21 replies to this topic

[happydude2012]

Hi Guys

I myself had a swiftune cam and 1:5:1 rollertip rockers, as some of you know - ive been asked what i thought of them by someone whos looking at getting an engine built with a swiftune duplex cam kit.

1275 A +

 

I said id not had a problem with mine , aside from the fact im now looking at an engine refurbish and cam/ follower  replacement after 3-4 odd years,  i couldn't really complain.

However, what do the wider community think of the above? and going back to an old topic, are 1:5 high lift rockers really needed given their apparent wear on cams.

 

Ive heard some say just have the cam with 1:3 rockers and others swear by the 1:5, even 1:4 some have suggested.

 

I did point him in the direction of Md Dodds cams selection but hes already bought the swifty.

 

Ive said what i think (for what its worth) what do the rest think?

 

thanks.

[Ethel]

There's no reason why the wear need be any worse. The bigger lever rate means you can use proportionally softer springs. Achieving the same with a cam alone would need steeper ramp angles leading to even more wear. The problem isn't the rockers it's matching them with a suitable cam and springs, the SW5 is supposed to be one though.

[happydude2012]

yes nick swift specifies 1:5:1 rockers with the sw5 cam - honestly ive never had trouble with it until now.

Hes just looking for advice i think and my knowledge only extends as far as what ive experienced personally.

[Bat]

Hi,

I ran a second hand Piper 285 cam for 10 years, sold the engine still turning out 110bhp...

I think you should complain if it's worn out after 4 years. 

I killed 2 engines before I got it right but that cam was in every one, never a spot of bother or signs of wear when inspected.

Cheers 

[Pigeonto]

There's no reason why the wear need be any worse. The bigger lever rate means you can use proportionally softer springs. Achieving the same with a cam alone would need steeper ramp angles leading to even more wear. The problem isn't the rockers it's matching them with a suitable cam and springs, the SW5 is supposed to be one though.

Exactly. I've  recently been through this whole thing. I had to ask myself  'do I need springs that will allow me to rev. to 7000 in a road car' ?! 

When you realise you don't then you can sort out spring rate, fitted height, safe lift, rocker ratio.

The factory red line on my Mayfair is at 6500 with single springs so you know that's a safe limit and will take a bit more

[happydude2012]

well the kit came with double valve springs theyve been ok for me

[nicklouse]

well the kit came with double valve springs theyve been ok for me

and double valve springs means nothing. there is a correct spring rate and wrong spring rates. double/single straight or bee hive it makes no difference their is one correct rate for the build.

 

high wear is do to people just throwing high lift rockers on. the same as people breaking the rockers when the first start the car up (or rev it) they have no idea what they are doing.

[Retroman]

I would question the springs

 

Your valve tips are hammered and at least one probable cam lobe follower issue.

 

Ultimately the A series was not designed for 1.5's and as such they are an after market performance item

 

After 4 years and how many hours and many many thousands of revs, using what poundage springs its no surprise to see an issue

 

Some race engines are rebuilt after very few hours running

 

Even a SW5 cam though relatively mild is a high performance cam combined with the very high leverage of 1.5's and heavy springs the stress on the peak of the cam lobe and valve tip is massive.

[happydude2012]

so the bottom line here  - and what seems to be my issue overall, is that the high lift 1:5s are really not ideal on a road car -  he (and me come to think of it) should be aiming maybe 1:4 or 1:3?

 

Ultimately i took nick swifts advice on his products - hence the set up i personally had put together.

So what im saying is, they wrent just thrown on, it was built to a spec suggested by swiftune, for a road car. not track.

 

Yeah youre right, ive done many miles and many revs in the car - but it seems to me that the cam should have lasted alot longer - if indeed that is whats wrong with it.

We wont know 100% till its stripped down.

Edited by happydude2012, 10 August 2018 - 10:28 AM.

[Retroman]

They are just over stress for a road car long term 1.3 is enough, you will bearly feel the difference.

 

Even the MG metro used to do cams and tappets, Rover specified the wrong oil

[happydude2012]

They are just over stress for a road car long term 1.3 is enough, you will bearly feel the difference.

 

Even the MG metro used to do cams and tappets, Rover specified the wrong oil

 

Interestingly, or maybe completely irrelivant - its only recntly i went to 20/50 oil

was 10/40 or 15/40 before (cant remember, anyway it was the oil that rover cpecified for all its vehicles that turned out was naff for the A+ engine....the tapping started not long after i changed oil and reset the valve clearnaces) 

[Midas Mk1]

Got sw5 and 1.5;s, wouldnt go for lower ratio rockers on mine, get's the power and drives just how I wanted.

[happydude2012]

Got sw5 and 1.5;s, wouldnt go for lower ratio rockers on mine, get's the power and drives just how I wanted.

omg at last someone who doesnt think 1:5 with an sw5 is rubbish!    - seriously ive had a few great years with this set up - its just a bit bent.

[Stevie W]

+1 for an SW5 and 1.5 rockers, makes for a really nice fast road engine!

[gazza82]

I don't suppose it could be a bad batch of valves that weren't hardened properly .. or maybe have had the tops ground down exposing softer metal?