proengines

I've currently got 2 heads here that I'm doing, one using 1.5mm o/s Naprec valves and one using 1mm o/s Ferreas and personally I would go for the Ferreas. They have a better finish, for example the raduising on the valve heads. The Naprec valves use a 6mm stem on both intake and exhaust which require custom exhaust guides while the Ferrea uses a 7mm exhaust stem, the same as standard so you don't require different guides or seals. Another option is the Pep Pro valves, these are sold by Austral distributing. They are Taiwanese and are a top quality valve and a little cheaper than the others, definitely cheaper than a genuine Nissan valve. They are made by Shin Ichi which distributed in the US as SI Valves. I have used them in a lot of different engines without any failures. After saying all that, the standard valves dont have issues. I have a head here that made over 700 RWHP with standard valves and they look like new.

You can't just use any bolt with the right thread. The shank of the bolt locates the cap so you need the nissan bolts or one specifically designed for it otherwise the cap can end up misaligned. I know tomei make studs for them, didn't know ARP did but they would be nice.

I wouldn't pay the extra for an HKS gasket over a Cometic one. Personally, I wouldn't o-ring it if it was mine, for all but extreme cylinder pressures it's not necessary. Dont use any extra sealers on the gaskets, they have a coating on them already and adding goop to them increases the chance of them failing. Leave everything dry and clean and bolt it together. All the SCE gaskets I have seen are copper, In reality they are great for race cars and were really good for street cars until MLS gaskets were readily available. Copper is great for sealing compression if you use an o-ring but not great for water and oil. I think the SCE gaskets have a silicone bead around the water holes but i would still stick with MLS. Copper has a tendency to continue squashing and needs to be retensioned every now and then. MLS gaskets only need to be done once.

RB20's do have a smaller journal, CA18 bearings are the same as RB20's but you'll need to buy 2 sets and end up with some spare bearings.

It's very rare for a metal gasket to fail, no matter what the brand. Check the head and block with a straightedge to see if there is any warpage, you will find that a lot of the time if the block is surface ground rather than milled it will have high areas between the bores and low areas along the sides of the bores, sometimes .002-.003". Metal gaskets need a dead flat finish, both on the head and block to seal effectively. I have seen one fail where one head dowel was left out and there was thermal walking and the gasket fretted and failed. I've seen an engine that was detonating so badly it ate away most of the quench pad on the intake side and the gasket still looked like new apart from some alloy peppered onto it around the bore. You can run o-rings with a metal gasket, I use 1mm copper wire for anything I o-ring and it is a little easier on the gasket as it squashes a little rather than cut into the gasket. You can fit the o-rings to the head rather than the block if you dont want to strip the engine. You'd only want .006" or so protrusion if you use the steel gasket. I normally leave it .015" out for a copper gasket with a .008" receiver groove cut in the head. You will need to retension it a few times which can be a pain, especially with HKS cams without the notches to get to the head bolts easily.

Just finishing off the pickup, we've gone for weld together bends using a sleeve and tig welded where they join to make it lower profile in the sump. Should have the pickups done in the next day or two. I've advertised them on ebay to gauge interest and by the look of it there is a bit. I'd like to advertise them on SAU, any idea who I contact about advertising? Sorry about the mobile phone photos, should have some proper ones done soon. Cheers, Greg.

Paul, they will bolt straight up with no mods and accept the standard timing belt cover etc. We are moving the relief valve to the intake side of the engine, outside the sump so you will be able to shim and adjust the pressure if you need to, the pump will run at typical pressure as it comes. The other benefit is that the pump should be able to be removed with the sump still fitted as it doesn't have the relief valve boss hanging down inside the front of the sump. We are also eventually going to be doing an external dry sump pump which will be a bolt on setup to replace the original pump but this is still a few months away. The pump gears should have been ready in the next week or so but we have spent the last couple of weeks designing a new sump adapter for the RB30 blocks. I fitted one to an engine yesterday and it takes around an hour start to finish, the oil pickup is internal and bolts on. We wanted something that makes it an easy job so we spent heaps of time digitising the block and sump and getting it all to mate up properly. The plate is 10mm laser cut steel, all the holes are CNC drilled and tapped and silicone reliefs are CNC milled in the plate. The plan is to offer the kit with everything, the plate, pickup, templates for the 7 notches to be cut in the sump rail to clear the heads of the bolts that replace the original studs in the sump, all the fasteners required, loctite and detailed instructions for under $1000. The idea is that anyone (with some basic mechanical knowledge and tools) can fit the plate themselves without any hassles, misalignment or leaks or the need to have their own machine shop. Cheers, Greg.

