998 Pistons and conrods

[Andrew1967]

OK, this might sound a stupid/obvious question but I will ask anyway

The 998 engine for my pick up has circlip retained gudgeon pins.

Can I use the press fit type gudgeon pin pistons using the original conrods, or do I need to use a later set of rods to suit ?

Cheers

Andrew

[CooperTune]

No, the floated rods require a piston cut for snap rings. If you have a set of teflon buttons to retain the pin that could be done. Best to plan on floated pistons on floated rods and press pistons on press fit rods. Steve (CTR)

[Spider]

Can I use the press fit type gudgeon pin pistons using the original conrods, or do I need to use a later set of rods to suit ?

I'm pretty sure the answer here is Yes.

We had Press Fits in our locally made 998 engine in the 60's. They used the same Rod minus the Bush. The Pin pressed straight in to the Rod. To further clarify, you could use these rods with circlips pins, just by fitting (and sizing) a standard bush to the little end.

I'm fairly sure the late A+ small bore Rods were the same.

[Andrew1967]

Thanks for the replies guys

Can anyone confirm that Hepolite 20396 are circliped 998 Pistons please ?

Or indeed 998 Pistons ?

[ianh1968]

... and obviously, if we are using press fit "rods" or "normal" rods but without
the bush, the gudgeon pin would need to be larger and so would the
bore-hole in the pistons themselves. (Unless I've lost the plot, here...).


Andrew, do you actually have these pistons and can you measure the pin
diameter. Unless this is worked out, the rest of the discusion could turn out
to be a bit complicated.

Regardless, for a circlipped setup, I would always recommend the use of
"Teflon Buttons" instead - I've had circlips "disappear" before now...

Ian

[Andrew1967]

Thanks for the reply Ian.

I think the pistons are the circlip type (some in the box and the Pistons have the grooves in them.

Now trying to ascertain that they are 998 not 1098 before buying.

Cheers

Andrew

[rich@minispares.com]

if you are using the p22463 type late a plus press fit pistons then you will need to use the correct later press fit rods

p20396 are 998 pistons

[Andrew1967]

Thanks Rich for confirming that and thanks again to all those who replied

Andrew

[Spider]

I've just consulted 'the book' and the late press fit A+ Rods are indeed different, though it appears it is the same piston and pin as the diameters of the pins are the same, though the piston may not have the circlip grooves.

... and obviously, if we are using press fit "rods" or "normal" rods but without
the bush, the gudgeon pin would need to be larger and so would the
bore-hole in the pistons themselves. (Unless I've lost the plot, here...).

Ian

On ours, yes, the Pin dia was 0.7568" dia, circlipped pin is 0.62245".