Post rebuild clatter!

[TVR450s]

A question, has anyone experienced piston slap on a 4.6 chim? I refreshed mine, 2000 miles ago now 53000, new rings, bearings, cam etc and now @ 1200 rpm there is a 'clatter/slap'. I was convinced it was a cam/follower/rocker issue, but the noise is more audible from the bottom end. No noise on initial start and becomes apparent after aprox a minute.

[2 sMoKiN bArReLs]

Not the gasses escaping around the exhaust manifold?

[TVR450s]

Wish it was, its internal. My query is... piston slap usually occurs on a cold engine and improves when warm, this is opposite! maybe due to being a ally block+pistons?

[phazed]

Absolutely certain it's not piston slap!

[TVR450s]

I'm not 100% either. My initial thought was a characteristic of the new cam/followers. It sound like a bag full of followers in oil being jostled around. if you blip the throttle to 2000 rpm its only audible as the rpm drops through 1200-1100 and that's it.

[SILICONEKID343HP]

TVR450s said:

I'm not 100% either. My initial thought was a characteristic of the new cam/followers. It sound like a bag full of followers in oil being jostled around. if you blip the throttle to 2000 rpm its only audible as the rpm drops through 1200-1100 and that's it.

After a new Cam and followers on the old 4l I had the same problem .The ports where the lifters fit if that's the right word went oval due to ether poor oil or to long periods between oil changes .

It was like a clatter ,the engine did not sound right.

Try some Millers 20w60 oil.

[TVR450s]

Funny thing, Oil change was next on the list, I'm currently on Valvoline 20/50 I'll try the millers. 4 of the lobes of the old cam were less than 50 % so i guess the followers weren't rotating as they should, which would = uneven follower cavities. mmmmm i wonder?

[TVR Beaver]

TVR450s said:

It sound like a bag full of followers in oil being jostled around.

Read my description of a noise I had... 'like a bag full of ball bearings in oil being shuck up' I think I said....
Replaced the pistons and it's gone... small ends or so they say.... Will put the link up once I've found it


http://www.pistonheads.com/gassing/topic.asp?h=0&a...

and this

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

Edited by TVR Beaver on Thursday 12th September 08:10

[QBee]

I am using 10W60 oil in the summer (track days) and 5 W 40 in the winter. Am puzzled as to why there is so much variation between TVR owners?

[macdeb]

TVR450s said:

Funny thing, Oil change was next on the list, I'm currently on Valvoline 20/50 I'll try the millers. 4 of the lobes of the old cam were less than 50 % so i guess the followers weren't rotating as they should, which would = uneven follower cavities. mmmmm i wonder?

I doubt very much if different oil will cure it. Did you manage to get the correct preload over all valves? It was the cause of my 2nd Griff making same noise due to differing valve heights. Some have had little end problems too. Keep us posted.

[SILICONEKID343HP]

QBee said:

I am using 10W60 oil in the summer (track days) and 5 W 40 in the winter. Am puzzled as to why there is so much variation between TVR owners?

Engine tolerances are exactly the same as the 1961 Buick Skylark .

http://en.wikipedia.org/wiki/Buick_Skylark#Engines


That's why I use thick oil .

[Pupp]

SILICONEKID343HP said:

Engine tolerances are exactly the same as the 1961 Buick Skylark .

http://en.wikipedia.org/wiki/Buick_Skylark#Engines

That's why I use thick oil .

The basic architecture of the engine may be similar and the lineage directly traceable, but you're living in cloud cuckoo land if you think a late 4.6 was made to the same tolerences as a 61 Buick. There will be innumerable differences in detail design, dimensions, materials/matallurgy, and, yes, machining tolerences. And your choice of oil is not 'thicker', it just pours less readily at colder temperatures than a 5w50 (say). If you really think your engine needs 'thick' oil, try running a monograde 50 or 60 and be sure to post up the results

[SILICONEKID343HP]

Pupp said:

The basic architecture of the engine may be similar and the lineage directly traceable, but you're living in cloud cuckoo land if you think a late 4.6 was made to the same tolerences as a 61 Buick. There will be innumerable differences in detail design, dimensions, materials/matallurgy, and, yes, machining tolerences. And your choice of oil is not 'thicker', it just pours less readily at colder temperatures than a 5w50 (say). If you really think your engine needs 'thick' oil, try running a monograde 50 or 60 and be sure to post up the results

Its still an ancient V8 lump needing a lot of CC to generate little power, nothing like modern engines

[Pupp]

SILICONEKID343HP said:

Its still an ancient V8 lump needing a lot of CC to generate little power, nothing like modern engines

Which has precisely what to do with the twaddle you were spouting earlier?

[SILICONEKID343HP]

It`s not twoddle .. basicly the same engine. The 3.5 made 190bhp in 1961 so not to different to the 4l with fuel injection .

[Sardonicus]

SILICONEKID343HP said:

It`s not twoddle .. basicly the same engine. The 3.5 made 190bhp in 1961 so not to different to the 4l with fuel injection .

Daz you would be lucky if the original 3.5 made 120 let alone the claimed 190 for the EFI 3.9 version much later on you need to

[QBee]

Never mind - I'll do my own oil research.

[Chilliman]

Sardonicus said:

SILICONEKID343HP said:

It`s not twoddle .. basicly the same engine. The 3.5 made 190bhp in 1961 so not to different to the 4l with fuel injection .

Daz you would be lucky if the original 3.5 made 120 let alone the claimed 190 for the EFI 3.9 version much later on you need to

To be fair, my BGT V8 made 138bhp at the fly This was on the same rollers that I put beastie on. It was a boggo 3.5 factory car (twin SU's) apart from K&N filters and electronic ignition Oh, it was a '74, last of the chrome bumper cars

I bloody loved that car

[SILICONEKID343HP]

Chilliman said:

To be fair, my BGT V8 made 138bhp at the fly This was on the same rollers that I put beastie on. It was a boggo 3.5 factory car (twin SU's) apart from K&N filters and electronic ignition Oh, it was a '74, last of the chrome bumper cars

I bloody loved that car

Yes and the MBGT 3.5 is a low comp engine because of the stress on the GT chassis.

[Pupp]

And even that iteration of the engine was cast, machined and assembled in Britain; not Detroit. Using entirely different tooling