Da Fisch Posted March 18, 2014 Share Posted March 18, 2014 Hello everyone, I am knew to engine rebuilds and figured that this would be the place to start out with how helpful you guys have been recently! I am hoping to run over 450hp at the wheels in my 73, I purchased a 5 speed and rb25det. On Raw Brokerage I got some goodies for the rebuild but when it comes to the internals I am lost. Can someone help explain what each of these options are for me? Thanks! (If it helps my engine is a series 1) http://www.rawbrokerage.com/wiseco-pistons-eagle-rods-combo-r33-rb25det/ Quote Link to comment Share on other sites More sharing options...
redlinevo7 Posted March 19, 2014 Share Posted March 19, 2014 I am no pro engine builder but I'll give it a shot till someone with more technical experience can clarify. Bearings are thin metal sleeves that usually encompass the crankshaft to the block/cradle and the rods to the crank. The clearances mentioned have to do with the small spaces between the parts that allow for a bit of play and oil flow. Generally speaking the larger the clearance the more power you can theoretically make but the quicker the wear on the parts. Race engines usually have higher clearances but are rebuilt more frequently. For your modest goals I would suggest either stock or a nominal size over. Piston bore would be the diameter of the piston itself as it relates to the block. I'm not overly familiar with the RB25 but I would imagine first option may be stock and then up from there. The reason you could go bigger is to allow machining of the block in case there was any issue previously and the walls had to be machined open to clean them up, then the new pistons would be up to spec. (the machinist would bore the block to match the new pistons). I assume you would get a very slight power increase also. The crank collar is the end of the crank that the oil pump mechanical gear is driven by. On pre R33 engines these were thinner and therefore had less contact area to turn the pump, often resulting in oil pump failure, one of the common issues with these engines, especially at higher rpm. The R33 and up resolved this issue by making the crank collar about twice as long. A common upgrade as offered by the option here is to have an afternarket collar the same size as the R33 fitted on the R32 crank, thereby upgrading it. It is pretty much a no brainer upgrade that you will want, along possibly with restricting flow to the head and making sure the return pathways from head to block are clear of any casting slag so oil can flow back to the sump easily. The ARP bolts are upgraded bolts and while the stock ones should handle the hp you're looking for I would suggest to be on the safe side and upgrade them. Hope I have clarified it for you a bit. But willing to be corrected if I'm wrong... Cheers Quote Link to comment Share on other sites More sharing options...
redlinevo7 Posted March 19, 2014 Share Posted March 19, 2014 My advice if you're going to the point of rebuilding the engine, even if you aren't doing it yourself (which I would not suggest given you have to ask the above questions), knowledge is power. Google and youtube are your friends and even though you can't believe everything you read/watch and there is no replacement for hands on experience, you will still be far better equipped to understand it all and at least make sure no one carries you for a ride. Quote Link to comment Share on other sites More sharing options...
RB26powered74zcar Posted March 19, 2014 Share Posted March 19, 2014 If I were you, I'd save your money on all those high dollar parts, and stick with stock internals for now. Get it up and running so you can trouble shoot and get it reliable before going with a built motor. If you want a good education on the rb25, start reading how JTaylor did up his rb25 Z. His is all stock long block, and it will spank my forged, high dollar rb26. Have a read of JT's post's > http://forums.hybridz.org/index.php?app=core&module=search&do=user_activity&search_app=forums&mid=67&sid=8e63add93065fbb3d66376def6429abc&search_app_filters[forums][searchInKey]=&userMode=title His profile > http://forums.hybridz.org/index.php/user/67-j-taylor/ Quote Link to comment Share on other sites More sharing options...
mtnickel Posted March 20, 2014 Share Posted March 20, 2014 (edited) If I were you, I'd save your money on all those high dollar parts, and stick with stock internals for now. Get it up and running so you can trouble shoot and get it reliable before going with a built motor. If you want a good education on the rb25, start reading how JTaylor did up his rb25 Z. His is all stock long block, and it will spank my forged, high dollar rb26. Have a read of JT's post's > http://forums.hybridz.org/index.php?app=core&module=search&do=user_activity&search_app=forums&mid=67&sid=8e63add93065fbb3d66376def6429abc&search_app_filters[forums][searchInKey]=&userMode=title His profile > http://forums.hybridz.org/index.php/user/67-j-taylor/ I second this approach. These engines have been known to handle 400whp+ without too much trouble. The tolerances and build quality that come out of the factory are exceptional. I read of far too many big builds that develop problems early on and read of many many shocking stories of big HP numbers on stock blocks that last a fair amount of time. Stony (a member) for example, was running over 600whp on an RB25 stock block (albeit with NOS). He's going bigger now, but it is just a testament to the quality of the stock build. One thing I can say for certain though is to have it professionally tuned. That will go a long way towards longevity. Good luck on the build! Edited March 20, 2014 by mtnickel Quote Link to comment Share on other sites More sharing options...
Coolwhip Posted March 20, 2014 Share Posted March 20, 2014 Hello everyone, I am knew to engine rebuilds and figured that this would be the place to start out with how helpful you guys have been recently! I am hoping to run over 450hp at the wheels in my 73, I purchased a 5 speed and rb25det. On Raw Brokerage I got some goodies for the rebuild but when it comes to the internals I am lost. Can someone help explain what each of these options are for me? Thanks! (If it helps my engine is a series 1) http://www.rawbrokerage.com/wiseco-pistons-eagle-rods-combo-r33-rb25det/ Let me know if you have any questions and I'm sure I'll be able to assist. ricky@rawbrokerage.com Quote Link to comment Share on other sites More sharing options...
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