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Message started by Armen on 11/07/19 at 20:05:10

Title: Rocker arm oiling
Post by Armen on 11/07/19 at 20:05:10

Must be a layer of brain rust, but I can't for the life of me see any way that oil is getting to the rocker shaft-to-rocker surface. Seems amazing that the system would live with just splash lubrication.
i'm missing something, yes?
Enlighten me.
thanks,
-Armen

Title: Re: Rocker arm oiling
Post by batman on 11/07/19 at 22:17:03

I'm no expert on this subject ,but I believe the following to be true,I'm sure others know much more than I.
All cams stock ,(and possibly webcams based on stock cams-not sure) , have a central passage through their shafts and branches leading to the lobes of the cam that supply oil to the side "cheek" of each lobe , as well as splash lubrication . Stock DR650 cams ,have a smaller channel and no passages to the lobes, so the lobes are splash lubricated only .(but I believe one member drilled his DR to stock specs ,restoring those channels). I don't believe the rocker arms supply any oil.

Title: Re: Rocker arm oiling
Post by Serowbot on 11/08/19 at 14:23:19

"Splish splash, I was takin' a bath"...

Title: Re: Rocker arm oiling
Post by Dave on 11/09/19 at 02:56:56

The oil supply to the head comes up the right rear of the cylinder in a passage around the head stud. When the oil reachesd the top of cylinder it then flows in a passage that goes to the left side of the cam. The oil flows to the cam journals - the left rear journal allows oil to flow to the hollow cam. The inside of the cam has a small hole on the cam chain side that limits how fast oil can flow out the right side to the cam chain area. The oil inside the cam can pass through a small hole at the base of the cam lobe - this oil lubricates the cam/rocker surface.....then it flies off and supplies oil to the rocker shaft. The rocker shaft doesn't receive any oil at pressure - it is oiled by the spray off the cam. The head has a small oil reservoir under the cam and it likely has a small amount of oil in it while the engine is running - but when the engine stops the oil inside the cam drains out the holes at the base of the lobes and the oil drips off the rocker shafts.....and the little reservoir fills up with oil - and this lubricates the cam at "start up".

The system works well - but at idle there is not a lot of oil flowing up into the head (especially if you have your idle speed set really low). Idling the engine with the bike leaning on the side stand starves the right cam/rocker for oil - as there is not enough oil flow to push oil uphill inside the hollow cam, and the oil level in the reservoir is on the downhill side and none reaches the right cam lobe. (Don't idle the bike on the side stand.....and don't idle the engine for long periods of time.

Title: Re: Rocker arm oiling
Post by Armen on 11/09/19 at 19:32:42

Thanks Dave.
Have to say, I'm amazed the rockers survive. Most bikes have some way of getting oil to the surface between the rocker arm and shaft. I was going to make up shims to set the endplay on the rockers and eliminate the wave washer. Glad I didn't. No oil would get in there at all!
Really makes me not want to use aftermarket valve springs. Last thing the bike needs is more pressure between the rocker and shaft.

Title: Re: Rocker arm oiling
Post by Dave on 11/10/19 at 02:53:57

23100F070C620 wrote:

Last thing the bike needs is more pressure between the rocker and shaft.

Absolutely - each rocker compresses 4 valve springs (2 valves with 2 springs each)......and I believe it is very close to being at it's limit.

With good oil and an adequate idle speed to provide oil flow they can last a long time - Youzguys is at 160,000 miles and climbing on his original cam and rockers.

Title: Re: Rocker arm oiling
Post by DragBikeMike on 11/10/19 at 15:22:48

The rockers receive oil via a hole in the top of the assembly. It's splash oil. I think you could improve oiling significantly by applying a very generous chamfer to the top of the hole, which would increase the available surface area utilized to catch/trap the splash oil, and also significantly increase the volume of the reservoir.

Looks to me like the wrist pin (also splash lubed) is of greater concern. It has no reservoir, and the splash oil has to migrate up rather than gravity feed down.

Regarding stiffer springs. There's only one way to find out. ;)

Title: Re: Rocker arm oiling
Post by Armen on 11/10/19 at 18:08:20

Thanks DBM
Somewhere in my paperwork is a book of hotrod tips for Nortons. In there is to chamfer the oiling hole for the right cam bearing so it gets more oil.

