gmac708 Posted November 25, 2009 Share Posted November 25, 2009 What angle should the deck of the block be sitting at for proper orientation? By this, I mean the sideways cant that all RB's have. I think I have 13 degrees at the moment. I took an inclinometer and stuck it right on the top of the deck while looking at the face of the motor from the front of the car. Here is picture of McKinney mounts / RB26 in 70 Z. Please note that the aluminum 3/8" spacer or shim is installed on the exhaust side (I will be using a full washer type spacer later). I did this to achieve the desired clearance for the RIPS pan. Notice that the front belt cover split line (where the two halves meet) is almost horizontal or level. I think that is the angle of the engine block you want. Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted November 25, 2009 Author Share Posted November 25, 2009 Here is picture of McKinney mounts / RB26 in 70 Z. Please note that the aluminum 3/8" spacer or shim is installed on the exhaust side (I will be using a full washer type spacer later). I did this to achieve the desired clearance for the RIPS pan. Notice that the front belt cover split line (where the two halves meet) is almost horizontal or level. I think that is the angle of the engine block you want. Ah, OK. That will definitely help. Thank you! I take it you don't have the other side shimmed at all, then? Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted November 25, 2009 Author Share Posted November 25, 2009 The mounts have a 1.5 " stud so you can shim the engine to the correct clearance and angle...We wanted the engine as low as possible so we designed the clearance to be only 1/4 to 3/8 inch... 75-78 trans mount are being redesigned to provide better fit do to some problems with fitting on some cars. Expect to have new designed trans mount done asap. will advise when done... Yeah I need to get you some info. I may make a profile shape of the trans tunnel and floor pan cross section (right at the trans mount studs) to send to you as well. Quote Link to comment Share on other sites More sharing options...
RIPSNZ Posted November 26, 2009 Share Posted November 26, 2009 Correct angle is 10 degrees and even in the pix above it looks like adding 3/8 to the exhaust mount wasn't quite enough, might have to go 1/2 to allow for a little squash in the rubber mount. Also keep in mind that the exhaust side lifts under power so even 1/4 in clearance on the rack on the exhaust side is plenty. Or..........after the 3/8 shim is in there, maybe the intake side mount is too long and could be shortened to get the correct engine angle rather than packing the exhaust side even more? Rob Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted November 27, 2009 Author Share Posted November 27, 2009 Correct angle is 10 degrees and even in the pix above it looks like adding 3/8 to the exhaust mount wasn't quite enough, might have to go 1/2 to allow for a little squash in the rubber mount. Also keep in mind that the exhaust side lifts under power so even 1/4 in clearance on the rack on the exhaust side is plenty. Or..........after the 3/8 shim is in there, maybe the intake side mount is too long and could be shortened to get the correct engine angle rather than packing the exhaust side even more? Rob OK, thanks for the great insight. I presume in the proper orientation, the newly fabricated oil pan should have little to no lateral slant to it? Quote Link to comment Share on other sites More sharing options...
fast-datsun Posted November 28, 2009 Share Posted November 28, 2009 oil pans have the10deg built in for a reason unless you plan to completly redesign... any and all help on the 74-78 trans tunnel help will be used...... Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted November 28, 2009 Author Share Posted November 28, 2009 oil pans have the10deg built in for a reason unless you plan to completly redesign...any and all help on the 74-78 trans tunnel help will be used...... Nah, I just meant the fore/aft slope. Quote Link to comment Share on other sites More sharing options...
dizzle Posted December 2, 2009 Share Posted December 2, 2009 So you are saying that the top of the engine should read a 10 deg slope? Or the oilpan? I Have rebuilt my engine mounts 3 times now trying to get my pinion angle under control. Has anyone noticed any vibration issues from running a poly trans mount? Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted December 3, 2009 Author Share Posted December 3, 2009 So you are saying that the top of the engine should read a 10 deg slope? Or the oilpan? I Have rebuilt my engine mounts 3 times now trying to get my pinion angle under control. Has anyone noticed any vibration issues from running a poly trans mount? Honestly, I think to get an appropriate pinion and offset, you'd need to tweak the diff a bit. If you get the offset decent, either the front of the engine is too high or the pinion is not right. I don't have my trans mount just yet, though, so I am just messing about with jacks and shims. AFAIK, the bottom of the oilpan is flat with the road; even though it is angled when looking at it compared to it's mounting flange. The deck of the engine is slanted when installed, yes. According to RIPS, 10 degrees. With the McKinney engine mounts, it sits at 13 with no adjustment shims. You definitely don't set it flat. Dizzle, you need an inclinometer to determine what you actually have. It sounds like your pinion angle is wrong. That is the difference in inclination between the output of the trans (which can be measured by the face of the block when you have the water pump and whatnot off of it) and the input flange of the differential. As I understand, at or around 2.5 degrees difference is good. Some cars can get away with more, but I suspect the relatively short propshaft leaves us with a tighter tolerance. What I notice is that the diff is angled up a hair (at least how I have the chassis sitting) and as I jack the rear of the trans up so the trans output and diff input are at the same level (reducing the offset or elevation difference), the engine/trans noses down and I lose too much angle compared to the diff. (If this makes sense) I can get the angle back by shimming the engine mounts up more, but that's a slow process and I suspect I would end up getting it too high; perhaps hitting the valve covers on the hood, etc. Anyone that installed an RB in an S30 actually measure their pinion? Quote Link to comment Share on other sites More sharing options...
