Mini Mis-fire-ette-let

PostPost by: sk178ta » Tue Aug 03, 2004 12:44 pm

On the one hand I`m told the excesive blue smoke on start up may be caused by a damaged oil control ring plus at light throttle openings the drive line is a bit "shunty" and there is more blue smoke and throat clearing when the throttle is opened suddenly. Also, pick up from rest is hesitant.
On the other hand it`s not using much oil and I`m told the hesitancy is caused by wear in the Weber spindles. The carbs have been set up on a rolling road and the ignition is new Lumenition.
I`m inclined to the view that maybe one of the plugs is oiling slightly at low revs, but I`m a bit mechanically ignorant anyway!
If you are not, what do you think?
Jim
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PostPost by: Fred Talmadge » Tue Aug 03, 2004 12:52 pm

Pull the plugs and see if they are oily. Most probably cause is valve guides worn. Should do a compression & vacuum test, and a leak down if able. These will confirm if it's engine problems or not. If not then you can work on carbs & ignition. If so then well it's going to get a bit expensive.

Good luck, Fred T.
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PostPost by: tdafforn » Tue Aug 03, 2004 1:21 pm

Jim,
Got EXACTLY the same things with my +2.
Checked the compression dry and with oil in the bores and it is good (160 across the board +/- 5psi). The head was rebuilt to take unleaded about 3 years (<3K miles) ago, so I think the guides are fine.
Apart from Oil rings (can't tell how much it burns as too much pisses out of the sump gasket), I think it may be running rich, I replaced the idle jets on my Dellorto's with the next richer ones to cure hesitation on pickup, but I think it may just have been out of tune. Will replace with the older ones and see what happens..
Cheers
Tim
1972 +2S130
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PostPost by: type26owner » Tue Aug 03, 2004 2:53 pm

Guys,
Any performance type engine which lacks valve stem seals is going to exhibit blue smoke, period. Back in the day a little blue smoke was considered normal. Only in recent times that's all changed and deemed not politically correct. It's just the physics of the engine. That's why today virtually ALL engines have some sort of valve stem seals. Btw, most of the smoke is from the exhaust guides leaking oil and therefore normally the spark plugs will appear oil free. Just pull the exhaust manifold off and look in at the guide area and you'll be able to see the telltale track of oil streaming from the exhaust guide. It's due to the venturi effect of the escaping exhaust gases. Perfectly normal stuff. Reducing the stock designated guide clearance is a very risky solution if the engine is operated at full power for more then a few seconds at a time.

If you have the ~.350" lift stock cams installed it's possible to retrofit valve stem seals in the available space just barely. Doing so eliminates all the blue smoke for about 50k miles until the seals need replacing. BTW, that coincides perfectly with the time interval when the water pump assembly should also be renewed with new parts. I documented how to do this sometime back with pictures. Any interest?

I'm coming up on another 50k interval myself. It's part of Lotus ownership. For me the pleasure it provides it's well worth this level of maintenance.
Regards,
-Keith
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PostPost by: type36lotus » Wed Aug 04, 2004 1:00 am

Gee Keith, you are making me feel guilty for not enjoying my Elan more. At my present rate it will take me 98 more years to have driven my Elan 50K miles.
Mike Geiger
66 S3 Coupe', no more :-(
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PostPost by: type26owner » Thu Aug 05, 2004 1:57 am

Hey Mike,
I'm running up 50k smoke free mikes every four years on my Elan. It's definitely my favorite collector's road car based on the sheer amount of fun from driving such a light weight vehicle within a rather large traction circle.
Regards,
-Keith
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