9 replies to this topic

[MIGLIACARS]

Ok.
A pal of mine is having a race engine built. It's the 16v head BMW. Its been in the dyno and it's peak power is at 9000rpm. Claimed.

I responded wow lots of revs for an a series.

As the conversation unfolded I explained that the old cam is still in there and used for the oil pump so all the a series timing gear is all still turning.

He claimed that all this is removed.

Ummm I thought.

Surely it's still in there for the oil pump??????

[GraemeC]

Unless he has some form of external electric scavenger pump fitted?
Otherwise, yes the cam will be required to turn the pump as a jack shaft - it could have all the lobes etc turned off it though.

Edited by GraemeC, 11 January 2015 - 06:15 PM.

[mini93]

Indeed, called a jack-shaft by some, although it doesnt need any timing in, I would assume a normal simplex would surfice.

 

Can you get electronic oil pumps?

[Fast Ivan]

Normally yes for the oil pump only, not for timing though, so no chain, this is replaced with belts

[mini93]

Actually thinking about it, does the belt to the OHC replace the convential timing set up? so it would look like a idle pully from the ouside, but really its turning the jack shaft

[MIGLIACARS]

Actually thinking about it, does the belt to the OHC replace the convential timing set up? so it would look like a idle pully from the ouside, but really its turning the jack shaft

Yeah that's it pal there is a big pulley there. So it must replace the timing gear. But cam must still be there for the oil pump.

[ANON]

http://www.twinkam.c...d=25&aid=SC068

[sledgehammer]

The cam has a groove machined in the front bearing to increase the oil flow to the head & de lobed

 

would be the easiest way to do an oil pump anyway

 

9000 rpm - scary for an a series bottom end - even if up rated

Edited by sledgehammer, 11 January 2015 - 06:56 PM.

[MIGLIACARS]

I know. 9000 rpm for 20 mins at a time. Racing.

It's a 1500cc now too. Stroked crank.

[Spider]

A good friend of mine used to do Honda Headed Mini Engines, similar to the BMW idea, Twin Cam, 16 Valve.

 

He always drove the Oil Pump off the rear Cam on the Head and the Dissy from the front one. This then allowed him to plug the Oil Feeds in the Block to the original Cam and do away with the Cam in the Block. There were several reasons he did this, but I think the main reason was to reduce the profile at the water pump end and bring the Cam Belt closer to the Block.

 

I have no idea if this can be done with the BMW conversion.