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Message started by T-Mack1 on 07/11/07 at 14:27:32

Title: Oil Pump question
Post by T-Mack1 on 07/11/07 at 14:27:32

Just picked up a 2001 LS650. It was a Ebay rolling frame and the seller threw in the dead engine. The Frame is almost showroom condition. Well, the engine isn't showroom ......

The problem w/engine was a melted piston. I saw a picture somewhere here of almost exactly what mine looks like.

So, here's the question for the forum: Do you think the oil pump should be replaced while I have the engine apart???? Do they go bad??? Does anyone make a replacement with a little more pressure?? Maybe 10-20 psi verse the 7-10 psi the service manual calls for.

Thanks in advance for any advice.......

Title: Re: Oil Pump question
Post by vroom1776 on 07/12/07 at 07:02:52

I'd love to find a stronger oil pump, but alas, no time and I doubt one exists anyway...

a new one is about $90... you may just disassemble yours and see if there's any garbage in there and check to see if it's in good shape. if you're throwing lots of money at a total rebuild, another 90 might not hurt...

Title: Re: Oil Pump question
Post by T-Mack1 on 07/12/07 at 12:39:27

VROOM1776,
Thanks. I was debating buying one or not. I was leaning torwards just doing it.

T-Mack1

Title: Re: Oil Pump question
Post by vroom1776 on 07/12/07 at 12:54:15

can't hurt anything but your wallet!

Title: Re: Oil Pump question
Post by T-Mack1 on 07/24/07 at 13:28:48

Update,
Got some advice from the salvage yard owner when I picked up a replacement head (old one had a bad cam journal). He said pump most likely is ok. He said the problem the Savages have is the passageways. Not enough oil pressure to push thru. He's the son of the founder of the yard (motorcycles only) and has been around bikes all his forty some years. I've been told by my good friend who grew up with him to trust what he says. Any thoughts from the forum???

I'm still in the process of cleaning. Passage ways look fairly nice but I will say the residual oil in the pump was black. I did get the oil pump apart. The little phillips screw came out easily, even through the service manual says it's glue in. Pump look very nice. Does anyone know the spec for clearances?? I did a quick look in the service manual but didn't see any. Will look again tonight after reading some Harry Potter to my son.

Also, plan to replace the cam chian since engine is taken apart. Old chian is at ~127 @ 10460 miles. Does anyone know what a new chain measures???? If not, I'll post when I get the new one.

Next question, and it may sound odd. For the cylinder, once we cleaned off the embedded melted aluminum with a solid machinist hone and before we honded out the scrathces, the cylinder measure a tiny bit under the factory spec. So..., do you think the melted psiton could be from a overheated piston that grew in a cylinder that was on the small side of the spec??? I think the black oil didn't help either.

After honing out the scratches, looks like we are just over the std piston spec. A 0.5mm O.S. piston is on order.

T-Mack1

Title: Re: Oil Pump question
Post by verslagen1 on 07/24/07 at 13:59:02

127mm or 5" ctc is stock, besure to apply a little weight to stretch it a bit.

The passage ways may be either too small or large for the pressure the oil pump can produce. Several factors to consider, we have a tall cylinder, the larger the passageway the more oil weight (head) the pump has to push up. Too narrow and the velocity of the oil increases causing more friction causing the pressure to go up. And the oil pump does not produce a lot of pressure, but that's ok as long as the volume is there for cooling.

On a gear pump, the clearances to be concerned with (if I remember correctly) are the end (gear to housing) clearances. Gear to gear clearances aren't as important as long as one gear drives the other they will maintain contact. But end clearance will allow the oil go back thru the pump. If you can't find anything, look at a old vdub manual.

Title: Re: Oil Pump question
Post by Kropatchek on 07/24/07 at 14:46:10

Your yard guy is right, the passageway is the problem.
An (internaly) leaking clutchcover gasket cold be the problem.
The crankshaft gets its oil from a long way:
oilpump, then trough the clutch-cover to the filter. Then the oil goes 2 ways: one to the crankshaft, there is a oilseal in wich the crankshaft turns, the other flow goes up to the passage on top of the clutch cover. on the back is a little oiljet to build-up pressure for the head.
You see, there's lots of places where the inexperience mechanic can make a mistake.
Have fun rebuilding your engine, I'm doing the same at the moment with my spare engine.

Title: Re: Oil Pump question
Post by T-Mack1 on 07/24/07 at 20:12:35

Thanks for the replies. Looked thru the manual again and no oil pump spec's. Had the same thought as you, look up some other vehicle's spec. Looked in a real old Chevy book but is was more of a general tune-up book. Went over to the other pile of books and found my old Honda 250 Rebel book, Yea, a metric bike and an engine that has also been around for 20+ yrs. And.....the book has oil pump specs.....

Here they are:
Honda Outer rotor ring to Housing (max): 0.25mm / 0.010 in.
My pump= 0.005 in.

Honda Inner rotor to outer rotor ring (max): 0.2mm / 0.008 in
My pump= 0.003 in

Honda Rotor end to housing (using straight edge) (max): 0.12mm / 0.0048 in

This one is hard to measure. The design of the pump has a offset in the cover. The rotor parts actually stick up a little when sitting in the housing (took a while to find a small enough straight edge). So, put the pump back together, bent the feeler gauges (darn, got to get yet another set....again, my son's Honda '73 SL70 valve clearances bent the last set.) then I measured the gap between the cover and the rotors thru the output opening.
My pump= 0.004 in.

So, does anyone have experience on the differences bewteen Honda and Suzuki spec's? Which are normally tighter???