clubstylus

stylussprinter wrote:I phoned Paul Dunnell this morning and he's fairly sure the valves have contacted the pistons when I dropped from 5th into 2nd by mistake entering Paddock bend at Brands . He reckons that would account for the loud tappety noise due to the hydraulic tappets having a bigger gap after the valves bent If that turns out to be correct then I am really lucky not to have done further damage because I did one more lap after that mistake . Equally a spring could have snapped

I spent most of the day disconnecting everything ready to get the engine out tomorrow --- just starter , engine mounts and throttle cable to do then hopefully into the L Cruiser and off to Dunnells on Wednesday . We'll see

well hopefully it isn't too bad then - thats the problem with hyd lifters i suppose - maybe you should go to solid lifters now??

CMA wrote:I used to remove the springs on my old essex V6 by using a cheaper method than compressed air. I fed a load of rope into the bore through the plug hole then turned the engine slowly by hand till it locked up therefore pushing the soft rope up against the valves, keeping them closed

now thats resourceful! and a chuffing good idea too!

norma wrote:

CMA wrote:I used to remove the springs on my old essex V6 by using a cheaper method than compressed air. I fed a load of rope into the bore through the plug hole then turned the engine slowly by hand till it locked up therefore pushing the soft rope up against the valves, keeping them closed

now thats resourceful! and a chuffing good idea too!

I can't claim credit for coming up with the idea, I got it from the Robin Hood Owners Club, very resourseful bunch of people!

Hope things aren't too bad with the engine Rob. Keep us posted.

norma wrote:

stylussprinter wrote:I phoned Paul Dunnell this morning and he's fairly sure the valves have contacted the pistons when I dropped from 5th into 2nd by mistake entering Paddock bend at Brands . He reckons that would account for the loud tappety noise due to the hydraulic tappets having a bigger gap after the valves bent If that turns out to be correct then I am really lucky not to have done further damage because I did one more lap after that mistake . Equally a spring could have snapped

I spent most of the day disconnecting everything ready to get the engine out tomorrow --- just starter , engine mounts and throttle cable to do then hopefully into the L Cruiser and off to Dunnells on Wednesday . We'll see

well hopefully it isn't too bad then - thats the problem with hyd lifters i suppose - maybe you should go to solid lifters now??

It's not whether hydraulic or solid , it's the fact that rev-cut devices can't prevent over reving on down changes , especially from 5th to 2nd Once the valves touch due to bouncing springs(even competition ones)then the stem's shorter so the ' gap ' / tappet ------ is bigger , hence the noise That's if his diagnosis proves to be right that is

ah ok - for some reason i thought hyd lifters couldn't take high revs like solid lifters as compressing the oil causes a millisecond delay...?

Just had a call from Paul Dunnell and can't quite believe what rev's I pulled when grabbing 2nd instead of 5th at BRANDS ----- the ECU shows max revs of 9993 rpm The result being , bent valve stems , damaged guides and tappets Pistons , big & small ends are ok , as are the cam carryiers thank goodness(that would have cost a new race head --- no bearings in zetecs cams)
So it's a rebuild plus parts , ARP's and gasket set ------------------ h'mmm Non standard valves/guides plus new tappets

Unfortunately there's no protection from over reving from the 7750rpm rev-cut when it happens this way I'm amazed it was just a ' tapping ' I could here considering the damage Paul said that was mainly due to the guides

Price will scare me next but not costed yet ----- at least I can enjoy the weekend before the inevitable pain

we had a Audi A3 1.8t that had tried to see how many rpm he could do slowing do via gearbox which resulted in £........ he had several bottles of red before he could take it in.....................so stay merry till at least thursday

I'm semi prepared as I know from the first build of this engine at Dunnells , the big valves with tiny stems were £17 a piece plus the vat .

I've had a few days to take in the cost of my blunder £3300 is the figure Once you read all the individual items it makes sense ----- all competition springs replaced due to the rev's reached , refacing every surface , guides , exhaust valves , seals and gasket sets. , all new ARP's top and bottom ---- the list goes on then the rebuild and dyno run in A VERY expensive ACSMC sports libre championship win for 2010 but looks like I've grabbed it according to the coordinater That's the 3rd time in ten years although the first was for road going class in 2004 with many more events -- 15 from memory

Looks as though my last post on costs won't be the end of it Had a phone call to say they'd found a crack in the head port number 2 cylinder around the waterways Awaiting welding attempts and pressure test ---- ugh

Why don't you get a black top head (whole engine new is only £650) and fit that with its bigger valves?

We had a cylinder head on a special audi that had a crack and we used a company called Jim Stokes http://www.jswl.co.uk/
they stitched the crack together, very clever repair and its still being hammered around 4 years later. maybe worth a shout.

Can't take part of a job away from Dunnell when he's already started on it . Welding , drilling back out , opening that port then pressure testing will define my next move . At this bhp waterways are very thin plus heads vary even from new so it's tricky and luck is needed. Some metal has been eroded from within even using water wetter and zx1 .

norma wrote:Why don't you get a black top head (whole engine new is only £650) and fit that with its bigger valves?

I believe the blacktop will not fit the silvertop without some work. If it was a case of starting off with a better base, then an ST170 would be the way to go.
I can only assume that a "modified" silvertop is as good as a modified black or St170 head. Otherwise everyone is wasting money with the older units for nothing.
A question I would like to know the answer to.

Werner, like the car. Is the wheels thing deliberate? I sprayed my wheels up, 2 at a time. But I did the same side together, so no one noticed.

It really depends whether you've already developed a silvertop or simply changed cams , TB's etc. Starting from scratch with no manifolds to consider or ECU change then an St170 would seem logical but I wouldn't go up that route before discussing it with a well respected race engine developer. Having said that the ST170 head will bolt to the silvertop block and has better waterways around it's exhaust ports but you'd lose the advantage of having forged conrods not using the block as well . Valves are much larger as standard which saves cost over paying and fitting for big valves in your silvertop head. My exhaust manifold and silencer would have to be made again to get the best from an St170 and the existing one cost £800 Inc a secondhand BTB silencer. My head has had three attempts to weld the waterway area on one port and now given up due to the very restricted access which just kept making an even larger area to sort out. He's now working on a secondhand full race head which needs some work to suit my bottom end spec. If it works out , rev's will still need to be as before so no huge gain , merely an easier fix to my problem. I don't plan on running the engine waiting in the startline area in future so will need pit crew until a few cars off the start . Abindon's 120 degree fiasco in the queue was surely the beginning of my engine problems. I'll be terrified of missing 4th gear out of 5th now too