proengines

In all reality you can go a long way with std rods and pistons but honestly, if you pay someone to do everything properly you don't save a lot. Have a set of standard rods checked, new bolts fitted, closed and honed, pin bushes replaced etc and see what it costs. Then compare that to a cost of Spool rods, you might save $350-400, if that. Forged pistons will set you back maybe $700 more than a set of cast stock ones, maybe as little as $500. Compare the price to re-ringing a set of 20 year old factory pistons and doing nothing to the rods and it might seem a big cost but if someone's going down that path the argument is pretty null anyway, the difference between doing it properly with cast pistons/stock rods and forged pistons/aftermarket rods is small. They might cost you $1000 extra but over the total price of the engine, it isn't a huge percentage for the piece of mind it gives you.

Marko, I'd recommend against raising the limit, only because the engine hasn't been tuned at those sort of revs so you really have no idea what it will be doing fuel or timing-wise above the revs it was set up at.

Marko, that was torqe plate honed. As I said, oil change @ 500, one after that and let rip. I saw a car driving along the shoulder of one of the parkways here doing about 20km/h with RUNNING IN on a big cardboard sign in the back window. sometimes you've got to laugh.

just to clarify, it's not me having it made, I'm sure the company that is will announce it when they have it ready.

Paul, that forklift is a diesel, maybe you should post it in the diesel block thread?

I'll snap some photos and sonic test the bores in this RD28 over the weekend. I have to start machining it then anyway. There is an aluminium block coming soon for RB's, RB30 height, RB26 sump pattern, Darton sleeves etc. It sounds very impressive and a lot of work has gone into it. The block is cast, not billet. I'd say there will be some news about it in the not to distant future, won't be cheap though.

You can use caps off any RB head but you will need to have the cam tunnels bored once you fit them. The caps are not interchangeable unless you do this, they are bored as an assembly at the factory and a set of caps will only work properly on the head they came on on unless the tunnels are remachined.

Much the same as a 30, I can snap some photos if you like, I'm doing a little dummying up this w/e. Let me know what you want to see.

I've got an RD28 block here at the moment. The rear oil drain on one side is missing, it's slightly different timing wise at the front, set up with a high mount tensioner from the factory. The head bolt holes are in the same spots though and main tunnel sizes are the same as an RB30, it also has piston oil squirters and weighs a heap more than an RB30. It's very do-able and has been done in the past.

I attached a photo showing both 25 and 26 positions. The block is in the mill to spotface the pads for the 26 sensors which are drilled and tapped M8.

They are ACL race series to suit an RB26, 1mm oversize. The .1 is the clearance at the rib

I've made a 10mm plate which bolts to the original tensioner and 6mm stud holes then cut 10mm off the back of the tensioner and bolt it to the hole on the exhaust side of the belt. I have a cad drawing of it here somewhere I could post up if you like. This is to use with the top mount tensioner setup.

The only difference may be the diameter of the head bolt holes in the gasket, apart from that they're the same. 26 gasket fits fine on a 30, maybe not the other way around.

I use rings from Austral Distributing, could organise you a set but I'm going away this weekend for a week. They are japanese, nippin or riken, cheap as chips and a steel top ring. Ring Austral and they can tell your local engine shop to buy them from.

Because the moly is inlaid in a groove machined in the face of the ring, with detonation it can dislodge and end up scoring the bore badly. I've seen it on two different engines, both turbo, never on an NA engine. The other problem is that the ring itself is cast iron, not steel. You can bend a steel ring 180 degrees and it will bend, try to do the same with a cast ring and it'll snap before it gets half that far. That's not only for Hastings rings but any cast top ring. Once again, just my opinion. In a perfect world you could run cast pistons and cast rings and never have a problem but why take the risk?

I just remembered the guy who did extrude honing in Sydney had stuff for sale on ebay, maybe he has closed up. I bought a machine a few years ago but the cost to run one and the jigs you needed turned me off it so I sold it again. Here's a graph of your head Marko with the port and no manifold, port and std manifold and port with the runner and outlet opened up, not a massive difference with the porting, there is some though. The manifolds are a definite restriction though as you can see in the graph. I'd like to test those 6 boost twin manifolds, they really look the goods.

Just my opinion

Wiseco. they run tight clearances, are quiet, strong, have a skirt coating and excelent rings. You can get a flat top to suit 25/30 that has a 22mm pin as well. I use them quite a bit. The Spool rods can be bored to take a 22mm pin no problem.

The diff guy's getting them, not me. Nissan dealer here can be slow at times, usually quite good though. As long as I have a sump back tomorrow I don't mind. There's a reef in QLD waiting for me on Saturday, it's gotta be done before then. The manifolds don't look the goods though Marko, bolting them up is like doing some "unporting", even with a good cleanup inside. Anyway... back to pistons... Did I mention Wiseco's are good?

It sure is Marko, even has a head on it but no sump as yet.. hopefully will have it back tomorrow. The diff is set up, still waiting for the seals from Nissan was the news I got today.

If you're going to use the standard rods, fit new bolts, close & hone the rods and have the pin bushes checked.

Don't use them if they don't have a steel top ring. Moly rings are bad in turbo engines.

I run the clearance the piston is set to at nominal size, That is, if the piston set is made for an 86.5mm bore, I finish it to 86.5mm. I machined up a 26/30 last week using Mahle pistons and it ran .0032". I never run less than the manufacturers recommend, occasionally a tad more, maybe .0005" if it is running really high boost or nitrous plus a bee's dick more ring gap. The Mahles run quite large pin clearances but again, there's a reason for it and they're not noisy. Piston manufacturers know a lot more about their pistons than me, I trust their judgement.

ACL pistons are made by Ross and are well priced, nice and strong, maybe a tad heavy and run a little too much clearance for an everyday engine due to the material they are made from. I don't like the second ring in the set, it is machined as a hook scraper and is too narrow on the contact area, very easy to break. I use a Japanese ring set on them, Nippon or Riken. They use the standard width ring set which makes this easy to do. The Japanese rings still come with a steel top ring so I just use the full set. Wiseco's are much nicer.

Good to hear Duncan, was Mark happy with it?