proengines

6 out of 10 Formula 1 teams use Mahle pistons. Thats a fair indication of their quality. Mahle is one of the worlds biggest piston manufacturers and supply F1, IRL, Nascar, WRC, V8 supercars etc.. as well as Mercedes, BMW, Porsche, Ferrari, GM, Ford etc.. They also own Cosworth Technology and ACL piston products. They are a little dearer than most other pistons but quality costs money. Look at their F1 pistons, 19 500RPM, 15 000G when they change direction at that RPM and they stay together, thats a fair indication that they have it right. Attached is a pic of their box-n-box design.

I just did some checking and I have to correct myself. a standard RB26 bolt has an underhead length of 60mm and the ARP SR20 bolts have an UHL of 58.5mm so there is a 1.5mm difference in the length of the bolts. If you fit the bolts to the rod, the ARP protruded 7.3mm from the spotface where the nut seats and the std Nissan bolt protrudes 8.5mm. The nissan nut is 7.8mm thick so the bolt protrudes 0.7mm through the nut. The ARP nut is 9mm thick so the bolt finishes 1.7mm down inside the nut. thats probably a lot of figures but from them I wouldn't use the SR20 bolts. As I said, we have used the VG30 bolts with no problem, they are part # 202-6004 and work fine. They are a touch longer, I'll attach a photo so you can see.

The ARP SR20 bolts are a tad shorter but the threads are plenty long enough to engage the entire nut. From memory, an ARP VG30 bolt also fits.

It's a pretty common problem, I had one last week the same. The bolts are a very snug fit in the caps as they work as a locating dowel to locate the cap properly on the head to ensure the caps align in exactly the same spot as when the tunnels were bored. You can usually get them out pretty easily if you warm the cap up and spray some good penetrant around the bolt and leave it for an hour or so to work its way in. If you then use a spanner to work the bolt back and forwards it will usually loosen up and come out. I did have one that wouldn't and had to hold the cap in a vice (use soft jaws!) and tap it through with a pin punch, you may need to replace the bolt though if you damage the thread. Go slowly and carefuly and you should be fine, once the bolt starts to move it will pop out easily. I soda blast the inside of the bolt holes to remove any gunge and buff the bolt clean and use some nulon when I reassemble them and it works fine.

Jayce, to get the oil pump off its a matter of removing the timing belt, crank gear, tensioner/idler etc and removing the pump. It's the bottom aluminium housing, the pump gears are in the back of it and the cover plate screws on from the back with countersunk screws. If you were replacing the timing belt its probably another couple of hours work after that. It's a bit of rooting around though as it's on two dowels and the sump bolts hard against the bottom of it with no gasket, only silicone so it might be a little awkward to fit it all back up. The only thing I'm not sure of is if the boss for the oil pressure relief valve would let the pump move far enough forward before it hits against the inside of the sump. Then again, if you were going to remove the sump to fit a baffle it would be dead easy. Having said that, I wouldn't bother doing it unless you had a low oil pressure problem or erratic readings. The engine I just finished is an R32 and the screws were loctited in that from the factory and everything was all still tight.

The RB26 rods are a good idea, just make sure you fit new bolts to them. You should never reuse rod bolts. Fit a set of ARP bolts and have the rods resized and you shouldn't have a problem. The standard RB25 rods are a toy compared to a 26 and they do break through the beam, especially when engine braking where the tensile loads are high. If you have a spare $1500 a set of REV conrods are well worth fitting. Compare the price to properly prepping a set of 26 rods: buying the rods, buying bolts, beam polish, shot peening, close and grind, balance, pin fit etc to do them properly, you save around $800 compared to a brand new set that are much stronger and new. It really depends on what you plan to do with the engine but I've found most people eventually try for more performance once the new engine is up and going and a set of aftermarket rods are pretty cheap insurance.

oops... it's worth updating those credit card details when you get a new card.. the sites there now.

