The Best Machine Shop for RB Motors

[proengines]

gawdzilla- I think the main studs are part #202-4206, dont quote me on that, but its pretty close. I can check up if you need. you may need to have the block tunnel honed as the studs clamp a bit tighter, it's a matter of bolt it up and measure.

Carlos, in my opinion, if the rings aren't bedded in within the first 500-1000 or so km they never will. once they are bedded in there is no reason not to use synthetic oil. The biggest problem with bedding in is the bores not being round and the rings running on high bits of the bore and missing other bits, thats why we torque plate hone them.

I like the idea of a RB30 twin cam, good torque, its a compromise, it may not hit the revs a 26 will but then it doesn't need to to make the same power. It's one of those things that a lot of people are either for or against, I'll sit on the fence, both have their benefits.

[pitchd]

proengines you have a PM

- adz

[gawdzilla]

gawdzilla- I think the main studs are part #202-4206, dont quote me on that, but its pretty close. I can check up if you need. you may need to have the block tunnel honed as the studs clamp a bit tighter, it's a matter of bolt it up and measure.  

i believe part # 202-4206 is the head stud kit for "L24, L26, L28 series, 6-cylinder". could you please confirm the p/n for the ARP main studs?

also... when checking for if the mains need to be tunnel honed- will the block just go out of round or will the mains also become slightly misaligned with respect to each other? all i have is a dial bore gauge to check roundness. there is no way for me to check alignment through the tunnel.

Thanks again!

[proengines]

oops.. thats why I said dont quote me. I'll check it out today and let you know.

[pitchd]

proengines can you check your inbox plz

- adz

[gawdzilla]

oops.. thats why I said dont quote me. I'll check it out today and let you know.

thanks, appreciate it.

[knore]

Awesome thread, i think invaluable for alot of people on this site

Could u post the parts list for the finished engine pic you uploaded and what that package would cost approx?

cheers

[etang789]

On 4/15/2005 at 4:03 PM, proengines said:

I'd have to say that compared to what is around today, as an engine the RB's aren't particularly advanced. For starters, a cast iron block is very 1980's, the crank isn't fully counterweighted, the main cradle is bolted on with the same bolts as a datsun 1200 uses etc.. but saying that, it is very strong. Also, for when it was designed it was very advanced. The head is brilliant for when it was designed and capable of big power, I don't understand though why Nissan didn't flatten the valve angle a tad, make the combustion chamber a bit shallower and run less of a dome on the pistons, Id say it would burn better with less chance of detonation if it was. Something similar to an SR20 or EJ20 subaru is a nicer piston/chamber combo.

Machining and assembly wise, we do spend a fair bit of time on them, you just cant afford to have a problem because people drive them pretty hard and it's an expensive job to pull them out and fix them. Having engines blow up is also a pretty good way to guarantee you wont get many more to do as well.

Basics below:

Block- strip, chemical clean, remove oil gallery plugs, CBN mill deck surface to set piston heights, bore and hone with a torque plate and main cradle tensioned, check mail tunnels and tunnel hone if needed, remove casting dags.

Crank- remove oil gallery plugs and tap for screw in plugs, check for size and straightness, micropolish, balance. I prefer not to grind them as there is a chance of grinding through the case hardening . I suppose you can have it rehardened but I'd prefer to replace the crank if it was that bad.

Rods- I prefer to replace them with an aftermarket rod, it's pretty cheap insurance. Otherwise, the STD rods crack tested, beam polished, shot peened, ARP bolts, closed and honed, new small end bushes, balanced. With new rods, we check the tunnel sizes and hone the rods to achieve the proper bearing crush and clearances, the small ends usually need to be honed to suit the pins being used. Balance the rods to +/- .1g both big and small end.

Oil pump- Replace if worn, otherwise clean, reassemble and fit new relief valve and spring.

Head- depends on the customer, but at least chem clean, check straightness, pressure test, soda blast, new exhaust guides, 3 angle or raduis valve seats in Serdi machine, reface valves, PCD mill head face, reassemble with new springs, set tappets. Other work depends on what the customer wants, we do a fair bit of porting and it's a shame not to port the head, especially an RB26 as you can get quite substantial gains in a relatively short time. We've played with them on the flowbench and 15-20cfm is pretty easy to pick up. I'm currently doing some testing for one of our suppliers with some stainless 1mm oversize head valves. They have a slightly undercut stem and a lot nicer finish than the STD valves, along with a nice profile so they should show some good gains. We also mill the sides of the bucket bores to clear the cam lobes if high lift cams are fitted.

Pistons- Measure, debur any sharp edges, clean, especially in pin bores as they usually still have honing grit in them.

