My engine's tappy, anyone else fitted a BP270 camshaft?

My engine's tappy, anyone else fitted a BP270 camshaft?

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Kitchski

Original Poster:

6,514 posts

230 months

Tuesday 23rd June 2015
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So since I got the S1 back on the road, I've noticed the 2.8 engine is on the tappy side. It runs fine, pulls fine....seems fine. But it's noisy. My plan is to delve deeper over the upcoming winter, but on the phone to a well-respected engine builder the other day it popped up in conversation. As soon as I said I'd fitted a Piper BP270 camshaft to the Cologne, he said that's the issue as they're noisy cams due to the way they drop-off lift. Admittedly, the noise isn't actually tappets (checked them and they're fine) and when fitting the cam it also had matching springs, new lifters etc and was bedded in correctly. It's just this noise!
I've also fitted a solid alloy timing gear, but was assured these are no noisier than the originals, and that it's the steel ones that don't sound great. Oil flow to the head is good (heads were dip-cleaned and rebuilt) and the engine's only done 68k miles.

Wondered if anyone else in the 2.8 world had been down this road before I go ripping the cam out to put a standard one back in (the BP270 gave no power gains, incidentally).

Cheers

phillpot

17,105 posts

182 months

Tuesday 23rd June 2015
quotequote all
Got a piper 270 in my 2.9, tiz a bit rattly!


recommended valve clearances are 2 thou more than standard, I've got mine at 2 thou less which helps a bit.

Just out of interest was yours a re-grind or from a new blank?

I guess big manufacturers put hundreds of hours into designing cam profiles to get a balance of performance, economy, driveability and acceptable noise levels? to improve on one is probably to the determent of another? Bit more power = bit more noise, bit less economy scratchchin


I thought it should give you a bit more ummph over standard? mine came out at 184.9BHP on Austec's rolling road (TVR claimed about 175 I think for the 2.9). This goes along with Pipers claim of about 10/12 BHP gain I think?
First impressions when I drove were that it does feel as if it is "breathing better", with a bit more go at higher revs. Is that a wider power band/ more torque, I don't know!

Kitchski

Original Poster:

6,514 posts

230 months

Tuesday 23rd June 2015
quotequote all
phillpot said:
Got a piper 270 in my 2.9, tiz a bit rattly!


recommended valve clearances are 2 thou more than standard, I've got mine at 2 thou less which helps a bit.

Just out of interest was yours a re-grind or from a new blank?

I guess big manufacturers put hundreds of hours into designing cam profiles to get a balance of performance, economy, driveability and acceptable noise levels? to improve on one is probably to the determent of another? Bit more power = bit more noise, bit less economy scratchchin


I thought it should give you a bit more ummph over standard? mine came out at 184.9BHP on Austec's rolling road (TVR claimed about 175 I think for the 2.9). This goes along with Pipers claim of about 10/12 BHP gain I think?
First impressions when I drove were that it does feel as if it is "breathing better", with a bit more go at higher revs. Is that a wider power band/ more torque, I don't know!
The valve clearances should be the same though, surely? The lifter needs to follow the profile of the cam lobe what ever that profile might be. Could be wrong, though Piper never sent me any gumph with the cam, just lube and a timing wheel that doesn't fit the 2.8!

The 2.8 is a pain to get more grunt from due to the heads. It's possible, but a cam won't do it, especially a mild one. Problem is I fitted the cam amongst a load of other work, so I can't say for sure it was fine before it was fitted, especially given the exhaust manifolds used to leak something rotten!

phillpot

17,105 posts

182 months

Tuesday 23rd June 2015
quotequote all
Kitchski said:
The valve clearances should be the same though, surely?
I'm no expert on cam design (or much else come to think of it) but many "hot cams" will come with their own specified clearances for whatever reasons.

v8s4me

7,234 posts

218 months

Tuesday 23rd June 2015
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I think it is something to do with controlling the point the valve opens. "Hot" cams don't necessarily open the valve further but they do hold it open for longer and they modify the over-lap ie the difference in time when one valve opens and another one shuts, and the brief period of time when they are both open.

Have a look here for the technical explanation.

http://www.compcams.com/Pages/416/valve-timing-tut...

It's a very interesting subject and there is loads of other stuff on the Web as you would expect. Variable Valve Technology (VVT), was developed to allow engines to run efficiently at low revs but change the valve timing to something "hotter" at higher revs to allow the engine to breathe more efficiently and so deliver more power.



Edited by v8s4me on Wednesday 24th June 00:04

Kitchski

Original Poster:

6,514 posts

230 months

Wednesday 24th June 2015
quotequote all
phillpot said:
I'm no expert on cam design (or much else come to think of it) but many "hot cams" will come with their own specified clearances for whatever reasons.
I've emailed Piper to find out. I had to reset the clearances once I'd fitted the cam of course, but assumed the clearances themselves would be the same. The noise doesn't sound like tappets so much - similar, but concentrated around the cam area. Ruins the car, to be honest - it drowns everything else out, even the exhaust as the cabin amplifies it!

Kitchski

Original Poster:

6,514 posts

230 months

Wednesday 24th June 2015
quotequote all
v8s4me said:
I think it is something to do with controlling the point the valve opens. "Hot" cams don't necessarily open the valve further but they do hold it open for longer and they modify the over-lap ie the difference in time when one valve opens and another one shuts, and the brief period of time when they are both open.


