Couple of 2.7i questions.

[digger]

with a mild cam as a minimum id opt for new set of stock springs. obviously some camshafts will require stiffer springs but on a mild cam stockers should be fine

[89325iturbo]

Thanks digger, figured that's probably the best route.

[digger]

bimmerheads offer a set which probably arent any more $$$ than stock ones so worth comparing the price

[89325iturbo]

Anyone know the specs on m30 b35 dual valve springs? Oem m20 dual valve springs, seem to be out of stock from a few sources (atleast the the outers). Curious if bmw used the same size springs,Part numbers are different, but maybe based on there spring pressure.

[jeffnhiscars]

I just ordered new BMW inner springs and they are $6@. Outer springs are the same.

6x$24 = $144 for a full set

[mikebloco]

Even if you could make the m30 springs work I bet the extra pressure would whittle your new cam down real fast.....Your valves would definitely shut though. Stay with m20 valves. I'm doing the 2.7i conversion in my 91 right now. I don't plan on running a turbo on this conversion unless I find a SETA crank or 524td crank so I'm going to be messing with my CR and keeping it NA for now. The proper and right way to that is with pistons but I've built motors in the past by excessive decking of the block and head. With the E block and i head you get 8.35:1 a bit of a drop. If you take 1mm (.039) off the block CR is 9.07:1. If you then take a mm off the head as well CR is 9.95:1. I need to go back out in my garage and check the second step but if tolerances are fine then.....fun times are to be had soon.

[89325iturbo]

Yeah figured spring pressures were different even if the same physical size. So the 7.8:1 number people throw out isn't correct? 8.35:1 isn't terrible. I'm not doing any turbo either.
Stock 325i is 8.8:1 correct?

Jeff were did you find your springs at? If it's a different place maybe they have outers. I called turner and bavauto both prices 5.95$ each. Turner was out of stock on outers and bav only had 10 outers. They would need to be special ordered from Germany said it would be 5-6 weeks. I wanna use stock m20 ones, was just curious about m30 ones cause they were in stock.

[mikebloco]

I honestly have no idea were people get the 7.8:1 but they are wrong. Yes stock i CR for a US m20b25 is 8.8:1
Heres a full set of OEM outers

http://www.ebay.com/itm/BMW-E28-E30-E34-86-93-Valve-Spring-Outer-30-2-mm-Diameter-Set-of-12-GENUINE-/291575914699?hash=item43e34760cb&vxp=mtr

[digger]

Yeah figured spring pressures were different even if the same physical size. So the 7.8:1 number people throw out isn't correct? 8.35:1 isn't terrible. I'm not doing any turbo either.
Stock 325i is 8.8:1 correct?

Jeff were did you find your springs at? If it's a different place maybe they have outers. I called turner and bavauto both prices 5.95$ each. Turner was out of stock on outers and bav only had 10 outers. They would need to be special ordered from Germany said it would be 5-6 weeks. I wanna use stock m20 ones, was just curious about m30 ones cause they were in stock.

the really low compression like ~8.0:1 is eta crank, eta rod, i piston, i head. the piston sits 2mm down the bore....

[mikebloco]

E rods. Duh!!

[jeffnhiscars]

Yeah figured spring pressures were different even if the same physical size. So the 7.8:1 number people throw out isn't correct? 8.35:1 isn't terrible. I'm not doing any turbo either.
Stock 325i is 8.8:1 correct?

Jeff were did you find your springs at? If it's a different place maybe they have outers. I called turner and bavauto both prices 5.95$ each. Turner was out of stock on outers and bav only had 10 outers. They would need to be special ordered from Germany said it would be 5-6 weeks. I wanna use stock m20 ones, was just curious about m30 ones cause they were in stock.

In your backyard. They held my order a few days til they had them in hand and they should be here tomorrow. I'll confirm when I have my hands on them.

They are listed at most of the usual online suppliers as are the outers but I can't comment on inventory.

[89325iturbo]

Gluten Parts, had plenty of inner and outer springs in stock according to there inventory numbers. @ 5.21$ each too. So I ordered them up, shipping was also cheap.

[jeffnhiscars]

I received a dozen of these today. They were shipped loose so I can't confirm much although the paint markings do seem authentic :)

Dimensions seem right and they came from eeuroparts.com in CT and were $5.99@