AJP Engine Numbers

[TVdinneR]

Noticed this across in the "General" section.

http://www.ebay.co.uk/itm/TVR-CERBERA-EXCELLENT-CO...


Just a question.
I know some later 4.2`s can be 4.5 blocks with 4.2 inlet and this can be checked via the engine number, ie number contains either 4200 or 4500.
Was there ever a time when a 4.5 would have an engine number showing 4200 ?

[Mr Cerbera]

Never heard of that combination or possibility but you never can tell with TVR

[Jhonno]

Maybe he is saying 4.5 knowing it is a 4.2 with a 4.5 bottom end..?

[anonymous-user]

TVdinneR said:

Noticed this across in the "General" section.

http://www.ebay.co.uk/itm/TVR-CERBERA-EXCELLENT-CO...


Just a question.
I know some later 4.2`s can be 4.5 blocks with 4.2 inlet and this can be checked via the engine number, ie number contains either 4200 or 4500.
Was there ever a time when a 4.5 would have an engine number showing 4200 ?

Yeah, mines a 97 4.5 with P42 on the engine stamp.

[TVdinneR]

Mr Cerbera said:

you never can tell with TVR

Yes, I had considered that

[TVdinneR]

djstevec said:

Yeah, mines a 97 4.5 with P42 on the engine stamp.

Well there you go - proof indeed.
Question answered.
Next question - Why did they do that ?
Why introduce a numbering system to identify a particular engine configuration then apparently just choose to ignore it ?
That`s just going to be downright confusing...isn`t it ?

[anonymous-user]

TVdinneR said:

djstevec said:

Yeah, mines a 97 4.5 with P42 on the engine stamp.

Well there you go - proof indeed.
Question answered.
Next question - Why did they do that ?
Why introduce a numbering system to identify a particular engine configuration then apparently just choose to ignore it ?
That`s just going to be downright confusing...isn`t it ?

There's a big old thread about the "GT" cars so not going to go too far into it, but AFAIA, mine is one of first batch of 4.5's TVR made, prior to them deciding to go for a proper 4.5 production run. The GT stamp signified the difference in the engine capacity at that time, but not sure when (or if) the P45 stamp became standard for a 4.5.

Edited by djstevec on Friday 1st February 12:29

[TVdinneR]

djstevec said:

There's a big old thread about the "GT" cars so not going to go too far into it, but AFAIA, mine is one of first batch of 4.5's TVR made, prior to them deciding to go for a proper 4.5 production run. The GT stamp signified the difference in the engine capacity at that time, but not sure when the P45 stamp became standard for a 4.5.

Right, so the earlier the 4.5 the more chance it has of having the 42 engine number ?
Kinda makes sense as the advertised one above is an "R" reg.
Would that mean that this particular car should also have the GT stamp to signify the larger capacity ?
Once the proper 4.5 production was up and running then the 45 engine numbers started to appear ?

Edited by TVdinneR on Friday 1st February 12:42

[anonymous-user]

TVdinneR said:

Right, so the earlier the 4.5 the more chance it has of having the 42 engine number ?
Kinda makes sense as the advertised one above is an "R" reg.
Would that mean that this particular car should also have the GT stamp to signify the larger capacity ?
Once the proper 4.5 production was up and running then the 45 engine numbers started to appear ?

Edited by TVdinneR on Friday 1st February 12:42

The engine number 00758, looks a little high for it to be a "GT" stamped engine. From memory of a conversation with APM about 18months ago, the initial run was only around 10 engines. But perfectly feasible for TVR to have a batch of blocks originally cast with P42, that were then modified to be 4.5's subsequent to the go ahead of the 4.5 production.

There will be many on here with greater knowledge of the engine history that will pop along shortly I'm sure.

[TVdinneR]

djstevec said:

The engine number 00758, looks a little high for it to be a "GT" stamped engine. From memory of a conversation with APM about 18months ago, the initial run was only around 10 engines. But perfectly feasible for TVR to have a batch of blocks originally cast with P42, that were then modified to be 4.5's subsequent to the go ahead of the 4.5 production.

There will be many on here with greater knowledge of the engine history that will pop along shortly I'm sure.

Many thanks for all the info.
Appears you have a decent knowledge yourself regarding these engines.

[anonymous-user]

TVdinneR said:

Many thanks for all the info.
Appears you have a decent knowledge yourself regarding these engines.

I can only really say what I read on the GT thread and from my conversations with APM, but hopefully its accurate!

Aside from capacity, the main difference from the 4.2's to the "GT", is the GT's had a steel billet crank in favour of the cast cranks on the 4.2's. But pretty sure TVR went back to cast for the 4.5's on cost grounds. APM reckoned if I needed to replace my crank I'd be looking upto two grand!

[Steve_T]

Suspect the billet crank thing was quite simple. TVR would have done a short run of billet cranks when developing the 4.5 capacity, before committing to the cost of getting molds done for a production run. The first few GTs/4.5s would have had a billet crank to use up the stock, but it's quite possible not all did. I also have a GT but I've no idea if there's a billet crank in there. I hope I don't need to find out for a good while yet too!

[FUBAR]

Mine's an early 4.5, stamped GT and has the steel billet crank. '98 R

[APMAUTO]

Steve_T said:

Suspect the billet crank thing was quite simple. TVR would have done a short run of billet cranks when developing the 4.5 capacity, before committing to the cost of getting molds done for a production run. The first few GTs/4.5s would have had a billet crank to use up the stock, but it's quite possible not all did. I also have a GT but I've no idea if there's a billet crank in there. I hope I don't need to find out for a good while yet too!

all the gt's iv'e seen apart have billet cranks lifted from the challenge car parts stock 4.2s and 4.5s share the same stroke, cast cranks came in as a cost saving and coincided with the dropping of the gt stamp afaik

[HarryW]

I understand the first 4.5 race engines also shared the small journal crank of the early 4 .2 engines. So you could have a small journal billet cranked 4.5 as some made it into customer cars.

[APMAUTO]

HarryW said:

I understand the first 4.5 race engines also shared the small journal crank of the early 4 .2 engines. So you could have a small journal billet cranked 4.5 as some made it into customer cars.

true harry but most of these had extra welded on counter weights so they could rev without exploding like early cerb cranks a very few small jornals were made in billet with the extra wieghting as one piece rare as rocking horse do-dah i've only ever seen one

[Jhonno]

As ever then TVR decided to keep it consistent..

[Steve_T]

APMAUTO said:

all the gt's iv'e seen apart have billet cranks lifted from the challenge car parts stock 4.2s and 4.5s share the same stroke, cast cranks came in as a cost saving and coincided with the dropping of the gt stamp afaik

Happy days!

Thanks Andy

[TVdinneR]

Thanks to all for the informed replies.
Amazing the knowledge out there
Never as straight forward as you would think
but then, hey, it's TVR and you wouldn't have it
any other way