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#181
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Re: Engine Bearing Failure
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Anymore info on this would be really great Also for interest sake, one of the World Time Attack Subaru's that did well last year used one of those accusump devices and had it plumbed into the top back of the EJ2X engine to feed it during surge. Seemed to work rather well which is decent when the engine was pushing close to 200 hp per cylinder!! |
#182
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Re: Engine Bearing Failure
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I reckon an accumulator is a very necessary accessory for a big engine. It can fill the gaps in pressure, and fitted with an electric valve that will hold pressure when you turn the engine off. It will provide pressure when it is turned on to start, so that the soft surface of the bearing shells are protected from damage. Especially if the engine kicks back when starting. Harvey.
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One Arm Bloke. Tell it like it is! 95 Lsi. Bordeaux Pearl, Aust. RHD.149,000Kls Subaru BBS wheels. 97 Liberty GX Auto sedan. 320,000Kls. 04 Liberty 30R Auto Premium. 92.000kls. |
#183
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Re: Engine Bearing Failure
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#184
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Re: Engine Bearing Failure
When I started building the dry sump I was of the opinion that installing suction in each head was a bit of over kill. I could see the other benfits such as removing the air from the oil etc. The more I have been developing my dry sump the more clear it becomes that you can not get around the problem of oil build up in the head on hard cornersing. At one point I thought that the supply lines to the head don't supply enough to the heads to cause that much of a problem during a corner. Then I looked at the engine more closly. In a hard corner the oil can splash out of the pan and down the oil return galleries into the head. THere would be enough room for at least 3 litres in the cam area and the block under the pistons.
In short you are beating your head against a brick wall trying to keep oil in the existing sump in a hard corner. Tony
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1995 - SVX 700,000 K Mine, DMS Struts to lift car 2in. Tyres Wrangler Silent Armor 235/70R16, PBR Radiator. 6 speed with DCCD and R180 rer diff, Heavy duty top strut mounts front and rear. Speedo correction box fitted. New stero (gave up on the old one). Back seat removed and 2 spare tyres fitted for desert driving. ECUTune SC sitting in the box for the next SVX. 1992 - SVX 255 K Wife (Want to stay Married so not allowed to fit SC) 1992 - SVX Pearl with black roof race car roll cauge etc ready to race. Ex Tasman Targa car. 1995 - SVX Green low k mint condiation. 1995 - SVX Rally car, ex Matts car. Now to be used on track. 1992 - SVX red & Black being converted to Mid Engine. 1995 - SVX Red 143,000 bit rough. Owned 5 others Subaru back to a 1974 1400 GSR. |
#185
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Re: Engine Bearing Failure
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I disagree about keeping the oil in - it is possible to ensure the oil stays at a good level during racing. And I think we're forgetting something major here - we've got to remember an SVX with a lot of mods would do around 1:50 @ Winton, 2005 Legacy H6 and 2002 Legacy H6 are around that laptime with a lot of mods, coilovers, more power and semi slicks etc etc. Last year I did 1:34 with the stock sumped EG33 the oil gauge didn't surge at all. This should give you an idea of what the stock sump is capable of doing and handling, basically a huge amount of abuse - more than most give it credit for including myself. Also with Jack's I don't think anyone has mentioned the cause - was it oil related?! Last edited by bazza; 08-26-2012 at 05:56 PM. |
#186
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Re: Engine Bearing Failure
Bazza do you read this as oil?
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1995 - SVX 700,000 K Mine, DMS Struts to lift car 2in. Tyres Wrangler Silent Armor 235/70R16, PBR Radiator. 6 speed with DCCD and R180 rer diff, Heavy duty top strut mounts front and rear. Speedo correction box fitted. New stero (gave up on the old one). Back seat removed and 2 spare tyres fitted for desert driving. ECUTune SC sitting in the box for the next SVX. 1992 - SVX 255 K Wife (Want to stay Married so not allowed to fit SC) 1992 - SVX Pearl with black roof race car roll cauge etc ready to race. Ex Tasman Targa car. 1995 - SVX Green low k mint condiation. 1995 - SVX Rally car, ex Matts car. Now to be used on track. 1992 - SVX red & Black being converted to Mid Engine. 1995 - SVX Red 143,000 bit rough. Owned 5 others Subaru back to a 1974 1400 GSR. |
#187
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Re: Engine Bearing Failure
Ah that's what I was looking for - thanks. Yes that's oil related, sorry I didn't read that post properly.
