Tech@EPR

Anyone have a good link or copy I can download? Thanks

if you install the pin in the pin bore and you can not not rotate/spin the pin in the bore as is then its considered pressed/pushed....whever you want classify it for yourself. I've been building engines for quite some time and any forged racing piston I've ever come across is always full floating. Take it for what its worth. good luck

I wouldn't be too worried about the pin bore area of the piston until you have the bore measured to see what the clearance is set to as is. A full floating pin once pin fitted will glide/slide with no press fit. Thats the point of being a full floating pin design. Forged pistons will never have a press fit pin design its old technology and floating is a far superior foot print for pin bore design. Stock cast pisons only have a few tenths clearance on the pin bore as its a press fit application. Even at operating temps the expansion isn't enough to make any real noticable difference and is still considered and retained as a press pin applicant. As for the offset pin bore housing that is pretty shitty situation..however, the rod small end is not the entire width between the pin bore housing areas. Regardless of what you or your engine builder may think the rod small end is going to move a little side to side when in a dynamic condition. If you measure total width of the small end compared to the overall space between both pin bore housings you'll notice that the rod still will have plenty of area but this does not negate the fact that the pistons were machine improperly. Guess its time for you to get another set of pistons.

the oiling system in the is the DEATH of this engine. It has horrible pressure issues and inadequate oil feed design from the rod journals to the bearings. The pump needs help as well and can be improved upon.

Be sure to also check the rod housing bore to ensure its dimension wasn't altered when the bearing spun. In some cases the journal on the crank is damaged as well resulting in the crank to either be turned down or replaced if you have a spare crank laying around. Further more I would ensure you tear everything down and look over everything extremely well and begin to see what you can reuse in the way of internal parts. If you plan to upgrade the internals which most will suggest you will incur more expense due in part by the machining of the block/heads and balancing of the crankshaft. At best have all your parts torn down and inspected and checked to ensure they are within spec as is. If any are not you may want to just source some OE replacement parts and begin your journey from there. Even a well built OE rebuild can do wonders in reliability and power production. Don't cheat yourself and slap it together for the sake of getting it back on the road. I build many VGs and I see a lot of missed steps in the assembly and issues that lead to engines down their fatal road very early in life. if you have any questions feel free to PM/email me. All of us here are willing to guide you in the right direction as best as one can.

Sup everyone, I wanted to get some ppls responses on an upgraded oil pan. I am currently working closely with Moroso on building a 7-8qt capacity oil pan for the Z31s. I do not have pricing or images at this time but we have already begun the sheet metal fabrication process. My question to you all is this...do a lot of you or does the market hold a want/need for an upgraded oil pan for this community (Z31)? Are there many of you out there that are wanting/needing the extra capacity for X style of racing? I'm looking for any and all information from you all to see how far I'd like to go in developing oil pans for this engine/car. Thank you for your time.

yea that thread I made turned violent on 300zxclub.com I just think its ridiculous that the owner of AMS lies about his products and belittles the community members for standing up to him and catching him in the act. Oh well. Such is life. You noticed no one from AMS ever posted in that thread.

Do you have information backing that statement up?

I don't think you guys get what I'm saying. I'm a machinist/engine builder for a living. I build Nissans specifically. I bought this RB as a project to build and get to know the RB lineup a bit more. I understand that the parts will be up there to some extent however I can machine a bunch of stuff myself and I can have parts made for me such as pistons/rods quite affordable. My goal is to research this engine to find all of its weak points and do my best to fix/resolve them while increasing efficiency. Overall...an iron block/aluminum head with a closed deck design will handle more power than an all aluminum block/head combo with an open deck. The materials are better and the platform is better for making power with an RB over an SR purely by design and composition. Even if this engine only makes 600whp it will be fine. I plan to build it to handle much more but Im not building this for myself or any car I own. Im just building this to build it and then sell it. Its a project. I own Z32s and race them primarily. RBs are fun to mess with and are interesting to me to build and get involved in. I'm quite confident that this RB20 will be able to handle any type of power a typical owner would dream of putting to it.

are the heads interchangable between the 25 and the 20? Honestly...the money going into this engine isn't going to be too much. But overall it seems that most don't like to use the 20 because its baseline is quite weak. Thats ok honestly because im doing a full build and then selling the engine off. The engine itself will be built with a lot of key points being addressed. The one other thing I had a question on was the oil pump. Do these have issue like the other RB engines? Thanks so much for the information. Clear cut and dry.

Hello folks. Im normally in the VG realm of engines the majority of the time but fell into a deal for an RB20DET for $100 and figured I'd go through a full tear down/rebuild on this particular engine. I did several searches on here and did find some good info but nothing concrete enough to tell me what is and isn't First off. What are the pros/cons between the RB20 and RB25? Besides the fact of displacement obviously. Secondly..why are so many ppl in favor of the RB25s vs the 20s? It would seem that regardless of overall displacement the RB series engines while in variance still make expendable power and are easily modified once built. I am fully aware of displacement values and how it affects power and so forth but overall have there been 500-800rwhp RB20s? Do those of you who have swapped the RB20 build these up to any stature to make good power? I have no problems soaking in information but I just need to have someone steer me in the direction of the info or can show me some ins and outs of the series. I've built a few RB26s but they were pretty straight forward for what the customer had and wanted done. For this engine i"m looking to put down 600-800rwhp out of this RB20 (if applicable) thanks for your time.

yes you will have some lope at idle..have you checked your AIC and TPS to ensure they are calibrated correctly?

for what its worth both Eagle and Scat buy the same forgings from China. They just have a few different machining ques they do that differentiates them from each other. Scat you can usually buy cheaper than Eagle. Both are damn near identical as they are the same forging. Just figured I'd shed a little light.

there aren't many out there but there are a few. Are you inquiring to know about DD situations or someone who built a forged race engine and running it on the street? Give me some details as to what you are looking for.