X-flow, mystery engine noise.

[YW Sin]

Or it could be from the Carbs.

 

Help!!

I am scratching my head these days as a new noise has developed from my 1.7 X-flow with just 8800 miles.

The noise in question is only present at LOAD meaning that at stand still or at speed with clutch pressed and reved, the engine sounds perfectly happy and healthy.

 

The noise gets stronger especi~~~y when I have a passenger, accelerating, or going up hill.

Sound is either rotational or from the combustion. At the beginning, I thought that it may be tappet noise.

The noise sounds like: “pa.ru ru.r.r.r.r.r.r.r.r.r.r.” or even, “tru,ru.r.r.r.r.r.r.” (is this helping?)

To be honest, I don’t know if this is mechanical or by gas.

Engine at full speed, (above 4500 rpm?) the noise seems to disappear and sounds ok.

 

I have just noticed today that with the weather gears on, the noise is less audible.

 

I have adjusted:

Valve clearances,

Cleaned the air filters,

Balanced the carbs,

Checked the floater level,

Changed the oil,

Checked compression on each cylinder which were fine,

Checked ignition timing at idle which was bang-on at 14 degrees BDTC,

And

Checked the spark pug gaps. But no help.

 

Judging by the black exhaust pipe, I may be running rather rich these days but haven’t sorted this out yet.

My car at the moment is doing around 160 miles full tank driving norm~~~y.

 

Oil pressure of my car has always been low-ish at around 1.3 bar at idle and 1.8 bar at cruising speed but NEVER exceeding 2 bar at any circumstances except when engine is cold. ( 3.5 bar at idle when engine just started up).

I have recently changed the oil pressure sender and new uprated oil pump.

 

I am beginning to worry if this could be the worn valves or worn main bearings?

 

Any suggestions ????

 

 

Edited by - yw sin on 21 Oct 2002 21:54:01

[Graham Sewell]

Hi,

 

Firstly, unless you use genuine leaded petrol your exhaust pipe will always look black and this is no guide to engine health any more.

 

As you say the noise only occurs under load and between 2000rpm and 4500rpm, I would probably suspenct ignition timing. Try checking the timing between idle and high speed as this should be between 10' and 14' at idle and 35' abover 3500rpm. (Roger King can prpbably be more precise).

 

I once had a dizzy where the ignition advance locked solid for no apparent reason and just seemed to misfire at anything above idle when under real load.

 

Hope this helps.

 

Graham

 

Low tech luddite - xflow and proud!

[YW Sin]

Thanks Graham,

 

I forgot to mention that, I checked the ignition timing as well but only at idle speed below 1000 rpm with strobe scope.

It was spot on at 14 degrees advanced but no idea how to time it for 3000 rpm etc..

How can this be done?? and what to adjust if it is off.

 

Yes, I forgot again that now I am using unleaded fuel with additives!

 

Silly me.

 

~~~ standard 1.7 X-flow

[John E]

timing at full advance is the same proceedure as at

static. Do this with the strobe after slackening off the clamp on the dizzy.

Best with two people so that one can hold the strobe light and the other keep the cables away from hot places and work the throttle.

I wonder if you are getting some resonating from the carbs

 

Edited by - John E on 22 Oct 2002 16:06:25

[YW Sin]

John E

Thanks for your kind suggestion. My x-flow only indicates up to 12 degrees (Like the others I guess)so how would I know it's forexsample, at 35degrees???

 

What does " resonating from the carbs " mean.by the way.

I do think that the noise does possibly comes from the carb! Since I have noticed a similar sound coming out from a inlet ventury connected to Number one cylinder when I was balancing.

 

Sorry for silly questions but I must admit I am very much of a novice mechanic 😬

 

~~~ standard 1.7 X-flow

[puremalt]

Don't like the sound of your oil pressure. I get 1.5 bar when warm and idle, up to 3.5 bar under load, and at least 2 bar at all times when running on a 1700 s/s.

