P1 and P2 t4 engine parts interchangeability...

clarkey1984 · Dec 14th, 2018, 22:13

Hi all, as you may have seen in my other thread about engines, I'll be getting the replacement b4204t5 lump for the t4 after the weekend, the seller is also chucking in a p1 t4 block and pistons that the cylinder head from the engine I'm buying was destined to be fitted to as the whole project has been abandoned, which is the 1855cc b41904t, obviously less CC, but as we know, the crank (and maybe also the rods) are forged as standard.

I have researched a little just now and seen that the 1855 has an 81mm bore whereas the 1948 is 83mm, and that's pretty much all the info I can find.

Logic tells me that this means a b4204 head will not fit this block, as this is what the seller was actually trying to do, although he stopped work with it because he could see that side by side the heads are different, but what with the many weird and wonderful Frankenstein ish engines I have encountered in the past, such as a ford cvh head on a zetec block, and something honda flavoured with a cylinder head fitted upside down, so I know that odd stuff can and does work, so just wondering if this could actually work, as I will obviously have my old engine which will have a perfectly decent head going to waste, but if not it doesn't matter, it's just an idea.

Many thanks in advance

960kg · Dec 15th, 2018, 18:39

All the heads are interchangeable....

The things that are not are the ECU/wiring loom as the T5 code compered to the T4 code has extra boost sensors to try and stop it splitting the liners etc.!

Only the pistons on the 1855 T4 are forged.

Dec 14th, 2018, 22:13	#1
clarkey1984 Premier Member Last Online: Apr 13th, 2022 09:41 Join Date: Jul 2014 Location: Beccles	P1 and P2 t4 engine parts interchangeability... Hi all, as you may have seen in my other thread about engines, I'll be getting the replacement b4204t5 lump for the t4 after the weekend, the seller is also chucking in a p1 t4 block and pistons that the cylinder head from the engine I'm buying was destined to be fitted to as the whole project has been abandoned, which is the 1855cc b41904t, obviously less CC, but as we know, the crank (and maybe also the rods) are forged as standard. I have researched a little just now and seen that the 1855 has an 81mm bore whereas the 1948 is 83mm, and that's pretty much all the info I can find. Logic tells me that this means a b4204 head will not fit this block, as this is what the seller was actually trying to do, although he stopped work with it because he could see that side by side the heads are different, but what with the many weird and wonderful Frankenstein ish engines I have encountered in the past, such as a ford cvh head on a zetec block, and something honda flavoured with a cylinder head fitted upside down, so I know that odd stuff can and does work, so just wondering if this could actually work, as I will obviously have my old engine which will have a perfectly decent head going to waste, but if not it doesn't matter, it's just an idea. Many thanks in advance __________________ 02 V40 T4 S, "Sargent silver" she's back!

Dec 15th, 2018, 18:39	#2
960kg Premier Member Last Online: Dec 28th, 2022 12:25 Join Date: Jun 2009 Location: Mercville	All the heads are interchangeable.... The things that are not are the ECU/wiring loom as the T5 code compered to the T4 code has extra boost sensors to try and stop it splitting the liners etc.! Only the pistons on the 1855 T4 are forged. __________________ Mercedes C320CDI Sport Estate 3 litre V6 7 Gear Auto Remap 290bhp 628Nm torque @ 1600revs 45.1mpg

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