davetoff
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Posts posted by davetoff
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Hi Roland,
I'm in the process of rebuilding my 910 engine which is similar to the 907, with the difference to the cylinder head valves and dry sump. Both more expensive on the 910 engine because the exhaust valves and oil pump are difficult to get hold of. The spend at the moment is around £2500 for parts and I'll probably have to spend another £2000 for machining on the head and block and the additional parts for the head. I've already rebuilt the carbs myself, an easy job, well worth doing yourself for around £100 for the rebuild kit plus a bit more if you want to get the castings vapour blasted. The rebuild includes forged pistons and HTD pulley, light weight flywheel etc but no SS exhaust, light weight steel cam buckets or polishing and porting. So all in all the main expense comes from buying parts? Hope this helps a little?
Cheers
David
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Hi All,
I've just picked up Dave's email regarding this register, great idea, would have added mine earlier if I'd been been on the ball! ?
Chassis no: 1079
first reg: 25/08/81
Original colour: gold
Current colour: Black
interior : Cream
Original wheels: BBS
Roof stereo: Not sure (after market sunroof installed)
Point of interest: Under restoration
cheers
David
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43 minutes ago, molemot said:
What inherent issue would that be? I've done over 120,000 miles on the same set of exhaust valves now....
Only an in-reference that there are very few exhaust valves available, this could be because Lotus made very few, or because they are "chewed up" by the turbo engine. However I'm reaching into the recesses of my memory to a previous forum topic that stated that these are rare because of their delicate nature. Either way there aren't many of them about which is what I would like to correct. Happy to be proved wrong and there are millions lying about that I can pick up cheaply (-:
21 minutes ago, 910Esprit said:Gary kemp does replacements.
Gary hasn't any in stock at present, he has them made, but hasn't replenished his stock....again he is selling them at £65 but with an additional 6 week lead time.
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Hi,
I'm having to replace the exhaust valves (and the inlet valves) on the head of my Lotus 910 engine. Unfortunately because of the inherent issue with the 910 engine munching exhaust valves like they are going out of fashion, they are now going out of fashion. As such they are a rare and valuable commodity, looking at SJ and Lotusbits they are retailing for around £65 each and as I have to replace 8 of them this isn't a cheap option. Looking around there seems to be nothing similar, however I can get some made, but from Inconel instead of the sodium filled originals. Now for the questions:
Has anyone on this forum done this conversion, or does anyone have intimate knowledge of this material and the use of it in these engines?
Alternatively does anyone know of the sort of temperatures that this exhaust valve would see so that I can research the material properties myself.
And lastly if after all this research would anyone be interested in some for themselves? Not sure of the quantities yet and so the price, but I reckon that we would see a reduction in price to around £30 each.
Cheers
David
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57 minutes ago, winners said:
There's a massive gap, the car is in Nottinghamshire and the Heat shield is at SJ Sports cars ;-)
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Sorry if I'm stating the obvious, but is there a sufficient air gap between your heat shield and your mount? If not then all that's happening is the heat shield is conducting heat into the mount, rather than diffusing it.
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Just thought I'd add my twopence here, I find the best thing to diagnosing the problem is start with easy things like, checking if the alternator is charging your battery. You can do this by placing a voltage meter over the terminals of the battery and if it's around 14v then all is well with it, if less then the alternator needs attention. Next check oil level, is there too much/ too little. The maybe concentrate on coil. But imho I think it sounds like the battery, low voltage causes, fluctuating revs at idle, and consequently the other symptoms you are having. Volt meter on dash is not very reliable, I find it seems to give an approximation rather than the actual voltage. Surprised that the breakdown guy didn't check this though?
Good luck though, it doesn't sound too serous, just very annoying.
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2 hours ago, ian29gte said:
Is that price for an exchange crank?
No you don't have to exchange it.
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10 hours ago, DaveyT said:
David, when you say the Vee wasn't lined up with the chamfer, can you expand on this?
Reason I ask is that mine had a chamfer added at some point in the past, and the mains look barely worn, but the crank end float was at the wear limit when I measured it 75k miles.
Ive no idea at what point the chamfer mod was carried out, but the state of the mains vs the thrust brg would indicate that insufficient oil was getting to the thrust bearings. The original chamfer on my engine was in the opp side of the carrier to that recommended in the book, too, so I added one to the other side as well. The notch in the main bearing was overlapping the chamfer, if that's what you meant?
The chamfer on the casting should overlap the V on the bearing so that oil can run onto the inside of the bearing. I'm at work at the moment, but I can take a picture of the block this evening to highlight what I mean.
19 minutes ago, ian29gte said:Where on earth would one purchase a new crank, though?
Lotusbits do a -0.01" crank for around £200, does anyone know of anyone else who is selling these?
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Yep it's all very odd. Looking at the main bearing (5) the one with the V groove, I think this failed as the 'V' wasn't lined up with the filed chamfer on the block. Therefore failing due to lack of oil, this in turn popped the thrust bearings out and then the crank started to grind against the case where the ring of the crankshaft casting failed. Just so happens that it was a perfect circle, maybe a crack in the original casting, or possibly a very bad repair, I suspect we'll never know now.
