proengines

True, you could buy 5 Nismo copy oil caps from ebay for that price!

I'd say you will find the actual rotors of the gear are the same width, in the photo the centre gear sits up because of the hub that locates the gear in the pump. The VL pump I have in the photo may have been a turbo one, I can't be sure, it was just lying around when I thought I'd compare a few different ones.

Heres some gear sets for comparison.

Hi guys, I've made a few changes including the phone number as I spent all day talking to people in Bombay trying to change my phone plan etc. I've also got out of general reconditioning but I'm still doing this stuff. You can get me on 0448 826256 (bh) if you need a collar. Sorry moderators, I'm not trying for a free plug, just getting the details right. The address is still the same, so is the website though very underdone due to time constraints. Cheers, Greg.

There is absolutely no problem with the Cometic gaskets. Like any MLS gasket, the surface finish needs to be spot on, any decent machine shop should be able to give you a suitable finish. Don't use any goo or spray on them, they have a viton coating which works better than any spray. A lot of the sprays will stop the viton sealing properly against the block and head. No MLS gasket will seal properly if the block or head is not flat. You can file any high spots off if you are fitting the gasket in the car, use a straight edge and a feeler gauge to check. Most blocks will pull up slightly around the head bolt holes which you will need to rectify before fitting the gasket. I've used cometic gaskets on engines making over 150Kw per cylinder without the gasket failing. I've also used one on an SR20 which detonated so badly it ate away the quench pads on the head and the alloy at the top of the bore but the gasket did not leak or even look damaged. The ACL race series MLS gasket is made by Cometic, they won't put their name on anything they dont think is top of the line.

As long as the block and head are machined you wont have a problem. If the block is flat and the head machined you shouldn't have a problem either.

There is nothing wrong with the gaskets and they don't need any coating/spray/gasket goo on them. They have a fine layer of viton rubber (or similar) applied to them which is all that's needed to seal the wather and iol in conjunction with the embossing on the gasket. The main reason for leaking when they are installed on a used engine is the surface on the block is not flat or smooth. I have never milled an RB26 or SR20 block where the surface cleans up completely within less than .1mm (.004") they are always slightly low on the exhaust side and slightly pulled up around the head bolt holes. This would seal ok with a composite gasket but not an MLS gasket. Any MLS gasket requires an Ra of 15-30 where a composite gasket requires 50-60 Ra (roughnes average) which gives a pretty good idea of what's needed, 2-4 times as smooth a finish and dead flat. Steel gaskets have very little conformability, which means they can't squash up on the high spots to seal the low spots effectively. Talk to any machine shop and they will tell you how much money they have spent retrofitting or replacing their surfacing machines to use CBN (cubic boron nitride) and PCD (poly crystaline diamond) tooling to be able to achieve these finished. Most gasket manufacturers make composite gaskets to suit engines that originally came with MLS gaskets so the head can be refitted without machining the block, it's a bandaid method but it gets cars back on the road where they would leak if an MLS gasket was refitted. After saying all thaty, you can file the surface of a block to remove high spots but it must be done very carefully as it's easy to do a fair bit of damage if you're not careful or dont know what you're doing. One thing I'd recommend is to never fit a steel gasket without at least machining the head. If you have a head machined and you can feel the machining marks in the head it's too rough. I wouldn't reuse a steel gasket if it was avoidable, once the embossing is flattened out there is not the preload to properly seal the water and oil. If you do reuse it, use a very good sealer. You also need to remove all the viton/nitrile coating if it is damaged. Whatever you use, none of it will seal in compression, thats a totally mechanical seal and no amount of goo will help seal it.

Theres a black wire loop behind the drivers side tappet cover that you can clip your timing light pickup on to.

Some pics are hopefully attached. Because the pistons are a slipper skirt design, the strut that runs from the pin boss out to the skirt interferes with the squirter in its normal location. It's just a matter of rotating the squirter slightly to clear the piston. They are making a running change on the pistons and machining a small relief in the skirt to clear the squirter once it's moved. These are one of the first sets they have made so it was a little R&D as we went. ACL/Mahle give fantastic support, I spoke to Paul in Sydney about the squirters one afternoon at almost 5PM and by 8AM the next morning I got an email through from Mahle in the US agreeing with what to do with the squirters and they had made a running change to the design to suit.

ACL piston products is owned by Mahle. The ACL race series pistons in the yellow boxes are made by Ross for ACL and are a nice piston. The Mahle pistons for the RB26 are new, I used one of the first sets and they are made by Mahle in the US, Mahle is a German company but Mahle Motorspot pistons are made in the US. I've got some photos of them here that I can upload if you like.

