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Fixing A Rb30 Bottom End On The Cheap

unique1

By unique1,
in Engines & Forced Induction

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unique1 Mentor

unique1

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hey guys i got hold of a rb30 bottom end today (i have the rb26 head ready to go) and i didnt plan on pulling it down to be honest, but it didnt have the water feed for the turbo tapped (though its got the turbo oil feed tapped and the machined front for the tensioner) so i thought i better strip it and give it a clean up. This motor is for throwing in a stripped out track car and having some cheap fun, if it blows up i dont care ill buy another bottom end, so cheap is the aim of the game incase it does let go and i dont want too much invested in the bottom end :ermm:

1. The core plugs on the block are all brand new except the rear one behind the auto flywheel so i need a core plug for that, the crank seals have looked to have eaten into the crank a tiny bit as well, is this a big problem or only if its eaten into it a real lot? how do u fix that if its an issue, and how can i tell if its too bad or not?

2. The big end bearings looked fairly good and are standard NDC ones, i think i wont bother changing these at all, and the main bearings are ACL std size as well which look good too so ill be leaving them as well.

3. Now i have a hks 1.2mm drag metal head gasket lying around from my other 26 motor builds and wouldnt mind using that instead of buying a new stock gasket, but do u think to use a metal gasket i need to get the block decked to make sure its flat? how much can u deck the 30 block before piston to valve clearance becomes an issue? whats a cheap rb26 gasket worth?

4. i also have to tap the head bolt holes for the rb26 bolts, is this possible to do by hand as i doubt u could get it out of square with the hole already there, or should i get it put onto a drill press and do it?

5. so i need to buy a large core plug (30mm i think they are), front and rear crank seals and possibly a stock 26 head gasket and oil restrictor, now whats these part usually cost each? can u get cheap generic seals instead of paying $55 for a nissan rear crank seal, etc?

6. has anyone found a rb30 workshop manual online as i need torque specs for the bottom end stuff (rod bolts, main bolts, etc)?

sorry for the huge list of questions, hopefully other people have been there and done it to give me abit of advice :banana:

Edited by unique1
Adriano Grand Master

Adriano

Posted
Posted

I wouldnt worry too much about the crank being eaten away by the seal. You could fit speedy sleeves over the surfaces, but they are about $75 each. If its only a track car, its not going to leak that much oil anyway. Just reuse the metal head gasket, using some coppercote spray. I would just get a set of rb25 head bolts or studs if you want to get fancy. Dont even attempt to redrill and tap the head bolt holes yourself.welsh plug is about $2 try an Auto One, but ive found the cheapest place to get seals is a bearing shop like CBC. Oil restristor can be cheaply made from a MIG welding tip. Just buy one with a hole the right size, about $5.

What oil pump are you going to run? I would be tempted to use the standard rb30 onw, as they dont seem to fail ?!?

unique1 Mentor

unique1

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thanks for the replies...

Adriano, good news on the crank seals then ill leave it and see how i go, ill try cbc for the seals i have bought seals from there before and they are cheap. Metal head gasket sounds ok then, you dont think a deck of the head is worth doing to make sure it seals ok? rb25 head bolts so i dont have to tap the bigger holes u mean? i thought about this and surely the locator pins on the head will keep it central and i doubt head will lift with around 400rwhp and low boost levels, i dont see the rb25s having any issues with head lift.

Ill also be using a low km stock gtr pump from my first rb26 motor which had a genuine 30 000km on it that i bought 7 years ago and changed the pump to a jun one. I plan on keeping power to around 400hp as i said and under 7000rpm so i dont wanna risk using the old rb30 one, who knows how many km's its done.

Dahtone Racing, the engine is a spare motor for drifting mainly and i have another rb26 fully built motor for proper track days, i just dont wanna risk the expensive track rb26 engine doing drifting. Bearings are fine, i'd say they are 90% perfect, if i pay to replace them and the motor lets go on the dyno after 5 min i'll be annoyed, i might not even wanna keep the rb30 as ive never drivin one so this is a test engine to see how it feels compared to the 26. The rings i will check today and make sure they are ok, if not ill replace them.

cheers again for the advice

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