Lotus Elan

Update... Re: Stil no luck--- Deep vibrationa t idle problem

PostPost by: "Stan Aarhus" » Sat Sep 09, 2006 3:36 pm

Her's a theory to explore. Assumption: Your exhaust system is contacting
the body/chassis or your exhaust hanger is damaged/mis-aligned. Rationale:
If this is so, the engine is idling (ticking over) lumpily (rough) and that
movement is causing the exhaust system to bump the body at the rate of
engine "lumpiness". But, while motoring along, the torque action of the
engine moves the exhaust away from its contact point and thus, no noise.

Stan

Subject: [LotusElan.net] Deep vibration at idle problem


Here's hoping someone can point me in th right direction.

Well, I changed the one engine mount on my car that looked damaged in
hopes that this was the cause of the vibration I experienced on the
way home--of course it was not. The vibration is still there. The
only way to describe it is as a deep thumping vibration that feels
like it is coming from under the seat. When I rev the engine it goes
away and this was the case when I was driving home when it originally
ocurred. At speed it was driving about normal, but at idle something
is definately not right.

It has me and my mechanic friend a bit stumped. Anyone have an idea
of where to look?

David
+2S Helsinki, Finland
"Stan Aarhus"
 

PostPost by: davidwinegar » Sat Sep 09, 2006 3:40 pm

Here's hoping someone can point me in th right direction.

Well, I changed the one engine mount on my car that looked damaged in
hopes that this was the cause of the vibration I experienced on the
way home--of course it was not. The vibration is still there. The
only way to describe it is as a deep thumping vibration that feels
like it is coming from under the seat. When I rev the engine it goes
away and this was the case when I was driving home when it originally
ocurred. At speed it was driving about normal, but at idle something
is definately not right.

It has me and my mechanic friend a bit stumped. Anyone have an idea
of where to look?

David
+2S Helsinki, Finland
davidwinegar
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PostPost by: davidwinegar » Sat Sep 09, 2006 3:41 pm

Here's hoping someone can point me in th right direction.

Well, I changed the one engine mount on my car that looked damaged in
hopes that this was the cause of the vibration I experienced on the
way home--of course it was not. The vibration is still there. The
only way to describe it is as a deep thumping vibration that feels
like it is coming from under the seat. When I rev the engine it goes
away and this was the case when I was driving home when it originally
ocurred. At speed it was driving about normal, but at idle something
is definately not right.

It has me and my mechanic friend a bit stumped. Anyone have an idea
of where to look?

David
+2S Helsinki, Finland
davidwinegar
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Posts: 150
Joined: 23 May 2004

PostPost by: tvacc » Sat Sep 09, 2006 4:22 pm

I would tend to agree. If it was a "bad" low vibration.I would think it
would increase with the increase in RPM. It would then just be faster.



That not being the case.If it is a slow (well.1/4 the speed of a fast
vibration).I would suspect a thrown weight on the flywheel.or a nut coming
loose on the crank(which I doubt),. A faster (double speed of a slow )
would be the cams.and then faster would be like the belts.



I still vote for a muffler rattle..



Tony Vaccaro



_____

From: ***@***.***lto:***@***.*** Behalf
Of Stan Aarhus
Sent: Saturday, September 09, 2006 11:32 AM
To: ***@***.***
Subject: Re: [LotusElan.net] Deep vibration at idle problem



Her's a theory to explore. Assumption: Your exhaust system is contacting
the body/chassis or your exhaust hanger is damaged/mis-aligned. Rationale:
If this is so, the engine is idling (ticking over) lumpily (rough) and that
movement is causing the exhaust system to bump the body at the rate of
engine "lumpiness". But, while motoring along, the torque action of the
engine moves the exhaust away from its contact point and thus, no noise.

Stan

Subject: [LotusElan.net] Deep vibration at idle problem

Here's hoping someone can point me in th right direction.

Well, I changed the one engine mount on my car that looked damaged in
hopes that this was the cause of the vibration I experienced on the
way home--of course it was not. The vibration is still there. The
only way to describe it is as a deep thumping vibration that feels
like it is coming from under the seat. When I rev the engine it goes
away and this was the case when I was driving home when it originally
ocurred. At speed it was driving about normal, but at idle something
is definately not right.

It has me and my mechanic friend a bit stumped. Anyone have an idea
of where to look?