We make a baffle for any 26 engines we do now and weld it to the bottom of the std windage tray, it's square shaped around the pickup with 4 trapdoors, front, rear, left and right that all open inwards towards the pickup on a loose hinge. Whichever way the oil tries to move away from the pickup closes the trapdoors in that direction to keep the oil around the pickup. A dry sump is a heaps better option though if you have the money to spend. Has anyone thought of fitting an oil accumulator? when you're running the lines for a remote filter and cooler it's a pretty easy thing to plumb in and can make up for those few seconds of low or no oil pressure. Some info on accumulators at : http://www.moroso.com/articles/articledisp...l&catcode=13600

The oil pump screws coming loose was always a problem on the RB30 engines as well. A dob of loctite fixes it though. Most early RB engines have one or two loose when you strip them but it's not as big a problem on an RB30 as they very very rarely have a conrod bearing failure. A combination of detonation and low oil pressure is a killer for conrod bearings though. An N1 pump is an expensive fix though as from what I've seen the gears are the same size and they just run a tad stiffer relief valve spring. you can do the same to the STD pump if the gears and housing are ok.

Richard, if you need an engine hoist, creeper etc.. give me a yell. It's a shame to see such a nice car broken. BTW, i'm not trying to drum myself up work, just sorry to hear what happened. You may be able to just remove the crank and regrind/replace it if the conrod isn't damaged. It would be worth checking out the oil pump while it's off too.

One quick question... Why would you want to convert to LPG? The reason you probably dont see any LPG GTR's around is because there aren't too many GTR taxis or courier vans. Until someone perfects LPG injection you would need to run a blow through gas carby setup which would be a huge step backwards. You would end up with poorly metered fuel running through an intake setup not designed to carry anything but air. The ignition timing would need to be changed to suit the lpg, so you would need a separate ignition computer. The octane rating of LPG varies depending where you buy it, a lot of it is now apparently mixed with butane as it's cheaper. Then you need a tank in the boot to hold the gas, fit a converter or two in the engine bay somewhere etc.. etc.. This is before you even consider the accelerated wear on valve seats, the tappet clearances closing up, the lack of upper cylinder lubrication and cooling provided by petrol, the increased chance of detonation, not to mention the valve timing which would need to be changed to run efficiently on LPG. If you then weigh up the cost of the conversion compared to the fuel savings.. say $3000 at a very minimum, the fuel usage, running LPG you may save 50c a litre but then each litre only gets you about 2/3 as far as a litre of fuel, so say a 60L tank of fuel will last you a week, you will need 80L of LPG to go as far, so $60 of petrol will get you as far as $40 of LPG. Thats about $20 a week you save or $1000 a year. Theres at least 3 years driving before you save a cent considering the cost of the conversion. Finally, imagine trying to sell the car in a few years.. who would buy an LPG GTR?

Cometic are a good MLS gasket, the price is good to, around $400 and as good as the big name Japanese ones for half as much again.

If you're using the RB30 main bearings it might be worth drilling the extra oil feed holes in them, the same as the Nissan RB26 bearings have standard. Apparently ACL will eventually do this to their race series bearings.

A lot of aftermarket conrods run more side clearance on the crank journal and there is oil passed through there which splashes onto the bore. The original squirters are there to increase the life of the piston and bore by lubricating the thrust face, many engines get by using only splashed oil for the same purpose. I would say the main reason the squirter is not drilled is to keep the strength in the rod. A hole drilled through the rod has tiny flaws where cracks can begin. I think it's more important to keep oil flowing out the sides of the rods and fresh oil being pumped in as the oil stays cooler. The pistons get plenty of splashed oil, plus what comes from the piston cooling jets in most modern engines.

A common cause of conrod bearing failure that hasn't been mentioned is detonation. Have a look at the top half of the other conrod bearings and see if they are marked from say 10:30 to 2:30 (if the big end bore of the conrod was a clock with the piston sitting straight up, looking at the front). Marks here are a fair sign that the engine has been detonating and it would be worth playing with the tune when you get it going again, taking out a little timing or putting in a little more fuel. Just a thought anyway.

Theres sure going to be some pissed off late model corvette owners around...

bore: 85mm stroke: 83mm Bearing sizes and bearings are the same as a RB30. The rods would be no use in a performance engine as they run a huge piston pin, 26-27mm-ish from memory and the rod is way too heavy. The crank is forged steel, not sure about snout/flywheel pattern. It would be top quality being a diesel as they are under a lot more load than a petrol engine, diesels also usually have larger radiuses on the journals although the RD28 might have fillet radiuses but i'm not sure on that. The head gasket is very similar to an RB30, the bolt pattern is the same, I use the same plate to pressure test both. The RD28 uses a MLS head gasket which might be worth having a look at to use on an RB, it's available in 1.42, 1.5 and 1.58mm to set piston to head clearance on the diesel engine. Thats about all I can tell you without having one here to look at.

