cam rattle on over run info required plz

[v8 racing]

I think i have found the on going saga of the cam rattle noise on over run, what i am realy in need of is to find someone who has the noise on another engine other than the tvr 5 ltr to outrule the possibility of what i think it is thanks

[Paul V]

Had a interesting chat with the guy’s at V8 developments last weekend, they were saying that a certain type of high rev lifter can cause a rattle on over run as they let to much oil out as they are only designed for race use. Is it possible your car could of have had different lifters fitted previously?

[Guillotine]

Hi rob

you almost certainly know this, but...

the only time i heard this, it was the lifter pre-load.
only tapped at around 3 - 2k as the revs died.
(this was on on a std 500)

cheers

andy

BTW the 4.6 got some reasonable money in the end.

[v8 racing]

Hi Andy
Yeh the engine made good engine the guy who won the auction came round sat so i could take him up the road in it, lets just say he had a rather large smile!! the cam rattle is very common on these tvr,s there was a massive thread on it and nobody including myself got anywhere on the subject untill today.....

[Paul V]

Quinny said:

Hi Paul, Just so you know V8 Racing is Rob from V8 Developments.

Oh, well he might have forgotten, it was a week ago

[IPAddis]

Rob,

I'm VERY interested in the latest diagnosis. Just FYI, my car has started making the noises again despite the cam retaining place and complete top end rebuild (including the valve springs). It's since done 5,000 miles. I'm hoping new oil will quiten it down a bit.

I've heard someone mention that Rhodes lifters make a racket at low revs because they bleed down creating some slack. What hi-rev lifters do you usually fit?

It still pulls like a train though so no problems on the performance front.

Regards,

Ian A.

[johno]

V8D have recently rebuilt mine and I get a load of noise as the car returns down to idle.

For example sitting at idle, blip the throttle and as the revs drop back to normal the top end seems to take some time to settle .... almost like they are working their way back down, sounds like gravel being wshed up and down on the beach !

Doesn't seem to affect it though and it had always done it, the top end was rebuilt.

[stesrg]

macdeb said:

Been trying to solve this for some time. Think I may have it sussed but intersested on your thoughts/theory. To cut it short. Got MC1 cam and pump up lifters from yourselves complete with timing chain/gears etc. When fitting retaining plate was in place. Did my best to get preload correct with pedestal shim kit, but still not all within the tolerance required so went for best average. However, did notice this time that the valve heights were not all level differring some 2-3 mm overall. So, this leads me to conclude that because of this, it's seems impossible to get preload correct which may be the cause of the rattle on overrun. [Please feel free to tell me if this is complete bollox] My next step was to be either; have the heads off and the valves re-seated or fit adjustable push rods in order to get correct preload set individually. NOTE; I had previously reset preload which did quiten it down a bit [to the best average over the head] PS. Revs a lot smoother with MC1 cam [ta]

Hi macdeb i went for the high rev lifters but i used the adjustable push rods, then i made a tool for setting the pre load on each one this was very bad on my back but well worth it tollerence within 5 tho no problems so far......

Steve....





>> Edited by stesrg on Tuesday 5th October 16:02

[pete]

I also have the dreaded "rattle on overrun" on my 42,000 mile '97 500.

I thought it was a worn cam for ages, but a session on the rolling road showed it to be producing about the right power (275bhp, 300lb.ft), and not to have any nasty flatspots, so it can't be that serious. It's been doing it for 30,000 miles with no apparent ill effects...

Pete

[groucho]

Yes, mines had it for as long as I've had the car but you have to listen really hard to hear it. Sometimes I wonder that if you listen hard enough you'll find a noise that isn't really there.
Oh dear I'm going off on one, what I'm trying to say is that you can get over paranoid about things as I do.

BTW mine's a 1998 Griff 500 with 17000 on the clock.

Grouch.


