Lifters Won't Bleed

[Darius]

I'm just completing a rebuild of a series 1 RB25DET. I built the bottom end and while I was in the process of machining the block, I installed a Tomei restrictor orifice on the rear oil feed and blocked the front oil feed on the block. The car ran great, the lifters primed, and I drove it for 700 miles.

Then, I pulled the head to do a port/polish job and get new oversized valves. When I put it back together, everything works fine except some of my lifters won't bleed (leaving about .25mm of valve lash). They are quiet for the first 30 seconds, but noisy after the engine heats up. So, I pulled the trouble lifters and disassembled/cleaned/reassembled them and they still have about the same amount of lash, which means they aren't expanding to the cam. I am now concerned that I am not getting enough oil pressure through the single orifice and VTC feed to prime the lifters. Most of the trouble lifters are towards the rear of the block.

Anyone have suggestions? I think I"ve tapped all my resources on the US forums and need the aussie experts to help

[Al]

Your best bet is Sydneykid, R33 racer or Cubes. Just drop them a PM

But there are also plenty of others, on this forum, that can assist you with this problem.

[r33_racer]

you need new lifters then mate.

Or find another second hand set to replace them that arent stuffed..

Also i think this was explained in the oil control thread which is somewhere around.

Edited April 16, 2007 by r33_racer

[LatinR33]

My lifters are a lil noisy on start up only, would changing to solid lifter make any difference??? or just replace to new standard lifters.

[Sydneykid]

As per my PM, and for others benefit......

Did you check the valve stem length of the new valves before you installed them?

Did you check the installed height of the valves after you fitted them to the head?

The hydraulic followers have a limited range of adjustment, it sounds to me like they are not refilling with oil because the valve stem length / height is incorrect.

Cheers

[Darius]

I did not check the valve stem length because I had them cut by Ferrea according to the FSM. I didn't measure the installed height either because I figured the lifters would expand to rest the lifter on the cam during operation.

I measured the valve lash of each lifter bucket prior to removal and again after cleaning and installation. The valve lash did not change much, if at all. I originally thought the lifters were just dirty or stuck and that disassembly and cleaning would allow them to telescope again. Didn't work as I planned. I still think the lifters should be able to expand 0.25mm if given the proper oil pressure and that's why I am curious if the head feed modifications for the RB25 are recommended for hydraulic lifter applications?

[r33_racer]

no lifter noise in either of our 25/30's

just the few lifters which were rooted and we replaced with some others from a spare head...everything come good.

[Darius]

I've been doing some research online and since the problem is temperature related, it is leading me to believe that the hydraulic lifters are leaking down as the oil thins when hot. I started it with 10W-30 and it was quiet but then got loud as the engine temp rose. Then I replaced the oil with 10W-40 and the engine ran quiet for longer, but still got equally loud as the engine temp got to operating temp.

At this point, I am going to replace the lifters and pray that the issue goes away. Anyone have input or comments on this?

[T04GTR]

were they bled on the bench before you put them in?

just as a referance vg30 ones are the same

[Darius]

were they bled on the bench before you put them in?

just as a referance vg30 ones are the same

Yep I bled them according to the link that I listed above. And thanks for the reference. I've been calling around to local dealerships and they want $35US each. For at least 14 new ones, that is going to cost me a bundle of money. Anybody have any good hook-ups where I could get them for cheaper? Are OEM lifters worth the money or are aftermarket/OE parts producers okay too. There are some that I have found that are non-NISSAN for $17 each. Anyone have insight?

[Dobz]

you've put a restrictor on the back oil feed to the head and blocked off your front one completely!

there's you problem!

you've been starving the whole valve train of oil which would be causing you these problems.

the standard oil restrictors in the block for hydraulic lifters are both there to give the lifters enough oil flow to operate properly and have enough for camshaft lubrication.

the restrictors are mainly used for engines that have been converted to solid lifters because the head simply doesn't need the extra oil anymore.

the type of oil and the condition it's in will affect things too.

for instance oils with a low hot temp. viscosity (eg. 10w-40) won't work well if things have been modified to make more power and if the car is driven hard sometimes due to extra heat produced.

it's a bit safer for your engines sake you get an oil with a high hot temp. visc. rating like 10w-60.

[T04GTR]

tru tru. and in the block im pretty sure there a check val;ves to.

just a question. when you install the cams is there any noticable "clearance" or lash between the cam and the lifter when its installed?

[Darius]

tru tru. and in the block im pretty sure there a check val;ves to.

just a question. when you install the cams is there any noticable "clearance" or lash between the cam and the lifter when its installed?

