Dropped my VH45 at the engine shop

[John Dixon]

Dropped it off today at a race engine shop for rebuild.They guy there that does the heads says the basic design is pretty good, so they don't need too much work done. He's going to do some work on the ports then mod the combustion chamber to match the bigger bore.Block is going to be bored to either take mirage's larger pistons, or have some Hi comp 98mm ones made. Having carillo rods and retaining stock crank.Cams are coming from mirage too hopefully. The engine guy's pretty happy we can get ~100bhp/l from it give the valve area available and the IR intake (8x45mm throttles) + good headers.

[450zxtt]

good luck,glad to see you are making progress...-450zxtt

[elwesso]

Glad to see things are coming along John.. Be sure to share the wealth (of information) and some pics

[maxnix]

So the bores are cast in iron? Don't be shy with the details! Post profusely!

Great to see a thread on performance and not cosmetic issues. It's become a real henhouse around here lately.

[John Dixon]

Thanks guys, will keep you up to date.Yes, the bores have liners. They're going to bore the old ones out then fit new ones

[DAEDALUS]

Pretty sure the bores aren't iron, since they don't rust when left exposed.

[97Q45t]

A little off topic but can I bore the VH41DE's cylinders lager and use VH45DE's pistons and parts for it?

[zinkie13]

I thought the bore was the same size on the 45 and the 41 the stroke was just longer on the 45??

[maxnix]

No, bore on VH41DE is 98mm, while on the VH45DE it is 95mm.

[Q45tech]

Better check your conversion numbers 92.9 [93mm] mm = 3.66" bore for both

82.7mm stroke on 4.5 [90-96 and 2002----2006].4130 cc V8 [97-01] = 73.33mm stroke

The 5562 cc motor has a 98mm bore

[maxnix]

Nope, bad memory cells or poor eyesight or both. 93mm bore is correct on both.

Give me 101mm bore with a 75mm stroke and I would be in 5L heaven. Won't happen with the VH or VK block, though.

[Q45tech]

EFFICIENCY - wise, longevity-wise----there is an optimum bore size based on multivalve diameter and curtain area [and of course emissions] for penta roof cylinder heads..................and it sure isn't much over 4.5 liters in total. Notice every manufacturer zeros in on 4.2, 4.3, 4.4, 4.5, 4.6 with ~~3.66 bore.

As one approches 4.0 from 3.66 the ring friction adds up........why those big bores don't last 300,000 miles in street duty with 50,000 cold cranks.

[QShip]

Dropped it off today at a race engine shop for rebuild.They guy there that does the heads says the basic design is pretty good, so they don't need too much work done. He's going to do some work on the ports then mod the combustion chamber to match the bigger bore.Block is going to be bored to either take mirage's larger pistons, or have some Hi comp 98mm ones made. Having carillo rods and retaining stock crank.Cams are coming from mirage too hopefully. The engine guy's pretty happy we can get ~100bhp/l from it give the valve area available and the IR intake (8x45mm throttles) + good headers.

Is this engine shop in Brockton, MA?

[John Dixon]

No, it's in dagenham, UK!

[QShip]

LOL!!! OK! Wrong side of the pond!

[szh]

Yeah! Different Birmingham, I guess!

Z

[John Dixon]

Lol, yes. Think my Birminham is the original one