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#188
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Re: Engine Bearing Failure
Jack's engine lost #5 rod bearing again, same as last time.
When he had standard cams and hammered on the car mercilessly for two seasons but only shifted at 6500 rpms, he had no issues. As soon as he started running to 8200 rpms that all changed. |
#189
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Re: Engine Bearing Failure
Thanks Bob and please thank Jack for leting us know. Info like this is really important.
I am happy to be challanged on my next coments of what I think we know. In all cases were we have seen number 5 rod fail there has been two factors required to make it happen. The oil pressure must be dropping in the corners. And the revs must be up around 8,000. What I don't see is that one happens with out the other in other words. There is no info to say that running the engine at 8,500 all day mounted stationery in a car or on a test bed will result in number 5 rod failing. What I think we need to do is mount a standard engine in a test unit or dyno and hold it at 9,000 to see if number 5 fails. If that doesn't happen we need to move the revs up and try again. Thats my take on the info. Tony
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1995 - SVX 700,000 K Mine, DMS Struts to lift car 2in. Tyres Wrangler Silent Armor 235/70R16, PBR Radiator. 6 speed with DCCD and R180 rer diff, Heavy duty top strut mounts front and rear. Speedo correction box fitted. New stero (gave up on the old one). Back seat removed and 2 spare tyres fitted for desert driving. ECUTune SC sitting in the box for the next SVX. 1992 - SVX 255 K Wife (Want to stay Married so not allowed to fit SC) 1992 - SVX Pearl with black roof race car roll cauge etc ready to race. Ex Tasman Targa car. 1995 - SVX Green low k mint condiation. 1995 - SVX Rally car, ex Matts car. Now to be used on track. 1992 - SVX red & Black being converted to Mid Engine. 1995 - SVX Red 143,000 bit rough. Owned 5 others Subaru back to a 1974 1400 GSR. |
#190
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Re: Engine Bearing Failure
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Last edited by bazza; 08-27-2012 at 05:28 PM. |
#191
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Re: Engine Bearing Failure
I'm curious as to why only the #5 rod bearing is failing. What is unique about the oiling passages such that #5 is failing and not #4 or #6? Why a rod bearing and not a main bearing (other than the fact that the main bearing should have a more direct oiling path)?
Hard cornering would imply a related reduction in oil volume in the pan, but then Jack's custom pan had a lot of additional baffling added (http://www.subaru-svx.net/forum/showthread.php?t=47176). Bill
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Retired NASA Rocket Scientist Most famous NASA "Child" - OSIRIS-REx delivered samples from asteroid BENNU to Earth in Sept. 2023 Center Network Member #989 '92 Fully caged, 5 speed, waiting for its fully built EG33 '92 "Test Mule", 4:44 Auto, JDM 4:44 Rear Diff with Mech LSD, Tuned headers, Full one-off suspension '92(?) Laguna, 6 spd and other stuff (still at OT's place) My Locker Last edited by SVXRide; 08-27-2012 at 09:06 PM. |
#192
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Re: Engine Bearing Failure
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Also because a baffled sump looks good and has baffles doesn't mean it will work as desired - no offense of course Bob. You really need to test / R&D them and document pressures / temps / g forces like what Tony does to ensure a good design and understand what is happening or you're effectively blind folded. I think Bob snapped that up as a favour for Jack IIRC - had he been able to do ongoing testing I'm sure it would've been extremely advanced or he'd have just gone dry sump. This guy revs his turbo version to 8300 rpm... stock pump and no water mod (interesting)... no issues thus far. http://www.youtube.com/watch?v=6ll8u0QQpho Last edited by bazza; 08-27-2012 at 09:21 PM. |
#193
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Re: Engine Bearing Failure
Its about use... 1/4 mile cars will never have reliability issues like a road race car. Endurance of an engine is far more difficult to obtain than a 10 sec blast of power.
