531 Head

[James_N]

Hi

Seen these mentioned a few times on the forum, and more recently, in a thread on the forsale forum:

940 B230 engine with 531 head (normally aspirated) - complete from a running car, although been in my garage for about a year £75

Obviously I know what the head is, and I have an n/a B230E, but could someone explain to me:

- Whats a 531 Head
- Would it be better than the head I currently have on my '89 740 B230E
- If no, Why not, and if yes, Why?
- Would there be any power gains?
- Any other advantages to fitting a 531 head?

Also seen them mentioned on Tbricks a lot.

Cheers
James

[minesa240x3]

Hi james,I can't remember the specifics but basically there are two types of head fitted throuout the 200,700 and 900 series,from what I can remember the non turbo pistons are less dished in the combustion part up by the top of the piston and the turbo pistons have a deeper dished area so as to lower the compression. Now comes the tricky part,My old "B"reg 240 with a B200K non turbo has the same head as my "J"reg 940 B200FT Turbo the 530 head??
Only difference is that the valves in the 940 are made of stronger or harder metal,Do a search for 530,531 head and some one with more technical knowledge can explain better!I am about to do a head change on the 940 as the head gasket has gone.I was told that there are only two types of head on the redblock engines one for the 2 litre(530) and one for the 2.3 (531).
Brian.

[jacksonb123]

There are more than 2 different head types on the redblocks, 530, 531, 405, 398. My 1983 760Turbo has a 405 head on a B23ET redblock.

I'm no expert here though, just reading stuff to get to know this myself. I'm guessing that when for example you start of with a B23 like 'Tuning Redblock' was selling & you want to turbo it, part of the job would be to add different pistons with more of a dish to lower the compression ?

Actually, just found this link on Turbobricks which has a good bit of info :-
http://turbobricks.com/specs.php?content=sohc_heads

Ben

[HappyGreySquirrel]

Originally Posted by minesa240x3

I was told that there are only two types of head on the redblock engines one for the 2 litre(530) and one for the 2.3 (531).
Brian.

I think you might have to go and slap whoever told you that on the back of the legs... My 740 has the 2.3 litre lump and a 530 head, there's a chap local to me Southampton selling a 2.3 Engine with 531 head. I believe that the 531 head is a better flowing head and more able to be tuned easily, but I'm still groping my way around and finding out!

[foggyjames]

Ok...chapter and verse!

The "normal" 8v heads for the B230 were the 530 and 531. For the UK market, 531s came on B230ET cars (most 740/760 turbos) and mid 90s non-turbo 940s with the B230FB engine. Turbo 531s got filled/coated exhaust valves. Everything else got a 530.

The B200 only came with the 530.

The later B230K engines were a 'heron' design, with the combustion chamber located in the piston, and a 'flat' version of the 530, which was called the 631.

EDIT (I knew I forgot something!): The 398, 160, 405, etc, were all heads for the old "high-friction" redblocks - the B17, B19, B21 & B23. The 405 is the 'hot' one, like the 531. If the original quote was that the 530 and 531 were the only 'standard' 8v heads for the B230, that's quite correct...but there are a few additional qualifications there

Trivia: the B234 (16v) head is marked 532!

As for whether or not it's worth it...probably not, to be honest. If you're swapping heads anyway (due to corroded water passages, for example) and you happen to find a clean 531, or if you plan to modify the head in the future, then it's worth doing. But if you're just slapping it on and not touching it, the improvement is minimal. The casting supposedly has more meat on it, allowing more extreme porting, and a better port design to start with.

cheers

James

[LankyTim]

Doesnt the spark plug stick into the combustion chamber more on a 531 so the mix burns better?

[foggyjames]

I think you might be right Tim. The word "unshrouded" springs to mind. I do have both downstairs, but I'll too lazy to go and look

cheers

James