Lotus Elan

What Happened To My Engine?

PostPost by: Hegg » Sat May 14, 2005 3:55 am

So I was cruisin' on the freeway today on my way in to work and the car starts acting just a little funny, kinda studdering a bit. After a few seconds of this, I get a jolt and hear a rapid "clack clack clack", which resembled the sound of a chain being drug over a sprocket! I immediately put in in neutral and pull over to the side of the road. As soon as I put it in neutral, the engine dies.

Finally after 4 hours of running around to get a dolly, I get it towed home to inspect. I thought for sure my timing chain was bustificated. We pull off the valve cover and everything is in-tact! The chain is there and seems to have the right tension. I put the car in gear and push it a little and the engine parts all start moving as they should. Cranking the engine with the key turns just as it should, but it won't fire. I checked spark and it's all there just dandy.

I decided to pull the plugs out and check compression and I found my first clue. Plug #3 looks like this:

Image
Image

So what happened?!? Judging by the angle that the plug is damaged, I'd guess that it would have to be a collision with the valve. Could a valve have "come loose" and dropped into the cylinder? I can't see my piston (will take the head off tomorrow), but it doesn't look like it was hit from the bottom too much. The rest of the plugs look normal.

I guess I don't have many questions yet since I haven't figured out all I can, but does anyone have any comments on this situation? I must say I'm a little depressed at this point.
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PostPost by: Matt7c » Sat May 14, 2005 8:42 am

Ouch! That looks painfull. I have insufficient knowledge to disagree with your analysis...but it sure looks expensive! :(
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PostPost by: types26/36 » Sat May 14, 2005 8:58 am

SAD! dont know what carbs you are using but with Webers/Deloto's the nuts /studs that secure the air box back plate have a habit of coming off and be ingested by the engine, the damage looks a bit extensive for a nut so I'm guessing a valve, think its immaterial anyway as you've got to pull the head.
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PostPost by: poiuyt » Sat May 14, 2005 11:18 am

I'm guessing a broken valve spring allowed the piston to bend or break a valve, which hit the plug. Let's hope the piston isn't damaged and it's only a valve fix needed.

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PostPost by: Hegg » Sat May 14, 2005 2:23 pm

Thanks for the comments and sympathy. I'm sure we all agree that an Elan is really a living entity - a part of the family, so it's sad to see your kid trip and break his teeth on a valve.

I'm about to head down for the morning and dig in. I'll keep you posted.
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PostPost by: type26owner » Sat May 14, 2005 3:23 pm

Hegg,
I've had this happen to me twice before. First take the head off and examine the piston around the squash deck area. If there aren't any dents there and the pistons don't have any through holes then you won't have to pull the piston out of it's cylinder. If there are signs of metal being moved above the ring lands then the piston will have to come out since it's likely the rings are bound up tight in their grooves. I've simply gone into the groove with a jeweler's file and filed away the interference area and reinstalled the piston. However measure the top the pistons to the block height as they pass TDC and make sure the cylinder with the bent or broke valve is the same as the others. If it's short then the rod is possibly bent too.

You would be wise to check the running clearances of the pistons to the valves. !/8" (3mm) should considered the minimum. Quite common on the domed pistons that the valve clearance pockets must be machined deeper when replacing the pistons and fitting them for the first time.

If you need to remove valve guides or seats let me know and I'll tell how it's done the trick, no fuss or bother way. BTW, if don't do it this way there is a good chance you'll destroy the head. Even if you have the work done by others you are armed to ask how they are going to do it ahead of time. You can cull the incompetent ones before they do damage to your head.
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PostPost by: type26owner » Sat May 14, 2005 7:17 pm

You'll need plugs with a heat range one setting hotter. Looks like you were lucky though. Both of my heads were damaged cause the plug threads got smacked and when the plugs were unscrewed the threads in the head got wiped out too.
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PostPost by: gjz30075 » Sun May 15, 2005 12:31 am

Really sorry to see that. Ouch! Similar thing happened to a friend's twink. Instead of having a needed valve job done, a PO had ground down the tips of the valves to get even the thinnest of shims to fit. There just wasn't enough material above the keepers to keep the keepers :blink: and blamo! The tip broke off with said results.

