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[Marks DTM Calib]

I'm confused...

Facelift has different nuts for holding the manifold in place, yet same studs???

Part numbers differ on the nuts...

Yep, they are a 10mm head rather than 13mm.

Will try to establish why later but, it may well be to make it easier to get a deep socket on them with the larger manifold body

[Marks DTM Calib]

Kepp up the good work Mark .....just one query though, thought you were just gonna keep an eye on the tyre pressures .....why's the engine in bits

Ow bugger, forget to do the tyres!

Not a problem though, there on ebay so will have a new owner shortly!

[Taxi_Driver]

Kepp up the good work Mark .....just one query though, thought you were just gonna keep an eye on the tyre pressures .....why's the engine in bits

Ow bugger, forget to do the tyres!

Not a problem though, there on ebay so will have a new owner shortly!

Yes, it would look a lot better with steel rims on it  
I would suggest getting some wheel trims like these to top it off  

http://cgi.ebay.co.uk/Pimp-your-ride-Spinning-spinner-BLING-Car-Wheel-Trims_W0QQitemZ360133584611QQcmdZViewItemQQptZUK_Cars_Parts_Vehicles_Wheels_tyre_Trims_Trims_ET?hash=item360133584611&_trksid=p3286.c0.m14&_trkparms=72%3A1689%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318

[Martin_1962]

Can you carry out a plastiscene test and find out what minimum valve piston clearance is?

It is a very usefull test

[Marks DTM Calib]

Can you carry out a plastiscene test and find out what minimum valve piston clearance is?

It is a very usefull test

Not easily and anyway, pointless unless your going for custom ground cams plus we already know the max useable lift is around 10-11mm!

had a look at a few bits today, the pistona have a very slight dish but, they also do NOT come to the top of the bore like the 2.5 and 3.0!

So, we do at least know for definate how the compression has been lowered!

[Martin_1962]

Can you carry out a plastiscene test and find out what minimum valve piston clearance is?

It is a very usefull test

Not easily and anyway, pointless unless your going for custom ground cams plus we already know the max useable lift is around 10-11mm!

had a look at a few bits today, the pistona have a very slight dish but, they also do NOT come to the top of the bore like the 2.5 and 3.0!

So, we do at least know for definate how the compression has been lowered!

So unless there are some 2.5 style 2.6 pistons (there isn't) skimming is pratical - provided the inlet divider is trimmed as well.

Doing this on my Sunbeam worked out a 60 thou skim was possible, that was quite a bit higher than before.

Thinking of trying 20 thou if practical - if I get a spare set of heads to fettle before May - no hope of reburbishing and regrinding in two heads in one evening.

I am aiming for 10.8:1 as that will work fine, but I don't think I could skim that much off.

[VXL V6]

Can you carry out a plastiscene test and find out what minimum valve piston clearance is?

It is a very usefull test

Not easily and anyway, pointless unless your going for custom ground cams plus we already know the max useable lift is around 10-11mm!

had a look at a few bits today, the pistona have a very slight dish but, they also do NOT come to the top of the bore like the 2.5 and 3.0!

So, we do at least know for definate how the compression has been lowered!

So unless there are some 2.5 style 2.6 pistons (there isn't) skimming is pratical - provided the inlet divider is trimmed as well.

Doing this on my Sunbeam worked out a 60 thou skim was possible, that was quite a bit higher than before.

Thinking of trying 20 thou if practical - if I get a spare set of heads to fettle before May - no hope of reburbishing and regrinding in two heads in one evening.

I am aiming for 10.8:1 as that will work fine, but I don't think I could skim that much off.

Not sure how you propose to do that? If you skim the heads to that degree then the inlets are going to sit lower and closer to the centre so the plastic divider will be useless as it won't meet the heads and neither will the bolt holes.

[Martin_1962]

0.5mm off each one - just under 0.25mm off each side of the inlet divider.

54 deg/2 is near enough to 30 so 1 root3 2 triangle AFAIR so 0.5mm is 0.25mm then root 3 to a little under it

All rough on paper!

[PaulW]

Will .8 compression really make that much difference??

[VXL V6]

0.5mm off each one - just under 0.25mm off each side of the inlet divider.

54 deg/2 is near enough to 30 so 1 root3 2 triangle AFAIR so 0.5mm is 0.25mm then root 3 to a little under it

All rough on paper!

Actually I do follow that!   8-)

But thinking on, the inlets aren't at 54deg to each other as they aren't flush on the side of the heads.
I guess you'd also need to be careful re the coolant bridge.

James's oil cooler 'how-to' pictures shows what I mean:-

http://www.omegaowners.com/forum/YaBB.pl?num=1221081908

[Martin_1962]

0.5mm off each one - just under 0.25mm off each side of the inlet divider.

54 deg/2 is near enough to 30 so 1 root3 2 triangle AFAIR so 0.5mm is 0.25mm then root 3 to a little under it

All rough on paper!

Actually I do follow that!   8-)

But thinking on, the inlets aren't at 54deg to each other as they aren't flush on the side of the heads. I guess you'd also need to be carfeful re the coolant bridge.

James's oil cooler 'how-to' pictures shows what I mean:-

http://www.omegaowners.com/forum/YaBB.pl?num=1221081908

Hmmm the angle makes it more difficult to work out - the sides would be 0.5mm approx nearer so need about 0.25mm slack in the bolt holes.

All to be thought about anyway

[Martin_1962]

Will .8 compression really make that much difference??

Yes - Look at this thread earlier - they tuned the DBW engines to make up for power loss.

I reckon 2 or 3 bhp minimum would be found but also better mpg

[JamesV6CDX]

Will .8 compression really make that much difference??

Yes - Look at this thread earlier - they tuned the DBW engines to make up for power loss.

I reckon 2 or 3 bhp minimum would be found but also better mpg

Is it worth it, for a barge?

[Martin_1962]

Will .8 compression really make that much difference??

Yes - Look at this thread earlier - they tuned the DBW engines to make up for power loss.

I reckon 2 or 3 bhp minimum would be found but also better mpg

Is it worth it, for a barge?

Since I use a high octane fuel I think it could save a bit of fuel

[Marks DTM Calib]

Will .8 compression really make that much difference??

Yes - Look at this thread earlier - they tuned the DBW engines to make up for power loss.

I reckon 2 or 3 bhp minimum would be found but also better mpg

Is it worth it, for a barge?

Given the additional cost is small and only involves time (your won)......then why wouldn't it be