Jump to content
SAU Community

Recommended Posts

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 :3some:

Link to comment
https://www.sau.com.au/forums/topic/164848-lifters-wont-bleed/
Share on other sites

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 by r33_racer

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.

:huh: Cheers :D

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?

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?

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?

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.

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 by Darius

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 by Dobz

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.

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.

  • 2 weeks later...

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. :dry:

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Updating results following our SR20det project. Data collected form improves future turbocharger making and high flowing services. So far differences between G and GT series turbine wheels, we are in the process of making a new turbine, the aim is for better mid top range flow without gain too much lag.  Result is back to back comparison of G25-660 and GTX2867 spec turbochargers on the same car, nothing changed apart from turbocharger. Both tuned to knock limit from pump 98 fuel (US Ron93). GTX2867 was about 400RPM more responsive making 255rwkws while G25-660 made 17 extra Kws with wider spread of torque after 4500RPM finishing off at 272rwkws.  
    • @GTSBoy i tried to jumper the wires and got the steering wheel light to come on which is right under the gear indication but that still doesnt come on.  Can it be an issue with my cluster?
    • Given that you have seen the dash indicator work briefly, then it would seem like you have a simple wiring problem. What happens when you simply jumper the wires on the "steering wheel switch"?
    • Yesterday's day in review: All the wiring to the lights up the front how I want it, is ran, terminated, and all to length. The only lighting up front I haven't finished is the side indicators, as I need to get to the partly cutup factory loom, and find the plugs for them. Interesting note, the side indicators use the exact same plug that's in the doors for something else that I don't remember what it is... So that plug better be careful...   Power steering solenoid, on the R33 is variable, and from memory PWM. The Ford's control from the docs I have so far, is it's just a on or off control. So I'm not sure it's what I want, and in any case, power steering running, but at its heaviest (solenoid off) is likely what I'll want anyway, so I'm not yet touching it at all. All the wiring I can complete so far, is done. There are 3 wires I need to make a plug for at the ECU, and these are just for the vehicle speed sensor, of which I need to get a T5 from an AU, so I can use its output that has the speed sensor on it. (My car doesn't have ABS, otherwise I'd set it up to use one of the ring gears on that). I need to buy new headlight globes and front parker globes, otherwise I could show photos of lights working. Current fuel lines in and out on this motor are "5/16". I'll order hardline, and some AN fittings for that, and I just need to 100% check fuel line size at the tank end, to get the ends for it. I'm also looking at a few options for the banjo bolts to AN fittings for the power steering rack. I'll pull the reservoir off the Barras PS pump. There's an off the shelf fitting for that pump for a -10 AN feed, and it'll use a 16mm to dash -6 an outlet to feed the rack. I'll be making my own power steering reservoir, I'm going through the thought process at the moment of how I'll run the baffles, and I need to research another idea for it too.
    • Two inlet runners changes the engines characteristics requiring less fuel to make torque at different points in the rev range. The smaller diameter inlet runners on the DET increases air flow speed, which improves atomisation of fuel, particularly in low load/idle for better burn, and in specific areas of the engine, (areas you would use when driving normally) increases the efficiency. All of those items change how efficient the engine is at different speeds. The changes on the neo help slightly to improve emissions where it matters. The overall improvements won't be the likes of going from an engine built in the 70s to an engine built in the 2000s, it's just a small step. But still leaves it the RB with the best chance of improvement.   As for your comment about the whole using a cat to not need to worry about those gases. Two things, no system is 100% perfect. It won't eliminate everything. So reduce the quantity you put into it, you still reduce the output. Two, make that system do less work, and it's likely to survive a little bit longer. Funnily enough to, one trick employed to get cats up to temp, AND to drastically reduce emissions before they get up to temp, is to reduce ignition timing.
×
×
  • Create New...