David
+2S Helsinki, Finland
Tony Vaccaro
http://www.lotusowners.com
LOONY (Lotus Owners of New York)
Drive Fast Take Chances
71 Spyder Elan, ElanGTS, 93 Caterham, 05 Elise,
99 Elise190, 91 M100 Elan, 74 Europa, 72 Europa JPS #15
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Location: Buffalo NY

PostPost by: davidwinegar » Sat Sep 09, 2006 5:34 pm

Thanks Stan--I'm going to look into this tomorrow. It does seem like
a probable cause especially since before coming home the night I had
problem I did "bumb" the bottom on a bad parking lot entry way. I
checked under the car before leaving and didn't see anything and
drove it about 30 minutes before any problems but it can be that there
was something and it just took time to shift into contact.

I'll let you know what I find.

Thanks again for the pointer.

David



--- In ***@***.***, "Stan Aarhus" <[email protected]> wrote:
Her's a theory to explore. Assumption: Your exhaust system is
contacting

the body/chassis or your exhaust hanger is damaged/mis-aligned.
Rationale:

If this is so, the engine is idling (ticking over) lumpily (rough)
and that

movement is causing the exhaust system to bump the body at the rate of
engine "lumpiness". But, while motoring along, the torque action of
the

engine moves the exhaust away from its contact point and thus, no noise.

Stan

Subject: [LotusElan.net] Deep vibration at idle problem


> Here's hoping someone can point me in th right direction.
>
> Well, I changed the one engine mount on my car that looked damaged in
> hopes that this was the cause of the vibration I experienced on the
> way home--of course it was not. The vibration is still there. The
> only way to describe it is as a deep thumping vibration that feels
> like it is coming from under the seat. When I rev the engine it goes
> away and this was the case when I was driving home when it originally
> ocurred. At speed it was driving about normal, but at idle something
> is definately not right.
>
> It has me and my mechanic friend a bit stumped. Anyone have an idea
> of where to look?
>
> David
> +2S Helsinki, Finland

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Joined: 23 May 2004

PostPost by: ecamiel » Sun Sep 10, 2006 12:57 pm

Check the trans mount. The rubber tends to get soft from the usual Lotus
oil bath and it collapses under load.
Eric
64 S1 comp
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PostPost by: denicholls2 » Mon Sep 11, 2006 9:00 pm

Tony wrote:



I still vote for a muffler rattle..

Put me in the muffler rattle category. An internal bit would be more
likely to be heard only at low flow rates.

Any potential contact with the body should be easy to confirm and is
dangerous - your car body is cast out of fuel! Fix it now!



-- Doug Nicholls, 54/1822 Ma~
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PostPost by: s2lola » Tue Sep 12, 2006 9:29 pm

Les,

Have you fallen asleep on the "send" key??

-----Original Message-----
From: ***@***.***lto:***@***.*** Behalf
Of les mellor
Sent: 2006/09/12 17:10
To: ***@***.***
Subject: Re: [LotusElan.net] Update... Re: Stil no luck--- Deep vibrationat
idle problem


LOOSE FLYWHEEL !!



----- Original Message -----
From: david_c_w
To: ***@***.***
Sent: Wednesday, September 13, 2006 12:46 AM
Subject: [LotusElan.net] Update... Re: Stil no luck--- Deep vibrationat
idle problem


Thanks guys for the thoughts but I am sure that it is not related to
just rough idle as the sound is much more sinister than just that. It
sounds as if there is a big hammer being hit on the block. Also,
since this occurred as I was driving home one night--all of a sudden
this vibration started while stuck in traffic. Rough running is one
thing, but this is certainly more than that.

Again, the strange thing is it seems to clear at speed. Not sure if
this is still the case because I have not driven it since as the
couple of times I started it, the sound and vibration was such that I
didn't dare to keep it running.

Could it be something internal with the engine--connecting rod, piston
etc. Or would problems with those all be more obvious and serious?
What about the flywheel--so others think that should be looked into?

Thanks again for all the thoughts.

