29 replies to this topic

[ESPREE]

Hello all,
Sadly, after only 2 and a half weeks of owning my 99 Esprit V8 (my dream car) - in excellent condition with 24k miles - it started to make a loud rattling noise at 2000-3000 RPM, which was diagnosed as something internal by two different shops (one of them a Lotus specialist that I do trust). No idea if this was a pre-existing condition that the previous owner hid (if that's even possible) or just something that happened.

The Lotus mechanic removed the turbos, took off the cam covers, and is 100% certain it is a rod noise of some kind - possibly the lower rod bearings that connect to the crankshaft, or the upper wrist pins. Initial estimate was for $15-20,000 USD for a complete engine rebuild. Yikes! I had put aside some extra money for repairs, but nothing to that scale.

We are hopeful that if it is the lower bearings, he might be able to get access to them from below, and thereby spare us a ton of labor and parts that would be needed if the entire engine is rebuilt from the top.

Similar to what is talked about here (though of course a very different engine/car):
http://mysite.ncnetw...aring_Swap.html

Has anyone done this before on a Lotus? Do I have reason to hope, or should I plan on selling a kidney? (jk - no offense intended to any donors/recipients!)

I'm also curious if this is a common thing or not. What would cause this to happen on a car with so few miles?

Thanks for any suggestions.

- Kent

[Roger the Dodger]

I'm not qualified to speak on V8s, so I generalise.
What oil are you using, what is the oil pressure at low RPM, cold, hot and hot variations from 2000 - 6000 rpm, and what are the common noise factors, ie does it rattle more or less when hot ?
If it is the end bearings and they are bad enough to make an obscene noise, you will need to "Very" accurately measure the journals, but I'd suspect an engine out job.

[mc21.8]

changed ford v6 big ends in situ on scimitar 2hrs
not sure about lotus v8 whithout looking?if that is the problem!would be the way to go though if poss.well worth looking into mate.

[WEllison]

Since I didn't hear the "noise" I can't comment on what it might be, but if the Lotus mechanic is qualified and you trust his judgement, then the engine needs to come out of the car. I am surprised that the mechanic removed the turbos while the engine was in place, especially if he suspects rod or main bearings. Removing the turbos with the engine in place is not easy! Makes me question his confidence and knowledge. The heat shields around the exhaust manifolds crack at about 20,000 miles and they make a high piched rattle at about 2400 -3000 rpms, but then go away after the resonance point. you can confirm a single bad rod bearing by removing the plug wire to each cylinder one a time and see if the knock or rattle goes away. A pain in the ass to do on a Lotus.

[redshift]

I'm with Wayne on this.
Big ends dont usually rattle it is more a distinct knock. Small ends can rattle, usually most pronounced on the over-run.
Generally neither of two is like a 'resonance'.
I would start by looking for something loose or even something driven of the aux belt.

I'm surprised that they have started by removing turbos and cam covers though.

[Bibs]

Don't get a $15k+ engine rebuild if the worse comes to the worse. I can source you an engine for $7.5k or thereabouts to drop straight in, new or at least freshly rebuilt from Hethel or France!

[ESPREE]

Thank you everyone for the replies.

I recorded a short video so that you can hear it...


Engine was cold, and you can hear it when it first starts up, then it comes in and out with the RPMs around 2-3,000. Does that help?

To answer some of the questions...

Roger - my V8 doesn't have an oil pressure gauge (just a warning light I'm assuming), so I don't know what the oil pressure is. You can hear the noise when the engine is cold or warm, but I haven't been running it enough to know if it is louder in one condition or the other. Mobil1 synthetic is the kind of oil, not sure of the weight.

Wayne and Pete - Yes, at first we were hopeful it was something to do with the cam belts (pulley or belt flap), so the covers over the belts were taken off (not the actual cam covers of the engine - sorry for the confusion). Also, I think he disconnected one side of the turbos to eliminate them from the equation, but I don't think they came completely off. You are right about the heat shields - those were the first things to get checked. Everything with the exhaust is solid. When the car is up on the lift you can hear it coming mostly from the right side of the car towards the front of the engine.

Bibs - I would be very interested to know the details of the engines that you can get. Are they directly from Lotus, or from some other company? If it does need a full rebuild, I would definitely consider this. I can only imagine what the shipping cost would be to get to the US, but a new engine would be ideal, especially if it will cost less! Please let me know.

Thanks all,

- Kent

Edited by ESPREE, 11 July 2011 - 01:46 PM.

[Roger the Dodger]

What sort of lifters does the V8 have, are they hydraulic ?

