got a question I thought I'd throw on here, has anyone else had problems with their Hydralic lifters bleeding off after a long duration of time at high RPM e.g doing a powerskid or doing a pass at the drags? I've got an RB30 single cam with a decent size Hydralic camshaft in it-240, 252@50 with 520 thou lift, I have 100 thou machined off my lifter blocks and have brand new genuine lifters fitted. I've got a 5500 convertor and a glide so at the drags it's pretty much between 5-6500 rpm for 400meters. When I get to the end of the track and back off, my Hydralic lifters rattle for about 3 minutes and then settle back down. If I turn it off it will settle down but do another pass and the exact same thing happens.. I'm running an N1 pump with 7mm cut off the relief spring so my oil pressure is 25 at idle 50 above 2 grand and about 75-80 at full noise. I run Lucas Hot rod 20-50 oil Any advice from people experiencing the same thing would be good. I have had different cam shafts, rocker boxes, lifters, head, oil pump, and had the same problem in the past. Cheers Also thought I'd include. The engine is not in a VL. It's in an early Holden so it has a custom rear mount sump that holds 7.5ltrs of oil.

maybe the noise isnt coming for the lifters might be coming the block or the engine might be pinging ? after hard use. and with the oil pump what was the oil pressure at before you cut 7mm off the relief spring?

At that duration and lift most go solid... First thing is you need a thicker oil Penrite hpr40 25-70 is what people use Next you can try standard sized lifter blocks After that not much else you can do..good luck Its a normal problem Cheers Darren

we've used the tin can RB25 oil pump to solve that one. After belting down the freeway and pulling up at the lights at the end of the off ramp.. same issue. tappety tap tap tap for while. Cause, lumpier camtech 520A-115 camshaft, heavier valve springs, original hydraulic lifters, that combo has needed more oil pressure in two occasions we've experienced... you could try an add a restrictor to turbo line to assist with oil pressure but not the best solution. larger oil pan is first is helpful, ensure bottom clearances are right, but high volume high pressure oil pump to suit the extra valve spring pressure is the fix.

watch your oil pressure when you back off it will be oil surging when you let the throttle off, all the oil will be in the head or a poor designed/std sump.

Quote: Originally Posted by bachig24u [View Post] we've used the tin can RB25 oil pump to solve that one. After belting down the freeway and pulling up at the lights at the end of the off ramp.. same issue. tappety tap tap tap for while. Cause, lumpier camtech 520A-115 camshaft, heavier valve springs, original hydraulic lifters, that combo has needed more oil pressure in two occasions we've experienced... you could try an add a restrictor to turbo line to assist with oil pressure but not the best solution. larger oil pan is first is helpful, ensure bottom clearances are right, but high volume high pressure oil pump to suit the extra valve spring pressure is the fix. Thanks a lot for a knowledgeable reply. I belive this is the issue too. When I bought the pump I asked Mark at JPC why sometimes you hear people don't use N1 pumps. He said because they run so high oil pressure. He suggested to cut a quarter inch (7mm) off the relief valve Spring to bring it back down a bit. Wonder if my particular set up needs that oil pressure to keep the oil from bleeding out of the lifter..

Did you change the oil? cheers darren

Quote: Originally Posted by Jet R31 [View Post] Did you change the oil? cheers darren Hey champ, Thanks for your reply too. I have tried Penrite HPR30, Penrite HPR40, Lucas hot rod 10/40 and Lucas hot rod 20/50 All seems to be the same. Why do you suggest going back to a standard lifter block? Cheers, Trent