944ja väntvõll ja kepsusaale probleemid

Porschede mootori- ja veermikuprobleemid.
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joonas
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Re: 944ja väntvõll ja kepsusaale probleemid

Postitus Postitas joonas » 14 Sept 2009 11:21

Eric Rupertilt sain veel järgnevat infot.

Küsisin vastupidavuse kohta

I found the car to be extremely reliable. I bought a used ’89 944 with the 2.7 engine that had about 150K on it. We put fresh rings/bearings in it, did a valve job on it and I installed a header, custom chip and (per SCCA regs here in the states) an adjustable fuel pressure regulator. I’ve attached a dyno sheet. You can see from the sheet that it’s pretty much a waste of time running the car to the rev limiter because power falls off sharply well before that. Other than than, I did nothing but change the oil (I think that I used Castrol) and it never failed. Other s with fancy mods didn’t really make more power and were not a reliable.


Pilt

Küsisin, millist õli ta kasutas ja kas ta kasutas ka õli jauhutamiseks radiaatorit.

Don’t really remember the weight but I am thinking 20/50. Yes, I did run an oil cooler, it’s critical. The temps go way too high without one which causes the oil to get so thin that you lose oil pressure during a race. I broke my cooler one race weekend and saw the difference on my pressure gauge during a race. I think is more of a problem than the starving in the corners.
No one else that I know personal runs that mod. However, as I said, the recommendation came from Fordahl Motorsports. I was on a pit crew with Greg when he was Randy Pobst’s chief engineer. In addition to providing services to top-contending ROLEX Grand-AM and ALMS teams, he races a 944 personally and supports a bunch of 944's on the West Coast here in the states. He's one very smart guy.


Sellest jutust loen mina välja, et töökindluse tagas korralik õli jahutamine ja maksimaalselt 6000 pöörde kasutamine.

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joonas
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Re: 944ja väntvõll ja kepsusaale probleemid

Postitus Postitas joonas » 10 Dets 2009 14:49


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siim
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Re: 944ja väntvõll ja kepsusaale probleemid

Postitus Postitas siim » 11 Dets 2009 00:21

Siin üks 928-le pakutav: http://www.gantspeed.co.uk/showroom.php?ID=26" onclick="window.open(this.href);return false;
Nagu ma aru saan, siis pole täielik bolt-on kit.
928
996 C4

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joonas
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Re: 944ja väntvõll ja kepsusaale probleemid

Postitus Postitas joonas » 02 Juul 2013 13:24

Lugesin juhuslikult üle pika aja rennlisti foorumit ja jäi silma mis juhtub, kui anda prantslasele pleksiklaasi ja aiavooliku juppe :)

Bearing lubrication problems rod 2/6

Pilt
Pilt

Lühidalt sisu selles, et mõõdetakse õlitusavade vooluhulka ja õhu lisamisel tekkinud muutuseid. Ma ei oska öelda midagi nende tulemuste olemuse kohta, kuid omamoodi põnev lugemine. Eeldatakse, et õli vahutamine ja õhumullid õlis on saaledele saatuslikud.

Selle prantsuse teemaga seotud rennlisti teema http://forums.rennlist.com/rennforums/9 ... tests.html
Juttu ja omavahelist vaidlust on siin päevadeks. 928 omanike jaoks tundub siin olevat midagi huvitavat.

Positus #82
Oil packs into the heads, at high rpms, and then is ejected from the head breathers. At about the same time to oil began to eject from the heads, we had a significant "reduction" in oil pressure....but not enough for the dyno to automatically shut down....we terminated the test. I would anticipate that damage to the bearings would have resulted, if the testing had not been terminated. As it was, the rod bearings had definately "touched" the crankshaft and were replaced.

For the "aeration" crowd, it was not frothy, aerated oil, but solid oil. It was "ejected" in spurts of solid oil.


Postituses #83 Videod mootori testimiset.

Postitusest #161

See above. As long as the two "vessels" remain connected by a free air path, the pressure in the two remains the same. The "problem" with the "stock" design is that the drains quickly get overwhelmed and the pressure in the crankcase builds, until there is a huge "burp". Once that burp occurs, oil is pushed up and out of the crankcase, through the oil return holes. At that point, there is a lot of oil in the heads...and being pushed into the intake system (on a stock vehicle.)

Ehk tundub, et 928 omadus on see, et pikka aega kõrgete pööretel koguneb õli "pähe" ja nii jääb karter kuivale. Väidetavalt on selle lahenduseks olemas ka kaks erinevat komplekti, mis on välja töötatud kasutaja GregBBRD poolt.
New Product: Precision Motorwerks Crankcase Ventilation Kit

This kit represents a rethinking of the basis for excess oil consumption in the stock 32V 928 engine. The final product not only addresses this problem, but also solves several other “limitations” found in the stock 928 engine. It is extremely extensive, and is not the simple addition of a filter and a few hoses, but is instead a complete redesign of the entire ventilation system.
Pilt

Benefits of the 928 Street Crankcase Ventilation Kit:

-Elimination of oil which is both pushed and sucked into the intake system

-Significantly better oil return from heads to crankcase, reducing oil starvation problems

-Significantly reduced oil consumption

-Reduced “pre-ignition” issues

-Increased ventilation of crankcase, reducing crankcase pressure

-Significantly better venting of the cylinder head area

-Reduced operation of knock sensors-Reduced engine emissions

-Increased performance and increased performance potential

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Re: 944ja väntvõll ja kepsusaale probleemid

Postitus Postitas Raceboy » 02 Juul 2013 14:50

Väga hea ülevaade probleemist jaeriti ilmekas on prantslaste test koos tulemustega.

Kokkuvõtteks võib ilmselt öelda, et kes tahab tõsisemalt 944 või 928 mootoriga rajal lustida, peaks investeerima vähemalt Accusump'i, veelgi parem aga kuivkarterisse.

Veidi nokitsedes ei tule see sugugi nii kallis, kui arvata võiks. Korralikumat sorti pumba saab juba max paarisaja euro eest ( http://www.ebay.co.uk/itm/Auto-Verdi-5- ... 23253de73f ), õlipaagi võib lasta alumiiniumist kokku keevitada, sama asi karteripõhja modifitseerimisega ning õlivoolikud teeb Hydroscand/Dunlop Hiflex vms meelsasti.
Arvestades, et kogu süsteem läheks kõvasti vähem maksma, kui mootori kapitaalremont, on see vägagi mõistlik.
'83 924 2.6 16v Turbo 570 hj
'67 911 hot-rod 2.4S
'78 924 Carrera GT projekt
'84 928 S
'90 944 S2 Cabriolet
'91 944 S2 [müüdud]
'82 924S/931 "Gulf" 2.0 Turbo [müüdud]
'84 924 2.0 "Turbo" [müüdud]

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