ABF tuning...then, to now...

Discussion in '16-valve' started by Ess Three, Mar 5, 2009.

  1. Ess Three Forum Member

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    Got ya...
    I was getting hung up on the swapping of cams and moving the powerband about, as that's all I've managed to do thus far by swapping cams in and out, and swinging cam-crank timing.

    I think I'll need to get the standalone on again to play further.

    I should be able to gain 'something' by advancing the cam-crank timing...but to achieve what you suggest, can you point me in the right direction cam-cam wise?

    Either way, it sounds like another expensive day on the dyno, and more burned hands from playing with cams corered in hot oil!
     
  2. Brookster

    Brookster Paid Member Paid Member

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    268/268

    my mate Paul Bargate had these cams in his Rocco 2.0L 16v before he went 2.1 and was getting 215 BHP with the 45mm Weber Alpha set up.

    The Exhaust duration is very good when running Nitrous oxide.

    The 300 deg CAT Cams he is now running ahve adjustable gears on inlet and Exhaust which are very good for setting up optimum timing.
     
    Last edited: Mar 5, 2009
  3. H8SV8S Forum Member

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    Great write up. Have added it to my ever long 'ABF file'!!
     
  4. Mike_H Forum Addict

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    If you're going to run both of the schrick cams, then a smidge more compression would help keep the low down torque - you may well be struggling lower down due to cam overlap, and partial cylinder fill.
     
  5. Neal H Forum Member

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    Due to low dynamic compression (valve closing later on the compression stroke), not overlap, Mike.
     
  6. Mike_H Forum Addict

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    Aye, probably [:$]
     
  7. Ess Three Forum Member

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    I'm fully expecting to find out what I already know...
    On my engine, I either make it drive well, by mixing 258/std and accept a loss of around 4-5 BHP right at the top....or I chase 'pub numbers' and loose 15 lb-ft over a wide spread lower down.

    Hmm...
    I expect the cams will stay as they are. But, we will see.

    I'm prepared to play with cam to crank timing...and even intercam timing...but to go to more compression at this time is a no go.
    That's a whole new ball game...and if I go that way, I'd be looking for a stronger bottom end anyway so I could go 2.1 and raise the rev limit...then it would be bigger cams etc.
    Bottomless pit?


    Out of interest, what's a 2.1 high compression 8500 RPM capable ABF bottom end going to cost me, anyway? ;)
     
  8. Mike_H Forum Addict

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    Lots!

    If you go for 8500 rpm you need titanium valve gear, race valves, and solid lifters, which I can't justify to myself, except on a competition engine (once a Fifer, always a Fifer ;))

    If you stick at 7500 with occasional 8000, you can stick with hydraulic lifters and standard valvegear, as long as you stick below about 11.5mm of valve lift.

    I just brought some stuff back from the states to build a 2.1 16v lump - JE '9A' type 83.5mm pistons CR 11.3:1 in a 2.0 lump, Scat rods (159mm with a 20mm small end), and ARP bolts. Cost about 900. Add to that a diesel crank, ABF or 2E block, and a couple of hundred quid on machining, and the bottom end will cost about 1300-1500 quid.

    I'm thinking of building it into a diesel block, but I need to test build, to make sure all of the parts fit together, like intermed. shaft and oil pump. My mate in Perth has a couple of spare diesel lumps with 95.5mm cranks. Needs a big bore to get them from 79.5 to 83.5mm, but I know a mad welshman who can do it for a small fee.

    I've already got a head for it, so all I need after that is a set of cams - got my eye on cat cams 283/279 duration hydraulic jobs.


    You could do it cheaper than I have though, if you stick with a standard bore size, and machine standard pistons, rather than using forged pistons and fancy rods. I'd think the standard stuff should be good for 7500 rpm, if it's properly lightened and balanced.
     
    Last edited: Mar 9, 2009
  9. Ess Three Forum Member

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    I know where you are coming from.
    It's a toy & hobby for me...so I'm not spending multiple thousands looking for the 'n'th BHP.
    It's not worth it to me.


    I'd figured 7500 was fine on my current top end set-up (re-worked std valves, Ti retainers, lightweight lifters and new std springs) as I use 7200-7300 currently, and have been for years.

    I had guessed the lifters will be the next limit to revs.
    I really can't be bothered with solid lifters etc at the moment.


    Less that I'd imagined...but that's you doing it yourself though. I'm not convinced I have the ability or confidence.
    So that becomes 2000+ to farm it out.
    Hmm...


    I'm thinking the intermed shafts are different?
    I tried a diesel vac pump into the ABF and the oil pump drives are very different.
    What's your plan?
    Diesel intermed shaft and oil pump?

    Ideally, I wanted to run the diesel vac pump for the servo, instead of tapping the ITBs, but it was a no-go.


    Showing my ignorance here...but what advantage using the diesel blocks?
    I've never looked into swapping bottom ends.
    A 2.1 higher CR block would be nice...


    Ooh...interesting.


    The bottom end on mine is standard bar a light flywheel and some new std flywheel bolts...and it seems happy at 7200-7300, so I wouldn't have thought 7500 would be too much of an issue.
     
  10. s1m0n Forum Member

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    That still gives you quite a lot of "room to play" though, 7500+ / 11mm when combined with a decent comp increase should be quite good fun for not too much

    I would have thought machine the head and block then check/machine the pistons for valve/head clearance would give you a very cost effective comp increase, you'd balance everything at the same time of course.