As for #5 failing... its the first to lose pressure and last to get it back during surge Tom |
#194
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Re: Engine Bearing Failure
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Heres why:- - The good book shows the right hand side of the engine having 8 bearings (1,5,6,7, Journal & 1,4,5,6 Big ends) all being feed oil. One of these has larger requeiment due to #5 bearing the thrust as well as feeding the two big ends. We have no idea how much extra that thrust bearing will take before the bigends or if it has been designed by Subaru to get pirioty oil. - The Left bank only supplies oil to 5 bearings (2,3,4, Journal & 1 & 3 Big end). Journal 3 is just a plain old bearing so it doesn't have the demands of #5 - When Subaru designed the oil system they needed the engine to maintain pressure at low revs as well as high. At low revs of 600 rpm the good book says the pump only supplies 5.5lpm. To get the oils system to function they had to keep constant restriction in the oil galleries so they fitted a number of little sheet metal restricter. See attached photo. If these were removed bearing failure would result at low rpm. - Next point is that at 8,500rpm the existing pump would be pumping 95 litre per minute. The sump contains roughly 6 litres and that is pumped around the engine 15.8 times per minute or once ever 3.8 seconds. Even if you had the best sump in the business the amount of oil in transist at any one time will be major part of the engines capiciaty. - Oil going around the system every 3.8 secs will become highly airrated and there for no longer work effectively. Given what I have see and learn't about the bearing failure issue over the last 6 months I am sure that once the dry sump is fitted the problem will go away. There are a number of reasons, (1) We will get higher flow 70% more oil in the system, getting 170 lpm at 10k rpm. (2) Due to the larger tank installed for oil the air will be removed and the quanity will alway keep the engine happy. (3) I intend on running test then following this I will remove the restrictor plates in the oil galleries to increase flow but keeping in mind that I need oil pressure at low revs. (4) Us thinner oil so the overall pressure at hi revs doesn't go to high. As I have mentioned before the oil system on this engine is a work in progress and needs some testing to put solid number on what will happen with higher flow. Tony
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1995 - SVX 700,000 K Mine, DMS Struts to lift car 2in. Tyres Wrangler Silent Armor 235/70R16, PBR Radiator. 6 speed with DCCD and R180 rer diff, Heavy duty top strut mounts front and rear. Speedo correction box fitted. New stero (gave up on the old one). Back seat removed and 2 spare tyres fitted for desert driving. ECUTune SC sitting in the box for the next SVX. 1992 - SVX 255 K Wife (Want to stay Married so not allowed to fit SC) 1992 - SVX Pearl with black roof race car roll cauge etc ready to race. Ex Tasman Targa car. 1995 - SVX Green low k mint condiation. 1995 - SVX Rally car, ex Matts car. Now to be used on track. 1992 - SVX red & Black being converted to Mid Engine. 1995 - SVX Red 143,000 bit rough. Owned 5 others Subaru back to a 1974 1400 GSR. |
#195
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Re: Engine Bearing Failure
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Thanks! Bill
__________________
Retired NASA Rocket Scientist Most famous NASA "Child" - OSIRIS-REx delivered samples from asteroid BENNU to Earth in Sept. 2023 Center Network Member #989 '92 Fully caged, 5 speed, waiting for its fully built EG33 '92 "Test Mule", 4:44 Auto, JDM 4:44 Rear Diff with Mech LSD, Tuned headers, Full one-off suspension '92(?) Laguna, 6 spd and other stuff (still at OT's place) My Locker |
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