Yep, we've been doing some work on them over the last few weeks and have decided to make the gears we will be using in our pump the same width as the Jun ones as we only need to make the outer gear a different diameter on the OD to fit the Jun pump housing. The tooth form is different though, similar to a Toyota pump so you will need to fit the gears as a pair. We have a batch of gear blanks machined up in standard and wide widths, we just need to finalise the tooth form and make the jigs for the EDM machine. Hopefully they will be done in the next month, while it's being done we are building a pump dyno to test them on. The plan is to be able to run them up to 13,000 or so revs and different pressures. If anyones interested I'll snap some photos as we get to that stage.

There's nothing at all wrong with Cometic gaskets. What you occasionally find though that is someone stuffs up fitting it and rather than admit it, they blame the parts. You do need a good surface finish for any MLS gasket and the surface also needs to be flat. Run a flat single cut file over the block and it will show up and high spots, remove them and you should be fine. Any decent machine shop can give the finish you require for the gaskets, CBN and PCD milling cutters do it easily. ACL thinks the gaskets are good enough to put their name on and you can imagine the testing they have done trying different gaskets.

At the moment it doesn't have an external adjustable pressure relief, though we could probably incorporate it without too many problems, it could be a good idea. As for isotropic finishing, have a look at http://www.hiperformancesurfacefinishing.com/products.html, should answer some questions.

Who would be interested in an oil pump that solved the gear cracking problems? A new oil pump, CNC machined and hard anodised billet 7075 aluminium housing, CNC machined billet 4140 chrome moly gears, nitrided and isotropic finished rather than the powdered metal of the other pumps around. Gears will be 2mm wider than standard Nissan. The pump will bolt straight on and fit all the standard accessories, timing belt cover, crank seal, sump etc. Should be available in the next 8 weeks or so. Or a set of billet 4140 chrome moly gears, nitrided and isotropic finished to fit the standard or N1 pump housing? We are just finishing the development of the pumps, should be doing some testing in around 3 weeks. I don't have a definite cost but it should be competitive with the Jun or Trust pumps.

Have a quick look arounf for a set of RB26 rods. They should be cheap as dirt given how cheap aftermarket ones are. They are a straight bolt in and vastly stronger than the 25 rods. I've seen plenty of broken RB25 rods, never seen a broken 26 rod in that type of application.

ACL is making Nismo bearings, that should be enough of a recommendation. If not, Sainty's top fuel car is also using ACL race series.

A standard Nissan RB26 gasket is 87.1mm, probably just under 87 once it's compressed. Did you use one of the ACL MLS gaskets?

Pull the engine out of the car. There are 2 sump bolts at the rear of the engine, inside the bellhousing adjacent to the flywheel. It is possible to grind/drill the sump to get to the bolts but it just makes it a prick of a job. To get the sump right out you need to remove or lower the crossmember and you really need it right off to get it clean enough to seal it up again. If you had the gearbox out to do a clutch or similar it wouldn't be too hard to do but if you dont, you will be doing 60% of the work involved in pulling the engine just to get the sump off. Add to this that sealing the sump up again will be a nightmare and getting the 2 rear bolts back in will require some telekinetic ability, you will save yourself a lot of grief by pulling it out. The benefit of this is that if you do find any damage once you get the sump off you can easily remove the crank to repair it and the sump can be sealed and bolted up properly when you refit it. Just for reference sake, if you drench the timing gear with inox/WD40 etc from the front and back and leave it overnight you will usually find it will just slide off without any damage. They get moisture between the gear and the crank and rust which is what locks it on. If this doesn't work, I drill and tap 2 M8x1.25 threads into the gear, 180 degrees apart and use a balancer puller to pull the gear off. Greg.

I used to race at the old track here and it was brilliantly run, Jeff Develin worked incredibly hard to get the last track up and running and invested a lot of his own time and money to do it. If running the track was left up to him and the group that ran the last track it would do very well.

Adriano is right, you do need the exact volume of what you are using, the only way to do that is to cc your head/piston dome etc.. let me correct what I wrote before with the correct stroke for an RB25, this is using a 71.7mm stroke, 86mm bore, 1mm head gasket, 15cc piston dome, 85mm piston top OD with the top ring 6.4mm from the top with a range of different chamber sizes: 64cc- 8.46:1 63cc- 8.6:1 62cc- 8.74:1 61cc- 8.89:1 60cc- 9.04:1 Now the same using an RB26 crank and pistons, 73.7mm stroke, still zero deck and 15cc dome, 1mm head gasket, 85mm piston top OD with the top ring 6.4mm from the top: 64cc- 8.67:1 63cc- 8.81:1 62cc- 8.96:1 61cc- 9.11:1 60cc- 9.27:1 These numbers are assuming that the volumes are what's written above, a smaller dome will drop the compression, a thicker head gasket will do the same and vise versa. Don't rely on this or what's in a catalogue or you find on a google search, use the volumes that are specific to your own engine. The domes on the forged pistons available for these engines range from around 5cc to 16cc from what I have seen and this makes a huge difference to the compression you will achieve. Also, the compression height of these pistons vary by .2-.3mm depending on the brand which will change your deck clearance. The best way to check this is to dummy the engine up and measure it. Also, many people ignore the volume around the piston top down to the first ring but this is a part of the chamber volume and on one of these engines comes out around .9 to 1cc depending on the ring depth and the piston top diameter. If you want to give me the actual numbers you have I dont mind calculating it for you.

