How can you tell a 4.5 block?

[TT Tim]

This may seem an odd question, but how do you tell a 4.5 block? I don't mean how do you tell a 4.2 from a 4.5 when it's in a car, I know that, purple pipes etc.

But if you had two blocks next to each other how would you tell the difference? And, is it possible to put 4.2 induction on a 4.5 block?

I ask as I've just come across an advert for my car dating back to 1999, I'm sure it's a typo but it says 4.5 block, and it just got me thinking.

'96 P 97 spec, 4.5 block, all updates, new tyres, ski boot purple (as featured in a Top Gear TVR Story!), oyster full hide, 16,000 miles, £31,000'

Thanks

Tim

[_Deejay_]

Externally, I don't think you can. What does your v5 say?
I'd imagine the easiest way would be to call the factory and ask them what the car was fitted with, and what the engine number was.

Sure someone will be along shortly to correct me though

[TT Tim]

To all intents and purposes it's a 4.2, log book says 4.2, handbook says 4.2. But I do know that strange things happen in the world of TVR, whether it left TVR with a standard 4.2 and later had a 4.5 block fitted was my thoughts. But, as I've said I expect it was simply a typo on the advert.

Tim

[longbow]

Well the bore of the liners is different - 88mm for the 4.2 and 91mm for the 4.5 I believe, both have a stroke of 86mm and so are over square. Do you mean how to identify it externally with the engine intact? I doubt you could, you'd need to get inside and start measuring crank journal diameters and stuff......

[_Deejay_]

longbow said:

Well the bore of the liners is different - 88mm for the 4.2 and 91mm for the 4.5 I believe, both have a stroke of 86mm and so are over square. Do you mean how to identify it externally with the engine intact? I doubt you could, you'd need to get inside and start measuring crank journal diameters and stuff......

Assuming for a minute that it is a 4.5, wouldn't you be able to tell by the ECU mappings?
Tim, did you also mention that you have the 4.5 induction kit on it?

If it were mine, I'd take it to Joospeed and get it on the RR. I'd imagine he'd know what a standard 4.5 map looks like (and can probably quote each mapping point off the top of his head ). If it is a 4.5 block then I'd be remapping and making induction mods!

D

[TT Tim]

_Deejay_ said:

longbow said:

Well the bore of the liners is different - 88mm for the 4.2 and 91mm for the 4.5 I believe, both have a stroke of 86mm and so are over square. Do you mean how to identify it externally with the engine intact? I doubt you could, you'd need to get inside and start measuring crank journal diameters and stuff......

Assuming for a minute that it is a 4.5, wouldn't you be able to tell by the ECU mappings?
Tim, did you also mention that you have the 4.5 induction kit on it?

If it were mine, I'd take it to Joospeed and get it on the RR. I'd imagine he'd know what a standard 4.5 map looks like (and can probably quote each mapping point off the top of his head ). If it is a 4.5 block then I'd be remapping and making induction mods!

D

No, mine externally at least, looks pure 4.2. No evidence of it ever being a 4.5 other than the ad that I quoted in the first post.

Tim