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rallyboy77 Alfasud
Joined: 08 Apr 2003 Posts: 76 Location: Sydney
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Posted: Tue Sep 28, 2004 8:59 am Post subject: best 8v camshaft? |
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We are conceptualizing a new motor for the Alfasud. The engine will be based on our 1600cc bottom end (1500 bored to 87mm) so we dont enter the 1600-2000cc class. It must also be 8valve due to restrictions on changing the number of valves and cams.
Now looking at the alfa 33 workshop supplement I notice the 1.7 8v carby engine has the best cams, is it that simple? A possible upgrade will be to find such a motor and use the cams, heads and carbies on our current bottom end. Will use solid tappets as well.
Comments and suggestions?
thanks!
Jeremy |
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Eddie W Alfa 33
Joined: 31 Jul 2003 Posts: 375 Location: new zealand
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Posted: Thu Sep 30, 2004 12:31 am Post subject: |
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Hi Jeremy
From my checking the solid lifter setup will bolt straight on to the 1.7 head provided you use the shorter hydraulic length springs and standard buckets. However the racing guys over here use the buckets from the 105 (lighter) and this seems to require longer valves as they use lash caps on the valve stem instead of the shims in the standard setup.
Reground cams probably have a bearing on this too.
A couple of points to consider:
Hydraulic cams normally have a different type of profile which is not allways compatable with solid lifters.
Compression ratio would be a problem especially if you mod the chamber. It could certainly be improved. Skimming would require adjustable cam wheels to compensate for the timing change.
Have fun and keep in touch.
Regards Eddie _________________ A LITTLE FURTHER A LITTLE FASTER |
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rallyboy77 Alfasud
Joined: 08 Apr 2003 Posts: 76 Location: Sydney
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Posted: Thu Sep 30, 2004 7:32 am Post subject: |
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Hey Eddie,
Thanks for the info. I currently only have Alfasud style shims which I assume would not be suitable for the Alfa 33 1.7 cam (I doubt it is a split lobe design I thought the easiest swap would be to find some second hand or even buy new shim style tappets from the earlier 33 engine. The 105 shims may be interesting though it sounds like even more work.
Do you know about the profile causing a problem with tappets?
What chamber?? We have adjustable cam wheels, and the block is skimmed at 10.5:1 for the old motor. That would need to be re-measured though. Valve piston clearance may also be an issue as well?
Jeremy |
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Serpent33 Alfa Sprint
Joined: 06 May 2003 Posts: 210 Location: Singapore
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Posted: Sat Oct 02, 2004 4:30 am Post subject: Re: best 8v camshaft? |
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Please take note of different piston height. 87's are shorter. Best compensation is of course longer rod for engine durability. Do consider 16v rods. Just a suggetion. Do update us of the outcome. Good luck. And the QV cams are indeed the fiercest. Inlet port can afford to go larger by a little due to higher torque of 1.7l. _________________ Each time I speed I say, "Dear lord, make me fast and accurate..." |
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Guest
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Posted: Sat Oct 02, 2004 6:18 am Post subject: |
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hi i rally the sud in england i used to have 1600 similar spec to you the guy who built my engine used piper 349 cams the engine revved freely all the way to 8000 but actually peaked out on the rolling road at 7900 i used this set up for 4yrs with no problems . i am now using a 1350 and using same cams the engine is still good and first time out 2 weeks ago the car performed well . whilst building the car we also did some inivitive suspension work coil overs it hanlded superb on the welsh forestry . i am looking forward to doing some more events now car is finished . keep in touch all the best simon |
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Eddie W Alfa 33
Joined: 31 Jul 2003 Posts: 375 Location: new zealand
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Posted: Sat Oct 02, 2004 9:10 pm Post subject: |
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Jeremy.
It's the quietening ramps on the lobe profile that differ between solid and hydraulic cams. If you run the solid setup with the hydraulic cam it will rattle like it's got a 60 thou clearance and probably beat its brains out. The extra timing of a hydraulic cam is to compensate for the slight takeup effect inherent in the lifters. I would suggest going for a good grind on the solid cams as per Simons post. The 105 buckets are chosen by some guys because of their light weight without the thick shims but the standard setup would appear to be good for 8 grand or so which should be enough.
Simon.
Some details of the suspension please. Do you run an LSD?
Regards Eddie _________________ A LITTLE FURTHER A LITTLE FASTER |
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Guest
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Posted: Mon Oct 04, 2004 6:35 am Post subject: suspension |
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hi jeremy/ed the suspension i use are now coil overs on front using yellow koni inserts . i taken strut body cut off whereold bearing used to sit so half way down leg if you look at one and i bought a 50mm universal coil over kit £75.00 this includes the adjusters to adjust ride height and the springs which are 65mm in diameter and 2oolb / 10inch high . then welded the thraded part on to strut be careful when doing this to get upright . then put insert backin fitted spring . this was then the hardpart the top obviously needed a bearing to be located i used a koyo bearing approx 40mm in outside diameter i then got to metal sleeves made to take bearing either side the top one was also drilled through centre to take shock aswell . then the origanol top was used disguarding originol spring holder. ihope this makes sense its not as complicted as you might think but is worth doing because handling is superb and ride height is adjustable either for tarmac or stage forestry .ithen decided to do the rear all you need is 2 12inch/ 120lb / 65mm springs itook rear beam off flattened where spring sit welded to 5mm steel plaes in with a centre hole of 60mm to let shock throughusing origanol fixing theninside top of beam welded in a round pice of tube 3mm thick inside diameter of 65mm to take spring 1inch high . ithen cutold seating out on car and got 5mm plate again and weled inplacce using same tube 1inch again welded to this hole in centre at 60mm to let shock through and using origanol top fixing hop this makes sense iset rear red konis to half adjustment and front to three quarters this really works well i have also done brake modifications aswell simon |
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