I work on a minimum of .030" (.75mm) piston to head clearance for a customers engine, usually closer to .040". On RB engines I run the pistons .008" (.2mm) out the top of the block with a .048" (1.2mm) head gasket. You can get away with a little less if you want but you do need to allow for expansion, rod stretch, piston pin flex, crank flex and the piston rocking. Some pistons that are made for a lot larger bores than 86mm actually have a slight angle milled on the top running down to each side to provide clearance with the head when the piston rocks but this is getting very close to the limit. One thing that needs to be considered as well is bad tuning, I've seen pistons that have touched the area above the top ring against the bore and transferred metal across. Considering that on any piston this area is about .030" or so smaller in diameter than the bore that is a lot of rocking that the piston is doing to touch the bore. I've run an engine with .025" piston to head clearance and the piston has touched the head very slightly and not damaged anything but would never do it on a customers engine. This was on a friends speedway engine and we were chasing every last bit but the engine came apart regularly so engine life wasn't an issue.

Strangely enough, very close. I've used heaps of Wiseco's in RB26's and they run the same size dome as a standard piston. I've run them up to 9:1 with a 1.2mm head gasket, the piston flats .005" out of the block and milling the head to suit. I wouldn't put too much faith in the catalogue. For RB25's though, they have supplied us 2 different pistons, one is very similar to the factory piston dome wise and the other only runs a 1.5mm or so dome which doesn knock out some compression that you can make up for milling the head. Either way they are a top quality piston, most now come skirt coated as well which is an extra $200 or so worth for free. I used a set of Mahle Motorsport pistons in the last 26 I did, nothing compares to them for quality and design, they are completely different to any piston that I've seen for a 26 before. They are a proper slipper skirt, very short pins, very short skirts, "graflon" coated skirts, 1mm steel top ring, Mahles new design locks and are nice and light. They do require some modification of the cooling squirter but are well worth the effort. They are twice the price of a lot of other forged pistons but you do get what you pay for.

Going off your picture with the centre of the piston dome moved toward the intake side looks along the lines of the rollerwave pistons that Larry from Endyne has made for the Honda's and Mitsi's. It does make sense to move the charge toward the exhaust valves before it fires, you have most of the charge in the same area to save the flame having to move all the way to the intake side of the chamber when the plug fires,it's closer to the valve to get out and it also means that on overlap there is less burnt gas on the intake side so theoretically you will have less reversion of burnt gas moving back into the intake ports when the intake valves first open. I still think that the quench pads are a very important part of the combustion process, as the flats on the piston run up close to the pads it creates a shockwave that forces the charge towards the sparkplug. If I was going to modify the pads at all I would make the exhaust pad slightly smaller so the charge ends up slightly towards that side. Another trick that I have seen recently, this is on wedge chambers on V8's is to machine tapered grooves in the quench area to direct the charge toward the exhaust valve, the idea is to ensure as much of the charge is burnt as possible. Anything that reduces the chance of detonation is a good idea, when you see most RB engines that have had detonation problems it is on the intake side of the chamber and piston as they get a pocket of fuel and air that is stuck there and preignites. In theory, if you could have the piston just kiss the head on the quench pads it would be the best you could get combustion wise as all the charge is forced in toward the plug. The biggest problem with and RB, as well as quite a few other japanese engines is that they run a domed piston which will never burn as well as a flat top piston as the flame front doesnt have a clear path. The problem is that with such a short stroke engine it's not possible to get the compression without the dome. I've just spent quite a bit of time on an EJ25 Subaru which run a dished piston along with quench pads, the chamber is a much better design, it's a proper pent roof chamber and even at 9:1 compression it has no signs of detonation with 30psi boost. It would be great to have the time and money to make a new head for an RB with a similar type of design. Just to finish this novel off, I think you'll find that Jun remove the quench pads on their "customer engines" which makes you wonder if they do the same on their own engines or if it is done as a bit of a safety feature rather than for outright performance gain.

Give the guys at Direct Clutch a call. They can recondition any twin plate I've ever sent to them and a lot better price than replacing it. As for fitting it, I'm not sure if they do that as well, there will be plenty of guys on here that can help.

