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Roller Rockers
Posted: Thu Jul 31, 2008 3:38 pm
by ian.stewart
Heres a question thats bothering me a bit, -----When I crank over my engine I get LOTS of oil up at the rockers, these are Kenne Bell Roller Rockers, im wondering if there should be a restrictor plug in the heads to stem the oil, I know the oil is beneficial to keeping everything cool at hi revs, bit I have a feeling I will be running with my rockers covers brimming @ 7k

Posted: Thu Jul 31, 2008 11:24 pm
by HairbearTE
I would Ian. My set up comes supplied with just such a restrictor. It's basically a 0.25" grub screw with a 0.028" hole drilled through it. Tap the front oil hole of each head and install them. Job done.
Posted: Fri Aug 01, 2008 9:48 am
by ian.stewart
Cheers mate, Time to machine up some restrictors, probably do mine slightly differently, 6mm grub screw fitted into the pedistal, this way so I dont have to remove my heads. I may have some brass screws that i can drill , Makes life easier drilling small holes rather than trying to drill thru a grub screw with a small drill
0.028 is going to be a bit harder, .7mmdrill or No70drill, or a 48letter drill, perhaps I may just go to 1/32"
Posted: Fri Aug 01, 2008 5:57 pm
by HairbearTE
It should be simple enough to make yourself but if you want to save some grief and if you can find 'em the yella terra part number for the restrictors is YT6167.
Posted: Fri Aug 01, 2008 6:35 pm
by ian.stewart
Im fairly certain I have a full set of Number drills in the loft, so I dont think it will be a problem, even so, a .7mm drill is not that far out, I dont think it would be a problem even if I went out to 1mm
Posted: Fri Aug 01, 2008 7:38 pm
by sidecar
Des Hammills book reckons that you can fit restrictors even with the standard setup, it's worth a few PSI on the oil pressure.
I did fit some but I then spoke to RPI who said take them out!
Pete
Posted: Fri Aug 01, 2008 9:53 pm
by mgbv8
This is interesting. Why do RPI say not to use them? Surely if you had enough oil up top, the residual pressure would aid cam, dissy drive, lifters and crank lubrication?
Posted: Fri Aug 01, 2008 10:15 pm
by ian.stewart
I cant see the reason not to restrict it, there is LOTS, even at cranking speeds, its coming down the springs in what you could described as curtains., I think its a wee bit more than whats needed.
Posted: Fri Aug 01, 2008 10:19 pm
by mgbv8
Mine doesnt gush like that Ian. But after a few seconds at idle there is certainly a good flow from the rockers. If you are getting curtains I would say thats a bit OTT ?
Posted: Fri Aug 01, 2008 10:28 pm
by HairbearTE
sidecar wrote:Des Hammills book reckons that you can fit restrictors even with the standard setup, it's worth a few PSI on the oil pressure.
I did fit some but I then spoke to RPI who said take them out!
Pete
The standard arrangement does require a good supply of oil, it is quite crude after all. I personally wouldn't go over the top restricting the oil supply to it!
Ian i've just thought of something. The specs for the restrictors that I listed above are for my rocker system that employs needle roller bearings to mount the rockers to the shaft. If your system is of the type that has a roller tip but is still mounted to the shaft via a bushed arrangement then I think you had better allow for more oil flow as more will be required.
Posted: Fri Aug 01, 2008 10:32 pm
by ian.stewart
Mine are full needle rollers.
Posted: Sat Aug 02, 2008 6:30 am
by sidecar
mgbv8 wrote:This is interesting. Why do RPI say not to use them? Surely if you had enough oil up top, the residual pressure would aid cam, dissy drive, lifters and crank lubrication?
Holley at RPI just said something like "why would you want to do that". I replied that I thought that the RV8 had a reputation for over oiling the top end. The subject then moved on to something else. I must point out that we were talking about the standard plain bearing stuff which I guess might need more oil than roller rockers, especially if they have needle bearings on all the moving surfaces.
Pete
Posted: Sat Aug 02, 2008 12:15 pm
by ian.stewart
Everybody missed my C-ckUp, with the idea to plug the pedistals, you cant!!!!!, The oil runs into the shaft Via a necked bolt shank, so thats a non starter,, its now going to have a restrictor turned up as a small "TopHat" that will slide into the head with a1mm hole up the middle
Posted: Thu Aug 07, 2008 6:37 pm
by kokkolanpoika
I just wonder what hapends on cam "nose" lubrication if you resist top end lubrication? What i understand and had experience with rover“s cam is usually "wear" at 180-200 000Km..? But i think our weather in winter -20-30celsius deg can be one reason why they wear so quick?
Posted: Thu Aug 07, 2008 7:34 pm
by ian.stewart
its not the cold temp, we only have a few days a year when our temp is below -5, and normally only in the mornings, so I would think the temp has very little to do with the cam wear.