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Frozengrip

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Posts posted by Frozengrip

    Rb25 Rookie timing mistake , damaged ?

    in RB Series - R31, R32, R33, R34 (1986-2002)

    Posted

    On 7/31/2021 at 9:15 PM, GTSBoy said:

    Yes it is correct. Whenever a cylinder is on compression/firing stroke (ie, #1 in this case) then the other cylinder that is also at TDC will be on the exhaust/induction overlap.

    Thank you for being so informative gtst, this is awesome ! So seems like I’m on the right path and all is good!

     

    @ben that’s how I got them back from the shop , but I didn’t torque head down yet. Just mocking everything up and make sure it’s all ok.

    now just gotta wait for my days off to get it all assembled and done!

    Rb25 Rookie timing mistake , damaged ?

    in RB Series - R31, R32, R33, R34 (1986-2002)

    Posted

    Hey guys !!! Sorry been super busy with work and some rather odd shitty weather that managed to take a touch of something’s. 

    Unfortunately a storm hit and flipped my Canopy over and managed to get my head wet but my block is fine ! 

    Surface rust embedded on the cams and surrounding areas 😞 

     

    but just got back to work on this beast , and set the pistons 10mm before tdc and set the  the first pair the lobes up? 

    Look good ? Thanks guys for all the help really do appreciate it !

     

    one last to mention I did like a newbie torque both cam gears before adjusting back when I first made this post.. should I untorque and then set lobes up ?

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    Rb25 Rookie timing mistake , damaged ?

    in RB Series - R31, R32, R33, R34 (1986-2002)

    Posted

    On 6/27/2021 at 7:05 PM, GTSBoy said:

    Cam position is easy. #1 firing is simply set up with both intake and exhaust lobes on #1 pointing away from the lifter. They are independently rotatable. They don't have to be exact - just pointing as close to directly away as you can eyeball them. Then all the other valves will be open (or closed) to safe positions wrt their pistons.

    The other thing you can do is put #1 piston at TDC then back it down by, say, 10mm before putting the head on. This just gets the pistons well away from TDC on all cylinders as you put the head on, so that even if you have your valve angles a bit wrong, you shouldn't be able to hurt anything. Then, when it comes time to set up the timing, you just roll the crank that bit to bring the piston back to TDC and keep them cams as close to the right spot as you can and then throw the chain on it.

    The main thing with this just to work slowly and carefully enough with as much double checking as you feel is necessary at each step to make sure you're not leaning on it wrongly. Experienced assemblers of engines rapidly get past even having to think about it. Novices just need to know and apply the commonsense rules.

    Wow gts can’t thank you enough for this drop of knowledge! Honestly was in a rut and was wondering if shot myself in the foot but happy to have people like yourself help out!

    with that said , would it be the safest option to set #1 lobes away from lifters and set piston 10mm down? Or is that too much? 

    And when I’m pointing the lobes up do I have to unbolt the clamps holding the cams down ? Thank you ! 

    And it’s my first engine build so getting familiar with everything but enjoying the process nonthless! Making the best engine shine in the us !

    and oh! Took some extra pics to show that verything is fine (valves/Pistons) and I think the metal shavings were definitely from the machine shop :/

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    Rb25 Rookie timing mistake , damaged ?

    in RB Series - R31, R32, R33, R34 (1986-2002)

    Posted

    15 hours ago, GTSBoy said:

    You always assemble any engine with #1 at TDC firing. Anything else is just asking for trouble. If the head is going back n with cams installed (where that is possible) then you also need to set the head up to match the engine angle. Or, when you're putting cams back into the head with the head on the block, then you need to install the cams at a compatible position to the engine position. Otherwise you're likely to drive valves into the pistons somewhere.

    In this case, you were turning the motor by hand and cannot see any places where the valves have scraped metal off the pistons, etc etc. That means that you simply haven't done the damage (created the swarf) that you see. So stop worrying about that. But.......Now you have to wonder why there is swarf in the head, when there absolutely shouldn't be. Whoever worked on it has not done a good job of cleaning up after themselves. I would not put it back together without a surgical inspection.

    Thank you for this important piece of info gts! I always saw engines being assembled with #1 tdc but didn’t think to much of it till recently. But with that known I’ll be postining #1 at tdc today. 

    As for the head , I was planning on putting in with cams since I never took them off. But yes I do have to angle to the pistons positioning now. How do I go about it or should take cams off and postions the lobes on the corresponding place? 

    And I hope it was, just cause when I was turning the cam gears it was clunks and hard. But yes no scrapes on Pistons or valve surface. 

    Is it possible that I could have hit a valve with a piston and forced the valve to go up a little ?? 

     

    Thank you guys for all the critical help! 

