is a late 4.2 really a 4.5?

[sjc1969]

Hi,
I have been reading about the forum threads and a TVRblog and have heard people mention that a post 2000 4.2 Cerb has a 4.5 bottom end. I read there were some differences: inlets, ecu mapping etc.

Seems a daft question i know but i have to ask: Are the late 4.2 Cerb engines actually 4.5cc capacity engines? Hope that made sense.
cheers
Steve

[bionicjim]

Yes the bottom end block / pistons / crank

[mikeinsheffield]

Hi I have a 2002 "4.2" and it has always been "very healthy" on the dyno.... with some very light porting, a Jools remap, it has repeatedly made 393-399bhp on the RaceProoved (Jools old) dyno.....

When the head gasket went pop and the head came off - we confirmed that it was a 4.5 in capacity, but obviously has the 4.2 induction etc

[C3BER]

A 4.2 is a 4.2 and not a 4.5 in any way shape or form.

I know that because it says so on a badge on the boot

[sjc1969]

wow how interesting. That must make the late 4.2 models easier to tune like the 4.5 are?

[gruffalo]

Yep, some say that as they have the 4.2 induction system which makes the car easier to drive they are the best ones.

[Mags]

My '04 4.2 appears to be 4.5 internals, on an RR session at Austec Paul said the torque at lower rev's gives it away, the 4.2 induction becomes the limiting factor at higher revs I am told.

What are the differences from a factory 4.5 and a late 4.2 apart from the induction setup? Are the heads different, manifolds, exhaust, ECU?

Mark

[sjc1969]

Mags said:

What are the differences from a factory 4.5 and a late 4.2 apart from the induction setup? Are the heads different, manifolds, exhaust, ECU?

Mark

Taken from TVRblog.com:

Late Cerbera 4.2…
There’s an interesting question to point out. A late 4.2 cerbera has a 4.5 engine with different inlet’s. The 4.2 inlet’s make it a better car to drive low down compared to a 4.5 due to the position of the injectors in relation to the throttle butterfly’s. It is possible to check if it has a 4.5 engine by looking at the engine number if it is a 4.2 it will have 4200 in the number and 4500 if it is a 4.5. The change came in late 1999 and the engine can be checked via the engine number (If it is a 4.2 then the engine number will say 4200 and if it is a 4.5 then it will say 4500). If it is a 4.5 inside but is in a 4.2 car the cam timing is also different but this can be adjusted to make it a true 4.5. Of course you could trasnform a 4.2 into a 4.5: if you use a 4.5 ECU and throttle body’s it would be a 4.5 set up, also the exhaust manifold’s were different.
The reason why TVR did this with the engine was to save on cost of not having to carry stock of different item’s for 4.2 and 4.5 Cerbera’s. Also the early 4.2 is known for it’s noisy cam’s, this is not a fault it is just due to the profile of the lobe on the cam.

[Mags]

sjc1969 said:

Taken from TVRblog.com:

Late Cerbera 4.2…
There’s an interesting question to point out. A late 4.2 cerbera has a 4.5 engine with different inlet’s. The 4.2 inlet’s make it a better car to drive low down compared to a 4.5 due to the position of the injectors in relation to the throttle butterfly’s. It is possible to check if it has a 4.5 engine by looking at the engine number if it is a 4.2 it will have 4200 in the number and 4500 if it is a 4.5. The change came in late 1999 and the engine can be checked via the engine number (If it is a 4.2 then the engine number will say 4200 and if it is a 4.5 then it will say 4500). If it is a 4.5 inside but is in a 4.2 car the cam timing is also different but this can be adjusted to make it a true 4.5. Of course you could trasnform a 4.2 into a 4.5: if you use a 4.5 ECU and throttle body’s it would be a 4.5 set up, also the exhaust manifold’s were different.
The reason why TVR did this with the engine was to save on cost of not having to carry stock of different item’s for 4.2 and 4.5 Cerbera’s. Also the early 4.2 is known for it’s noisy cam’s, this is not a fault it is just due to the profile of the lobe on the cam.

Cool, thanks.