Total seal for RV8?

[350Matt]

Well chaps? Are they available for the old thumper? ( std 94.0 bore)

More to the point are they worth the extra cash?

Matt

[stevieturbo]

Contact Dave at Performance Unlimited

01904 489332 he does the Total Seal stuff.....


And are they worth it....Id say probably not, unless its a very specific build pushing the limits.

[HarryW]

Might be worth asking if Paul at Austec had put these on any of the RV8 rebuilds they have done. They put them in my AJP8 rebuild but that's a different kettle......

[Boosted LS1]

I use the gapless rings in all my builds, be they cosworth, lsx or rover v8. I can't say they're any better but the blurb suggests they are and the gapless idea makes sense in some respects.

Boosted.

[HarryW]

As I understand it, there has to be some blow by if only to confirm the rings are not binding in the bores, too little is poor, too much is poor, but what is the right amount.

[350Matt]

None at all

Blow-by costs power, so I'd like none please

however in practice this isn't achievable

Matt

[stevieturbo]

Pretty sure some blowby does assist the oil control rings function ?

[HarryW]

350Matt said:

None at all

Blow-by costs power, so I'd like none please

however in practice this isn't achievable

Matt

I understood if you had none then the rings were probably binding and scoring the bore and you develop a bit more unwanted blow by as time goes by .
Yes ideally no blow by, in practice you will have some afaik.
I assuming you can measure it by crank case pressure, as I remember my lump spending many an hour running with a crank case pressure gauge fitted, best part was watching water coming out of it swiftly followed by water out of the intakes .
Which leads onto, what is an acceptable crank case pressure

[GreenV8S]

HarryW said:

Which leads onto, what is an acceptable crank case pressure

One tip I was given when I supercharged mine is that highly stressed engines blow by a lot more. To the extent that in some cases the heads will literally lift under pressure and allow blow-by to leak into the pushrod holes. As long as the breather is capable of handling the flow rate, it's OK. When pressure starts building up in the crank case you're wasting power and risk trouble with the seals. My uninformed guess is that 1 psi is too much, half a psi may be OK, something of that order.

[rev-erend]

Matt probably knows a lot more about this than he is letting one..

I seem to remember the Cossie Turbo race days and they would 'select' the best blocks as the high turbo pressures would literally push the cylinder walls ..
and Lancia made the S4 turbo / super charger combo engine with a one piece block and head casting ..

Boy the casting rejection rate must have been high there..

[HarryW]

rev-erend said:

Matt probably knows a lot more about this than he is letting one..

......

I realised that when he first posted, just thought it would be a bit more two way once we'd bitten, hence I posed questions too .

I don't doubt a total seal type ring improves things, somesay up to 3% on output .
I have them fitted and they played a large part in the 4 revisons of piston developed using my lump, but that was for the AJP and not the RV8.

[350Matt]

Ideally you want a crankcase pressure of about 700mBar absolute ( so -300ish mBar under atmospheric pressure) this gives the best trade off in power and going any further doesn't reduce the friction appreciably. Obviously you need a dry-sump system to achieve this.

And blow-by doesn't help oil rings or if it does the effect is minuscule compared to the effect of the piston charging up and down the bore

Matt