Edited by v8s4me on Wednesday 24th June 00:04
This cam has a slightly more aggressive lift but not a particularly extended duration, which apparently is the reason it's noisy. Struggling to figure out why that might be at the moment, unless the BCD is greater than the ramp of the lobe as it's coming on and off lift. That might create a dead spot where the lifter could be allowed to rattle a bit, but that's all I can come up with. Engines aren't our speciality!

v8s4me

7,234 posts

218 months

Wednesday 24th June 2015
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I think you might have answered the question in your first post ie

Kitchski said:
... he said that's the issue as they're noisy cams due to the way they drop-off lift. ...
So might the sound you're hearing be the valves slamming back onto the seats as the cam closes them more quickly than the standard unit?

Le TVR

3,092 posts

250 months

Thursday 25th June 2015
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The 2.8 was never a quiet engine due to the solid lifters. Apparently the fibre timing gear actually makes it quieter. Just going to a steel or alloy timing gears will make it a lot noisier. Then add an agressive cam too and I can imagine it is LOUD!

Top Gear TVR

2,244 posts

153 months

Thursday 25th June 2015
quotequote all
Mine's a 2.9 but if i set the clearances correctly and get a quiet engine it runs like a dog. Open them up 2 thou' and its loads better if a tad tappety.

My grandad (triumph man) always always left a thou' or two extra, much preferring a shut valve to one thats just a bit open, leaking, burning or getting nasty deposits on it.

I don't think he was wrong.

Kitchski

Original Poster:

6,514 posts

230 months

Monday 29th June 2015
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v8s4me said:
So might the sound you're hearing be the valves slamming back onto the seats as the cam closes them more quickly than the standard unit?
I possibly have, but I was really hoping to find someone running the same cam in the same engine, so I can actually hear the difference.

Kitchski

Original Poster:

6,514 posts

230 months

Monday 29th June 2015
quotequote all
Le TVR said:
The 2.8 was never a quiet engine due to the solid lifters. Apparently the fibre timing gear actually makes it quieter. Just going to a steel or alloy timing gears will make it a lot noisier. Then add an agressive cam too and I can imagine it is LOUD!
Hi Pete (it's Rich!)

It's true, the 2.8 was never a smooth lump. That said, yours sounded 100 times smoother before I pulled it out, and we know what sort of mileage you've got! The steel timing gears create a whining sound, but I'm told the alloy ones make no extra noise over the fibre unit. The cam isn't aggressive at all; it's pretty mild in fact, but it was the chap I sent your engine to who has sowed the seeds of doubt.

Kitchski

Original Poster:

6,514 posts

230 months

Monday 29th June 2015
quotequote all
Top Gear TVR said:
Mine's a 2.9 but if i set the clearances correctly and get a quiet engine it runs like a dog. Open them up 2 thou' and its loads better if a tad tappety.

My grandad (triumph man) always always left a thou' or two extra, much preferring a shut valve to one thats just a bit open, leaking, burning or getting nasty deposits on it.

I don't think he was wrong.
That's completely true, better a tappy tappet than a burnt valve. I've got a clatter at the moment, I'd be happy to downgrade to a tap hehe

Kitchski

Original Poster:

6,514 posts

230 months

Thursday 2nd July 2015
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Further research is pointing towards it being more likely that the alloy timing gear is to blame, but seeing as it's effectively an engine out job to change it (because I'd need to change the crankshaft gear too) it looks like I'll need to book some time to do that. Question is, do I wait and do it over the winter, and just endure the noise til then, or crack on and get it done?

Hmmmm. A decision I didn't want to have to make! scratchchin

glenrobbo

35,083 posts

149 months

Thursday 2nd July 2015
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Richard,
You could wear ear defenders until winter wink

Kitchski

Original Poster:

6,514 posts

230 months

Thursday 2nd July 2015
quotequote all
Well you joke.....

Supposed to be going to Millbrook in it this month too (the proving ground, not the dodgey area in Southampton). I'll probably just grin and bare it. Probably keep it on the road until late August and have a look then. Oh, and sort out the droopy doors (second attempt on driver's door). And the oil breather system. And the rattly dashboard. And the heater blower fan. And the.......

phillpot

17,105 posts

182 months

Thursday 2nd July 2015
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confused the metal timing gear on my Essex engine is noisy, but nothing like tappets or cam lobe wear etc?



Sure there'll be plenty of opinions at Millbrook!

Kitchski

Original Poster:

6,514 posts

230 months

Thursday 2nd July 2015
quotequote all
Well, normally the metal gears are reported to produce a whining sound. Thing is, the gears are made by loads of different companies, so the mesh between the two they've supplied might be making the noise.

I'll be pissed off if I change both cam and gear and achieve nothing, that's for sure. I think that's why I'll wait til winter!

phillpot

17,105 posts

182 months

Thursday 2nd July 2015
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Have you tried running with rocker covers off (bit messy) and putting a feeler blade under each rocker in turn, may be one particular bad one?

Kitchski

Original Poster:

6,514 posts

230 months

Thursday 2nd July 2015
quotequote all
phillpot said:
Have you tried running with rocker covers off (bit messy) and putting a feeler blade under each rocker in turn, may be one particular bad one?
I haven't though I am going to go over the rockers a 3rd time. I know one of them is a bit noisy, but I've actually got them set 0.005 tighter than they're supposed to be. Rocker pads are fine too, no grooves or anything.
It's hard to explain, it's not strictly a tappet-type noise. Similar, but doesn't quite sound the same.