Hi guys, I dont like to post up a lot in here in case it looks as if I am trying for some free advertising. I just wanted to let the people who are interested know that we are making some changes to our business. At the moment we do regular reconditioning work as well as performance engines and heads. As anyone who we have done work for so far will know this means that we seem to always take longer to do a performance engine than we originally think. We have decided to get out of the regular reconditioning/machine work side of things and downsize the workshop so we can specialise in only performance work, taking on less work overall but enabling us to complete the jobs more quickly, it also means that engines in the workshop are not put on hold when an emergency job turns up from a trade customer. We will be directing all regular work to another workshop, reducing the space and equipment we need to have. I will be working at the same shop as well but this will be regular hours which will enable me to allocate my time a lot more effectively here to performance engines. (It also makes it a lot easier to borrow some money to buy a few hundred acres in the bush that we are currently looking at). It also reduces overheads by a lot. Currently I'm working to clear the backlog of work that's here and once that is done I will be able to take in more engines and finish them more quickly. I should have everything sorted by the beginning of August. Thanks again to everyone who has sent us work and I look forward to being able to provide a better service in the future!

Personally, I would go for hks cams, you do need to machine the head to fit them with the higher lifts but they use the standard base circle which means you can use shims in the standard range. The cams with the smaller base circle are made so you can fit them without having to remove the head from the engine as they can give the same lift without having to make the top of the lobe sit higher and hit the head. It will cost you to have the head milled to clear the cams but means you can use the standard buckets and shims. We assemble the head with the standard shims, check the clearance and tip the ends of the valves to set the clearance. Usually by the time the seats are cut and the valves faced the clearance will close up by .005-6" which isn't much to remove from the end of the valve.

I'd lend you one if I had one but sorry i dont, we very rarely work on cars themselves. I wont be in tomorrow, we're only 100m from the ACT so I thought we should have a holiday!

nope, they come with one. They are a very easy thing to make though.

It's the way you balance the rods, they hang on a roller bearing mandrel, one end on the scales and one off. So you get all the little ends the same weight and then all the big ends the same weight. it's because the little end of the rod reciprocates and the big end rotates with the crank. It's more critical on V engines as you use percentages of each to work out the weight of the bobweight you use when balancing the crank. None of that is probably relevant, but if the little end if heaps lighter it's like having a lighter piston in there, so the actual weight that is changing direction at tdc and bdc is less.

It's a fair difference, I just weighed a standard rod at 637.5g and an Eagle rod at 495.3g. A 142.2 gram weight saving is fairly impressive! If you want end to end weights let me know and I'll measure one up.

If you're just pulling the head off and fitting the restrictors just tap the original restrictor down with a pin punch and put the new one in on top of it.

VG30DETT bolts are actually slightly longer that the factory RB26 bolts and there is plenty of thread, the regular VG30 bolts are nowhere near the right length, SR20 ones are about 2 threads too short. There is nothing dodgy about using the VG30DETT bolts, we use them regularly.

The RB30 block doesn't have the boss cast into it to take the squirter or the locating lug. It's a lot thinner through to the oil gallery also, with core shift in the castings it can end up too thin to tap a decent thread into by the time you have machined a flat for the squirter to sit against. It needs to be a very accurate job to locate the squirter in the correct position. I did a 3S toyota not long ago to take 3SGTE squirters and it was a 3 hour job by the time it was finished. I'd say around 4 hours on a RB30, thats $400, it makes coatings pretty well priced.

I've beam polished RB26 rods and removed the squirter boss entirely. The only problem is that the way that the holes are drilled for the squirter, once you remove the boss you have a 2mm or so hole instead of a .5mm or so hole. I just braze the hole up from the bearing bore side before I resize the rod. There is plenty of oil spraying up from the piston cooling squirters and you dont need the extra from the rod squirter. I pulled an engine apart today that I did this to that has done 30,000km since and the piston and bore look like new. If there is anywhere that a 26 rod will break it is around the oil squirter as there are some pretty sharp edged. The engine i pulled apart has gone over 10,000rpm on missed gear changes and the rods held together well. Saying all that, why bother fiddling with the standard rods when you can buy a set of eagle rods for $800, they're brand new, stronger, have ARP bolts and a much better design and are lighter.

And? The idler bolt isn't a torque to yield bolt, why would it need to be replaced unless there was something wrong with it? I've done 30 or more RB's and never replaced one? What is the problem with a gates belt? Is it that it's not called a "High Tuned Hyper Super Ultra belt for timing situations" and costs $350 more? They are stronger than a standard Nissan belt and they are also a pretty blue colour so they look fully sick with your anodised cam gears when you leave the cover off.