Yes what I refer to as the "trouble" lifters have anywhere from .1 to .25 mm of valve lash when the cams were installed.

you've put a restrictor on the back oil feed to the head and blocked off your front one completely!

there's you problem!

you've been starving the whole valve train of oil which would be causing you these problems.

the standard oil restrictors in the block for hydraulic lifters are both there to give the lifters enough oil flow to operate properly and have enough for camshaft lubrication.

the restrictors are mainly used for engines that have been converted to solid lifters because the head simply doesn't need the extra oil anymore.

I only did this to follow Sydneykid's guide to solving the problem with over oiling the head. There are issues with the sump going dry during periods of extended high revs and oil not being able to return fast enough.

Why is it an issue NOW? I drove the car with the stock valves and upgraded cams/springs for 700 miles (two months) and never heard the lifters ticking except initial startup.

Out of curiosity, what is the operating temp of the RB25? I have an 84*C thermostat from a VG30 in there now. I ask because the ticking becomes noticeable at about 70*C.

Edited April 23, 2007 by Darius

[Dobz]

if the engine is going to get extended high rpm running and you want to keep the hydraulic lifters you'll need a bigger capacity and baffled sump and you'd need to get all the oil drain galleries drilled bigger.

a simple solution is to get solid lifters put in.

by the way what oil have you been using in the engine?

i forgot to ask what sort of driving was done in those 700 miles that it was fine?

Edited April 29, 2007 by Dobz

[T04GTR]

if theres lash there had it.

[Darius]

Dobz - I am really only concerned with long duration high rpms possibly during some future autocrossing/track driving, but that will be rare since I don't live near event locations. I may go with a baffled sump in the future, but right now I only want to get the motor running correctly and get a good tune on it. Once I feel comfortable that my build is mechanically sound, then I will upgrade turbo/fuel/IC. I have installed external oil drain lines from the back of the head that will lead to a t-fitting in the turbo oil return line in the future. A baffled sump is something I never really considered necessary, but if it didn't cost me an arm and a leg to get one here in the US I would think about it. Any recommended brands and shops to buy from that ship internationally? RB parts are somewhat scarce here.

And for the 700 miles after my build, the car was driven like I was an old man. Nothing near redline at all. I think 4500 rpms was the max I got it up to and that was after 500 miles and two oil changes. I'm thinking that the storage of the lifters for an extended time period and not submerging them in oil caused some to stick/fail when I got it all back together again after I rebuilt my head.

And I have always run 10W-30 (dinosaur) during break-in. I'm planning to switch to synthetic once I get the new lifters installed.

T04GTR - I am beginning to think its the lifters and am planning on buying a set today.

I will keep this thread updated as I go. Thanks guys.

[Guilt-Toy]

Wrong wrong. and WRONG.

There is plenty of oil supply with blocking one oil feed and restricting the other.

Mine has been working for ages. i did have noise that i thought was lifter noise but it ended up being main / conrod bearings.

Maybe you have spun one as it sounds like its doing exactly what my engine does. no noise when its cold but when it warms up its noisy as hell.

you've put a restrictor on the back oil feed to the head and blocked off your front one completely!

there's you problem!

you've been starving the whole valve train of oil which would be causing you these problems.

the standard oil restrictors in the block for hydraulic lifters are both there to give the lifters enough oil flow to operate properly and have enough for camshaft lubrication.

the restrictors are mainly used for engines that have been converted to solid lifters because the head simply doesn't need the extra oil anymore.

the type of oil and the condition it's in will affect things too.

for instance oils with a low hot temp. viscosity (eg. 10w-40) won't work well if things have been modified to make more power and if the car is driven hard sometimes due to extra heat produced.

it's a bit safer for your engines sake you get an oil with a high hot temp. visc. rating like 10w-60.

[pssiii]

Valve stem height is wrong!

The valves might have been the same length but the seats have been re-cut also.

Install solid lifters and shims, fixed.

[Darius]

To follow up on this thread, I just installed new lifters to eliminate the easiest fix but it didn't help at all. So now I have 24 lifters that are used and good and a motor that still sounds like a thrashing machine.

I think Sydneykid and psiii hit the nail on the head with the improper installed height, because the lifters never made noise earlier when I had the front oil passage blocked.

What is the best way to adjust the installed height of the valves because they are obviously too short. Should I back-cut the valves or should I have the valve seat set deeper? I could go with solid lifters I suppose, but I've already got $250 into a valve job, $500 into valves, $300 into springs, and $360 into new lifters. These are U.S. values BTW...I don't really think taking a totally different approach is an option at this point. Maybe the next time around.

Thanks for the support guys. I greatly appreciate it.