2,5 tdi block with 7a head?

[Mikemul]

Hello is it possible to Get a 2,5 liter diesel engine and place a 7a head on it? The compression ratio with a normal 2,5 is 19,5:1 hoe can you lower that? Does the head bolthreads at the same place as a normal 2,3 or 2,2 engine ? I saw a video on youtube that have a 2,5 20v build from a diesel engine are there some topics on here ?

[Tom_]

Its a diesel block with diesel crankshaft and petrol 7A/3B/AAN head, but there is need few modifications on the block. You can use that 7A head, but you need to change conrods for a 155mm or 159mm lenght rods with stock pistons or some "stroker" pistons.
You also need to redrill the head holes for bolts as in the block are bigger holes.

[SSPRL]

Hi. I can use 2,5tdi ACV block from vw t4?

[michaels2s]

Hi yes you can use the ACV block......but when you want to use the original trigger for ignition and rmp you have to mill the face for connecting them to the block.you can copy them from a AAN block.Also you have to do some more modifications when you want to fit the 20v head on the diesel block.

-Drill the holes in the 20v Head from 11mm to 12 mm
-close the big Oil return in the back of the block
-close the hole for diesel crank timing sensor
-need to weld a pice of metal on the block for the 20V gasket (put the gasket on the block and you will see) need to surface the deck of the block
-drill the back hole for the heating colant hose conector (Diesel block is closed)
-need to drill a hole for oil dip-stick
-need to drill 3 holes for timing belt tensior roller
-put out the metal plug for crank case breathing (Diesel block is closed)
-put out the metal plug for turbo water line (Diesel block is closed)

Hope this is it maybe some individual stuff

Br Michael

[Tom_]

No need of drilling hole for a dipstick on AAT engine block and no need to drill 3 holes for timing belt tensioner roller if you have a oil pump with tensioner roller.

[twenty valve]

Have a read through this thread, you'll find nearly all the information you need. https://www.s2forum.com/forum/member...-gentle-stroke

I did one a few years back but cant remember everything which goes into it. Looks like michaels2s has done a pretty good job of summarising it anyway.

[SSPRL]

thanks for the info!

[SSPRL]

Is it possible to modify the block head? I would like to avoid welding the block

[Tom_]

No need to weld a head as that headgasket is on the block and there is a tiny little part of headgasket in the "air" with no support of the block

[_ShurikeN]

Head can be modified instead of block if turbodiesel headgasket is used.