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why main bearing falure ?
seagull - March 4th, 2006 at 02:50 AM

I had a 1641 motor built , all the bears were new , crank ground , rods sized , new barrles( 1641 size >) pistens , new cam , heads recond .the list goes on of new parts

The oil light came on and we had found the oil pump valves full of bearing matirial .

its not looking good

I am not clear as to oil coolers added but the bus has a large cooler fitted & pipe work , the capacity of the vw stock sup is very poor , fill the sump turn it over oil light comes on , stop motor fill with more oil repeat till the light goes out

The motor was using oil , why would this be so if its a new motor , recon heads , valve seats and guides all done


The above is the main reason for me to give the vw motor the flick & go Subaru , but its not helping my mate who purchased the above donk from me as its done about 2000ks and its dead .

it has not been thrashed , clean oil used

I am looking for a 1600 cc case by the way to get pat up and going .If some one has a case in Perth please let me know .as I gave away all my vw motor parts some time back when I went to subaru

cheers seagull


76camper - March 4th, 2006 at 07:46 AM

if your external oil cooling system was drained after the rebuild and you only filled the engine with enough oil for the stock oil system it is likely you had run out of oil... did you hear the crank nocking the bearings or anything? Were the bearings installed correctly? Maybe an oil gallery got blocked by some glue or sealer and the bearing provided with oil from that gallery ran dry.... Should be plenty of cases around... pretty cheap aswell. good luck with it


Bizarre - March 4th, 2006 at 09:42 PM

pinched bearing when put together??


Menangler - March 5th, 2006 at 08:34 AM

Could be a lot of things,
If it was using oil in the first place, something wasn't right from the begining, and probably should have been pulled down to investigate.
Did you put the piston rings in the right way round?, check if all the bearings were the correct size on the crank, and nice and tight in the case? did it have enough oil pressure to cope with the extra cooler? what size oil pump, dual relief case?
I am sure you will see what caused it when you pull it down.

[ Edited on 4-3-2006 by Menangler ]


seagull - March 9th, 2006 at 02:23 AM

Pat & my self pulled the motor down tonight .we found a shot main bearing with no sign of any other parts failing in side the motor .

This brings me to the oil cooler Pat had fitted and the mods to case to make the oil pump direct oil to the external oil filter that was fitted .

The oil pump has the port blocked to pump oil out via the face plate .the correct port is drilled & taped to allow oil to return to the case .
we have found a pile of shavings from the main bearing in the oil galery ( after the filter ) This port is normaly seeing oil fed from the oil pump but the plug in the oil pump stops the flow and dirrects it out the face plate port how can it get to the port after the filter ?
shavings in the relief valve as well

The new 1641 pistion kit that was installed was ok no signs of incorrect rings in stalled , main oil rings have worn more than I would of expected .wih lots of black crud on the tops of the pisions .Both heads were compltley rebuilt , new guides , valves all correctly done , faced ect , heads cleaned up good .no sign of valves hitting the pistons every thing iside the motor looked like it was fitted correctly .

the case looks very good , ports all very clean after we washed it all out with fuel ( got high doing this )

over all I am at a loss to whats going on

some one shed some light , so we can get this sorted and Pats ride on the road


& chris I pulled the 1835 motor down mate ,case was realy stuffed ! pistons are 85mm ,stock cam , the motor is a stock 1600 cc , heads are 040 & in very good cond .Main bearing had failed , the same as pats motor .

good bits I will return as requested other in the skip bin

seagull


76camper - March 9th, 2006 at 06:21 AM

maybe the oil galleries were not flushed properly after being drilled and tapped. Can you tell a bit more about the shavings? What sort metal is it?


seagull - March 9th, 2006 at 08:25 PM

Oil galerys were clean .
the metal was the white metal from the bearing


koolkarmakombi - March 9th, 2006 at 08:44 PM

unlucky mate. Try plastigauging them next time, Ive had a tight one before, rods too.


Bizarre - March 9th, 2006 at 08:45 PM

did the main bearing pin miss?? ie not go in the hole and hence spin?? or miss and crush??


seagull - March 9th, 2006 at 09:08 PM

no that was correct , every bearing was correct .

I think its some thing to do with the crank case pressure relief valve , this to have the bearing matirial in it .Is the pace to look .

I am not going to use this case we will chase another one down


Bizarre - March 9th, 2006 at 09:17 PM

100% the right sized valves??

Not too tight??

My first engine build i was give over sized bearings (10 thou instaed of 20)

Made a vibration when revved

Could yours have been reversed??


seagull - March 10th, 2006 at 09:21 PM

these were all good