POCKETED PISTONS PLEASE HELP

[thegman]

Is there any way e.g. from engine number for me to tell whether or not the pistons on my 450 are pocketed without taking the heads off? Looking to do a cam swap (stealth) and the garage is asking as obviously it makes the whole job longer if I can't order the cam in advance.

[The AJP Griff]

I think you'l find that if you talk to the guys at V8Developments,you can use their stealth cam without pocketed pistons

[350Matt]

Does the garage have a borescope? then you could whip a plug out and have a look?

Alternatively take off a cam cover, turn the engine over until an inlet is at full lift and then try and move it down some more and measure the difference before it stops

Matt

[Meatball]

Ive got a stealth cam and i thought it had to have pocketed pistons

[thegman]

sean at v8d told me i needed pocketed pistons

[spend]

Stick something down the plughole & see if you can feel the cuts (don't drop it in - or scratch the pistons - barbecue kebab stick?)

Dave

[That Daddy]

350Matt said:

Does the garage have a borescope? then you could whip a plug out and have a look?

Alternatively take off a cam cover, turn the engine over until an inlet is at full lift and then try and move it down some more and measure the difference before it stops

Matt

Not a recommended way to check you have enough clearance,what if the lobe as worn for example then it would appear to have loads of clearance on that valve sorry Matt,just my cents worth

[rev-erend]

That Daddy said:

350Matt said:

Does the garage have a borescope? then you could whip a plug out and have a look?

Alternatively take off a cam cover, turn the engine over until an inlet is at full lift and then try and move it down some more and measure the difference before it stops

Matt

Not a recommended way to check you have enough clearance,what if the lobe as worn for example then it would appear to have loads of clearance on that valve sorry Matt,just my cents worth

You would hear it..

A bore score or get it close to TDC and feel around carefully with a wooden implement and don't drop it in

[That Daddy]

rev-erend said:

That Daddy said:

350Matt said:

Does the garage have a borescope? then you could whip a plug out and have a look?

Alternatively take off a cam cover, turn the engine over until an inlet is at full lift and then try and move it down some more and measure the difference before it stops

Matt

Not a recommended way to check you have enough clearance,what if the lobe as worn for example then it would appear to have loads of clearance on that valve sorry Matt,just my cents worth

You would hear it..

A bore score or get it close to TDC and feel around carefully with a wooden implement and don't drop it in

No you wouldenti have seen cams with almost no lift(WORN LOBE)at the valve and yet make no tapping or clacking sound(hydraulic as is the RV8)i still stand by this not being a accurate way to check for enough clearance,and remember you only need approx 70thou(buffer)clearance before valve/piston contact for most engines,should i get me Hotdog and Popcorn now?

Edited by That Daddy on Wednesday 26th March 14:34

[rev-erend]

Oops - forgot most people run hydraulics

[The AJP Griff]

thegman said:

sean at v8d told me i needed pocketed pistons

My mate was told by V8D that he wouldn't need them on his 4 litre griff,if he wanted to fit the stealth cam

[Boosted LS1]

Looking down the plughole should reveal if the pistons are pocketed or not. Failing that the scraping a blunt instrument across the piston may reveal a valve recess. A bright pencil torch would be useful.

[rev-erend]

See picture below for what you are looking for - the pockets or eyelets in the piston can be very slight - I run a mechanical 404 cam (0.505 lift).

Sorry it's not all that clear but the picture was taken before I cleaned it up - pockets on top half of piston.

[Markh]

The AJP Griff said:

thegman said:

sean at v8d told me i needed pocketed pistons

My mate was told by V8D that he wouldn't need them on his 4 litre griff,if he wanted to fit the stealth cam

My 450 did nt need them with a stealth

[hiltonig]

must admit i was told it needed them on a 500 when asked v8dev

[Boosted LS1]

The OP could convert a scrap lifter into a solid lifter and rotate the engine slowly to see if anything fouls. Then if wanting to measure valve/piston clearance something like a shim could be 'installed' under the rocker arm and it's thickness measured.

[dickkark]

If the engine is in a position or state to accept a new cam surely it`s not far away from just unbolting one head to have a look,anyway?
the gaskets are hardly expensive take both off and you could clean up the heads and pistons and re-seat/re-cut the valves at the same time,just a thought.

Edited by dickkark on Wednesday 26th March 18:55

[v8 racing]

ok stealth cam and pocketed pistons!! firstly sorry i havent been to active on here recently, expecting my first baby soon so been looking after the better half!!
The stealth WILL fit into a 400 non hc, this is PROVIDING the heads or block havent been machined and is still using the correct thickness of head gaskets, a few thou for a clean up is ok too but if any part has been milled to increase the compresion ratio then you may be struggling, also there is the fear of over revving the engine and getting lifter pump up, although the valve springs will cope with around 7000 rpm before this happens, changing down the gears wrongly or too soon could make this occur hope this clears up a few gremlims with the stealth. rob

[Boosted LS1]

v8 racing said:

expecting my first baby soon so been looking after the better half!!

Congratulations Rob. You must have found a spare 5 minutes

[v8 racing]

Boosted LS1 said:

v8 racing said:

expecting my first baby soon so been looking after the better half!!

Congratulations Rob. You must have found a spare 5 minutes

Thanks Mike