4.5 big valve engine question

[culminator]

having just bought one of the genuine 4.5 BV cars, i'm trying to trace some of the history of what was done when the engine was rebuilt 2 years ago.

Dom at TVR Power did the work and has been really helpful but i just need to clarify something. He said that the crank was a cross drilled steel 4.6 and the block is cross bolted. My question is whether the crank being 4.6, makes the engine a 4.6 and not a 4.5? It's the original crank as far as i can tell.

Also, the cam is a 435. Is anyone familiar with that profile and the characteristics it should give?

thanks!

[Ant.]

Think a 4.5 is something like 4441cc, whereas a 4.6 is 4552cc.

A 4.6 crank will have 4.6 stamped onto it.

Journal sizes could be different aswell, the 4.5 may be smaller journal?

[JR]

Ant. said:

Think a 4.5 is something like 4441cc, whereas a 4.6 is 4552cc.

A 4.6 crank will have 4.6 stamped onto it.

Journal sizes could be different aswell, the 4.5 may be smaller journal?

Yes, it sounds like the OP's 4441 engine has been rebuilt to the later 4552.

[rev-erend]

JR said:

Ant. said:

Think a 4.5 is something like 4441cc, whereas a 4.6 is 4552cc.

A 4.6 crank will have 4.6 stamped onto it.

Journal sizes could be different aswell, the 4.5 may be smaller journal?

Yes, it sounds like the OP's 4441 engine has been rebuilt to the later 4552.

Ditto here..

My 450 SEAC destroyed the original 4441 engine and was replaced by a 4.6. The 4.6 cross bolted crank is far superior.

[JR]

rev-erend said:

JR said:

Ant. said:

Think a 4.5 is something like 4441cc, whereas a 4.6 is 4552cc.

A 4.6 crank will have 4.6 stamped onto it.

Journal sizes could be different aswell, the 4.5 may be smaller journal?

Yes, it sounds like the OP's 4441 engine has been rebuilt to the later 4552.

Ditto here..

My 450 SEAC destroyed the original 4441 engine and was replaced by a 4.6. The 4.6 cross bolted crank is far superior.

Also having a crank that doesn't float lengthways is a help.

[spend]

435M? cam is the 500 / 430 BV cam (at least in the early years) If Dom didn't say 435M it may be an predecessor?

I would be surprised Dom didn't plainly state that it was rebuilt with a 4.6/TVR450 bottom end if that is what happened. More likely Dom has explained what has been done but you have misinterpretted the subtlety of his enginuity I suppose he could offset grind a 4.6 crank so the big ends match the original size & stroke so the rods/pistons are maintained?

[culminator]

Thanks for the feedback so far. The feedback was through email, not verbal, so no misunderstanding. Here's what he wrote:

Crossed drill 4,6 steel forged crankshaft
cross bolted block
large intake and exhaust valves
ported manifolds and cylinder heads
435 camshaft with vernier timing chain set

End quote.

In a conversation, he also mentioned Cosworth pistons. Is the cross drilling in the crank there to aid lubrication? And what exactly is a cross bolted block, is it the way the main bearings are secured?

[JR]

Here's the funny thing: your car is now no different to any other similar age pre-cat Griff that has had the 4.6 tuned engine fitted but because yours is an original 4.5BV it's probably worth more than the other modified cars (but less than an original 4.5BV, even though you may now have a better car.) Such is life.

[culminator]

Depends on how you look at it JR. The block and crank are totally original, only ACT induction and manifolds detract from original spec really and I have the original parts if required to return to standard. I think Dom may have made a mistake regarding the 4.6 crank and meant 4.5. as the crank was not replaced during the rebuild.

I doubt if there are more than 8 examples left, so a genuine 4.5 BV has to be a pretty rare beast.

[rev-erend]

culminator said:

Is the cross drilling in the crank there to aid lubrication? And what exactly is a cross bolted block, is it the way the main bearings are secured?

Yes and yes.

[chrispitman]

I think from the mid ninetys all the 4.5 were infact rover 4.6, as they were easy to source as the 4.5 early ones were reborded 3.9's. Also all the 4.6 were cross bolted which make the bottom end very strong (additonal bolts from the side of the block). I think the 3.9 used a smaller dia crank (early tvr 4.0) the later 4.0 and 4.6 blocks were bigger.

[culminator]

Very useful, thanks guys!!

[spend]

chrispitman said:

I think from the mid ninetys all the 4.5 were infact rover 4.6, as they were easy to source as the 4.5 early ones were reborded 3.9's. Also all the 4.6 were cross bolted which make the bottom end very strong (additonal bolts from the side of the block). I think the 3.9 used a smaller dia crank (early tvr 4.0) the later 4.0 and 4.6 blocks were bigger.

You are a bit off the mark, Doms 450's predated Fat Crank days and hark back to Tuscan Racer & big Wedge days ~ many may even have been NCK engines?

TVR did have their own cranks cast, as well as using LR stock for 'cooking' motors, but not many of the 'specials' used forged components excepting the 'very specials'...

[JR]

They were rumoured to be Pontiac cranks.

[culminator]

Dom has clarified the situation and confirms what has been indicated here. Basically I have the original block and crank, which LR refer to as a 4.6 block, which was actually a 4.5 capacity. Seems that all the 4.5 big valve engines used these blocks, some had steel cranks, some didn't.

[JR]

culminator said:

Dom has clarified the situation and confirms what has been indicated here. Basically I have the original block and crank, which LR refer to as a 4.6 block, which was actually a 4.5 capacity. Seems that all the 4.5 big valve engines used these blocks, some had steel cranks, some didn't.

Hmmm. There's a big problem here in trying to identify what is in your car (although a great engine either way.) The 4.5 BVs had a development of the 4441 engine that was in the 450SE & 450 SE AC cars. The LR 4.6 came later than the build date of the 4.5BV Griffs, eg http://www.landroverbase.com/vehicle/by-id/1646146...