Thanks to all you guys out there who helped diagnose the issue and for putting your views across.
David
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I found out where it comes from, it looks like it's part of the casting around the rear main bearing area. Must either be a weak spot in the casting as it cracked very neatly around the circumference!
@Ian worryingly I think you may have been close to the truth!
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Thanks Giorgio for the picture and info. I'll have to recreate that tool when I get the time, which at the moment seems like a long way off!!!
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You are right (Ian) it does seem like the ring cannot be put on over the end! I'm yet to find out exactly where it belongs, but I am sure it was a fix for the early dry sump start with depressed clutch. Going up to Lotusbits tomorrow to get as much information on this that I can, hopefully have some more answers soon, that I'll feed back.
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Hi,
I've cracked open the dry sump to reveal the crankshaft to find the cause of the excessive endfloat I was having, the thrust washers had popped out and where still, miraculously, intact. However I also found a circular ring that was smashed to pieces, picture included, it was found in the "compartment" between the rear of the block and the rear oil seal. However I'm trying to locate where this once was on the crank and cannot find it. I'm assuming that this was a ring to space the rear oil seal out. Can anyone shed some light on this? Is it something to do with the oil seal, or is it something that's come away from the crankshaft? BTW please excuse my grubby fingers in the photo
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Yep it was rebuilt recently by PO but unfortunately the circlip in the gearbox decided to burrow its way into the crank, which obliterated the thrust washers ? So wanted to check it all out, including what the PO did to the engine, he was a little vague on details. But otherwise seems to have done a decent job.
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Hi
i've been delving into the depths of my engine to change the main bearings and thrust washers, there was excessive endfloat in the crankshaft. Trying to determine the bearing sizes but found this number scratched on the underside of piston 4. Does anyone know what it means? Is it the coordinates to where the holy grail is buried?
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Hi
I thought I'd tap into the collective intelligence of the forum to ask what is this:
its home is under the glove box on a 1981 dry sump turbo.
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Hi Molemot
Unless I'm missing a page from the manual (soft and hard copies) I cannot find it. Page 7 and 8 in TDD section states all torques settings but not the transmission ones. In the TDA/B section of torques this is also missing the transmission ones as is the FB section in the manual.
Does anyone have these to hand?
Thanks.
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Hi All,
I've just replaced my circlip on the primary motion shaft, a really easy job that I'm very happy that I did. However when replacing the bell housing I couldn't find the torque specs for the 4 main bolts in the bell housing nor could I find the torque figure for multitude of different fixings around the outside, in the manual. Would anyone happen to know where these are located in the manual please, or know what they are offhand?
Thanks
David
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A little more information as I delve a little deeper, managed to crack open the bell housing to reveal a very rusty primary shaft. Cleaning it up I realised that this wasn't the shaft rusting but what was left of the circlip. I cleaned everything up, replaced the circlip with a upgraded one I bought from Harry, and all looks well with life once more.
I then thought it would be a good idea to change the bearings and seals whilst I have the transmission all bare. Started on the output shafts but quickly came across the usual "no tool will do the trick, but a lotus tool"! Does anyone know the large nut size in the output shafts so that I can buy a box spanner to suit? Also does anyone know, will I need an extended extractor to remove the bearing, if so what size will I need? Help once again very appreciated...
D
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Managed to get the blasted thing off, hopefully without damaging it too much, and was about to stick it onto the new alternator only to find the shaft diameter is different to the original
Has anyone come across this before and what solution did you come up with? Please don't say bought a new alternator
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29 minutes ago, Lotusfab said:
Anyone have any further info?
I see you are getting on with the build, no hanging around.....
One thing of note is you have a wet sum as there is an oil filler cap on the engine, dry sumps have a separate oil tank located above the right hand wheel arch on the inside of the engine bay.
I'm in the process of restoring mine and have already gone through some of the trials and tribulations you are presently experiencing now, so if you need any information I'll try and help where I can.
Keep up the good work.
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Thanks Jon for your reply, very prompt.
Maybe a stupid question but do you know which bit doesn't rotate, ie which part should I counteract the unscrewing of the bolt, is it the Fan shaped bit on the front?
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Hi,
Had a search for this to no avail. I've removed my alternator to replace with a shiny new one. However the new one doesn't have the 'V' pulley wheel on the end, only a thread and keyed dog. On the old alternator the pulley wheel isn't very clear on how to get it off, was going to get a bearing puller on it but wanted to make sure I wasn't missing anything before I start yanking off the pulley only to find it's screwed on
Best picture I could find is one that has the alternator still installed on the engine with the 'V' belt still on, I've removed it from the engine and the 'V' belt is gone...
Thanks.
907 full engine rebuild
in Engine/Ancilliaries
Posted
The usual suspects.....most from Lotusbits and SJ's but also Kemp....
Fixings from Margnor and Co-ord Sport, carb kits from Dellorto
If you want any further information then I'll be happy to help where I can. I'm still in the process of rebuilding so don't know all the answers!
D