[John E]

I've checked on the oil pressure and agree that it seems to low. my spec sheet says 3/4 bar when hot at 5000 rpm so get the guage checked or do a swop to confirm pressure.

You have to set the advance using a strob which you set at the required setting. I dont know how they work but once its set you build up the revs and check the mark on the crank pulley against the full advance mark on the block. If you hve used a strobe to set up the static then its just the same proceedure and you will have to turn the dizzy until the marks line up.

Resonating is a vibration

 

[excess baggage]

2 bars is not nearly enough. My engine has just been rebuilt after a bearing failure due to oil surge. to be on the safe side a new oil pump was fitted, a genuine Ford one. Only gave 2 bars max. A phone call to a VERY nice man in Caterham (note in, not at!) resulted in a new pressure relief valve being fitted to the pump and pressure was up to its usual 4.5 bars when revved to the red line.

Hope you get it sorted.

EB

[YW Sin]

 

I am now inclined to think that my main bearings are definitely buggered!

 

Despite changing to new oil sender and up rated oil pump, the oil pressure is still under 2 bar.

Which means that I have been runing the last 2500 miles or so like an idiot with low oil pressure thus mostlikely the mean bearings are indeed worn.

 

Well, this is the zone where my knowledge of home garage mechanic ends so I think it is time to pay a visit to Tony Killburn’s garage which is the only specialist Lotus garage near Paris.

 

I will let you guys know of the outcome in a few weeks time!

 

Thanks for ~~~ your support!

*thumbup*

 

~~~ standard 1.7 X-flow

[Nigel Riches]

Monsieur Sin, some of the odd noises you mention could be from the gearbox bearings, and the gears themselves, the clutch release bearing, or from the carb inlets, when I changed from the "sandwich" plate Weber mountings to the ali plate "Misab" seals, a definate whistling noise was noticeable when running the engine at usual thrashing speeds, this was put down to the inner edge of the sealing plates acting as a reed, like in a saxophone, creating the noise mentioned, and if the motor in your car is a fairly standard Ford, then you may be able to find a local motor engineer to fix your bearings, if this is what it turns out to be, main bearing failure is often accompanied by a heavy rumbling sound as the surfaces rub together, are there traces of metal in the oil drained from the sump? so many noises, don't worry, be happy, as they say, Au Revoir, Nigel.

[rgrigsby]

Is it dry sumped? if so then 1.3bar at idle is a lot.....

 

Rob G

www.SpeedySeven.com

[YW Sin]

Rob.g My car is wet sumped. ☹️

 

Nigel - thanks for your feed backs!! I will certainly check the drained oil which I haven't deposited to the local garage yet.

 

About the local garages over here, I am very skeptical with non- specialist mechanics in France.

I have once given my Caterham to a fairly well established classic car garage dealing with classic Alfas and Ferraris to tune my weber carbs and few other things such as adjusting brakes.

When I had my car back, it was doing 120 miles full tank with very poor low end acceleration. I have also found that they have over tightened the rear drums so the rear wheel was HOT after drive back home ( good thing I have spotted it right away). For al l this damage, they have charged me 300 quid !!!!! + Their silly garage sticker stuck at the rear of my car.

 

Good local garage is a fast disappearing profession in France. Over here, there are less of automobile cultures compared to UK. And thanks to the French labor law and general business condition which are extremely unfavorable to sm~~~ enterprises.

 

~~~ standard 1.7 X-flow

[Simos]

Just rambling but did you check the guage and / or earth on it to make sure it'll read 4 bars if your sender is sending it. My local garage put a mobile guage on my golf when it complained of low pressure in 2mins flat (it was 6psi...)

[YW Sin]

Simos,

 

The guage does show 3.5 bar at idle when engine is cold so I guess it is working OK?

 

When engine fully warmed up, it never goes over 2 bars what ever I do ☹️

 

~~~ standard 1.7 X-flow

[YW Sin]

I will theck this "earth" - thing this weekend..

 