75&78Z Posted December 3, 2009 Share Posted December 3, 2009 As far as the fore/aft engine angle I would think that you should match the angle of the RB engine transmision assembly to what the original L series was mounted at, relative to some body feature such as the door sills. In other word use the body of the car as refrence and not the road/ground. As far as offset I would think that you would want the RB transmisions output shaft/yoke to be positioned as close as posible to the original position of the L series transmision output shaft/yoke (left/right/up/down) relative to the trans tunnel. Once the engine/transmision package is mounted properly relative to the body you would then verify that the differentials position is within spec relitive to the engine/transmision package. Keep in mind this assumes that the body is not horribly tweaked in which case you will probibly have other issues as well. This also assumes that you have taken these measurments when the original drive train was in the car or that you can get them from anouther Z. I'm sure there are other ways to align the engine/transmision to the diff but this is the aproach we are taking on our project. Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted December 4, 2009 Author Share Posted December 4, 2009 This also assumes that you have taken these measurments when the original drive train was in the car or that you can get them from anouther Z. Well, bugger, I did not check that when the factory system was in the car. That presumes that the new powertrain has the same effective propshaft length. If it's shorter, which the RB seems to be by maybe 4" or so, the pinion angle has to be smaller, as I understand it. Quote Link to comment Share on other sites More sharing options...
75&78Z Posted December 4, 2009 Share Posted December 4, 2009 We knew that the power train of the RB engine/transmision package was a bit longer than the L package so yes, the end of the RB transmision will be closer to the differential and in turn require a shorter drive shaft. My goal when I started building custom mounts, was to try to get the motor as low and far back in the chassis as possible (as Mckinney does) and to also keep the motor as close as possible to the same vertical and horizontal plane as the original motor/transmission, relitive to the chassis, to hopefully help prevent drivetrain vibration issues. Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted December 4, 2009 Author Share Posted December 4, 2009 We knew that ... Well, who is we? You have no signature. Quote Link to comment Share on other sites More sharing options...
75&78Z Posted December 4, 2009 Share Posted December 4, 2009 Oh, sorry for the confusion. We are my son and me. Not a bussiness or anything like that. Just you typical father and son, going on four year, car project, bonding type thing. The idea was to try and save a little bit of money by building our own mounts. Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted December 5, 2009 Author Share Posted December 5, 2009 Oh, sorry for the confusion. We are my son and me. Not a bussiness or anything like that. Just you typical father and son, going on four year, car project, bonding type thing. The idea was to try and save a little bit of money by building our own mounts. Gotcha. Of course you also know that the L motor slants to the other side, compared to the RB, too. So neither one really helps on that front. :-/ When I get my new mounts in, I will drop it in, tweak the exhaust mount up to 10 degrees slant (with none on the other side) and see what pinion is like and post it up. Then I will know what I gotta do to get offset/pinion decent. I still fear I will need a front diff mount to tweak/shim everything the way it should be. Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted December 8, 2009 Author Share Posted December 8, 2009 Just as a quick reply (on my way to work), I figured I would detail a few things with the new McKinney trans mount for 280Z's. First on the structure of it; there's a few tweaks I would recommend to McKinney, but I believe I have a prototype, so I am sure that will get worked out. Otherwise, it fit as well as any might be expected. The 280Z's just don't permit an easy solution. On fitment. All along I was concerned about pinion angle being correct (which most people check), but pinion offset angle is also very critical. This angle is measured from the centerline of the trans output to the direct line towards the differential flange center. Your pinion may be perfect, but if the differential is vertically offset from the trans a lot, this will cause a problem. Anyways, I took RIPS' statement of 10 degrees engine deck slant (thank you!) with the statement and photos of spacers for the McKinney mounts (thanks gmac708!) and standard limits for the two angles (from an SAE tech buddy of mine) and set it in the car. I came up with 3 degree pinion angle (which is what is recommended) and 0.68 degrees pinion offset angle (with 7 degrees being the limit). As you apply power, the nose of the differential will rise with the resistance to torque and cause the pinion angle to lessen and the pinion offset angle to zero or perhaps go negative. I think I have right at 10.25 degrees deck slant using stuff I had lying around for spacers. I believe this mount provides a great solution to get the proper geometry for the RB engine in a 280Z. I also measured the length for the propshaft using my 280Z propshaft's rear u-joint centerline and the RB's front u-joint centerline. I came up with 21.0" length between the centerline of the two u-joints bearings; while providing about 3/8"~1/2" of slack in the trans output to avoid bottoming out. I also noticed that I will need to notch both holes in the engine subframe a tad to get the mounts to drop straight on and have the engine mount bolts not angled to hit the hole. (I am using the poly mounts) Quote Link to comment Share on other sites More sharing options...
