Roman Posted November 14, 2023 Author Share Posted November 14, 2023 Its damaged the back face that mates up to the crank. Its just dug one side a bit too deep. 1 Quote Link to comment Share on other sites More sharing options...
rusty360 Posted November 14, 2023 Share Posted November 14, 2023 On your flywheel issue have you tried machine part welding in Penrose? I'd be surprised if they couldn't sort it. 1 Quote Link to comment Share on other sites More sharing options...
rusty360 Posted November 14, 2023 Share Posted November 14, 2023 Not sure now but Bruce was the man back in the day, he could weld anything! 1 Quote Link to comment Share on other sites More sharing options...
Hurmeez Posted November 14, 2023 Share Posted November 14, 2023 Possibly a silly question, but aren't a lot of roll cages/space-frame chassis welded chromoly tubes? Or is welded tubing fundamentally different enough from a monolithic material like a flywheel for the process to not really transfer over? 1 Quote Link to comment Share on other sites More sharing options...
Roman Posted November 14, 2023 Author Share Posted November 14, 2023 Yeah they do make roll cages out of it. I'm not sure to be honest, I've just heard it tends to crack or shrink a lot from welding and it causes issues. Since this is a flywheel that if all goes to plan it is going to be spinning at a fairly silly rpm. I'd rather not take too many chances with it. Buuuuttt yeah maybe I should have an ask around. I might go get a second flex plate/ring gear from pickapart and just bolt all that up. At least that way I can know if the motor can crank over or not. 1 Quote Link to comment Share on other sites More sharing options...
anglia4 Posted November 15, 2023 Share Posted November 15, 2023 I'd say its weldable, but probably requires the right process with pre-heat, post-heat etc. 1 Quote Link to comment Share on other sites More sharing options...
Popular Post Roman Posted November 23, 2023 Author Popular Post Share Posted November 23, 2023 The 5GR motor has been brought up a few times in this chat - the unobtanium China only 2500cc short stroke GR motor. Well ive found out some interesting stuff. The GR series of motors shares a considerable amount of dimensions with the previous MZ v6s. They have identical bore spacing, bore offset, and stroke length between various versions of each. This would solve the mystery of where the 5GR crank comes from - Its a bunch of left over 2MZ cranks shipped to China to build cheaper 2500cc non DI GR engines with 3GR blocks. It would also make sense for why it was a 2005 year only engine -just an end of line bitsa, as the 2MZ cranks would be the only ones left unused by the GR series. 3gr bore x stroke: 87.5 x 83 1mz bore x stroke: 87.5 x 83 5gr bore x stroke: 87.5 x 69.2 2mz bore x stroke: 87.5 x 69.2 1mz cyl spacing: 105.5mm 2gr / 3gr / 4gr cyl spacing: 105.5mm If this is true. Then the ultimate combo would be a 3GR block (cheap and easy to get in NZ) and a 2MZ crank which I could likely find at pickapart or just buy a motor. This wouldnt exceed 5000ft/min piston speed until a smidge past 11k rpm. So this might be version 2.0 motor one day if that works. 16 5 Quote Link to comment Share on other sites More sharing options...
Popular Post Roman Posted November 23, 2023 Author Popular Post Share Posted November 23, 2023 So even more stuff matches up. Both have: 22m gudgeon pin 56mm bigend 61mm main journal. Welllll shit. Thats another item on my pickapart quest list then. 2mz guts! 16 Quote Link to comment Share on other sites More sharing options...
VitesseEFI Posted November 23, 2023 Share Posted November 23, 2023 Detective Dave 1 Quote Link to comment Share on other sites More sharing options...
Stu Posted November 23, 2023 Share Posted November 23, 2023 All this tech talk and not a single MS paint graphical representation in sight? You've changed @Roman Quote Link to comment Share on other sites More sharing options...
Roman Posted November 23, 2023 Author Share Posted November 23, 2023 Dont you worry, I'll more than make up for it when the engine is running. Haha 2 Quote Link to comment Share on other sites More sharing options...
xsspeed Posted November 23, 2023 Share Posted November 23, 2023 my brain cant do it without writing it down but with that much stroke difference what does that mean for rods/TDC piston height, presuming would mean using 3gr block Quote Link to comment Share on other sites More sharing options...
