe that means taking the sump off. Should I be looking to take advantage of this and do some engine work while I'm there? The car was owned for 28 years by a Lotus specialist who used it as his own personal car and it now has 114000 miles on it. He only sold due to ill health but unfortunately I can't get any history of engine rebuild work for the same reason. It was running before engine removal but after spotting splits in the cambelt, this meant I couldn't crank it again for a compression test. What do you guys think? General service of fluids, belts etc and back in and see or a partial/ full diy rebuild and if I go this way, is this doable for an engine novice?

Thoughts appreciated!

Thanks, Steve.

You might want to take things at a steady pace if you haven’t delved into engine rebuild before, Steve. The good news is there’s some very clever chaps here who can provide all the advice you need.

Also, I think your engine is probably a wet liner, and if so, there’s no reboring the block, it’s a change of cylinder liners.

Good luck!

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Just be careful of mission creep chap.

get what needs doing done and make sure it’s right. You can always pull the engine again if needed - @Chillidoggy does his every winter

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27 minutes ago, Barrykearley said:

Just be careful of mission creep chap.

get what needs doing done and make sure it’s right. You can always pull the engine again if needed - @Chillidoggy does his every winter

Hmmm don't do as I do do as I say

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Thanks gents much appreciated. Certainly don't want to rebuild a perfectly good engine so will get the sump off and push on with crank out and assess from there. Cheers, Steve.

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It's easily possible to carry out a compression test with the engine out, by removing the spark plugs, replacing the cambelt flywheel and bolting the starter back up to the block and giving it a direct battery feed. If the engine has engine has not been turned for a while lubricate the bores via the plug holes. A few short blasts on the starter to obtain compression readings won't harm the engine and could save unnecessarily removing the head and pistons. Make sure you're ready to catch the remaining oil in the system or remove the belt from the pump.

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Well the main bearing panel is off and things look pretty good to my untrained eye. @drdoomthe rear lower bearing is already the modified version with the additional slot and the panel has the chamfer modification too so it's definitely had some work done to it. The lower main bearings look in pretty good condition too?! (opinions welcome). Also I've used a feeler gauge to see what the end float is like and this is .003" which is bang on spec. Appreciate this isn't the most accurate way to measure but I think it will be close. Next up get to the big end bearings/ crankshaft out and get that rebored as per @top-plumberrecommendation for uprated roller bearing. New bearings, big end shells and thrust washers and hopefully should be good to reassemble.

20180101_124743.jpg

20180101_124647.jpg

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On 22/12/2017 at 17:55, molemot said:

New bearings on reassembly, use the graphite grease...

@molemotdid you mean graphite or graphogen grease? Sound similar but the price is not! The latter is mentioned in the manual..

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Just looks like good honest wear in that engine.   However, you should also check the crank to make sure all journals round & within spec.  John will be referring to 'Graphogen'

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Indeed I was....my tube reposes in the relevant drawer in my workshop!! As has been said, two different beasts...graphite and graphogen. Graphogen will dissolve into the oil. I agree that it's just good honest wear....as long as the crank is within spec., just change the bearings. As long as you change the bearings before the crank goes oval, it won't.

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Thanks all, pleased to say it seems to be coming on nicely. Crankshaft rebored for bigger ball bearing, new big end shells and main bearings and hopefully bolt back together tomorrow. Which brings me to the next question, I would like to replace the nuts that hold the main bearing panel on to stainless. The m8 nuts around the perimiter are a small torque requirement at 14-16lb. ft. so think these will be fine but the ten m12 in the centre are obviously more substantial. There are no markings on the existing nuts and the m12 nuts require 75 lb.ft. torque

What do you guys think? Stainless ok?

Cheers, Steve.

 

20171218_144504.jpg

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Great progress Steve, personally I would stick to the original spec with these nuts, as the carrier is structural as well as mechanical, it probably wouldn't make any difference, but with different expansion rates and chemical reactions between different metals maybe better safe than sorry. Steve

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Most easily available SS nuts do not have the needed strength.  I would not use them in any structural or mission critical assembly. Stick with the stock parts.  

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I thought you weren't being serious. I was going to say,  'The engine is out. You can't go any whichway. '

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Thanks for your replies gents, I'll clean up the originals and go with those as suggested.

Steve.

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That picture takes me back to when I owned a dry-sump. From that angle for anyone who knows anything about high performance engines, thats a thing of great beauty from the underside with its lack of sump, just like a Cosworth DFV or other such engine.

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