Jump to content
SAU Community

Recommended Posts

It is with great disappointment i have to ask this question.

RB25 Neo head on RB30 block. Head was welded for VCT and decked flat. Block was scraped with a razor blade to get everything off and then cleaned using WD40 and brake cleaner to ensure a clean surface. I did not check block straightness at all with a steel rule etc. Using an RB25 Cometic Multi layer metal head gasket and RB25 ARP head studs torqued to ARP specs (80 ft/lb)

Oil is weeping from between the head and the block on the passenger side at the very front of the engine. Compression test on cylinder 1 shows 170psi and oil pressure at cold idle is 70psi, using a 10W-40 oil. The oil leaks very slowly but enough to be noticeable as a mark on the ground. Even once then engine has been shut down it will continue to leak for maybe 15 minutes, which i guess it only stops when all the oil has drained from the head.

I'm guessing that the block just isn't straight enough to get a good seal with the metal head gasket? I guess my options are take the head off and replace with a standard nissan fibrous gasket, or spray some hylomar (not sure exactly which one to use, the blue spray or the copper?) on the gasket and put it back on?

paCh2fp.jpg

Video attatched below of issue.

Oh that sucks :(

Are you sure its coming from the HG and not the cam seal and running around the HG

Even hylomar can only do so much and if the block isn't straight then that needs to be fixed to guarantee a good seal which would unfortunately mean having the block decked

Yeah I'm pretty positive that's where it's coming from. Block was removed from a running car with no oil leak issues so thought I would just be able to use Nissan gasket. :/

I would have expected a head gasket oil leak to come from the right side so I'm also leaning to a leaky cam seal.

Here's a photo of my 32's exhaust cam which made quite a mess. Previous owner had decided to replace cam seals and had done a poor effort.

Oil travelled a long way and it was hard to track where it originated, belt etc stayed clean as the oil leaks between the rear cam belt cover and the block.

post-73571-0-93685500-1410667195_thumb.jpg

I replaced the cam seals with brand new Nissan items before I put the engine in. It is very hard to track where the leak is with the cam backing plate on but I am very confident it's not from the cam seal (unfortunately)

It might be a long shot, but since It's been heat cycled, I would re-torque the head before pulling it down. Did you use the supplied ARP lube while torquing the head in sequence, or engine or similar? Maybe try another torque wrench?

Sucks to hear man, hope it works out for you.

Yeah I had the cam gears off only 3 days ago and there did not look to be any evidence of oil leaking from the seals. Will inspect before taking the head off though.

I agree it's unlikely that it's leaking oil from there, but as I said there is no oil above there or any oil from behind the cam backing plate (that I can see), have cleaned it multiple times and it only seems to be coming from where you can see in the video :/

Yep used arp moly lube in all studs and nuts torqued in correct sequence to ARP specs (80 ft/lb). Used my torque wrench which has hardly been used (done flywheel bolts 3 times and 2 sets of head studs)

Only thing with that is my 13mm deep socket just touches the cams when torquing them up. Some of the pressure I am applying would be applied to the cams not the nuts but I don't think it would be too much, it barely touches them.

Alright. I tried putting liquid gasket in where it was leaking to see if it would run down the front if it so I could see if it was coming from the cam seal or not. None run down the front but it did come out of between the head and the block just further down the engine where I didn't put liquid gasket. So I'm now almost positive it's not the cam seal. :( still the cam gears and backing plate coming off tomorrow night for inspection.

Am I able/should I also give a standard Nissan headgasket a spray with hylomar? Just for that extra sealing?

I'm about ready to set this thing alight if it leaks again.

2 things.

1) Check your torque wrench. Put it on a nut (like a wheelnut) so it sits horizontal and hang a known load from it. You can work out the torque from a known mass easily enough. All you need is mass, 9.807 and the length of the lever arm between pivot centre and the load point,

2) Having done that, use it to torque the head bolts up again.

my car leaked from there and it came from the cam seals. don't rule out coincidence!

I pulled the rocker cover gaskets off twice and replaced the VCT drain once and finally realised it was the cam seals.

Unsure how the cam seals were initially installed, but both front cam bearings are important.

Their front sections need a wipe of 3-bond to stop oil weeping between the cam cap and the head.