Roman Posted November 24, 2023 Author Share Posted November 24, 2023 Yeah would need to use 3GR block, 2MZ crank and 2MZ rods. Or you'd end up with the piston sitting way too low in the block. Then you might get lucky and find that 3GR or 2MZ pistons work and give an acceptable CR. The 2MZ piston has a dome on the top, where as 3GR/4GR are dished with weird DI stuff on top of piston. So hopefully would be able to mill them down to a good CR if they are "too high" rather than the opposite. But who knows. 3 Quote Link to comment Share on other sites More sharing options...
shrike Posted November 24, 2023 Share Posted November 24, 2023 Next update, and you have all the bits to build a frankenmotor for when this one dies haha, all cheap pickapart bits or FB marketplace etc Do all the GR heads swap over between blocks? Wonder which ones flow the best/are the best to port hmmmm Quote Link to comment Share on other sites More sharing options...
Roman Posted November 24, 2023 Author Share Posted November 24, 2023 The 2GR heads will be best, since they have huuuugggggeee valves because of the much bigger bore (94mm bore vs 83mm 4GR) So as a result the valves are 7-8mm bigger diameter which is crazy. If you put a 2MZ crank into a 2GR then you end up around 2.9 litre with a stroke that "should" allow 10 or 11k rpm. I guess the thing is, first I just need to get a motor together and see what happens when it runs. It is entirely possible that there is some insurmountable issue with the valvetrain (or whatever) so arguing semantics over which motor will do 11,000rpm is irrelevant when the whole thing explodes at 9000 anyway. Haha. God I love wildly speculating though 7 1 1 Quote Link to comment Share on other sites More sharing options...
shrike Posted November 24, 2023 Share Posted November 24, 2023 47 minutes ago, Roman said: The 2GR heads will be best, since they have huuuugggggeee valves because of the much bigger bore (94mm bore vs 83mm 4GR) So as a result the valves are 7-8mm bigger diameter which is crazy. If you put a 2MZ crank into a 2GR then you end up around 2.9 litre with a stroke that "should" allow 10 or 11k rpm. I guess the thing is, first I just need to get a motor together and see what happens when it runs. It is entirely possible that there is some insurmountable issue with the valvetrain (or whatever) so arguing semantics over which motor will do 11,000rpm is irrelevant when the whole thing explodes at 9000 anyway. Haha. God I love wildly speculating though Im assuming youll be upgrading valve springs? Quote Link to comment Share on other sites More sharing options...
Roman Posted November 24, 2023 Author Share Posted November 24, 2023 I already have. Got the Kelford springs and titanium retainers in there. Will be interesting to see how the factory cams can go when able to spin up a bit higher. 1 Quote Link to comment Share on other sites More sharing options...
Hurmeez Posted November 24, 2023 Share Posted November 24, 2023 For what it's worth my money is the oil pump getting into some weird harmonics and shattering into a million bits. Bet it sounds excellent on the way up to it though. 1 Quote Link to comment Share on other sites More sharing options...
shrike Posted November 30, 2023 Share Posted November 30, 2023 Keen for start up/running videos and shed skids Are your J160 all stock internals? Or have you had some mods done (Circlip?) Any idea how it'll go with many revs? I'm assuming power and torque are within specs for it? Quote Link to comment Share on other sites More sharing options...
Hyperblade Posted November 30, 2023 Share Posted November 30, 2023 8 minutes ago, shrike said: Keen for start up/running videos and shed skids Are your J160 all stock internals? Or have you had some mods done (Circlip?) Any idea how it'll go with many revs? I'm assuming power and torque are within specs for it? A friend races his RX7 with a 13B and a J160 and it's been pretty reliable for the most part (he's raced it since 2008). However last round he blew 4th gear, so the circlip mod may be worth looking into. The issue is a lot of the boxes for sale are all very high k's and it's not as easy as it used to be to find cheap good condition ones. Quote Link to comment Share on other sites More sharing options...
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