Low RON and Engine Noises
Discussion
Hello,
Quick question, I had to put in some 95RON petrol the other day as I was running on fumes and no Optimax in sight. Only put a tenners worth in to get me home. Ran the car this morning and seemed to have developed an extra engine noise at low revs, a kind of knocking tapping, although its a quiet noise, was wondering if using 95RON petrol could cause this?
Cheers
Simon
Quick question, I had to put in some 95RON petrol the other day as I was running on fumes and no Optimax in sight. Only put a tenners worth in to get me home. Ran the car this morning and seemed to have developed an extra engine noise at low revs, a kind of knocking tapping, although its a quiet noise, was wondering if using 95RON petrol could cause this?
Cheers
Simon
jonathant said:
Hmmm. I've (on my 99 Chim) recently developed (or more likely noticed) a knocking noise ONLY at idle with no load. The garage thinks it's camshaft slap but needs to open Trev up to confirm.
Sounds like you're knocking on the car window.
Hmm, camshaft slap? I'm no expert but I'd suspect little ends or some tappet related issue. The camshaft should be held in place by the chain drive and a thrust button (or cam retaining plate).
Ian A.
I hope its not the cam as that was only replaced about 6000 miles ago. I do have a knocking noise at low revs already, which the garage said is the rocker covers?? nothing to worry about aparantly.
But I think your right, picking up on that noise even more maybe as I put 95RON in.
Thanks for the replys.
But I think your right, picking up on that noise even more maybe as I put 95RON in.
Thanks for the replys.
fazz81 said:
I do have a knocking noise at low revs already, which the garage said is the rocker covers??
The rocker covers are bolted to the heads. Unless they are loose (in which case you would have oil EVERYWHERE), I fail to see how they can make a knocking noise.
It's more likely to be the metal plate on the rockers themselves, in which case it is something that needs addressing as the underlying aluminium is very soft in comparison.
Who is this "garage", and are you sure they know what they're talking about?
Ian A.
IPAddis said:
I do have a knocking noise at low revs already, which the garage said is the rocker covers??
The rocker covers are bolted to the heads. Unless they are loose (in which case you would have oil EVERYWHERE), I fail to see how they can make a knocking noise.
It's more likely to be the metal plate on the rockers themselves, in which case it is something that needs addressing as the underlying aluminium is very soft in comparison.
Who is this "garage", and are you sure they know what they're talking about?
Ian A.
The garage is a respectable TVR dealer, not sure if i'm allowed to give name, but have been very happy with them so far.
Now I may get this all wrong, but bear with me
They showed me another Griff engine that they had in bits, if I remeber correctly the rocker covers have a pole running through the middle of them, and I was told this can be ever so slightly loose causing the rocker cover to tap against it??
So is that the metal plate i'm talking about? I was told it was nothing to worry about, but could this cause wear on the aluminium underneath?
Engine is clean, no sight of oil.
Thanks
Simon
fazz81 said:
The garage is a respectable TVR dealer, not sure if i'm allowed to give name, but have been very happy with them so far.
Now I may get this all wrong, but bear with me
They showed me another Griff engine that they had in bits, if I remeber correctly the rocker covers have a pole running through the middle of them, and I was told this can be ever so slightly loose causing the rocker cover to tap against it??
So is that the metal plate i'm talking about? I was told it was nothing to worry about, but could this cause wear on the aluminium underneath?
Engine is clean, no sight of oil.
Thanks
Simon
Fair enough, I stand corrected. I only ask because some people use local garages where the mechanic MAY not be used to dealing with TVRs.
There's a plate (I think it's for oil control) that runs through the rocker cover. I suppose it's possible that could be loose. I would have thought it would have to be pretty loose to be audible from inside the car though.
Ian A.
IPAddis said:
Hmm, camshaft slap? I'm no expert but I'd suspect little ends or some tappet related issue. The camshaft should be held in place by the chain drive and a thrust button (or cam retaining plate).
Well I'm defo no expert but Trev had three mechanics over and under him for a quarter of an hour. One of them thought it was big/little end but apparently the knocking then gets worse under load.
They also described that the camshaft is only held in place by the chain drive - apparently there is no bracket or whatever.
>> Edited by jonathant on Monday 3rd October 16:58
IPAddis said:
The garage is a respectable TVR dealer, not sure if i'm allowed to give name, but have been very happy with them so far.
Now I may get this all wrong, but bear with me
They showed me another Griff engine that they had in bits, if I remeber correctly the rocker covers have a pole running through the middle of them, and I was told this can be ever so slightly loose causing the rocker cover to tap against it??
So is that the metal plate i'm talking about? I was told it was nothing to worry about, but could this cause wear on the aluminium underneath?
Engine is clean, no sight of oil.
Thanks
Simon
Fair enough, I stand corrected. I only ask because some people use local garages where the mechanic MAY not be used to dealing with TVRs.
There's a plate (I think it's for oil control) that runs through the rocker cover. I suppose it's possible that could be loose. I would have thought it would have to be pretty loose to be audible from inside the car though.
Ian A.
No, was worth checking, I know what you mean, some dodgy mechanics about.
I'm not clued up enough to argue with the mechanics, just have to take there word for it. I will ask them if they are sure next service though.
Thanks
Simon
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