Parts- Pistons- forged, very cheap insurance. Brands are much of a muchness, we've used Wiseco, ACL/Ross, Venolia, JE, Arias, CP, SPS and a couple of others. If I had to choose for my own I'd use Wiseco but thats just a personal preference. Venolias are a bit noisy but I've never seen one broken, they use a lower silicone alloy to most other piston makers and it is a little tougher but the noise is annoying. Rings- nothing that doesn't use a steel top ring. I'm still to be convinced that gapless rings are a huge benefit. Conrods- We've used Argo and REV. Both are good rods, I haven't used Crower yet in an RB but they are a nice bit of gear. The big end bore in the argos has been spot on, the REVs needed to be honed, this is because they finish them close to bottom size so the engine shop can hone them to set clearances, both needed the small ends honed for the same reason. Balance is good on both. Bearings- We use King, I'd rate them as the best but people have differing opinions. The king bearings are an alecular material and only run a thin coating of bearing material on a very hard backing. From seeing them after being used, they dont lose the spring in the backing even after being awfully hot. ACL race series bearings run a close second. I havent used Nismo bearings so I cant really comment, except that the price is pretty excessive. Gaskets- Genuine Nissan except for the head gasket, I rate the Cometic gaskets, three layers of stainless steel coated in a very thin layer of viton rubber and they fit perfectly around the bores, water holes etc. Valves- Genuine Nissan are top quality, Ferrea are better, Pep Pro are excellent. Springs- We use Performance Springs, great quality springs, made in Australia. Retainers/Locks- Genuine Nissan, although if it was a racing car running at big revs for a long time something titanium would be worth a look. Valve guides- Genuine guides work fine, I want to get bronze guides made but need to order them in the hundreds of each at $20 or so each so it's a lot of dollars to have sitting on the shelf waiting for heads to put them in. (anyone interested in a few sets?) Cams- We've used HKS and Tomei, both work well, same for cam gears. Sump baffles- we make our own, similar to the Jun baffles. Bolts/Studs- ARP main and head studs if the budget allows.

Assembly- We assemble our engines in a room separate to the machine shop so you dont have machining dust floating about. Dummy assembly before machining the deck is worth doing to set the piston heights and check for any interference between parts, there's always the chance of it happening using aftermarket parts from different suppliers. Then lots of cleaning, we hot tank the block again after machining, brush out all the galleries, scrub with soapy water and a brush, then the white rag treatment in the bores and tunnels. We soda blast the alloy parts and wash them off with hot water and blow them dry. Measure piston to bore clearance for each piston and bore, measure ring gaps and file if necessary, fit bearings to block and conrods and measure tunnel sizes, sometimes even with new rods you need to hone them to achieve the proper clearances, clean and measure crank, again brush through oil galleries. Fit new oil gallery and welch plugs.

We assemble all our engines with Nulon assembly lube on everything except the gudgeon pins and bores, we use 30w oil for that. Basically, once all the clearances are checked it's a matter of bolting the pieces together, we continue to check as we go. We use ARP assembly lube on the threads and under the heads of the bolts, this saves torque being wasted overcoming the friction and stretches the bolts so they clamp properly. We tension as we go and also give it a final once over before the sump is fitted.

We use either three-bond or wurth grey silicone for the sump and rear seal housing, mainly because of the colour, I hate the look of orange or blue silicone squeezed out the sides of the sump etc..

We preassemble the heads and set tappet clearances/crush depending on what head it is.

Then it's a matter of cleaning the block deck with carby clean to remove all oil, fit the head dowels & gasket and check for clearance around the bore, bolt the head on, tension it and then fit up the water pump, timing idler and tensioner, timing gears, Belt, covers etc.. followed by the accessories. The only difference is if we use a copper head gasket, we give the head and block a light smear of three-bond white motorcycle silicone to seal the water and oil, this is only on blocks that are o-ringed and the heads with receiver grooves cut. Lately, we have been using Cometic MLS head gaskets and from what I have seen so far they take as much punishment as a copper gasket but without the drawbacks in regards to coolant or oil seepage and there is no need to O-ring the block. It's kind of a disadvantage to us as we miss out on the labour for o-ringing the block but if they work better I'd prefer to use them.

I think thats about it but I probably have missed something. I know this is pretty long winded but basically it's a matter of measure, measure, measure, clean, clean, clean, quality parts and a fair bit of time, rushing is a sure recipe for disaster. If you want any photos of particular processes let me know.

Awesome post

[Shoota_77]

Yeah it's a great read.  Good to see a successful business sharing their findings and not being all secret squirrel.  In saying that I do understand why some of the high end engine builders do keep some of their hard found knowledge to themselves as they've done the R&D and blown numerous motors to find it!