David

--- In ***@***.***, "Stan Aarhus" <[email protected]> wrote:
>
> Roger,
>
> I still remain satisfied that the theory I posted earlier is close
to the
> source. I referred to "lumpiness" or rough idling, being the
contributing
> factor. Whether or not this roughness was present was never
addressed, one
> way or the other. It now seems to be the case.
>
> <snip>"I tried to start it
> > and it turns over but the thumping sound is so bad that I just did not
> > want to keep it running as there is certainly something wrong."
</snip>
>
> I agree that the problem probably has to do with carb syncing, mixture
> balancing, vacuum leaks or even crossed sparkplug leads. Has a
compression
> test been done?
>
> My previous response:
>
> "Here's a theory to explore. Assumption: Your exhaust system is
contacting
> the body/chassis or your exhaust hanger is damaged/mis-aligned.
Rationale:
> If this is so, the engine is idling (ticking over) lumpily (rough)
and that
> movement is causing the exhaust system to bump the body at the rate of
> engine "lumpiness". But, while motoring along, the torque action of the
> engine moves the exhaust away from its contact point and thus, no
noise."
>
> I think we're getting close, but internet troubleshooting is
difficult, at
> best.
>
> Cheers to all
>
> Stan
>






----------------------------------------------------------------------------
--


No virus found in this incoming message.
Checked by AVG Free Edition.
Version: 7.1.405 / Virus Database: 268.12.3/445 - Release Date: 11/09/2006
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Location: Toronto, Ontario

PostPost by: elansprint71 » Tue Sep 12, 2006 9:45 pm

Bill, out there in OZ, Les is probably counting sheep. At least I hope
he is only counting them. ;-)

Cheers,
Pete.


Tebbutt, Bill wrote:

Les,

Have you fallen asleep on the "send" key??

-----Original Message-----
From: ***@***.*** <mailto:lotuselan%40yahoogroups.com>
[mailto:***@***.***
<mailto:lotuselan%40yahoogroups.com>] On Behalf
Of les mellor
Sent: 2006/09/12 17:10
To: ***@***.*** <mailto:lotuselan%40yahoogroups.com>
Subject: Re: [LotusElan.net] Update... Re: Stil no luck--- Deep
vibrationat
idle problem

LOOSE FLYWHEEL !!

----- Original Message -----
From: david_c_w
To: ***@***.*** <mailto:lotuselan%40yahoogroups.com>
Sent: Wednesday, September 13, 2006 12:46 AM
Subject: [LotusElan.net] Update... Re: Stil no luck--- Deep vibrationat
idle problem

Thanks guys for the thoughts but I am sure that it is not related to
just rough idle as the sound is much more sinister than just that. It
sounds as if there is a big hammer being hit on the block. Also,
since this occurred as I was driving home one night--all of a sudden
this vibration started while stuck in traffic. Rough running is one
thing, but this is certainly more than that.

Again, the strange thing is it seems to clear at speed. Not sure if
this is still the case because I have not driven it since as the
couple of times I started it, the sound and vibration was such that I
didn't dare to keep it running.

Could it be something internal with the engine--connecting rod, piston
etc. Or would problems with those all be more obvious and serious?
What about the flywheel--so others think that should be looked into?

Thanks again for all the thoughts.

David

--- In ***@***.*** <mailto:lotuselan%40yahoogroups.com>,
"Stan Aarhus" <[email protected]> wrote:
>
> Roger,
>
> I still remain satisfied that the theory I posted earlier is close
to the
> source. I referred to "lumpiness" or rough idling, being the
contributing
> factor. Whether or not this roughness was present was never
addressed, one
> way or the other. It now seems to be the case.
>
> <snip>"I tried to start it
> > and it turns over but the thumping sound is so bad that I just did not
> > want to keep it running as there is certainly something wrong."
</snip>
>
> I agree that the problem probably has to do with carb syncing, mixture
> balancing, vacuum leaks or even crossed sparkplug leads. Has a
compression
> test been done?
>
> My previous response:
>
> "Here's a theory to explore. Assumption: Your exhaust system is
contacting
> the body/chassis or your exhaust hanger is damaged/mis-aligned.
Rationale:
> If this is so, the engine is idling (ticking over) lumpily (rough)
and that
> movement is causing the exhaust system to bump the body at the rate of
> engine "lumpiness". But, while motoring along, the torque action of the
> engine moves the exhaust away from its contact point and thus, no
noise."
>
> I think we're getting close, but internet troubleshooting is
difficult, at
> best.
>
> Cheers to all
>
> Stan
>

----------------------------------------------------------
--

No virus found in this incoming message.
Checked by AVG Free Edition.
Version: 7.1.405 / Virus Database: 268.12.3/445 - Release Date: 11/09/2006




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