[mike_sekinger]

Yes, the tappets are hydraulic.

If the rattle is truly internal, then it needs to be thoroughly investigated. Cheapest option might still be to ship the engine back to Europe and have it either overhauled or a fresh engine prepared, to salvage what is serviceable from your engine. As Bibs says, don´t pay 15-20KUSD - you can do a lot better price-wise from here.

Cheers,
Mike S

Edited by mike_sekinger, 11 July 2011 - 02:59 PM.

[WEllison]

I listened 4 times to the clip and it's difficult to be sure about the rattle/knock.

But,

1. Definitly not deep enough to be a main bearing.
2. Doesn't act like a rod bearing in that the knock doesn't seem to get louder on throttle off, but very difficult to tell as the IAC is bleeding a lot of air past the throttle plates and making the loud hissing noise, that hissing noise should reduce as the idles rev's come down (engine warms), then it might be easier to hear.
3. Get a mechanics stethoscope and set if you can trace the sound to the valve train area. Engine seems to run on all cylinders mabe you broke a valve spring though. I would pull the cam covers off and have look at the valve train. The knock/rattle seems to light to be a low end noise.

[ESPREE]

Hi Wayne,
Thanks for the ideas. There is a bit of valve tapping noise right when it starts up, which goes silent at about 8.5 seconds in the clip. If it were a valve noise, would it sound similar to that? To my ears the problem rattle sounds more solid than the valve tick.

I will get a mechanic's stethoscope and give that a try while I am waiting for my appointment with the mechanic.

- Kent

[Roger the Dodger]

The reason I asked about lifters is because that's what it sounds like to me. OK even with the recording it's difficult because it's not directional, so I'm with the stethoscope idea.

[Rich H]

I have an engineers stethescope, it's amazing what you will end up listening too... injectors opening, tappets, turbo's it's great fun but you do look like a special case...!
That will tell you in a few seconds where it's coming from, or more accurately it'll tell you where it's NOT coming from.
It's easy to poke things with it but you will find it's quite a bit harder to actually find the rattle...

Remember you probably won't hear a con-rod bearing with an 'scope as there is no clear path to transmit the noise: oil film bearings insulate sound quite effectively!

[ESPREE]

So the stethoscope is on order, along with a OBDII interface for future troubleshooting. I think Rich may be right that I may not be able to locate the sound directly, but can maybe eliminate some things (and have some fun listening to everything in the process). The Lotus pro is certain it is a rod noise, but I might as well check around while I am waiting for my appointment. I just don't want to run it too much and do any damage.

If i want to take off one of the spark plug wires to see if the rattle goes away on a certain cylinder, any suggestions what is the easiest way? At the plugs themselves or at the distributor? I've never seen either, but I know they have to be in there somewhere! I might need some details on how to access them. Or can the cylinders be disabled from the OBDII interface? Not sure what that is capable of.

But back to the original idea, does anyone know if the rod bearings on the 918 are accessible without removing the engine or completely rebuilding it? Anyone even seen them from below?

Thanks,

Kent

[redshift]

If you want to pull one of the HT leads, there's a cover plate which is on the cam cover.
Its an odd shape with 4 half circles on one side and is screwed on. The leads and plugs are underneath.
There is no distributor as there are individual coil packs under the plenum cover in the 'valley'.

Edit to add a link to some of Mike's rebuild work:

http://www.thelotusf...e-exploding-v8/

Plenty of pics of the internals

Edited by redshift, 12 July 2011 - 01:23 PM.

[Bibs]

Intermediate shaft?

Can you check for play - in and out and up and down, look for wear marks nearby? There should be no play whatsoever in the intermediate shaft.

[mike_sekinger]

In answer to the " can you access from underneath?" - the answer is yes.

You can remove the sump with the engine in situ, but it is a bit tricky. There are two cap bolts for the flywheel end of the sump that are really tricky to access. Once the sump and oil pick-up pipe are removed, you can remove each of the Big End caps and very carefully replace the BE shells through a combination of crank rotation and manual movement of the pistons/rods. It is tricky, but not impossible.

Here is an image of what you will see.



Cheers,
Mike S

Edited by mike_sekinger, 12 July 2011 - 03:51 PM.

[ESPREE]

Hi Mike,
Great, thank you so much for the info and the photo!

Kent

[mike_sekinger]

Just for prosperity and future reference, here is an image with the sump removed from an engine in situ

[ESPREE]

Hi Mike,
Thanks for posting that.

Do you perform your own engine work?