catastrophic bummer

[3929R]

Left my garage. Drove a couple miles, then rough idle at a red light, loss of power on the green light and then a huge plume of smoke out the tailpipe. I made it to the side of the road.

The smoke was from oil, not coolant, and quite a bit of oil seems to have blown back out the carbs. I see no external damage to the block or head. No loud bangs or clunks. Valve through piston? Dropped valve? Valve seal? Ring? Something else? Anyone want to wager?

I'm still waiting on the side of the road for a tow truck, the first one could not lift it without damage. My plan is to tow it back to the garage, then drink something cold and soothing. And deal with it another day.

[BDA]

I think you have a good plan.

Let's see... Off the top of my head it's NOT rings or valve guides (or seals) since I think it is too sudden for that and I don't believe either would generate the amount of oil you seem to be describing. Unfortunately, it sounds more catastrophic than that. How many miles are on the engine?

I wouldn't try to start the engine. After you have your drink, you should run a compression test. If you have access to a leak down tester (and an air compressor) a leak down test would be better. You can buy them on ebay really reasonably but my guess is that you'll probably find out the cause before you receive it. They're nice to have but you don't need them very often.

Chances are that the compression test should at least point you in the right direction in case it's not obvious when you take off the head, but, sadly, I'm guessing it might be obvious then anyway. I'd guess that you dropped a valve or put a hole in a piston. The former is more likely. Hopefully, I'm wrong. It's been known to happen!

Good luck and let us know what happened.

[blasterdad]

 
Wow, that is a bummer! Sounds like your plan is a good one, get her home & tuck her in.
Get a cold one, & a good nights sleep!
When you do get around to it I'd drain the oil, look for metal/coolant, conp test, pop the valve cover, just basic stuff before you get too wrench happy... Hopefully, it might be something easily fixed. Either way, we're behind ya 100 percent!

[BDA]

Good advice, Blaster! I tend to skip past the simple explanations, put the car on stands, and take out the rear suspension before I find out one of my tires is a little low on air! 

[EuropaTC]

Dash pot oil from the carburetors getting into the engine ?

If there's no banging then I'd be surprised to hear of any serious mess inside the engine. At the moment I'm puzzling how you can get oil coming out (apart from the obligatory drips on the floor) but I suppose it's possible an inlet valve has burnt out & no longer sealing to let oil/petrol mixture get pushed backwards.

My first job would be to remove all 4 plugs and then try to turn the engine over by hand. If it's free  and the plugs look clean, try a compression test and let's take it from there. It is a bummer though, I don't like it when my toys break either.....

Brian

[4129R]

If oil has come out of the carbs, that would seem to indicate an inlet valve problem. The oil should only have come out of one carb unless there is a balance pipe between the carbs and the head, which I don't think is there on a federal spec twin cam.

Take the plugs out, and one will show which cylinder is at fault.

Then do a compression test on the cylinder with the dodgy spark plug.

That should point you in the right direction. A dropped inlet valve is not the end of the world, but if it needs new valve seat inserts, that will take a while but is not expensive.

Good luck, and I hope you got the car back without damage.

[HealeyBN7]

I had a vacuum booster fail on a big Healey that laid down an impressively grand oil soaked smoke cloud.  Might be worth a look if you have boosters.

[EuropaTC]

^^  now that is a good call, well done that man.

I'd forgotten completely about that one and it's featured a few times before on the Elan forum.

[4129R]

I presume you are referring to the brake servo.

When mine failed on a 1965 Mini Cooper S that I owned many years ago, the brake fluid just disappeared.

So where does the oil come from if it involves the brake servo? That should only have suction from the inlet manifold and brake fluid. I suppose if the brake fluid leaked out of the servo, the vacuum pipe could suck the fluid into the inlet manifold, and cause a misfire on possibly two plugs.

[4129R]

I forgot that the federal has two servos, so each must be operating off either one pair of siamesed inlets or there is a balance bar somewhere with two take-offs, one for each servo.

[EuropaTC]

Servo failure was a topic on the Elan forum a while back and the most common failure mode seemed to be that the servo would leak internally and end up with fluid getting sucked back into the inlet manifold through the vacuum pipe.   No obvious external leaks and at first minor leaking would just produce some extra smoke,  but there were a few cases where there was a serious loss of fluid.  Nobody seemed to notice it happening in the early stages so presumably there was still servo assistance whilst the fluid escaped and burnt off.

It's a good call and one that's easy to check - if plug #4 looks markedly different from #1 & #2, then it's worth checking the brake fluid as well ! (vac take off is on #4 for the Federal cars isn't it ?)

Brian

[4129R]

Looks like #4 to me:-

[BDA]

I'm kind of liking a servo failing for this. I think 4129R & EuropaTC have probably nailed it.

If that is the problem, I'm sure there are places in CA that rebuild those boosters. You might ask over at Dave Bean for somebody ((209) 754-5802). If you can't find one, White Post Restorations in Virginia does them, I'm sure (whitepost.com, (540) 837-1140). They rebuilt my m/c and rear calipers and did a very nice and quick job.

Some have done without their boosters and reported no problems. Of course, that will require some plumbing and you may want a smaller dia. m/c. That might be more trouble than rebuilding the boosters, though.

Good luck!

[jbcollier]

Fingers crossed here that it's a booster, not that it will be cheap if it is.  I would recommend either fitting new boosters or removing them.  Many times it is difficult to properly rebuild old boosters.  Very common for them to hang up after being overhauled.

Also, your engine is missing the spacer with the balance tube between the two carbs.  The spacer gives more bottom end torque and Strombergs run better with a balance tube.

[3929R]

THANK YOU FOR THE REPLIES!

My garage is not at my house but I made a quick stop by tonight and first pulled the plugs. All a bit black and a bit oily. #1 was maybe slightly oilier? Piston tops looked ok through the plug holes. Next I did a cold compression test, all four within ~145 to 150. Consistent but low, but the car was stone cold. I'm not sure but this seems ok? So I reconnected spark and she fired right up. Damn I was surprised and 150% confused. I'm not an experienced mechanic but the smoke cloud she blew was thick enough to obscure my rear view. It was like a smoke screen from a James Bond movie. In hind sight (pun intended) I could have driven home but based on the smoke cloud and oil issuing out of the carburetor plenum I feared a valve doing damage to a piston or a piston doing more damage to the head or....

The car is still blowing smoke but at least you have to walk to the back to see it. The smoke sure smells like burning oil and looks bluish to me (I'm color blind). I ran out of time tonight but I plan to do a hot compression test next.

My father bought my car new in '73 when I was 5. "The Lotus" was always just there and I never thought to ask him any specifics about it. Dad was a good mechanic. I would call him, describe a problem (about whatever car I had at the time), and he'd usually be able to tell me what was wrong and how to fix it. He died very unexpectedly at age 52. When I pulled the Europa out of storage the speedo cable was seized so I don't know how many miles are on it. The seals on the brake MC were shot (as were the slave cylinders). I assumed the boosters were also toast so I removed them and swapped in a Datsun F10 master cylinder. I also plugged the booster vacuum port on the intake manifold. I never drove the car with boosters but really can't see why you'd want or need them. The car is so light, as far as I can tell it seems to brake great without them.

In conclusion..... I'm more befuddled than before.