16v questions

[bikeidaho]

How possible is it to convert a 1981 245 2.1 to a 16v? Is it possible? Anyone done it? I wanted to do it to my 2.3 but I got rid of it so now the project car is a 2.1. Should I just turbo it? I really want a 16v though...

 

[MikeHardy]

you will need to modify the firewall. i can take pics of mine for you. but i'll have to do when it get light tomorrow

 

[Gofast]

Convert 2.1 into 16v? If I'm understanding you right you want to fit a 16v head to the B21? It is possible! But not a straight swap. The block (and maybe the head, I don't know... ) needs to be modified. I do know it's been done many times both in Norway and Sweden. But it's not worth it if you're asking me. Unless you're building a serious racecar...

 

[MikeHardy]

i had a look at dan's 16valve head pics and it looks like the combustion chamber matches the bore for the 2.3engine. so might not be sutible for a 2.1. maybe using a B204FT head which i assume as a smaller combustion chamber

 

[Oskari]

i had a look at dan's 16valve head pics and it looks like the combustion chamber matches the bore for the 2.3engine. so might not be sutible for a 2.1. maybe using a B204FT head which i assume as a smaller combustion chamber

You are right, b234 head requires 96mm piston.

 

[lilpaz]

So what if you just bore out the B21 block to 96mm? Technically wouldn't that fix the combustion chamber to cylinder bore problem?

 

[nohbudi]

it could, and at the same time it could trash your cylinder walls, and end up with premature water jacket failure.... the cylinder walls on the b21 block are just too thin.

 

[MikeHardy]

you'd be better off getting a B23/B230 block. already has the 96MM bore and pistons too.

 

[Oskari]

it could, and at the same time it could trash your cylinder walls, and end up with premature water jacket failure.... the cylinder walls on the b21 block are just too thin.

You based this statment on what?

 

[MikeHardy]

LOL says the guy with a bored out B19

 

[lilpaz]

But...there have been people who have bored out their B21 blocks out that much with no problem right? So it's just luck...

 

[towerymt]

the cylinder walls on the b21 block are just too thin.

That's wrong without further qualification. A B21 can and has been safely bored to 96mm. However, not every B21 can be safely overbored that much.

But...there have been people who have bored out their B21 blocks out that much with no problem right? So it's just luck...

If the block is not checked for wall thickness, THEN it would be luck...

 

[Guest]

i have an extra b21ft in a parts car that i have been thinking about boring over to put b23ft pistons in. the engine would be a 16V turbo of course... what is the general idea of the min. wall thickness for a HO turbo engine?

didn't IPD used to sell a big-bore kit for the b21s?

 

[Oskari]

Copy and paste from our Finnish Volvolandia board:

" B21=2.35mm
B19=2.1mm
B19SN=2.9mm
B23 =3.6mm "

Those are wall thicknes figures, when each are borred to 96,01mm (b23 standard)

Written by Finnish machinist J. Hiipakka.

 

[TDi244]

Is there any way (machining, porting etc) to properly fit a 16v head to a b21ft block?

 

[dl242gt]

I've thought about doing this also. However, it's just so much easier
to get a 2.3 here in the US. So, why fight it? Just get yourself the
bigger motor because it's going to make more power and it won't
really cost any more to do. In fact if you get a B23FT or B230FT it'll
already have pistons you could use. Just have to get valve reliefs
machined into them.

B214FT does sound cool, but...

 

[TDi244]

True that. Any advantage of having one block compared to another? For example, could the b21 rev a bit higher due to less piston mass? Or is the speed limit the valvetrain, etc? Slightly off topic I know...

Edited for... I read somewhere that the b21 block is a thicker casting, as well as the b23ft. How do they compare to the b234?

 

[Hank Scorpio]

B21FT's will have M rods :wink: and are alot easier to find than b23FT's. Rob has b23F pistons in his 242 (b21)

 

[Anonymous]

First of all: the b234 head does NOT need 96mm pistons, but 94mm...
BUT
i can't see why you all have to try forcing the heads on old bXX-series blocks.

the b234 block is from all points of view superior to the old bXX blocks. and why do you think they put an external oil pump on it? yes, to feed 16v head and if the crank (which i look upon as being the weakest part of the engine) doesn't meet your requirements you can always do a few small modifications to fit a bXX crank. Stock b2X4 cranks will withstand at least 700hp. the newer blocks also have pistons that are able to handle LOTS of more power than the old cast and hypertheuntic pistons of the bXX engines. There are b234 turbo engines running stock pistons with over 500hp in sweden. some even claim that they can withstand more power than the forged ones of the b23et.


//tobias -- finland

 

[Hank Scorpio]

Very cool stuff to know.

We'll find out soon how stong a B234F is when turbo'd (exactly what Im building).