Cooling water passage on 2.5 stroker block

[flipper172]

Hi,

I am using a VW T4 2.5 petrol block for my stroker build.

The cooling water passage next to the thermostat is too small for the 2.2L head.
So there is a gap of a few millimeters.

What is the best way to "fill" this gap?

I have seen some people doing a weld, others bolted a machined flange on there.
And welding on a cast iron block seems to be very difficult.

By the way: Except the missing oil squirter bores, the petrol block is very similar to the diesel block.

[AndyP]

Get somebody who knows how to weld cast iron to weld it, that's what I did.

[Wrath]

planning on doing a stroker build as well and all I´ve talked to that have built similar stroker engines say to weld the aluminiumhead and not the block... I will weld the head...

[diesel des]

I welded mine with high nickel rods. Used a block of mild steel cut to fit the space. Then had block skimmed. Simple enough.

[flipper172]

OK, thanks.
Indeed welding the head is the easiest way. Unfortunately my head is already rebuilt.
Tomorrow I will ask some welders if they can do it for me, because for myself I do not dare to weld on the block.

[diesel des]

Really I found welding the block easy. Just weld a small amount then stop and pean what you have done with a hammer. Then repeat. Just maybe 10mm at a time.

[flipper172]

Ok, I will have a try when my welders around here cant do that for an appropriate price.
With how much amps did you weld that?

[diesel des]

2.5mm rod at about 80 amps I think.

[Dima ABY]

Exactly!!!Just one point.Do not hurry up.Between every 10 mm weld make pauses.Heat make distortion.Wait few minutes,carefuly/fast tuch the peace.If you can tuch it,advance.

[diesel des]

I'm no welding expert but this is how I do mild and cast steel joining.

I use these rods





I follow the instructions saying do short welds and don't heat up the casting. The only extra thing I do is to pean the weld with the slag hammer. Chip the slag off but keep tapping it until it cools. An experienced welder told me this is important with stress reliving cast welds. The welds don't look tidy like mild steel welds. Don't try and make them tidy. Just a simple few seconds and lift. Looks like this.





Hope that helps.

[flipper172]

Thank you!
Your weldings look quite good! Yes I was about to ask if I need to heat it up or not.
Should I let the block cool down for a few mins after welding it?

[varia]

you might want to check this: https://www.youtube.com/watch?v=Yopcz-IYDyQ

[diesel des]

Yes let it cool down between welds. Just a few minutes is fine. That video is exactly what I do!