dizzle Posted December 8, 2009 Share Posted December 8, 2009 I was having trouble getting enough adjustment on the diff angle, so I retrofit a trans mount from a camero to replace the front diff mount on my r200. Worked really nice. Now I can just add or remove washers to change the pinion angle. Not to mention that the mount was 7$ at auto zone. Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted December 8, 2009 Author Share Posted December 8, 2009 I was having trouble getting enough adjustment on the diff angle, so I retrofit a trans mount from a camero to replace the front diff mount on my r200. Worked really nice. Now I can just add or remove washers to change the pinion angle. Not to mention that the mount was 7$ at auto zone. ORLY? Hmmmm. Do you know what model it was, etc? I was going to buy the solid mount from AZC, but they were out. I suspected I might have to do the same to get everything to line up, but I guess I did not. Quote Link to comment Share on other sites More sharing options...
dizzle Posted December 9, 2009 Share Posted December 9, 2009 It was from an 89 camaro tranny mount. I just had to rasp out the holes a little. The section the rear cross member an. Weld in a piece of 3/16 plate with a hole in it. Worked really nice. And it is a good rubber mount, might still need to weld in a couple of braces on the plate though. The mount just had a stud coming off of the bottom, so I can just add washers to adjust the angle Quote Link to comment Share on other sites More sharing options...
fast-datsun Posted December 14, 2009 Share Posted December 14, 2009 Just as a quick reply (on my way to work), I figured I would detail a few things with the new McKinney trans mount for 280Z's.First on the structure of it; there's a few tweaks I would recommend to McKinney, but I believe I have a prototype, so I am sure that will get worked out. Otherwise, it fit as well as any might be expected. The 280Z's just don't permit an easy solution. On fitment. All along I was concerned about pinion angle being correct (which most people check), but pinion offset angle is also very critical. This angle is measured from the centerline of the trans output to the direct line towards the differential flange center. Your pinion may be perfect, but if the differential is vertically offset from the trans a lot, this will cause a problem. Anyways, I took RIPS' statement of 10 degrees engine deck slant (thank you!) with the statement and photos of spacers for the McKinney mounts (thanks gmac708!) and standard limits for the two angles (from an SAE tech buddy of mine) and set it in the car. I came up with 3 degree pinion angle (which is what is recommended) and 0.68 degrees pinion offset angle (with 7 degrees being the limit). As you apply power, the nose of the differential will rise with the resistance to torque and cause the pinion angle to lessen and the pinion offset angle to zero or perhaps go negative. I think I have right at 10.25 degrees deck slant using stuff I had lying around for spacers. I believe this mount provides a great solution to get the proper geometry for the RB engine in a 280Z. I also measured the length for the propshaft using my 280Z propshaft's rear u-joint centerline and the RB's front u-joint centerline. I came up with 21.0" length between the centerline of the two u-joints bearings; while providing about 3/8"~1/2" of slack in the trans output to avoid bottoming out. I also noticed that I will need to notch both holes in the engine subframe a tad to get the mounts to drop straight on and have the engine mount bolts not angled to hit the hole. (I am using the poly mounts) Once we have all the necessary feedback on the new trans crossmember we will add to the mounting kit for the 75 up Zcars,,,,, Quote Link to comment Share on other sites More sharing options...
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