Actual 998 Chat about rebuilds

[251 ENG]

Toby has a NOS set of D top pistons for sale to suit STD bore

[snoopy64]

Good shout, thanks

[snoopy64]

Ok, bores checked now… quite a bad taper …

[snoopy64]

So, what is the downside to sleeving/fitting liners in a block???

[Thorp]

Simple answer is cost, but no downside on a road engine really.

[snoopy64]

Simple answer is cost, but no downside on a road engine really.

I presume you mean compared with a bore out plus new pistons…?

[OzOAP]

you just need to countersink the 2 screws under the cam pulley

Crank pulley.

I would measure cc in head chamber and measure head deck thickness to the oil drilling. Then you'll have an idea on how to achieve required comp ratio.
D-Top, Flat-top, deck head, deck block......

[snoopy64]

Ok, machining all sorted, now +20.

Can anyone recommend a cam close to std and is it worth fitting a duplex timing setup?

[Polarsilver]

Minispares Evo 1 Cam is good value for the money. just a matter of what type Rockers are used & what do you want from your engine.

[mk1]

Another vote for the evo 1 or alternatively Calvers CST229 is a good bet too.

Personally I put duplex's on all my engines, not sure whether it's really necessary though.

[Peter Laidler]

Yes, Duplex...... peace of mind I say

[Costafortune]

Duplex chains are heavier and require more effort to rotate.

A good simplex chain is perfectly fine.

[mk1]

I believe that Swifty uses simplex chains on all his engines nowadays.

[Richspec]

I believe that Swifty uses simplex chains on all his engines nowadays.

if i was building a race engine I'd go highest quality single i could find, rotational losses and all that...
But for everyday longevity and not chasing every HP i use duplex as default.

[snoopy64]

Hi,

thanks for all the supplies, I'm not looking to vastly improve anything, just a std set up with std rockers...

[Costafortune]

Simplex JWIS chain. Has an A Series timing chain ever snapped? I've seen them so shagged they've worn through the timing cover, but never broken.

[snoopy64]

Vernier gear worth it?

[timmy201]

I prefer using an offset woodruff key. The vernier adds an extra level of complexity that can come loose

There’s also the type with extra key ways on the crank sprocket to dial it in
https://outlawspeed.com.au/shop/cs8000

[Costafortune]

It's absolutely worth timing the camshaft in properly as well as having a good distributor built with a correct advance curve. You can lose 10 bhp with ease if they aren't right.

That and bumping up the compression ratio to 9.75:1 to run on super unleaded will really give it some sparkle. A good standard 998 Cooper was only a couple seconds slower to 80 mph than a 1071 S.

[snoopy64]

Another vote for the evo 1 or alternatively Calvers CST229 is a good bet too.

Personally I put duplex's on all my engines, not sure whether it's really necessary though.

997 type cam isn’t quite the same as the 998 so will the dizzy need re curving?

Please excuse my ignorance!