I was going down the m4 and the rad cracked it started to make a loud tapping at about 110mph so i slowed and took it easy got it home and thought the tapping was the bearings so i changed them all (main and big) still tapping so ive been changing stuff ever since,still same noise ive tried new cam,new followers ,rockers and springs,new head,new oil pump,new dizzy ive checked the pistons and rings they seem fine the oil preasure is low at about 12psi when warm. But i have no noise and oil preasure is fine under load. Does any one have any ideas?

 

If your big ends make a loud noise you need a grank regrind mate.
just replaceing the bearings wont do .

 

You have to explain better than this:

"I was going down the m4 and the rad cracked it started to make a loud tapping at about 110mph"

Rad cracked? Do you mean the radiator, connecting rod or something else? Does it make the noise all the time? Are you sure it's the engine that is making the noise?

 

cheers for the feed back. 1st up when i changed the bearings they were'nt scored or coppered i changed them as a precaution just to make sure it was'nt them it baffled me at the time.
yes mate it was the radiator that had cracked which i found out when i'd got home and it does make the noise all of the time upto around 3500rpm then i think the tapping dies off or i just cant hear it . when i had it on the rollers lee at power engineering said it sounded fine under load and did'nt know what the noise was and its definately in the bottom end.

 

it can be the arm that is dissconecting the clutch. When that is worn it sounds like a diesel car. Try to push your clutch pedal fully in when its making that sound.

 

Hi Adsrst, I have had the same kind of strange noise from my S2 , it started after a good thrashing one night. Like your noise it was a sharp, loud, clicking or knocking sound? You could not hear it at idle but under acceleration light or hard it was as plain as day
I was convinced it was internal damage, having striped it down could find nothing wrong at all?
Put it back together and had the same noise !……..
Having changed all sorts of parts and still not found it, I just put up with it, as it was not affecting the running of the car !…
Some time later I driving home, all of a sudden there was a loud screaming from the engine and the smell of burning rubber, pulled over and shut off the engine ?
The cam belt idler had seized solid !…… and was shredding the cam belt!…….
Replaced the idler and belt, all is well and finally the clicking noise has gone.

It must have been the idler all along, although I had tested the idler by listening to it with a stethoscope and it sounded fine?

Hope this helps

Steve.

 

cheers for that mate but ive changed that last night and checked thclutch disconnecting arm and the bloody noise is still there. flashpoint did you find that it only did the noise under acceleration or all the time ?

 

Hi mate,
The sharp clicking noise could not be heard at idle, and even when you reved the engine. it was very hard to tell if you could hear the noise or not!….
But once you were on the road (under load) there it was !….. When it first started I was convinced that it was piston slap, and I thought that I might have damaged one of the pistons (again)!….
The strange thing was it never made the noise from cold, if it had been piston slap it should of been at it’s worst at cold It was most annoying when driving normally Under light or hard throttle from 1500-3400 rpm as the revs went higher you seem to lose the noise? Most odd, it had me going for months before it gave it self away
When is you noise at it’s worst?

Hope this helps.

CheeRS

Steve.

 

i have the noise from cold and at idle and when its reved but its the same sort of tail off revs at about 3500 when i cant hear it any more.im thinking im just gonna change the block as ive got a couple spare as i heard today that it used to be quite common for the cvh block to crack internally between oilways ,its just one more thing to try i suppose.
thanks for your help i'll let you know how it goes

 

One thing you might try before striping the engine (if you have not already) is with the engine running
Is to disconnect the leads one at a time, this is to stop the combustion cycle in whichever lead you have
Disconnected, the engine will run like crap on just 3 cylinders but if the noise stops at least you would
Know it was connected with that cylinder, Big end, Little end, Piston , etc.
The best way to do this is to stop the engine disconnect one lead and restart the engine!…….
This way you minimise the risk of getting a shock !…….
Let me know how you get on.

Steve.

 

hi mate i tried that as soon as i got home this afternoon and i sorry to say but i had the noise the same each time i swapped leads its been doing my head in for about two months now.i might just change the end cap bolts this weekend as ive been told they can stretch sometimes and cause the end cap to move a little bit,ill keep you posted if it dont work im gonna do another block

 

flashpiont whats the complete spec of your rs mate

 

Well what the hell is it !…… you say that you have replaced all of the bearings
And looked at all the journals and they seem to be ok, well what ells can it be?
I suppose it could be low oil pressure,(12 psi I have seen lower) but we are clutching at straws now. What pressure do you get at 3500 rpm?
If it was that low the engine would of expired by now?
I think if the big end bolts/caps had become that lose the whole thing would of gone bang “end of story! …..”
You say that you have changed the head so that rules that out.
When you had the head off what did the boars look like?
Were there any scoring or bruising marks on the boars?
Other than that change the block!!….. But that is almost admitting defeat.

Let me know what you find out,good luck

CheeRS

Steve

P,S spec to follow

 

Have you checked that the gudgeon pins have not eaten up the their bores in the pistons?

 

i had the pistons out about six weeks ago there was no abnornal movement from the pins they are also only 3000 miles old.thanks anyway if you think of anything else please let me know

 

does it affect the performance of the car?

 

no it runs fine mate but the noise is quite loud and the oil preasure drops very low when it gets warmer. flashpoint the oil preasure at 3500 is around 30ish also the bores were fine no scores the rings were perfect and hardly any carbon build up ive now stripped my spare block ready for a new rebore to fit the pistons

 

Hi mate, 30 PSI that’s a bit on the low side, no my last engine I would worry if it dropped under 45 PSI on boost, sounds as you need the crank reground.
In past posts you said the crank looks fine? Do you know what clearance the bearings are running?
In the past I have had a lot of difficulty in getting the crank reground what I call correctly, as it would seem that some machine shops do what I call a shopping trolley regrind e.g. the clearance are slightly on the large side! They seem to do this, as some of their customers may not run in an engine as quite they should? Which could cause bearing failure at high rpm to soon
Another contributing factor is the bearings themselves are you sure you have the right bearings? This may sound a stupid question !…. but the original RST bearings are
Quite difficult to get hold of even from ford, in particular the main’s you normaly end up XR3i bearings. Which will work, don’t get me wrong, : but you seem to end up with lower oil pressure, as the bottom main shell as a slot machined around the centre of them and are aluminium over tin in construction the RST one’s don’t and are lead over copper in construction.
It might be worth seeing what clearance you are running on you crank

CheeRS

Steve.

let me know how you get on ?

 

hi mate the info you have is cool and very useful cheers. the problem is that every time i have checked the shells they are perfect i mean there are no score lines or any exessive rubbing marks but when i get my block boared i will get him to check the crank and regrind if needed the only other problem is the bloke who does it for me is 150 miles away but hes really good so ill shut up and travel.spare block is stripped and im half way there on the lump in the car ill keep you posted she should be alive again in about two weeks or so

 

block in the shop more info soon

 

my man measured the pistons and the skirks have been pushed in about 10 thou too much boost and AE pistons need mahle ones now

 

Hi mate, it sounds as if you have found the source of you noise, skirt collapse, I’ve not managed to do that in any of my cvh blowups! …. but I did do some thing similar to 1700 cc Kent engine I had in an XR2 some years ago when the water pump pulley broke off of the end of the water pump at high speed on the motor way , the engine suddenly locked up due to over heating! …..,the result was a distorted piston in number 4 , when the engine was running it mate a very strange sound like some one taping a spoon agents a coffee cup?
So hopefully it will not be to long before you are back on the road

Cheers.

Steve.

 

it will be back on the road pretty soon then to be sold as i have a new project lots of fun