I haven't o-ringed an RB using the standard head gasket, I have done other engines though when customers want them done. You don't need a receiver groove with the std gasket but the ring needs to sit directly below the steel fire ring on the head gasket. The only problem I've seen with this setup is if the o-ring is too far from the bore it can squeeze the gasket in over the cylinder. You also dont want to run as much protrusion on the o-ring, .010" (.25mm) would be more than enough. I'd still get the guys that did the job to fit the wire and check the protrusion. It takes a bit of practice to butt the wire up spot on. There are a lot of different ways to do it, I'm not saying the way I do it is the only way but it works for me. In my opinion though, a MLS gasket like a Cometic or Tomei etc would seal better than a composite gasket with an o-ring. The next step up from those would be o-ringed and receiver grooves with a copper gasket.

You might be best off taking it back and getting them to fit the wire, I'd say it's part of the job when you o-ring the block. You have to butt the ends of the wire together and it needs to be spot on or it wont seal as well as it should. The wire should be an interference fit in the groove, meaning you have to tap it into the block and you need to snip of the ends square so they can butt up properly. When you say fencing wire, what is the diameter of it and what is it made of? I always use 1mm copper wire when I o-ring blocks. Also, if the wire isn't fitted by the sounds of it the head hasn't had receiver grooves cut in it? you need to fit the wire to mark the position of the receiver grooves before you cut them. If you're running a copper gasket you are much better off having the receiver grooves in the head. Ill try to attach some pics of what I'm talking about.

If you've got the budget to cover it, buy an RB26 head and ancillaries.

rev210, I didn't install the cams at all. Why I wanted the cam specs is so the cam timing can be checked, it's a bit awkward to do without knowing what the cam specs are. Why I wanted lift@TDC is so it can be checked accurately without dismantling too much of the car to fit a degree wheel to the crank. It's easy to find true TDC with a dead stop and check the lift against that. It's much quicker and dead accurate, if you have more than the specified lift@TDC you retard the cam, less than specified you advance it. By the way, I think that you will find that most people who fit cams do just "slap them in" as they dont have the facilities to check the cam position.

Does anyone have the lift@TDC figures for the poncams? or the full timing figures/lobe centrelines? I just thought it might be worth checking that the advance/retard on the cams is actually from where they are supposed to be zeroed. Also, what are the symptoms of one leaking wastegate on a twin turbo setup?

The ACL race series bearings are a nice thing, good material, hard back etc.. the only thing I would modify is to drill the extra feed holes through the oil groove in the upper bearing in the same way the original Nissan bearings are done. ACL will be doing this in the future on these bearings according to their rep I was speaking to a week or so ago. The other bearings I have found good are King, especially for conrod bearings. They run a very hard backing and a single layer of alecular bearing material rather than separate layers with an overlay that can flake under high loads/heat. Genuine Nissan conrod bearings don't seem to cope terribly well with any detonation. We recently had the sump off a 26 running around the 300rwkw mark and the Nissan conrod bearings had started to delaminate and had lost their tension. They wouldn't clip back into the rod, I've still got them here if you'd like a photo. We replaced them with King bearings. I haven't tried the Nismo bearings in the same situation but apparently they are a lot better than standard Nissan.

You probably could make a sleeve to fit but it would have to be awful thin as you will be boring into the cam tunnel when you bore out the head to fit it. I've done Jaguar 6cyl heads before but its a premade steel sleeve for them and theres plenty of room. It might be worth getting it welded up to start with and if it distorts too far then try to sleeve it. If it welded ok most cylinder head shops would be able to bore it back round again. Then again, it might be easier to start with another head if you weigh up the costs of fixing it vs the long term result. The best way to machine for cam clearance that I've found it to use a 20-21mm slot drill in a milling machine set to the same angle as the original recesses to clear the cam lobes. It takes a couple of hours but comes out spot on. Once you set the depth you cant go too far and every one is exactly the same.

20-22Nm is a pretty typical torque setting for a grade 8 m6x1 bolt.