    Cheers

    Simon
     
  11. Mike_H Forum Addict

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    Cutting a long story short, if you use the 95.5mm diesel crank in an ABF block, you need to do little bits of machining here and there to make sure the crank clears the crankcase, oil pump, intermediate shaft, etc.

    Using a diesel block avoids all the machining, provided (as you rightly point out) provided a set of standard bits can be found to fit. My information, which has yet to be checked, is that an ABF oil pump and intermediate shaft could/should work. A test build will be done before any machining takes place, My mate in Perth and his shed full of bits will be used to test out the theory (which is his).

    @ Simon - I'd think 200+bhp would be easily achieveable. I'm planning on bike bodies and megasquirt. Hotgolf got 209bhp/177(?)lbft with a similar spec. He spent a lot more time and money on the cylinder head, but that probably evens out what he might have lost by using carbs rather than mappable injection.

    Using Standard ABF pistons and rods, with a 95.5mm crank, the pistons will protrude 1.35mm (95.5-92.8=2.7mm /2=1.35mm) above the block, and the inlet valves will probably hit.

    Shaving 1mm off the inlet side of the piston, and cutting deeper valve pockets, was what Hotgolf advised me would need to be done. If you leave the exhaust side of the piston alone, it'll push up the CR to about 11.x:1, depending on gasket choice. I tried, but couldn't find ABF oversize pistons at a sensible price, so ended up buying JE ones while I was in the states.

    Obviously, pushing the piston crown closer to the valves on the exhaust side, needs very careful measurement and test building, to make sure there's enough clearance in there, and any cam timing slip-ups could get expensive!

    Hotgolf took me for a drive in his Mk1 and it was blindingly quick with that engine. It was also tractable, free revving, and all the other stuff you'd want in a car that's not just a track toy.

    I'll post a pic of the JE pistons as an example. I've used 9A pistons, because the deck height is about .8mm lower, meaning they protrude about 0.6mm into the gasket, at the flat deck height. the ones I've got also have a small dome on them. This also means that instead of 11.3:1 on a 92.8mm crank, I should end up with about 12:1 due to the longer stroke.

    I'm not planning to start the build in anger until the second half of this year. At the minute I'm collecting bits, and optimising the ex race 2.0 8v that's in the scirocco at the minute (and a million other jobs...)
     
    Last edited: Mar 9, 2009
  12. Matt82

    Matt82 Forum Addict

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    what is the bore and stroke once you use a diesel block?
     
  13. aj_gti Forum Member

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    188ft/lbs ;)
    His new one has a slightly higher spec on the head, plus quite a bit more work around the seats and throats.
    I know he's having trouble with the OBX diff he fitted. it's too wide for the housing and the drive cups stick out too far and leak oil from what he's been saying. Should be ready soon though. it's all in from what I've seen, just afew bits here and there too sort out.
     
  14. Ess Three Forum Member

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    Sounds pretty plausible to me.
    I'm intrigued to hear one way or the other.

    I was looking at things the other way...wanted to keep the diesel vac pump meant fitting a diesel intermed shaft and oil pump - and I wasn't happy that lot was going to fly, at 7500RPM.

    What's the diesel block in question?
    A generic 1.9, PD for example?
    I know of one for sale cheap... :-)


    I've only heard good things about that car and engine...
    Sadly, I have another 400Kgs to lug about in my Mk3.
     
  15. Ess Three Forum Member

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    Mike, should have asked earlier...
    What bodies are you planning on using?
    What management are you currently using?
     
  16. Nige

    Nige Paid Member Paid Member

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    I was !.

    Good post :thumbup:
     
  17. prof Forum Addict

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    i've got some gixxer bodies for sale if you want to play
     
  18. Mike_H Forum Addict

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    As for blocks, I think the PD is different - I think they're the long nose type crank, and the head gasket might be a different pattern from the 16v heads - you might be able to use it, but not so easy. I'm planning on the 1Y / AAZ type, which has no internal trigger wheel (might be an issue for you). You could probably buy a whole car with one of them in, for a couple of hundred quid. You could always fit an external wheel I guess.

    I'm not planning on running the vac pump, but that's an interesting idea. When I go for ITB's I'll delete the servo and run a racing master cylinder. With 280 brakes and a light car it should be fine. My old 911 doesn't have a servo either, and I manage to shove the pedal hard enough in that.

    The car is a Mk2 Scirocco, currently running a 2.0 8v (Ex Claire Tippet race engine) on Kjet, but it'll get a bit of a revamp at the end of the year, and hopefully some development before then, as I don't think it's anywhere near optimised at the minute.

    ITB-wise, I've got a set of BMW K1200S bodies, which are 48mm at the fat end, and 42mm at the head end. The best bit about them, is they're almost exactly the right spacing for a 16v head - about 1-2mm out.

    I'm aiming to install megasquirt to the track rocco (my daily is also a mk2 rocco), and learn how to set that up, before I attempt it on the expensive engine! I've already bought the ECU from a wise man on here.
     
    Last edited: Mar 9, 2009
  19. Mike_H Forum Addict

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    I should say at this point, that you could do all the stuff to the top end, remap the management, and forget about the 2.1 bottom end, and you'd probably get 95% of the power and torque. I'm doing this as much as an engineering challenge as because it's the right engine to build.
     
  20. sparrow Paid Member Paid Member

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    If any of you are interested, I've got a set of Piper 285 cams for sale. Just need to take some pics and they'll be up in the classifieds in the next couple of days.
     

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