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Another RB into an S30, what next?


wrcbonk

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Hey Guys, bought an R33RB25DET from Venus-Auto in Sacramento last week. I am hoping to swap the motor into my '71 240z. Venus performed a compression check (225, 225, 250, 225, 250, 225 psi). They provide a 30 day warrenty. We pulled the valve covers and to us things look very good, no scoring or dark discoloration, see pics below. I am wondering what a good course of action will be for a factory service of the engine before trying to mount it in the z. When my friend helping me rebuilt the 7M in his Supra he bought a "top-end" rebuild kit, which included items like a head gasket, throttle body gasket, injector seals, etc. I have not yet seen a product like this for the RB. Just wanted to touch base with you guys, let you see the new motor, and get your thoughts. Thanks for your help.

 

Bill

Clean head_thumb.JPG

Clean valve covers_thumb.JPG

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if it were me, and its what im going to do to my rb when i get around to it, is tear it apart, and replace all of the bearings, piston rings, gaskets, upgrade the oil pump, water pump, head gasket, just rebuild the whole thing. i dont think it would be that much, seeing as you wouldent have to buy any of the expensive stuff, cams, valves, crank, just rebuild and get going.

but thats just me. i have never bought an engine from an import service and not torn it apart. half of the time, with rotaries at least, they are either blown or have underlying issues that will rear their ugly heads right after the 30 days is up.

 

Lloyd

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I hate to break it to you but those compression number's are impossible to reach on an RB25DET, let alone any RB engine.

 

The maximum PSI that can be reached on a brand new RB engine is 185 PSI on each chamber, at least that is how the Factory Service Manual has it. 13 Kg/CM2 converted to PSI is 185 PSI which is actually only seen on the RB20DE engine. The RB26DETT only reaches 171 PSI meaning it's 12 Kg/CM2 in the manual.

 

I would temporarily hook it up and do another compression test on it as it seem's they put some oil in each cylinder to raise the compression number's to make it look good to buyers.

 

Now i'm no pro but I doubt that the FSM is wrong and that far off of real world spec's.

 

I installed an H22 engine into a family friend's Prelude and it ended up being a bad engine that was dressed up to look good, it was also bought from Venus Auto... Not trying to bad mouth them but they have still yet to impress me with the engine's that they sell.

 

As far as the top end rebuild kit goes I have yet to see one as well for the RB engine, I do know you can buy a gasket kit which would most likely cover the top end and also the bottom end gaskets for later use. I would suggest a new timing belt as well as the timing belt idler and tensioner.

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we bought a black top fwd sr20det from venus also a while back to install in a 92 sentra and im not lying about this one. when the valve covers were opened up, it looks like someone straight up lubed the camshafts and cam lobes with some thick black wheel bearing grease all over the cams, lobes, cam hold downs and walls. i mean, there was more grease on the engine then cream on a cake. when confronted, ronald(owner i think) claim it was not like that when it came in and to clean it up and should be ok. we were like, um, no, give me back my money. after a while he ended up refunding it. he then told us to get out if we are just going to look and not buy. he was probably in a bad mood but he was an ass.

 

just last week, i called one of my buddy for 2jz prices at venus since he get hook ups from them. he said, buy somewhere else. i ask him why and he said they had bought a red top rwd sr20 this year and had a blown piston. after pulling the engine out, venus replaced it with a black top sr20 since that was all he had left in stock and for customer satisfaction, he upgraded. installed again and couple days later, turned out it had a blown head gasket although it had good compression numbers. had milky oil!

 

your engine looks a little too clean to be jdm. lol, 99% of jdm motors i seen open has yellow to dark brown oil stains inside head and valve covers.

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No reason to tear into the motor. I have had very good luck buying motors like this and putting them straight into cars. I always change the timing belt and rear main seal. Thats about it. One of my rb's even came from Venus. The one in my car now is another bone stock motor, never taken apart and makes ~650 rwhp and runs well into the 9's at over 140mph in the 1/4. It won't last forever running like that but it's a damn good motor for now. lol

I would definately take a chance and stick the motor in as is. Once it's running, if you decide it needs work, then pull it back out and go through it.

 

It's suprising to hear the comments about Venus. Anyone I know that has gotten a motor from them has been very happy with them, including myself.

 

Jon

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J,

 

I agree, based on what I have seen from the motor already, I am only planning to replace the wear parts that appear worn from too much time out of the origianl car. I do plan to replace the clutch and throw out bearing. The wiring harness is hammered, I will be running through many hours and lots of soder mending things back together. I give Venus a BOO :angry: on that part of the deal.

 

Thanks

 

Bill

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That particular motor looks pretty clean from those pics, change the front and rear main seal while the motor is out and slap that bad boy in there... I usually take all accessories and covers off the motor and do a nice cleaning but never take a head off or inspect bearings or anything mechanical about the motor unless something looks funny. A nice coolant flush isn't a bad idea, lot of rust in these overseas motors, builds up like mud.

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RS,

 

I forgot to mention in my first post that the coolant which spilled out during transport was bright and clean, no clumps of corrosion. Pretty psyched to see that from a used motor stored in a warehouse. Definitely plan to pump lots of fluid through the system before we fire it up.

 

Your motor is looking sweet!

 

Bill

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Over here (Aust) the RB25s we get are usually very good buys as they come out of the normal Japanese models.

The Rb26s are the worry and the crooks who get involved dont give a shite.

The 30 days soon goes of course and who ever gets around to running the engine in that time? My engine was in a half cut and the radiator had sludge in it - they still told me it was one of the best they had ever seen - ho ho. After stripping it all down and searching high and low including pressure tests which showed nothing - when we machined the block suddenly we could see the cracks. It took me 2 years to get another block from them. They can be bast'ds be careful, but it is hard to catch them out - tell them straight away if there is any suspicion of problems and then ask if you can strip it down as they tried to tell me I had voided my warranty by stripping it down to find the problem!

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  • 10 months later...

Wanted to post an update of my RB25 build. This is my first engine project so the progress has been painfully slow. I wanted to get a look at the intake and exhaust side of the head to see if there appeared to be any problems. Didn't see anything that lead me to believe I need to pull the head. I also wanted to paint the block, so I took everything off the sides and replaced any gaskets needed. Planning to save pulling the head for when I need to replace the head gasket. I am going to be running almost a completely stock setup, stock plenum, turbo, fuel management.

 

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Need to order the mount kit from McKinney, clutch, install accessories, and begin getting serious about wiring. Here is where it's going.

 

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I put on the turbo and hooked up the lines. I also tried installing the alternator. Found out things don't quite line up with the new waterpump. The bolt that is suppose to go through the harden steel bracket is hitting the bracket just above the opening. Has anyone run into this? I will need a pretty hard bit to open the bracket up.

 

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Bonk

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