Engine rattle

[hubrick]

Hello Elan folks,
My 70 Elan has developed an engine rattle. Usually from 2000 to 2500 rpm. More steady now, but initially it was only when decelerating from higher RPM. I've looked all around above and below the engine, took off the fan belt to make sure it isn't the alternator or water pump, then finally concluded it must be the timing chain. I've read through many prior posts about it, and it sounds like adjusting the tensioner should have helped. It didn't.

Using 1/4 turns each time, I progressed to where I had two turns of adjustment and the rattle didn't seem to change much at all, might have gotten worse. I took a video, but it won't let me attach the mp4 file, at 1 3/4 turns. The rattle sound is now faint at idle too, you can hear it a little in the video. At that point, I removed the cam cover and found the timing chain to be very tight, so practically no play at all. I backed off the adjuster the two full turns and now I have just slightly less than 1/2" of play in each direction.

So I'm thinking that the rattle sound isn't the timing chain. Does that sound right? Any ideas what else I should look for before putting the cam cover back on?

Thanks for the help.

Cheers,
Rick
70 Elan 0045K

[h20hamelan]

You could try a stethoscope or more simply a funnel and hose, the latter probably better at this point.
Can you be sure its front of engine. Metal on metal sound/vibration travels easily.
For sure the exhaust is not the culprit?

[Slowtus]

You could try a stethoscope or more simply a funnel and hose, the latter probably better at this point.
Can you be sure its front of engine. Metal on metal sound/vibration travels easily.
For sure the exhaust is not the culprit?

Excellent point, we have all chased noises and lacking a funnel or hose, simply a longish screwdriver.

Pop the hoonnet off and have a friend hang their head out the window.

Yes, seriously.

PS, adjust your timing chain to spec as well, since you have fiddled with it.

PPs, this may (or may not) help.

https://www.bellperformance.com/blog/di ... ine-noises

[ericbushby]

Hi Rick,
I don`t think I can help with your rattle, but it sounds like you have not set the chain tension correctly.
Smack the chain downwards between the camshaft sprockets with a piece of wood or similar.
This moves all the play to that point. You should have half an inch total up and down movement not 1/2 " each way. which would be a total of 1 inch.
Good luck
Eric in Burnley
1967 S3SE DHC

[richardcox_lotus]

The only other quick suggestion is.... is your dipstick in the right way round ?

If it’s out by 180 degrees, it rattles more.

Been there; done that.

Regards
Richard

[hubrick]

Thanks all, wow rapid response from lots of you, appreciate it.

I wrote a response on my phone but when I pressed submit it didn't do anything. So now I'm back home. Here's that first response to h20hamelan.

"Thanks. Yes I've tried a stethoscope before adjusting the chain. Nothing found, probably just didn't put it on the rattling component. Forgot to mention that. It does sound like it's coming from the front of the engine, or maybe underneath the carbs, but hard to tell. I've been under the car while my brother revved it and got it to rattle, and I don't see anything, particularly the exhaust, which is what I thought it was, rattling."

slowtus

Seems like if I can hear the rattle standing by the car with me revving it at the carbs, how will a passenger hanging his head out the window help?

ericbushby

I've seen a diagram that shows the proper amount of tension on the chain. It clearly showed 1/2" from the top of the chain to the highest point, and 1/2" from the bottom of the chain to the lowest point. You're saying it should be half of that movement, so only 1/4" in each direction? I know I've been there while I was adjusting it, and the noise never did go away. When I took the cover off, there was essentially no movement in the chain at all, and I turned it back two turns to get it to where it is now.

richardcox_lotus

Which is the right way around on the dip stick?

Anybody heard that kind of rattling from the distributor with an electronic ignition magnet set trying to come apart. Someone has suggested that to me.

Trying to identify something else to check before I reinstall the cover with the new gasket, plugs, seals that arrived today.

While we're at it - I've read about how best to seal the cam cover. Do we really attach it to the cover with RTV and just put grease on the head? Seems like that lowest point at the head would be the most prone to oil leakage.

Cheers,
Rick

[Slowtus]

Thanks all, wow rapid response from lots of you, appreciate it.



slowtus

Seems like if I can hear the rattle standing by the car with me revving it at the carbs, how will a passenger hanging his head out the window help?



Cheers,
Rick

The rattle may become more/less noticeable when the engine is under load - being driven, hence my suggestion

[hubrick]

slowtus

aaah, yes, that does make sense. however, in this case, the rattle seems to be the same while sitting in the driver's seat or standing next to the engine bay.

[Slowtus]

slowtus

aaah, yes, that does make sense. however, in this case, the rattle seems to be the same while sitting in the driver's seat or standing next to the engine bay.

The same when being driven?

Is it possible it is on the intake side? rattling venturis caused by loose clamps - yes that IS a stretch but still possible.

[elans3]

If the car is still running the original 2 blade fan, check the rivets in it haven't come looks, and while you're at it, check that the cranl pulley is still tight. If it's still on the original dynamo, remove the fan belt and spin the pulley. A goosed dynamo bearing can sound like a rattle too. Mine did.....

[hubrick]

slowtus

yes, same when driving.

yes, seems like on the intake side. i'll check carbs/venturis for loose clamps

elans3

no, original fan is gone. i'll check the crank pulley. running an alternator, have already checked alt and water pump, rattling noise same when fan belt is off.

So, several suggestions for me to try. I'll check those. Nothing inside the head though. Looks like I'll tighten the chain to the 1/4" up and down movement contrary to the diagram I saw, reinstall the cover, and start it up and try to identify the rattle some more.

Thanks for all the suggestions. Anybody think of any more, send them my way.

Cheers,
Rick

[ericbushby]

Hi Rick,
Yes I think I know the diagram you mean, and this has been discussed here before.
The suggestion is that the drawing is done by a draughtsman not an engine man so is not necessarily accurate, but the text at the side of the drawing clearly says 1/2" total movement.
Eric

[rgh0]

Worn cam followers can also create a "rattle" as they rock in the sleeves.

cheers
Rohan

[h20hamelan]

Rohan, what is the best way to determine this please. Stethoscope?

[sprintsoft]

Hi Rick,

Don’t miss the opportunity to measure your valve clearances whilst you have the.cam cover off, that will eliminate a possible source of your rattle

Iain