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Re: A race bmw 316, 240bhp Atmo M10 now going s14 power!
right been busy, the place i got the head from also had a cam carrier, unfortunately they didnt have the caps! although as luck would have it i found them on another shelf, well most of them, 2 were nowhere to be found, a shame really because i had sold my own cam carrier for not that much money not realising they are getting thin on the ground, still available new if you have £1100 plus vat though, a phone call to someone else netted a couple of caps, in theory, you cant use the caps from another carrier but i decided to take a chance, as its only one cap of each cam i figured i could do some fettling if needed, but the hope was bmw's machining was good enough in the first place it wouldnt be needed
luckily that proved the case and the odd caps fitted fine and the cams still turned
moving on, it was time to look at cams, i have 4 in all, two are factory 220bhp spec evo cams and two are supposedly group n cams, TBH i dont really know what a group N cam is, i know its fairly std but must give more power, now its not easy to meassure the cams in the cam carrier so i chucked them up in the lathe, by running some making tape around the chuck and meassuring its curcumference i can convert markings on the tape into degrees, by ignoring the first 15 thou lift (tappet clearance) then the next 40 thou, i cam up with a set of lift figs in degrees, doubling the figs to turn them into crank degrees i had some idea of the duration of the cams relative to each other the evo and group N exhaust cams were almost identical, but the inlets differed the group N only had about another 4 degrees of timing but it has about 100thou more lift which will come in very handy
after the cams it was time to see the feasability of adapting my m10 manifold and jenvey set up to fit teh s14 and it looks pretty feasable
finally i set about opening up the rest of the ports to big evo port spec, thers a hell of a lot of grinding needed and frustratingly my die grinder died on the last port
Last edited by Graham; 20-11-2010, 11:32.Comment
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Re: A race bmw 316, 240bhp Atmo M10 now going s14 power!
I do love a nice E30, there is a local chap in Germany who I met who runs a M3 built up with Grp A spec parts. I did 5 or so laps with him and was totally shocked how well it performed. SUCH a nice sounding engine and the car was flawless. I'll dig out some pics !Comment
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Re: A race bmw 316, 240bhp Atmo M10 now going s14 power!
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Re: A race bmw 316, 240bhp Atmo M10 now going s14 power!
oh nice, thanks for the pics
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Re: A race bmw 316, 240bhp Atmo M10 now going s14 power!
No problem, keep up the good work, I find this is a really interesting thread
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Re: A race bmw 316, 240bhp Atmo M10 now going s14 power!
two updates in 1 day! after knocking out and filling dents in the alfa i turned my attention back to the beemer without a die grinder i couldnt make progress on the head so it was either tidy up or find something else to do, i found something else, machine some pistons, i had a spare set of flat tops made for the m10, so all i had to do was put some valve cutouts in them, as they were designed to take cutouts for the m10 valves i knew they had thick enough crowns to take the cutouts, but machining them when each piston has 4 and getting them all in the right place and depths is bloody difficult unless you have a proper proper milling machine as opposed to my sealey hobby machine, so i decided to mill slots in the pistons instead as it meant once i had set up to do one cut i could do all the inlets then exhausts without adjusting anything, well that was the plan and it worked just!
the difficulty i found was for some reason the jig which i had previously used to great effect didnt clamp the pistons in quite the same place each time, probably made worse by me having to use a smaller piston with a different compression height to the ones i was machining to set things up
back obviously are the new pistons, front right is a modified 94mm turbo v6 piston which i used when the motor was turbo'd complete with DIY valve cutouts and front left a std m3 piston
unusually for a build of mine i wasnt worried about gaining every last scrap of compression, which is another reason i went for a slot rather than individual cutouts, as a std 2.3 s14 is 10.5:1cr with dished pistons and mine will be 2.6 with flat top pistons so i will probably have more compression than i need on the mild cams i have, infact a quick calculation tells me the compression is likely to be around 11.75:1, pass the octane booster please................
im glad its done now i hate machining pistons, too much risk of things going badly wrong, i certainly wouldnt want to do anyone elses!Last edited by Graham; 20-11-2010, 20:20.Comment
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Re: A race bmw 316, 240bhp Atmo M10 now going s14 power!
I know what you mean about machining pistons. Last time I machined the crown of a piston on the lathe I had some back lash on the top slide and when the tool cut into the crown it dug in a lot farther than I wanted. No major damage done but like you I would not want to be doing this too often.To finish first, you must first finishComment
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Re: A race bmw 316, 240bhp Atmo M10 now going s14 power!
its when the pistons fly out the chuck and across the room the real fun starts!
in a moment of what do ii do next i took an angle grinder with a stiff wire brush to a couple of bits of the floor on the new shell, it took all the underseal off very nicely, i must say at this point i am wondering about the wisdom of dipping the shell, as its actually very good, and would seem a shame to remove the factory rustproofing from all the cavities as clearly its doing a good job, plus doing it with a grinder wil save me ££££.
after the wire brush wore out i turned my attention to the inlet manifold, the s14 inlet port is heavily downdrafted, the m10 isnt, so i've machined the inlet manifold flange at an angle making less of an abrupt turn to the inlet.
the top flange is now pretty thin, but i plan to bond the manifold on so the mounting lugs dont take all the strain, plus i'll add and extra mounting stud or two in the centre of the manifold which is still nice and thickComment
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Re: A race bmw 316, 240bhp Atmo M10 now going s14 power!
its a deal, especially as im hoping you get the right pistons that wont need machining in the first place
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Re: A race bmw 316, 240bhp Atmo M10 now going s14 power!
thats some days work
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Re: A race bmw 316, 240bhp Atmo M10 now going s14 power!
a bit of googling told me that a group n cam can vary the timing by +/- 2 degrees, which fits very nicely with the 4 degree timing difference i found between the group n inlet and std one,
i have to say the thought of all that compressions worrying me now, obviously i can machine more off the pistons to lower it which seems a retrograde step, what the motor really needs is cams to make the most of the compression, i'd ruled out buying cams because i simply dont have the cash for them, and if your gonna buy cams its seems pointless just buying slightly warmer ones, but very very expensive to go the whole hog and go to group A shims plus the close ratio gearbox to go with them!
what im currently considering
is moving an inlet cam over to the exhaust and getting an inlet reprofiled to something like a BD3, should be a relatively cheap way to get a bit more cam into it, although i might have a shimming issue if the reprofile takes the cam out the std shim range, machining the top of the head or cam carrier would be an option whilst using a factory spec cam on the exhaust
i guess what i need to do next is workout what my cr will be, not easy without all the bits and a broken bureette
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Cars, because you can't get enough kicks out of walking fast.Comment
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Re: A race bmw 316, 240bhp Atmo M10 now going s14 power!
having just been clever and mended an old bureette by gluing the end of a syringe to it
i meassured the head cc, put the bureette away again only to have it fall on the floor and smash
its 42cc which with my flat topped pistons gives me a wonking great 13.8: cr! skim the head a tad and i'll be able to run it on diesel
i've got no choice, cams or no cams i'm going to have to machine the pistons more !
edit:- crunching the numbers absolutely confirms it, to finish off at about 11.5:1 i need to loose about 10cc which is about 1.5mm off the entire face of the piston, it wont do the squish clearance any favours, but then again the turbo motor didnt have any squish and that coped just fine and it will mean the pistons arnt running right up into the decomp plate which is probably a good thingLast edited by Graham; 21-11-2010, 15:37.Comment
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