~~~ standard 1.7 X-flow

[Dave H]

Monsieur Sin,

To check the advance at angles greater than the 15Deg. on the timing cover, you need to make up or obtain a timing disc - it's just a simple disc with degrees marked on that slips down behind the pully - I used to blue tack mine in place. You can then use the strobe in the usual way.

I'd strongly advise getting hold of a copy of the Haynes Guide to the Ford Kent engine - you could probably do most jobs yourself then, unless you are a "clean hands" owner, and don't know one end of a spanner from a screw driver .

 

The oil pressure does sound very low - are the sender and gauge matched? (I.e. do you have a 10 bar max sender working with a 6 bar gauge).

 

One of my old Xflow Carbs used to produce a rhythmic beat at low throttle setting, never did find out why, it was one of the noises the car made

 

Dave H

[Simos]

In bad earth situation, pretty much anything can happen (although it's more usual for it to just not work) I was just throwing it into the melting pot as another thing to check while you're about it.

 

Earth strap for the instruments is on the left side under the dash. While you're about it there's a stap from the battery to one of the bellhousing bolts and one for the lights under the left rear wheel arch. A good unscrewing, brushing with emery paper and tightening never does any harm. if all your other instruments work fine then maybe this is a red herring. Can you connect your oil sender to your water temp guage and see if the behaviour is the same to sanity check the guage ?

 

I'd expect your oil pressure to be high (5) at cold idle falling when hot (1.5-2) but that it would pick up instantly when revved so it is back to 4 at 4,000rpm. 2 bars while thrashing it is too low if it is true. I suppose you've changed the filter, and, if a remote filter made sure the hoses are the right way around as some new filters have a non return valve to stop oil flowing the wrong way (which might previously have worked) If it WERE this you should see NO oil presure, but, while we're scrabbling for clues....

 

I had significantly lower oil pressure when I ran 5/40 (1-1.5 at 1,000 rpm rising quickly to 4 at 4-8k rpm) than the 15/50 I now run which is 2bar picking up to 5 at 4k.

 

A quick disclaimer to say I have a dry sumped BDR so not the same setup as yours, however you should still see a damn sight more than 2 bar on full chat.

 

On a different note, I am also on webbers and I have a very distinct induction hammer at two points in my rev range, first is around 4-5k and the second around 6-7. Just so we can rule this out, these sound distinctly metallic with a very quick but distinctly audible frequency. A bit like someone's got a bit of metal bar in a drill chuck and is panel beating my induction trumpets or perhaps I left a big nut in each one and they're bouncing around like crazy.

[Simos]

And I forgot to say the induction hammer is bloody loud, much louder than my exhaust at those points in the rev range. I find myself changing gear to avoid it in town lest I get nasty looks and changing gear to get it (the noise) in tunnels where it sounds like someone just fired of a 30 calibre machine gun in the tunnel entrance 😬

[YW Sin]

Simos,

 

It is a great info!

My wife is working today and also tomorrow, which means, I can play with my Caterham ~~~ weekend 😬

My Oil filter is 2500 miles old and I have a new spare one so I will change it and see how it goes. (but oil was changed 400 miles ago)

Wiring oil pressure sender to water temp sounds interesting, will try this too....

 

I didn't know that those Webers can make such big noises!

About this noise problem of mine, some times the car doesn't make nose as it has cured it self!!! Mind boggling

 

~~~ standard 1.7 X-flow

[YW Sin]

Changed to new oil filter yesterday, and the bliming oil pressure has DROPPED even further to 3.2 bars from 3.5 bars at idle when cold But, now max oil pressure has gone up slightly above 2 bars when revved at operating temperature instead of the usual 1.8

 

Miserable weather out there in Paris today, a perfect day to stay home and read some car mags!

 

 

 

~~~ standard 1.7 X-flow