This is easiest to do by first installing the cam with all caps, then removing the front cap to apply the sealant, and then finally torquing down all the caps.

It has to be done carefully so the seal oil drain back hole isn't blocked.

I also give the outers of the seals a very light wipe of 3-bond as they're only a light push fit.

As the head was re-built I presume the actual seal surfaces were tidied up.

I used grease on the cam seals (as recommended by my mechanic mate) and was considering using liquid gasket on the cam caps but didn't.

There is 3 points at which oil drains into behind the cam seal, one in the head itself and 2 little holes either side of the cam cap. So you are saying I should liquid gasket everywhere around the cap but not where those drain holes are?

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

    • I came here to note that is a zener diode too base on the info there. Based on that, I'd also be suspicious that replacing it, and it's likely to do the same. A lot of use cases will see it used as either voltage protection, or to create a cheap but relatively stable fixed voltage supply. That would mean it has seen more voltage than it should, and has gone into voltage melt down. If there is something else in the circuit dumping out higher than it should voltages, that needs to be found too. It's quite likely they're trying to use the Zener to limit the voltage that is hitting through to the transistor beside it, so what ever goes to the zener is likely a signal, and they're using the transistor in that circuit to amplify it. Especially as it seems they've also got a capacitor across the zener. Looks like there is meant to be something "noisy" to that zener, and what ever it was, had a melt down. Looking at that picture, it also looks like there's some solder joints that really need redoing, and it might be worth having the whole board properly inspected.  Unfortunately, without being able to stick a multimeter on it, and start tracing it all out, I'm pretty much at a loss now to help. I don't even believe I have a climate control board from an R33 around here to pull apart and see if any of the circuit appears similar to give some ideas.
    • Nah - but you won't find anything on dismantling the seats in any such thing anyway.
    • Could be. Could also be that they sit around broken more. To be fair, you almost never see one driving around. I see more R chassis GTRs than the Renault ones.
    • Yeah. Nah. This is why I said My bold for my double emphasis. We're not talking about cars tuned to the edge of det here. We're talking about normal cars. Flame propagation speed and the amount of energy required to ignite the fuel are not significant factors when running at 1500-4000 rpm, and medium to light loads, like nearly every car on the road (except twin cab utes which are driven at 6k and 100% load all the time). There is no shortage of ignition energy available in any petrol engine. If there was, we'd all be in deep shit. The calorific value, on a volume basis, is significantly different, between 98 and 91, and that turns up immediately in consumption numbers. You can see the signal easily if you control for the other variables well enough, and/or collect enough stats. As to not seeing any benefit - we had a couple of EF and EL Falcons in the company fleet back in the late 90s and early 2000s. The EEC IV ECU in those things was particularly good at adding in timing as soon as knock headroom improved, which typically came from putting in some 95 or 98. The responsiveness and power improved noticeably, and the fuel consumption dropped considerably, just from going to 95. Less delta from there to 98 - almost not noticeable, compared to the big differences seen between 91 and 95. Way back in the day, when supermarkets first started selling fuel from their own stations, I did thousands of km in FNQ in a small Toyota. I can't remember if it was a Starlet or an early Yaris. Anyway - the supermarket servos were bringing in cheap fuel from Indonesia, and the other servos were still using locally refined gear. The fuel consumption was typically at least 5%, often as much as 8% worse on the Indo shit, presumably because they had a lot more oxygenated component in the brew, and were probably barely meeting the octane spec. Around the same time or maybe a bit later (like 25 years ago), I could tell the difference between Shell 98 and BP 98, and typically preferred to only use Shell then because the Skyline ran so much better on it. Years later I found the realtionship between them had swapped, as a consequence of yet more refinery closures. So I've only used BP 98 since. Although, I must say that I could not fault the odd tank of United 98 that I've run. It's probably the same stuff. It is also very important to remember that these findings are often dependent on region. With most of the refineries in Oz now dead, there's less variability in local stuff, and he majority of our fuels are not even refined here any more anyway. It probably depends more on which SE Asian refinery is currently cheapest to operate.
    • You don't have an R34 service manual for the body do you? Have found plenty for the engine and drivetrain but nothing else
×
×
  • Create New...