Performance camshaft.... wont start!!!

Post by **picky** » Tue Aug 09, 2005 8:17 pm

yes, you have to remove the followers before you remove the old camshaft, but I found I had to remove the sump anyway because to undo the crank pulley nut I had to wedge a piece of wood in by the crankshaft to stop it from turning.

Many of the high lift rocker sets have roller rockers, so there is no side loading on the valve stems. Also because of the higher ratio there is more leverage from the valve springs on the followers, so valve bounce is pushed further up the rev range.

Post by **bmcecosse** » Wed Aug 10, 2005 1:26 pm

There is steady trail of stories on the Mini boards of worn out cams/followers/stuck valves/dropped valves - even broken rockers when using the high lift sets. It's better to have the higher lift at the camshaft - it will not give such high acceleration to the valve train - but any higher lift and/or higher spring pressure increases the wear rates quite considerably. Even the roller rockers still have to 'wipe' across the tip of the valve stem - it helps but it doesn't stop the wear. If going for this you should use the hidural bronze guides and NOT fit stem oil seals. The test was in one of the Mini mags a few months back. It's always better to increase the breathing by having bigger inlet valves and throat design - only when this route runs out of steam is it worth chasing more valve lift. Of course for out and out competition use wear is not important - and so maximum valve size and valve lift are used.

Post by **picky** » Wed Aug 10, 2005 10:28 pm

ok, took the radiator etc out and took off the timing cover for the third time this week

but the countersunk screws where definatly not fouling the chain... anyone any other ideas of what a rythmic clicking/tapping noise is?? badly adjusted tappets maybe??

Post by **bmcecosse** » Wed Aug 10, 2005 10:33 pm

Is the camshaft end-float ok ? Did you fit new cam followers ? I rather assumed you had already checked the valve clearances - check also none of the rockers are catching on the valve springs - or tapping the inside of the rocker cover. I set inlets to 12 thou and exhausts to 15 - to allow for the ex valve getting hot and expanding more than the inlets.

Post by **picky** » Thu Aug 11, 2005 9:31 am

how can I check the camshaft end float? also I dont see how that would make a clicking noise. the noise is still there when the rocker cover is off.. and listening to it running with the rocker cover off it sounds like one of the tappets, but I set them all to 12 thou only a couple of days ago.. ill recheck them anyway.

Post by **Cam** » Thu Aug 11, 2005 10:28 am

Fan not catching on anything?

Post by **rayofleamington** » Thu Aug 11, 2005 12:05 pm

Alternator bearing? (sorry if that comes across as patronising but I saw someone start to rebuild an engine which only needed a recon alternator!)

Post by **bmcecosse** » Thu Aug 11, 2005 1:11 pm

End float would mean timing cover off yet again - remove chain - pull/push cam via the big sprocket and try to measure the movement. Is the rocker shaft in good nick ? Usually the rocker bushes are fine - it's the shaft that wears. And is there oil getting up to the shaft ok ? You need to try to decide if the noise is once per rev or once every two revs.

Post by **picky** » Fri Aug 12, 2005 11:09 pm

I tried rocking the rockers sideway and they seemed to be a bit loose on the shaft so I swapped them fora a spare set from an A+ engine, and the clicking is still there and still exactly the same

while the engine is idling the ticking gets louder, and then fades and gets louder again, and it speeds up when u rev the engine. with the rocker cover off it sounds like it is coming from the tappets, but when I have the tappet clearence set to zero the clicking is still there!!! aarrgh.

Post by **bmcecosse** » Sat Aug 13, 2005 8:09 pm

Is it new cam followers?

Post by **picky** » Sat Aug 13, 2005 8:11 pm

I fitted new followers yes. They were minispares lightened ones.

Post by **bmcecosse** » Sat Aug 13, 2005 8:18 pm

Hmmm - maybe they are causing the noise - not too difficult to fit a different set for a trial.

Post by **picky** » Sat Aug 13, 2005 8:20 pm

If I run the engine with the tappet chest covers off and poke each follower in turn while the engine is idling, surely the sound will change/stop when I hit the right one??

Post by **bmcecosse** » Sun Aug 14, 2005 8:04 pm

May do - never tried this - bit oiley though and it will splash on the exhaust on smoke like h3ll. Is this a really loud noise - or just the well-oiled clickety whirr of a finely tuned machine !?

Post by **picky** » Sun Aug 14, 2005 9:42 pm

bmcecosse, I would prefer the latter description

It is not extremely loud at all, but can be easily hard above the exhaust with the bonnet closed, and even when you are stood outside the car with it running. It doesnt sound right at all, even though the engine functions fine. Anyway Im off on holiday and will have another go at it when I get back, using another set of followere as suggested. thanks for all the support,
Tim

Post by **bmcecosse** » Tue Aug 16, 2005 12:08 am

My 1275 Mini is much the same - I have decided it's well oiled ! Hasn't changed in two years - goes like stink.

Post by **picky** » Wed Aug 31, 2005 10:04 pm

I have found the the problem with the ticking noise... I had the engine ticking over then it made a loud crack and stalled...remove the rocker cover and one of the rockers had snapped in two..

standard rockers back on and only a very light ticking noise from the tappets to indicate they are "well oiled" as bmcecosse put it!! thanks for everyones help and suggestions, Tim

Post by **Stig** » Thu Sep 01, 2005 8:14 am

Eeek! Is the rocker shaft OK? I had the shaft break in my Sprite's engine once -replaced it with a tuftrided one just in case. Never had a rocker break though, and mine are bog-standard.

Post by **picky** » Thu Sep 01, 2005 10:42 am

rocker shaft seems fine, the rockers I was using are sintered, as fitted to the later A+ engines I think. The pressed steel ones are less likely to snap. Im using pressed steel ones now, but Im hoping to get some decent forged ones asap!!

P.S. Im using a high lift camshaft and double valve springs, which obviously put extra stress on the rockers.

Post by **bmcecosse** » Thu Sep 01, 2005 9:54 pm

That rocker has been extensively 'lightened' - which is a NO NO with the sintered ones !! The pressed steel ones are just fine. But why the double valve springs ? What revs are you hoping to pull ? Double springs just load up the whole valve train - adding wear and unreliability, as you have found out.