    Rb25 Rookie timing mistake , damaged ?

    in RB Series - R31, R32, R33, R34 (1986-2002)

    Posted

    29 minutes ago, admS15 said:

    I don't see how you'd get a shaving like that from what you've done and since you say the head came back from a machine shop, I'd be thinking it's swarf the shop has left behind or somehow got there another way. 

    Well thing is it’s not only that valve that has those shavings. It isn’t all but I really think i made the valves bounce down on the pistons as I was turning the cams or I was forcing the valves down with the lobes on the cams. Ah im just worried i messed up bad. 

     

    Another question, should I position #1 and #6 piston to be at tdc ? Or is it fine how it is ? Thank you this just has me wishing for the best haha

    Rb25 Rookie timing mistake , damaged ?

    in RB Series - R31, R32, R33, R34 (1986-2002)

    Posted

    14 minutes ago, Ben C34 said:

    So the engine was on a stand rotated by hand with the cam timing set to some strange position, and a piston hit a valve, but aside from the piece of swarf in a strange spot there are no signs of any damage?

    Yes, so I got the block and head back from the machine shop. I got it back with #2 piston and #5 piston at tdc. I then set the head on it , torqued it down and adjusted the camgears to the marks on the marks but did feel it force and clunk. Unfortunately that’s when it clicked to what was going on and yup. Found those shaving in the head ports. But no damage to pistons or valve surface. Just those shavings on the valve stems. Will update with some pics a little later..

    Rb25 Rookie timing mistake , damaged ?

    in RB Series - R31, R32, R33, R34 (1986-2002)

    Posted

    Hello all sau community, unfortunately I’m writing this here today for a rookie mistake I have done. Or so atleast i think. 

    I was adjusting my Cam timing , as I was turning the Cam gears I noticed a sound (that I know now is where I f’d up) and didn’t think too much since this was my first time. Anywho got both cams set on the timing marks and went to go check on the valves. I found metal shavings and this is when I realized what I had done smfh.

    I then proceeded to take off the head to see if any pistons or valves where damaged from underneath and nope. All pistons had no scuffs and valves where good besides the shavings on the inlet ports. 

    I clean the shavings out but should I consider this a damaged valve or should I be good to put it all back together?

    thank you guys, I’m gonna get some heat but hey it’s for the best haha

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    Rb25 rod power limit ? Replace pistons ?

    in RB Series - R31, R32, R33, R34 (1986-2002)

    Posted

    8 hours ago, GTSBoy said:

    Just prep the stockies if you're not wanting to spend money. If you're happy to spend some money, forged rods are "infinitely" stronger.

    I don’t mind spending on some forged rods , but want to know what’s the limit on the stock rods so I could maybe excuse that expense. If they survive my power levels for a good time that’s all I care for. Think I’ll definitely be getting some forged pistons though.

     

    thank you 

    Rb25 rod power limit ? Replace pistons ?

    in RB Series - R31, R32, R33, R34 (1986-2002)

    Posted

    Hello sau folks , last post was regarding some Hks rods I was interested in purchasing for my rb25. Little did we know a worldwide pandemic was in the works ?. Regardless those are already sold and I must move on. Must’ve been fate.

    Anyways I wanted to know what the durability of the stock rb25 rods were and what power they start to go at. It’s not like I’m looking for huge power (350-500hp) but I am looking for great long run reliability. I know the stock pistons are the first to go before rods so I don’t mind getting some forgies. 

    I have done some research and read rb26 rods are a great and cheap alternative for added beefiness. So might be on the look for some. 

    So should I just pair my stock rods with forged pistons or go the rb26 rod, forged piston route ?

    or am I just overthinking it lol.

     

    thank you guys. 

    Would Hks rb28 rods fit in rb25?

    in RB Series - R31, R32, R33, R34 (1986-2002)

    Posted

    Thank you for the detailed response piggaz! Glad it’ll be able to work since it’s a great deal I found on those. Not needing a rebuild at the moment but can’t let these slip noe knowing they’ll be good for my application.

    and for the rb26 crank and pistons , I have given the idea a go but since I’m in the states it’s a little more difficult to source one. But ill see as time goes. 

     

     

     

    Thank you!

    Would Hks rb28 rods fit in rb25?

    in RB Series - R31, R32, R33, R34 (1986-2002)

    Posted

    7 hours ago, Piggaz said:

    That’s a seperate issue all together.

    Wherr the pin sits in the piston itself. If the RB25, RB26 and some RB28 kits use the same 121.5 mm rod but have different stroke lengths then the difference must be where the pin sits in the piston considering they all go in the same height block.

    ok ok, think I get you. So considering the rods for all those different stroke lengths are the same Length then I assume they would just work with my choice of forged rb25 pistons ?

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