Not according to CR calc. This is assuming the head is 64cc and the piston is 15cc dome.

If you have access to a flowbench it makes it easy to see where you are going. Where you will make the biggest difference is to work mostly on the exhaust port and try to bring the exhaust up to around 75% of what the inlet flows. What I would do if I was you is: -Blend the bowls on both intake and exhaust, that is the area under the valve seat where it is machined. Smooth the transition from the machined bowl into the cast area. -Smooth the short side radius so it doesn't have a sharp edge there, don't remove any more metal than is needed to get a radius there. -Knock the bump out of the exhaust port to make the port evenly oval and blend this back up the port. -Remove any dags in both the intake and exhaust ports. -Sand the ports smooth. I use 80 grit porting rolls and flappers, dont go any smoother than 80 grit and leave it with the sanded finish. -Dont knife edge the intake divider, leave it with a smooth radius. You can knife edge the exhaust divider as it wil give you a little extra port. -I use a 3 angle intake cutter, 20/45/65, with a 1mm seat. For the exhaust I use a Serdi or Newen radius cutter, also with a 1mm seat. -back cut the intake valves at 30 degrees, from to about .5mm from the seating area. -Unshroud the valves in the chamber with a radius cutter (about 2mm radius) from the top of the top cut on the seat to the edge of the chamber. -Smooth out any bumps in the chamber and radius the top edges of the chamber carefully. That should be enough to make a noticeable difference, especially on a 3 litre. Some people say you don't need to port them because they are turbo'd etc.. but if you make the engine more efficient it will always make more power or the same power with less boost. Most heads are designed to flow really well but the reality of making them means that by the time the initial design is cast and machined they never work as well as they were supposed to. All you need to do is get it as close to what the initial design was. If you want some photos let me know and I'll dig some up.

RB25 std everything is around 8.5:1 (31.3mm comp height, 72mm stroke, 15cc dome) RB25 w/- RB26 pistons is around 7.8:1 (30.3mm comp height, 72mm stroke, 15cc dome) RB25 w/- RB26 crank & pistons is around 8.7:1 (30.3mm comp height, 73.7mm stroke, 15cc dome) this is working on both heads being at 64cc and 1mm head gasket, I measured a 26 head on Thursday and it came out at 64cc. It will vary slightly depending on the dome volume and the head gasket thickness.

You've got to love this Stanhope Government, he let our city burn down and then "didn't accept" the Coroners findings when they were handed down, slaughtered more than a thousand kangaroos at Googong to placate a few whinging farmers and then couldn't comment because he told the officials not to tell him anything about what was going on so he couldn't be questioned about it, promised a drag strip if they were voted in at the last election and then spent millions to try and find a way not to build it and then announce that they wont a couple of days before Christmas hoping that people will forget about it by the time next year comes around.. the blokes a f**kwit. I knew there was a reason I moved to Queanbeyan.

I have to say I'm sorry to see the way this thread is heading. All the XXXX's in the world dont stop any single issue being escalated into an awful lot more than the single issue it originally was. Anyway, Happy Christmas!

Use a gasket that will give you as close to 1mm piston to head clearance as you can, so if the piston is poking out the top of the block .2mm, use a 1.2mm gasket. Keep away from the really thick gaskets as they will ruin the quench between the piston and head. I would run a minimum of .8mm piston to head clearance, less than this and you may run into interference problems. More than 1.2mm and the engine wont burn as well as what it should.

Go for the aftermarket rods. A set of Eagles or similar will only cost you $300 or so more than modifying the standard rods and you have something brand new that hasn't done millions of cycles already and is a better design and stronger than the factory rod to start with. They may need slight machining to set the proper pin and bearing clearances but it will be minor, most aftermarket rods are supplied with the pin and big end bore finished to bottom tolerance to allow adjustments to suit the crank/bearings and piston pin. Don't be scared off by the rods being made in China, a lot of big name companies have either set up over there or have their parts made by chinese factories, it reduces the cost to make the same product.

They are $150 each plus postage, $120 if you buy 10 or more. They are cnc machined from billet 4340 chrome moly and include fitting instructions and the grub screws.