>> Edited by groucho on Tuesday 5th October 18:06

[v8 racing]

Well my honest opinion is that it has nothing to do with the valve train what so ever, i am probably going to make myself look a fool her but thats nothing new! i think it is wear between the piston gudgeon pin and the piston itself, i have just spent the last 3 days trying to solve this problem and because it has been a problem for so long i didnt just do the usual swap everything in one go, the cam/spacer/followers/rockerarms etc... were all done individualy end result the noise was still there!!, the 500 tiv is the only engine to use there own rods and with such a sevre rod angle it is trying to push the piston into the side of the cylinder wall as opposed to pushing the piston up, after building these engines for twenty years it has only ever occured on the 5 ltr tiv..........?? when you back off the throttle it basicaly allows the piston to just float the throtle is shut so no air getting in to load the cylinder, normaly a rattle in this area is down to little end on the rod but i realy beleive it is the piston instead..................

[Apache]

Should I be getting paranoid mate? this is exactly the problem I had with mine when I first approached you guys.

did you get my email btw?

[IPAddis]

Shaun did originally say mine sounded like a little end problem. Would the 5.2 and 5.3 engines have the same problem (presumably the same con rod angles) or are they fitted with better rods?

If your diagnosis is correct, what is the implication in terms of wear and future reliability?

Ian A.

[budgetgriff]

Hi all,

I am very interested in this outcome too! I tried a lot of investigation about 6 months ago and came out with nothing other than a sore head.

Can only add that mine makes exactly the noise you describe. In a desperate bid to achieve something I tried some valve gear treatment in the oil and it "seemed" to make matters worse. In a second desperate bid I added some oil treatment, molyslip i think, which "seemed" to quieten things a little.

Could all be in my mind of course and it could therefore be something other than valve gear noise.

Good luck with the investigations.

[budgetgriff]

Rob,

If this "noise" is bottom end related then how come Ian Addis' car has a delayed reoccurance of the noise after top end rebuilds? Surely if you only rebuild the top end the "noise" would be apparant from straight after the rebuild, not several thousand miles later?

Apologies if I am wrong and Ians car did have a more thorough rebuild.

Thanks.

[IPAddis]

I was thinking that. My noise does seem to get better when the cam is replaced, but then the oil is replaced at the same time and even slightly worn oil makes a big difference to the volume of the noise.

Ian A.

[shadowfax]

Somewhat reassuring to find this thread after searching for "engine rattle".

Upon returning home from gorgeous 200 mile drive after buying in South Wales yesterday, the 500 with 40k on it, standard all over, presented me with a not mildly disconcerting


"tlidldttltdlddldit" ( it has a definite rhythm, with 7 to 9 syllables),

when I reversed up the path, as the revs dropped to 2thouon the overrun. Not heard when viewed or on the drive yesterday.

Good Lord! Just paid £13360 for one with a big end that's about to go, methinks. And it's there this morning, too.

Sounds like a ball bearing loose in the block or sump, but it's a consistent sound, so it's a fixed item that sounds, well, loose.

Reading the above, it seems it's not uncommon. But IS it the same sound?

Awaiting replies from emails to local owners after midnight.....Need to have it heard, chaps, please

>> Edited by shadowfax on Sunday 26th June 09:55

[stesrg]

Hmm having done a few thousand miles since my last post,fitting these rhodes liffters my word do the rattle on overrun, must say a sweet as a nut and very quite on Idle, as there are so many different sounds which come from engines I suggest you take it to your nearest TVR dealer.
Ste...

[shadowfax]

Ste - will ask those in the know at the Blackpool meet on wednesday, which I hope to get to. It'll be my first tvrcc meeting. Shifting like a goodun today was Mr Griff, rattle there occasionally, but this car is just full of urgency and wants it's head all the while. Different world in a Griffith.

Mind you, my mate took a gentle curve to the right whilst keeping a camaro or trans am at bay at something a bit rapid, I feared we were about to twist and fly. Is that summat the Griff is known for?! Could do with lowering the suspension, perhaps. Or maybe tell my mate to stick to riding bikes. He thought the Griff was front wheel drive

>> Edited by shadowfax on Sunday 26th June 18:24

[apache]

shadowfax said:

Mind you, my mate took a gentle curve to the right whilst keeping a camaro or trans am at bay at something a bit rapid, I feared we were about to twist and fly. Is that summat the Griff is known for?!

absolutely not! something is amiss there, ours was rock solid on sweeping bends even with a few ruts and dips thrown