450 V8 "flabby"!
Discussion
Well, can't find anything relevant to my symptoms on here so I'll try describing it.
Everything's been running just fine until yesterday when I now get some/all of the following symptoms:
- the engine is now more difficult to start: now it needs a little more cranking and you can hear it catch a couple of times before starting proper. Makes no difference if hot or cold.
- the engine is MUCH more lumpy when at low revs. Idle seems just fine, but now when pootling around town you can almost feel every power pulse, the gear lever shakes around a heck of a lot more and all the smoothness is gone.
- the engine now sounds different too: sounds more "airy" when it used to be "tight". Difficult to describe.
- I'm sure that the pickup from low revs is much worse, throttle response is sluggish.
- The power band in this engine has always been from around 2500rpm - this seems to have shifted to from 4000rpm (see last point). From then, throttle response is (maybe nearly) normal.
- Don't know if it's related, but there's been a faint whistling sound, the pitch is matched to engine revs, for maybe a month now.
Help!
Jonathan
Everything's been running just fine until yesterday when I now get some/all of the following symptoms:
- the engine is now more difficult to start: now it needs a little more cranking and you can hear it catch a couple of times before starting proper. Makes no difference if hot or cold.
- the engine is MUCH more lumpy when at low revs. Idle seems just fine, but now when pootling around town you can almost feel every power pulse, the gear lever shakes around a heck of a lot more and all the smoothness is gone.
- the engine now sounds different too: sounds more "airy" when it used to be "tight". Difficult to describe.
- I'm sure that the pickup from low revs is much worse, throttle response is sluggish.
- The power band in this engine has always been from around 2500rpm - this seems to have shifted to from 4000rpm (see last point). From then, throttle response is (maybe nearly) normal.
- Don't know if it's related, but there's been a faint whistling sound, the pitch is matched to engine revs, for maybe a month now.
Help!
Jonathan
jtong said:
......
Bizarre thing is that the roughness has improved slightly with no intervention from me. Is there any possibility it was a dodgy batch of fuel?
Could be, had a rough lot of fuel on the way back from Le Mans last year and to say I was worried is an understatement.
Harry
Well, just had a depressing phone call with my indie and they're pretty certain that it's a worn camshaft. It seems "normal" that they wear faster around the back owing to poor oil flow.
The HT leads and extensions were changed which helped a little but didn't cure the problem.
Sounds plausable?
The HT leads and extensions were changed which helped a little but didn't cure the problem.
Sounds plausable?
Possibly, but it seems strange that all was fine at the last service then now (proberly not many miles further on) the cam has worn to such an extent that the difference is noticable?
It seems as there would be a different problem causing the rough running - but you have a worn (ish) cam anyway. I feel that perhaps when the cam is changed you may still the problems but to a lesser extent.
I'm no expert though. I had similar problems a while ago and turned out to be the injectors were dribling when the car was left standing. I had the leads changed, service, new injectors and a new fuel pump - the car now runs so smoooth and always starts first time.
Perhaps you could speak to another expert to get a second opinion. I used Horizon Motorsport, the owner Mike who is an ex- tuscan race engineer is always very helpfull and knowledgeable his no. is 01384 566660
It seems as there would be a different problem causing the rough running - but you have a worn (ish) cam anyway. I feel that perhaps when the cam is changed you may still the problems but to a lesser extent.
I'm no expert though. I had similar problems a while ago and turned out to be the injectors were dribling when the car was left standing. I had the leads changed, service, new injectors and a new fuel pump - the car now runs so smoooth and always starts first time.
Perhaps you could speak to another expert to get a second opinion. I used Horizon Motorsport, the owner Mike who is an ex- tuscan race engineer is always very helpfull and knowledgeable his no. is 01384 566660
Your profile indicates a 99 Chim with 31K same owner - New camshaft "sir"...........Don't know (obviously) how your drive your Chim, but 4/5-yrs, 31K, regularily Dealer serviced with Fully Synth oil, I would not expect the cam shaft to need replacing.
I would be seriously upset if that was the "real" problem.
My money would be on injectors, ignition, ECU/Lambda set-up and gummed up Plenum Chamber/Air meter before pulling the cam out.
Keep smiling
Trev McM
I would be seriously upset if that was the "real" problem.
My money would be on injectors, ignition, ECU/Lambda set-up and gummed up Plenum Chamber/Air meter before pulling the cam out.
Keep smiling
Trev McM
Second what K4TRV said. Forgot to mention i had the ignition module changed as well.
The point Trev makes about the ago of the car seems the most logical mine is a 93 with 60,000 miles on the original cam which when inspected while the rocker covers were being done was wearing but didn't need changing.
Lee
The point Trev makes about the ago of the car seems the most logical mine is a 93 with 60,000 miles on the original cam which when inspected while the rocker covers were being done was wearing but didn't need changing.
Lee
UIL9794 said:
Second what K4TRV said. Forgot to mention i had the ignition module changed as well.
The point Trev makes about the ago of the car seems the most logical mine is a 93 with 60,000 miles on the original cam which when inspected while the rocker covers were being done was wearing but didn't need changing.
Lee
Hi Lee, Likewise and mine's a "K" as well with almost the same mileage as yours. These V8 lumps can cope with all sort of mechanical mayhem (potential for 150/200K miles), but the supporting "stuff(electronics)" makes for a sorry engine when they are playing up!!
JTong - Don't let them change a Cam just to see !!! Check all the other avenues first. Sorry, I'll get off my hobby-horse !!
Cheers Lee and happy motoring.
Trev McM
Well, the implication on the phone and from some postings here is that it is not uncommon for camshafts to go so soon (seemingly). They're gonna take the valley gasket off and take a look. If it's not that then we'll have to come to some agreement over unnecessary work otherwise I'll have to start shouting.
FWIW we're almost six months and maybe 3000miles after a service. I could genuinely convince myself that I've been losing power (don't we all!) over the last random time period. Since moving house I'm putting more shorter (<10miles) journeys onto the car.
Not really grinning, more like grimacing.
>> Edited by jtong on Wednesday 3rd March 17:54
FWIW we're almost six months and maybe 3000miles after a service. I could genuinely convince myself that I've been losing power (don't we all!) over the last random time period. Since moving house I'm putting more shorter (<10miles) journeys onto the car.
Not really grinning, more like grimacing.
>> Edited by jtong on Wednesday 3rd March 17:54
3K after a service is along time IMHO and plenty of time for a cam lobe to wear. It is not unknown for some people to drive on 7 cylinders and not notice before now 
.
As has already been said the cam can last 25K or 60K
, pays your money and takes your chance.
The actual wear from being partially worn to fully worn (No7 is a favourite apparently), can happen fairly quickly once the hardened surface has gone on a lobe.
Harry
. As has already been said the cam can last 25K or 60K
, pays your money and takes your chance. The actual wear from being partially worn to fully worn (No7 is a favourite apparently), can happen fairly quickly once the hardened surface has gone on a lobe.
Harry
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