Engine knocking..

[KillerJim]

Hi,

Can someone describe what knocking sounds like on the speed six?

J

[Gaffer]

Candy was knocking from the top end - cue major panic from me.

Got it up to TorqueRVT - its just the tappets that needed doing.

Sometimes knocking doesnt mean the death sentence.

Claire

[J_S_G]

Gaffer said:

Candy was knocking from the top end - cue major panic from me.

Got it up to TorqueRVT - its just the tappets that needed doing.

Sometimes knocking doesnt mean the death sentence.

Claire

Are we talking loud tap, real "knock", or more of a clatter/rattle? All the time? Under load? At what revs? Altering with revs? (or road speed?) More when cold, or just as bad when warm? Car age/mileage?

Diagnosis-by-forum is probably the best way of getting 101 different, random thoughts, most of which will scare you. If the engine sound has changed noticeably, call the AA/RAC and get it trailered to an expert. When you say to them "the engine's rattling, the garage says don't start it or drive it" they tend to listen.

Good luck - it'll either be needless panic or an opportunity to upgrade...

[KillerJim]

Hi,

I`ve no idea what knocking sounds like but I notice a sound (fairly loud) when the under load when very hot (i.e. sitting in traffic for a while) - sounds like a shuddering rasping sound, mid frequency. Stops immediately I take my foot off the pedal and only under load.

The only other time I`ve heard it is when the car was stalled (at lights) and I started her and drove off under load.

Doesn`t happen when driving around normally or when the engine is cooler.. all fluids have been checked.

J

Edited by KillerJim on Monday 5th January 11:31

[Pharoah]

Have the engine mounts been changed on it yet? They make a noise if one / both has broken and they seem to go after about 3 years.......

[Gaffer]

When was it last serviced..?
How many miles has it done..?

Could also be the exhaust (mine was slightly loose) or one of the chassis plates just vibrating.

Edited by Gaffer on Monday 5th January 12:07

[TVR_owner]

KillerJim said:

Hi,

I`ve no idea what knocking sounds like but I notice a sound (fairly loud) when the under load when very hot (i.e. sitting in traffic for a while) - sounds like a shuddering rasping sound, mid frequency. Stops immediately I take my foot off the pedal and only under load.

The only other time I`ve heard it is when the car was stalled (at lights) and I started her and drove off under load.

Doesn`t happen when driving around normally or when the engine is cooler.. all fluids have been checked.

J

Edited by KillerJim on Monday 5th January 11:31

It sounds like it's pinking.

I would try a shot of octane booster in the fuel. That should cure pinking caused by sub-standard fuel, or if its low on juice, fill here up with Optimax.

[KillerJim]

Thanks for the replies..

Last service was less than 1,000 miles ago - full 12k service (aka tappets) with ~16k on the clock. The exhaust has been checked recently and the sound comes from the engine - i`ll check the mounts tonight, probably a good idea anyway

I did put some normal petrol in it (emergency on Christmas day when I couldn`t find a service station that did 97 Oct) but thought that would be through her given the two top-up's done since that.. (maybe not..)

Hopefully that is all the sound is, the pinging of the engine as the fuel was 95 oct. I`ve just no idea what pinging sounds like

J

[TVR_owner]

KillerJim said:

I`ve just no idea what pinging sounds like

J

Pretty much as you described. The heat build-up in traffic would be a cause, the post-stall thing also. Certainly the instand laod removal leading to the noise going sounds right too....

The cause, if its fuel, is an easy one to resolve. It may however be something more worrying. Octane booster with some good fuel should certainly stop the pinking and ensure that any poor fuel is "converted"

[Gaffer]

Candy hates a change of fuel - had to use BP Ultimate a few weeks back - that started my engine knocking - put through 4/5 tanks of VPower and had a good "motorway run" and its reduced the noise.

Ian @ TorqueRVT also put in some cleaner / booster and I did another tank, tappets are needing doing (didnt have time) but a quick set up on the laptop helped (also found that the 1 Lambda sensor was fubared so changed that as well).

Almost back to normal now.

Claire

[J_S_G]

TVR_owner said:

KillerJim said:

I`ve just no idea what pinging sounds like

J

Pretty much as you described. The heat build-up in traffic would be a cause, the post-stall thing also. Certainly the instand laod removal leading to the noise going sounds right too....

The cause, if its fuel, is an easy one to resolve. It may however be something more worrying. Octane booster with some good fuel should certainly stop the pinking and ensure that any poor fuel is "converted"

Got my vote as the first thing to try... unless you're a nervous soul with a trusted garage nearby, in which case that's always the safest option.

If you filled up at a petrol station that's out of the way/particularly quiet and likely to have their fuel sitting around there for a prolonged period going "off" (so to speak!) then it's even more likely to be that. Got a bad tank myself in the Audi a few months back, so not unheard of by a long stretch...