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View Full Version : Elan +2 is burning oil (come on in and laugh!)



Hegg
12-09-2004, 10:13 AM
Alright, I know that nobody should raise an eyebrow about an LBC burning oil, but this is serious!

I *finally* got my 1970 Elan +2 put back together and it starts up and runs now! However, after 20 or 30 seconds of running, the exhaust blows smoke that would put James Bond to shame. It is quite seriously bad -- this isn't just some casual engine smoking.

So here's my investigation results so far. I changed the oil because I thought I might have overfilled it initially anyway. I put 4 quarts back in and threw on a new filter. I pulled the plugs and all of them were VERY wet and oily, with the exception of #1. #1 was dry, but black (these are new plugs). I checked compression on all 4 cylinders with results as follows:

#1: 145
#2: 160
#3: 155
#4: 155

According to the book, compression should be 160 at sea level and I'm at 4,500 feet, so compression looks great to me.

I inspected around the entire engine by the head gasket and can't find the slightest evidence of even an oil dribble. The only thing I noticed that made me raise an eyebrow was how long it took oil to drain through the oil filler cap in the camshafts cover. It seemd to fill up quickly and I'd have to slow down to wait for it to drain through so it wouldn't overflow. Opening up the radiator cap reveals that I've lost some coolant, but I don't see any drips underneath the car.

So then, what should I consider? I initially thought that maybe the head was warped and/or the head gasket was bad, but it seems that the compression tests and lack of any leaks would suggest that they are in acceptable condition. But with missing coolant and oily cylinders, I would reconsider that.

Could it be in the head? Maybe the valve tappets are worn and leaking oil through? Doesn't seem like they could leak *that* much oil though.

Would my next best step be to pull the head and inspect the head gasket and have the surface machined flat?

Thanks everyone! I've driven the car around the block twice now and WOW is that a fun car! Can't wait to get the smoking problem resolved so I can get it registered and not feel guilty driving it around!

piman
12-09-2004, 11:36 AM
Hello Hegg,
what colour is the smoke? If oil it will be blue, white is water.

Alec

Hegg
12-09-2004, 11:41 AM
I've always done it at night (since that's when I get home), but it definitely smells like oil. I had an oil slick under the car from just the exhaust, so I know the oil is getting into the cylinders bad enough to leak out the exhaust.

Forgot to mention that in the previous post. I'll try to start it up today in the light and see if it's bluer or whiter.

Roger
12-09-2004, 12:02 PM
I'm betting on valve stem seals, particularly if the engine has been idle for a long while.

Hegg
12-09-2004, 12:07 PM
That's a darn good point, although my understanding is that the overhead Twin Cam doesn't have stem seals. My books also show they just have the tappet, shim, spring retainer, keepers, and the spring.

lotus_types
12-09-2004, 12:57 PM
Hi,
My first post being new to this list.
You are correct, the T.Cam does not have valves seals fitted
as standard (although I belive there is a mod to fit them)
It is normal for the oil to take a while to run down to the
sump when filling due to the drain only being on the inlet
side.
The T.Cams tend to wear the valves and guides quite quickly due to the design (short valves)and is usually the problem when they smoke but your smoke sounds excessive, if the valves/guides are worn and you have flooded the valve gear with oil (due to the slow draining)it may be getting this oil drawn in. I would suggest you leave it standing for a couple of days and try again,the smoke might just reduce with some time. Failing that it maybe a case of piston/bore wear, has the engine stood for a long time without use? or have you had the engine apart?
Regards Brian

64Elan
72Sprint
J.P.S.Europa
Birkin T.Cam Seven

coldplugs
12-09-2004, 08:42 PM
First (to lotus_types), welcome to the forum.



Re the smoking problem - I had the same problem with my Elan and lotus_types is right. When I first got it, the car hadn't been run for a while. I rebuilt the carbs and tuned things up and ran it for a while in the garage while I adjusted everything. Somewhere in there I changed the oil.

Towards the end of this process, it started smoking very heavily - so bad I waited until the neighbors left before I started it. Compression was in the 150 range on all cylinders. I really thought I had a few broken rings or something, it was so bad, although the compression test should have pointed this out.

I talked with a few folks who know Lotus twinks pretty well & they all said the same thing. Ignore the smoke until the car was driven at least 10 miles. I did this & things cleared up quickly.

Over the years I learned:

1) Don't trust the dipstick in a car you buy until you check it yourself. The are several tubes & dipsticks that fit these engines & somehow they often acquire the wrong ones. Drain the oil and refill with the exact amount called for in the manual. Check the dipstick & mark if necessary. (I once asked the guys on the Elan forum to measure their dipsticks & tubes and we had several different results.)

2) These heads in these engines have marginal oil drains back to the block. Make sure the drain tube (rear of engine, right side) isn't kinked. Sometimes people forget them when they put the head on & try to fit them in afterwards. Not a good thing to do.

3) A puff of oil smoke is normal at startup after the car's been sitting overnight.

In summary - drive it a bit more & see what happens. I suspect it'll clear up. If not, it could be worn stems or a blocked oil drain. It seems to me that some heads benefitted from drilling an additional drain hole.

Roger
12-10-2004, 03:34 PM
B Fool - write out 50 times. .
Elans have Twinks
Elans have Twinks
Elans have Twinks
Elans have Twinks
etc.

TypeRboy
12-16-2004, 12:02 AM
Yea, mine is brand new still, and when it has been sitting for more than a day it smokes on startup, but goes away after a few blocks.. Love those oil resevoirs over the cam buckets..Heh heh..