|
Browsing this Thread:
1 Anonymous Users
|
cam spray bars L |
|
Quite a regular
Joined: 2005/7/21 4:42
From hilo,hi
Group:
Registered Users
|
do you really need one?a spray bar for your cam on an L series?if so why,when and how does it work...and who sells it.
Posted on: 2006/4/6 6:22
|
|
|
Re: cam spray bars L |
|
Moderator
Joined: 2001/5/3 7:04
From 48 North
Group:
Registered Users Contentmaster Usermaster
|
Do you need one? No way, millions of L engines run fine without them. I believe they are used for extended high-rpm running (like circuit track race cars).
Posted on: 2006/4/7 3:33
|
|
|
Re: cam spray bars L |
|
No life (a.k.a. DattoMaster)
Joined: 2003/6/27 14:53
From Southern Tablelands N.S.W. Australia
Group:
Registered Users
|
According to the story, under some conditions, some of the L4 engines cam lobes can suffer prematurewear due to the method of lubricating the area of the rocker arm that bears the load of the cam lobe.
The cam is hollow & has oil pumped into it through the cam supports. It then emerges through holes drilled directly into the cam lobes themselves. The holes are found in three different places on the various lobes & this is said to be the cause of the [alleged] problem. Some lobes have the hole drilled at 90 degrees to the top of the lobe, on the opening ramp side of the cam lobe. This means that the contact patch gets a shot of oil directly before it bears the load of the cam & this is good. Other lobes have the hole drilled in the middle of the base circle [from memory], which is 180 degrees from the top of the lobe. This too gives the contact patch a shot of oil before cam lobe contact, but the cam now has to turn an additional 90 degrees before contact occurrs. The problem lobes have this hole drilled at 90 degrees to the top of the cam like the first group, but on the opposite side to the first ones, which places them on the closing ramp side. This means that the contact patch gets a shot of oil 'after' the cam has wiped across the contact patch & yet another 90 degrees more of cam rotation untill the cam contacts the patch again.
I have been involved with L20B engines since February 1981 in my work fleet & I still use one in my private 200B hack. I have never experienced this problem, & I have never met anyone who claims to have experienced it, yet early L6 engines seem to have used the spray bar which keeps a constant supply of oil on these contact patches, & this is supposed to be the fix for this [alleged] problem.
Preventing the oil from geting inside the cam is also a part of the modification as this method of lubrication becomes redundant with the spray bar & therefore constitutes just another internal oil leak that drains off precious oil pressure.
So,.. is there actually a problem with L series cam lobe wear? Maybee in race engines with very high valve spring pressures, & if so, then this is supposed to be the fix, but Ddgonzal is right, millions & millions of L series engines have soldiered on for decades all over the world without a hint of a problem.
Posted on: 2006/4/7 4:22
|
_________________
Love your Datsun. Treat it well.
|
|
Re: cam spray bars L |
|
No life (a.k.a. DattoMaster)
Joined: 2004/7/15 12:10
From Adelaide, Australia
Group:
Registered Users
|
Mainly used on L 4 engines with solid billet cams.
Posted on: 2006/4/7 9:26
|
_________________
cheap + fast = disaster fast + reliable = expensive cheap + reliable = stock IPRA Build
|
|
Re: cam spray bars L |
|
Quite a regular
Joined: 2003/5/28 9:56
Group:
Registered Users
|
This is a real requirement at times. On a friends L18 about 10 years ago he had an electromotive grind that was roughly equivilent to a "high lift 76" degree cam. All of the lash pads, rocker geometry etc. were set up correctly but if kept destroying the lobe face. After about 3 attempts, he fitted a custom spray bar fed by an external line t-ed off from the oil pressure switch feed on the side of the block. After that, he never had a problem ever again. The motor was being used in supersprints, so only about 3 laps at a time but still hard work for the engine.
Posted on: 2006/4/7 9:59
|
|
|
Re: cam spray bars L |
|
No life (a.k.a. DattoMaster)
Joined: 2004/5/28 5:02
From Adelaide, South Australia
Group:
Registered Users
|
Are you asking where to get one Matt?
If so I can dig up some names.
Posted on: 2006/4/7 10:51
|
_________________
"Anyone who has never made a mistake has never tried anything new"
Albert Einstein
Put stupid oversized photo here>>
|
|
Re: cam spray bars L |
|
Home away from home
Joined: 2000/11/8 8:58
From Taupo New Zealand
Group:
Registered Users
|
what about modifying a 6cyl one?
Posted on: 2006/4/7 23:33
|
_________________
1970 1200 coupe A15 1972 1600 original except for nana's sheepskins 1978 B310 SR16VE
|
|
Re: cam spray bars L |
|
No life (a.k.a. DattoMaster)
Joined: 2003/6/27 14:53
From Southern Tablelands N.S.W. Australia
Group:
Registered Users
|
Modifying an L6 system is probably the way to go but first you need to find an early L6 & confirm that it did indeed use a spray bar system. Then you need to determine that you could use the parts. I think that you would need to use the cam support towers as I believe that the spray bar is a part of these, & geting them to correctly align on another head might be a problem.
Anyway, see if you can find an early L6 & have a look.
Posted on: 2006/4/8 0:50
|
_________________
Love your Datsun. Treat it well.
|
|
Re: cam spray bars L |
|
Quite a regular
Joined: 2005/7/21 4:42
From hilo,hi
Group:
Registered Users
|
well this l20 will be feed with nitrous and a daily driver..when at the 1/4 mile or on the street i'm a rough driver and loves high RPMs..but i guess if the problem is on the least side i'll forget about it?or not..i hate to put my new .572lift,.292 duration schnieder cam to waste?
Posted on: 2006/4/9 7:09
|
|
You can view topic.
You cannot start a new topic.
You cannot reply to posts.
You cannot edit your posts.
You cannot delete your posts.
You cannot add new polls.
You cannot vote in polls.
You cannot attach files to posts.
You cannot post without approval.
|