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PostPost by: Hegg » Sun May 15, 2005 2:54 am

Welp, a picture is worth a thousand words, so here's a few thousand:

<a href='http://unabled.com/show/cars/Elan/TheBroke/' target='_blank'>My Friday the 13th image gallery.</a>

I'll have to give Dave Bean a call on Monday and start getting some head rebuild estimates. Obviously I need one piston, but I'm thinking of doing the entire block. Sure wouldn't hurt (other than the pocketbook), would it?

I finished my Falcon rebuild over a year, then went into the TR7 rebuild for the last year. Now it's on to the Elan rebuild. I need a break!

Hope everyone else's Friday wasn't as cursed. :(
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PostPost by: rgh0 » Sun May 15, 2005 12:07 pm

I dont think your to cursed. It could have been a lot worse !. When I dropped a valve head many years ago in the Elan it smashed the cylinder head in that bore totally. I guess the forged pistons were stronger than the Lotus head so the valve ended up punched through into the water passage in the head. Fortunately my engine place has a magic alloy welder who rebuilt the head by building up with weld metal and remachining. The only way to tell its been rebuilt is that the quality of the weld metal is better than the orginal casting with less porosity.

Good luck with the rebuild. Whenever I build a engine these days I always use new valves, a lot cheaper than a second rebuild.

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PostPost by: type26owner » Sun May 15, 2005 3:29 pm

Hegg,
Like Rohan said that damage can be fixed. Don't think you'll need any welding done either from the looks of it. The real issue is the pockets for the valve seats and whether or not they are okay. The picture isn't all that clear. Is the exhaust seat still in it's pocket or did it come out too? Valves don't normally just break off unless the seat came loose first.

I would not duplicate the surface finish on the aluminum head though. It's way too rough. Just look at the picture and you'll see where the metal compression ring of the head gasket has plastically flowed the metal. You are much more likely to develop a small compression leak into the coolant system and have it blow out coolant out the overflow.

I have the technical article on head gasket from Payen/FelPro which discusses this subject in fine detail if you want it.
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PostPost by: Hegg » Sun May 15, 2005 4:23 pm

Thanks for the reponses. I've been thinking about my options now just to be prepared for when I'm ready to fix this. Unfortunately, I'll have to let my sad Elan sit for a few months while I recover from the TR7 rebuild.

Just from reading around, it looks like I have 3 options to consider in my mind. This Elan would be a fun street car, not a "race" car. I like to drive hard and fast, which I understand the Twink loves anyway. I just put 4 new Koni's on it, as well as a solid rear CV driveshaft.

Given that, the 3 things I'm looking into are:

(1) Keep the engine stock/original. Basically just rebuild it to stock specs. I like having an original car because it just adds an amount of coolness. However, since I've replaced the rear driveshafts, I'm out of original territory already. This options seems the cheapest.

(2) Hop it up a little with some hot cams, big valves, etc. Seems like it'd remain relatively stock looking, but would have a certain stoplight terror about it.

(3) Replace the block and juice it up even more. I could look around the junkyards for an old Pinto "tall block" to build up and play around with, or even go with a BDA engine. Sounds like a lot of money, but would put my +2 on the police's "most wanted" list around here.

Any opinions? I haven't even looked at any cost factors yet, but I'm sure I'll be too scared by even option #1. :)
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PostPost by: Hegg » Sun May 15, 2005 4:26 pm

Oh yeah, and I've seen mixed opinions on the gearbox. Is the stock 4-speed good to keep, or should I consider a 5-speed? I've heard that the 5-speed boxes are rare, expensive, and not as good performance, but I do a lot of freeway driving (65-75 mph), and I have to admit the 4-speed was getting a little loud.
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PostPost by: type26owner » Sun May 15, 2005 4:31 pm

Oh hey, you'll notice #4 piston has less carbon deposit on it. That is a strong indication that that cylinder has coolant leaking into it. What type of head gasket are you using? If you would post pictures of both sides of the head gasket I'll diagnose the cause of those problems for you.

Definitely here is your golden opportunity to add valve stem seals.
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PostPost by: steveww » Sun May 15, 2005 9:49 pm

Ouch! :o

If you are just planning on using the car on the street, I would just hot up the old twinc a bit when you put it back together. Don't go for long duration cams, just a bit more lift is all that is required. Spend some time and flow the head or if you don't feel up to that get a good shop to do it for you. This will give you some more power but still retain some low down torque. Long duration cams need high rpm which needs a steel bottom end which needs $$$$

Pity it had to happen just as the summer was getting going :(
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