Can anyone tell me the combustion chamber volume for a 149/161 small chamber kidney shaped head??.
Or alternatively what compression ratio I'd get with a 149/161 head on a 179??
Or even betterer stiller would anyone have a chart with the various combustion chamber volumes for the various red heads so i can work it out meself.
I did have a chart from a mag years ago with various cyl head volumes but wouldn't have a clue where it is now.
I'm just too lazy to go out and and cc the head and was hoping someone may already know.
Terry.
Combustion Chamber Volume 149/161 Head
Combustion Chamber Volume 149/161 Head
I can't think what to write here so this will do.
Hi Terry.
This one gets asked regularly. I'll see if I can answer it for you.
The official nominal combustion chamber sizes for Holden Red motor cylinder heads is 45cc for the small (kidney-shaped) chamber & 54cc for the larger chamber. I say 'nominal' because they vary drastically because they are 'as cast' not machined. They can even vary from chamber to chamber in the one head, this explains why some motors are more powerful or smoother than others from new.
If you put a stock 149/161/173 head on a stock 179 engine you will get around 9.6:1 comp ratio. If you put the same head on a stock 186 or 202 you will get around 10:1. My advice would be to cc your head if you want to do it accurately, as I said they are pretty rough from the factory.
Dr Terry
This one gets asked regularly. I'll see if I can answer it for you.
The official nominal combustion chamber sizes for Holden Red motor cylinder heads is 45cc for the small (kidney-shaped) chamber & 54cc for the larger chamber. I say 'nominal' because they vary drastically because they are 'as cast' not machined. They can even vary from chamber to chamber in the one head, this explains why some motors are more powerful or smoother than others from new.
If you put a stock 149/161/173 head on a stock 179 engine you will get around 9.6:1 comp ratio. If you put the same head on a stock 186 or 202 you will get around 10:1. My advice would be to cc your head if you want to do it accurately, as I said they are pretty rough from the factory.
Dr Terry
Thanks DR T for the reply.
Knew it would be a fairly regularly asked question but couldn't find an answer to it anywhere when I tried to look.
I've got a 149 Yella Terror head to go on a 179 and was wondering approx what compression ratio I'd end up with.Chamber doesn't look to be relieved so it looks to be factory standard size chamber with the YT valves.
So now I know without having to cc my head although I'll probably end up doing it anyway down the track.
9.6 to 1....... Hmmmmm............. Don't think she'd run too well on Woolworths "no frills" 91 octane
...would probably nearly be a candidate for a premium petrol guzzler!
Again,thanks for the info DR T....... helps heaps!!
Cheers,
Terry.
Knew it would be a fairly regularly asked question but couldn't find an answer to it anywhere when I tried to look.
I've got a 149 Yella Terror head to go on a 179 and was wondering approx what compression ratio I'd end up with.Chamber doesn't look to be relieved so it looks to be factory standard size chamber with the YT valves.
So now I know without having to cc my head although I'll probably end up doing it anyway down the track.
9.6 to 1....... Hmmmmm............. Don't think she'd run too well on Woolworths "no frills" 91 octane
...would probably nearly be a candidate for a premium petrol guzzler!Again,thanks for the info DR T....... helps heaps!!
Cheers,
Terry.
I can't think what to write here so this will do.