Title: Re: Rocker arm oiling
Post by batman on 11/11/19 at 13:06:25

Armen , Why would you even consider stronger valve springs ? the stock springs are known to work with every cam we have available .

Title: Re: Rocker arm oiling
Post by DragBikeMike on 11/11/19 at 13:51:40

There are two cams available that require stiffer springs. They are Web grind 402 and grind 340b. 8-)

Title: Re: Rocker arm oiling
Post by batman on 11/11/19 at 23:23:35

What cams are they ? stage 1&2 ?

Title: Re: Rocker arm oiling
Post by Fast 650 on 11/11/19 at 23:47:25

Those are hot cams for the DR. They have even more lift and duration than the ones you are thinking of.

Title: Re: Rocker arm oiling
Post by batman on 11/12/19 at 08:23:35

So I'm mistaken , if one of these is installed in a Savage ,but we haven't heard of that as yet. Do either show any real promise? They look way to radical to me.

Title: Re: Rocker arm oiling
Post by Fast 650 on 11/12/19 at 10:34:17

3A392C3539366C60580 wrote:

So I'm mistaken , if one of these is installed in a Savage ,but we haven't heard of that as yet. Do either show any real promise? They look way to radical to me.

Too radical comes down to the type of riding that you do. If you like to just putt around and don't want to downshift much, the 340b grind is probably a bad choice for an otherwise stock motor. The 402 is about the same as a stock DR cam with a bit more lift and duration. Either of those will require modifications to the LS engine though, as well as the stouter springs.

Title: Re: Rocker arm oiling
Post by batman on 11/12/19 at 11:37:47

The 402 's duration @ .050 is 248 a bit high for the Savage, 240 will take you to 7000 rpm , 500rpm over redline ,do you really want the motor turning faster ? DBM is blowing out gaskets at 7250 to 7500. the 402's valve lifts are also high , while they do add to duration , they're not going to add to flow , the flow of fuel/air mix is regulated by the size of the valve seat area ,once the valves opening reaches about 25% of the valves diameter , which is way less than .390/.380 lift stated for this cam. I don't see either of the cams being used in the Savage they're over the top.

Title: Re: Rocker arm oiling
Post by Fast 650 on 11/12/19 at 11:52:56

5C5F4A535F500A063E0 wrote:

Like I said, they are not for stock or near stock engines. They will require modifications like Stage 2 porting, larger valves, and more compression. And at least one person has installed a 340b in their bike that I know of. I had looked at the 402 for mine but at the time the price was much higher than the stock DR cam so I passed on it.

Title: Re: Rocker arm oiling
Post by DragBikeMike on 11/12/19 at 13:15:15

" DBM is blowing out gaskets at 7250 to 7500."

DBM is not blowing out gaskets by revving this old single up past 7K. I've been doin that for months with absolutely no ill effect. I sucked that gasket in when I installed the KrankVent. It had nothin to do with engine rpm (just my opinion, but it is my bike, and I do have first hand knowledge on the failure).

I am still troubleshooting the gasket failure. I believe I have narrowed things down. The differential I measured across the gasket was miniscule, and to me, it seems highly unlikely that the failure was solely the result of that little bit of vacuum I pulled in the crankcase. My focus is currently on the fasteners. I doubled up on the copper washers to compensate for the material I lobbed off the cylinder. I'm thinkin too much soft copper in the sandwich.

Regarding the 340b & 402 grind cams, they are appropriate for my project. The objective is to learn and share. What's good for the goose is not always good for the gander. I want a hotrod, these are hotrod cams. 8-)

I will post the curves when I get a chance. They are interesting. These are not bolt-in cams.

Title: Re: Rocker arm oiling
Post by verslagen1 on 11/12/19 at 14:24:36

Sucked in not blown out.
http://suzukisavage.com/yabb2.2/Attachments/Blown_Gasket_Top_Side_2.JPG

Title: Re: Rocker arm oiling
Post by batman on 11/12/19 at 19:36:29

Ok ,My mistake, there is no oil pressure in that area of the gasket, as it's just a gravity drain back to the case. I would however use a sealant on both sides of the copper gasket , copper deals well with pressure /vacuum but is not so good with oil as it tends to migrate between the copper and the cases.