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33goingon38
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 Posted: Thu Nov 25, 2004 10:02 pm Post subject: Big end bearings |
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Can anyone provide any suggestions for a source of upgraded big end bearings? I've been warned that the std ones can fail and I want to use my car for trackdays and so on .... quite happy to drop the sump and swap the brgs if it saves a big failure later.
Thnkx |
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alexj
Alfasud
Joined: 25 Mar 2003
Posts: 66
Location: New Zealand
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| Posted: Sat Nov 27, 2004 5:49 am Post subject: |
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What engine/bearings do you have now? I heard the Tri-metal bearings from the 16v were best... but the main issue would be to get enough oiling to the centre main bearing.... firstly, make sure you add enough oil before going on the track. Full to the top mark if not a bit beyond.
Baffled sump certainly helps stop oil surge in corners and people more expert than me might be able to advise on how else to improving oiling to the centre main bearing.
You could investigate a higher pressure/flow oil pump, but maybe not advisable for a road car.
Good luck.... |
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Matt Stolton
Alfa Sprint
Joined: 14 Mar 2003
Posts: 233
Location: London
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| Posted: Sat Nov 27, 2004 9:29 am Post subject: Grooved bearings |
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Fitted in my P4 16V are some rather nice shell bearings that have a central groove running down the middle of the shell. As oil enters through the hole from the oil passageway, it is sqirted around the full circumference of the bearing.
The increased loading/pressure on the bearing shell, through loss of metallic surface, due to the groove, is more than out weighed by the much more even flow of oil, and the superior lubrication. Basically the extra oil film outweighs the negative factor of loss of bearing surface....
Try Lloyd at Clovertech for where he sourced them, or to get him to get you some. I doubt they are much more money than Alfa standard, as they are probably just from a different engine with the same bearing sizes, i.e standard OEM items, just for a different brand of car.
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Regards
Matt
Ex Alfa 33 'GTA' (P4 with Knobs On)
Now cruising in a 166 3.2 Ti!! |
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Eddie W
Alfa 33
Joined: 31 Jul 2003
Posts: 375
Location: new zealand
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| Posted: Sun Nov 28, 2004 8:03 pm Post subject: |
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I believe that quite a few of the racing guys use 105 bearings which are copper/lead. I think they have to be narrowed slightly. The copper/leads will usually take higher oil pressures without detriment. Also I.ve read of restrictors being used in the oil supply to the heads thus retaining more oil flow to the bearings. We used to do this in the Cosworth BDA rally engines. Without it you would fill up the top end at high revs and as it's slow to return you would effectively lower the sump level even though these engines were all dry sumped. The cam boxes are not where you want your oil reserves to be held.
Regards Eddie
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