A race bmw 316, m10, s14, m20, turbo, na, its been the lot!

[Roadsport]

Re: A race bmw 316, now S14 powered again!

What kind of exhaust do you have in mind?

[Graham]

Re: A race bmw 316, now S14 powered again!

done some physical work on the car today, made a new pair of engine mounts, the idea being to straighten the engine up a bit, so the sump works better, but mainly to give more space to get a decent exhaust manifold in, got to rejig gearbox mounts and linkage now

lh mount



lost the pic of the rh one but it looks pretty similar

[Graham]

Re: A race bmw 316, now S14 powered again!

some progress sort of, some time ago i bought a genuine 2.5 s14 head off ebay it was very cheap!





you now know why. clearly its dropped a valve, judging by one of the inlet guides being deeper into the port than all the rest its likely that what actually happened was it was buzzed or used an un-advisably radical cam on the std shim arrangement, std shims sit in the top of cam buckets and can be flicked out.

most likely a shim was flicked out, jammed and next time the inlet cam cam round, it tried to lift the cam way past its normal lift, the top of the retainer and collets punched the guide down and at the same time mashed a valve in a piston. ive just received a set of oversize valves from america, even with import duties etc etc they are a fraction of the price of buying them here. and have now dropped the head off to have it welded up and new inserts.

im just waiting on the new block to turn up, and some money so i can afford NEW valves springs, new steel followers and go to group A bda style top hat shims, so i can spend even more money on hotter cam, and not worry about it self destructing every time i rev it

[Graham]

Re: A race bmw 316, now S14 powered again!

maybe, but that might just down to plumbing, the oil leaves the pump via a dash 10 fitting which is about internal 14mm dia, goes into an adapter in the block which reduces things to 12mm, the oil ways in the block then makes a 90 degree turn to the main gallery which is about 10mm dia, so the galleries in the block cannot flow as much oil as the pipe from the pump, the original feed drilling into the block was even smaller, i opened it out, because the oil pressure is read after the block adapter but before the main gallery it might already be showing less pressure than the pump generates, and the actual pressure in the main gallery might be even lower still,

it could be if i open out the galleries the pressure will actually drop, but if thats the case its because theres more oil flowing to the bearings, and lets face it they need volume of oil more than pressure

[lee76]

Re: A race bmw 316, now S14 powered again!

Think 300bhp is about right for next year Graham thats what we are trying to hit. The cars should be close again next year it should be good fun with a few others joining in.

[Roadsport]

Re: A race bmw 316, now S14 powered again!

Could it be that you've met the limit of your pump? Well as you said earlier the Pace bays will propably have a clue whats going on.

[Graham]

Re: A race bmw 316, now S14 powered again!

theres more to it than that, the pressure isnt any different whether on lap 2 or lap 15, plus having a big dry sump tank i added about 3.5 litres more oil which would of meant the oil took longer to heat up and effect pressure but that had no effect

[Roadsport]

Re: A race bmw 316, now S14 powered again!

20/50 getting too thin when propper hot?

[Graham]

Re: A race bmw 316, now S14 powered again!

Does the Pace pump have an adjustable pressure release valve? Maybe tightenig it to raise the oil pressure would cause a bigger pressure to the big end thus leaving some oil for the mains.

it does though theres not much adjustment left and last time i adjusted it togive more pressure it made no difference on a hot engine. The more i think about it the more improvments i think i can make in the oil ways, its also probably time to switch oils, ive been running 20/50 because it always worked well in the past, but going to 10/60 is likely to help.

[Roadsport]

Re: A race bmw 316, now S14 powered again!

Does the Pace pump have an adjustable pressure release valve? Maybe tightenig it to raise the oil pressure would cause a bigger pressure to the big end thus leaving some oil for the mains.

[Graham]

Re: A race bmw 316, now S14 powered again!

since you have good oil pressure, will those mods help ? or are crank mods the only way due to the laws of physics working against you......... ?

yes it has good oil pressure, low rpm its as good as ever, but strangely not as good as it used to be with bmw cranks at high revs, which was something else confusing me, i think more oil way mods will fix it, but as i said i'll talk to pace, we might be able to fit wider pressure rotors to boost the pumps supply.

you see im now thinking ahead to further evolution's of the engine, stroking it out to 2.7 or 2.8. so i need to get to the bottom of whats happening.

why am i looking to go so big on cc? well in 2.5 form bmw got them upto about 365bhp, i believe rick wood got one to 380, but that requires so many revs it becomes a grenade and has a power band about 3 revs wide whilst lasting minutes between rebuilds, but i can go out to 2.8, then 350bhp should be achievable with some measure of reliability and a sensible power band, i had fun playing against cossies when it was turbo'd, now i want to beat them without one! i already beat some of them but the really quick ones just blow me away.

for the moment, if i can stop it wearing bearings and get a reliable and usable 300bhp i will be a very happy man

[alladdin]

Re: A race bmw 316, now S14 powered again!

since you have good oil pressure, will those mods help ? or are crank mods the only way due to the laws of physics working against you......... ?

[Graham]

Re: A race bmw 316, now S14 powered again!

right today i worked it out!

whats been bugging me is why the engine has been wearing main bearings, it never did as a turbo, or as an 8v, the other odd thing is bigends werent effected, indicating they were not being starved of oil which would suggest the oil supply was good enough and strangely the pressure always held up at low revs, as the oil supply system is the same 8 and 16v, the problem wasnt there, the blocks the same, yes i use more revs as a 16v, but not much more only about 200rpm, it kept coming back to the crank, but why would the steel crank wear mains?

today it dawned on me, the steel crank has two drillings feeding each big end, std bmw cranks one, at the same time i recalled something about long stroke high rpm mini cranks and cross drilling the oil way through the big end and plugging the origonal oil supply hole, the reason being at high revs centrifugal force was sending so much oil to the big end the mains were being starved, by turning the oil way through 90 degrees it reduced the centrifugal effect sucking all the oil from the mains.

it also perhaps answers anotehr thought, why did bmw use main bearing shells with 5 oil feed holes on the longer stroke 2.5 as opposed to 2 oil feed holes on the shorter stroke 2.3, to improve oil flow to the crank,

now im not about to go drilling and tapping galleries in the crank, but i figure if i can increase the oil supply to the mains i can have the same effect, i already mod some of the galleries to improve flow, but leave the main gallery largely alone, although i do know one well respected tuner that does mod the whole gallery. the other thing perhaps i should do is talk to pace about increasing the volume of oil the pump supplies.

[lee76]

Re: A race bmw 316, now S14 powered again!

Thats the only downfall as we all go quicker we get poorer.

[Graham]

Re: A race bmw 316, now S14 powered again!

Need to keep the reliability that has served you so well over the last couple of seasons mate, but that said iam sure everyone will be a little quicker next year so a few more horses are maybe a must.

your not wrong lee

thats mainly why i culled the season when i did, for fear of it going bang. lets not forget the entire top end of my engine was build from second hands bits, and the bottom end was built reusing second hand bearings! im scaring myself now though when it comes to replacing all those bits with proper new bits.
everything seems to be £250, valves were, so too will be valve springs and buckets, anything that isnt £250 seems to be multiples of that amount!