onekickkawi Posted July 8, 2012 Report Share Posted July 8, 2012 Ok, here is my dilemma. I have a 72 Datsun 510 with a VG30 carb conversion. This is the 2nd time that my motor has quit on me, since the swap. The motor is totally rebuilt. The first time I ran it with Z31 comp cams. It fired right up rumbling like a dream. After 5 miles it quit and wouldn’t start, though it would stumble a little and try. I did a compression check and it had almost none (20psi). I took the heads off, and figured out a few valves were bad/bent. Funny thing is this is supposed to be a noninterference motor! I decided to put stock cams in, and make sure the motor was totally stock to eliminate any possible issue. Now the 2nd time out and the same thing happened. Both times the timing belt and timing was done right, according to the factory manual and was rechecked 3 times by me and a friend. I am running a holly 2 barrel 500cc and a Saudi distributor. The car has a painless 12 circuit harness, the OE one was removed. I ditched efi for the simplicity (so I thought). I have come to a few conclusions, ONE the motor is cursed, rip it apart, convert to efi and pay someone to wire it up (I suck at wiring and really hate it). Two I sell the thing, cut my losses and move one. If I go with option one, know anyone in the CA bay area that is good at and willing to wire up a motor if I do the install? Below are a few stats about the car. All Autometer gauges Griffin aluminum radiator Battery in trunk Painless 12 circuit wiring VG30 motor and trans Autopower roll cauge Vinal (fake leather) seats with 4 point harness Stock suspension and rear end, was planning those being the next step. 1 Quote Link to comment
ggzilla Posted July 8, 2012 Report Share Posted July 8, 2012 Totally stock? Including pistons and heads? Sounds like when it warmed up the valves contacted the pistons. Quote Link to comment
onekickkawi Posted July 8, 2012 Author Report Share Posted July 8, 2012 yes it is in totally stock form.. minus the carb conversion. could be possible but that would mean the timing is off, way off. And im pretty darn sure it isnt, 2nd its a non interference motor so even if it were off the valves should not be able to contact the piston Quote Link to comment
Son_of_a_Datsun_Guy Posted July 8, 2012 Report Share Posted July 8, 2012 It's a VG30? the VG30 is an interference motor, the VG33 is not. Quote Link to comment
onekickkawi Posted July 8, 2012 Author Report Share Posted July 8, 2012 The manual I was refering to said it wasnt... but if it is, i dont think i did the timing belt wrong. I have never had an issue when I did my tacoma or integra. I also cant say I am to thrilled on tearing it down a third time to do this all over. just trying to figure out the next step... I am pretty sure no one here is going to advocate selling it... I am just running through the options of going with a efi motor, l20... having a pretty lawn ornament Quote Link to comment
Uber Deaf One Posted July 8, 2012 Report Share Posted July 8, 2012 The manual I was refering to said it wasnt... but if it is, i dont think i did the timing belt wrong. I have never had an issue when I did my tacoma or integra. I also cant say I am to thrilled on tearing it down a third time to do this all over. just trying to figure out the next step... I am pretty sure no one here is going to advocate selling it... I am just running through the options of going with a efi motor, l20... having a pretty lawn ornament Do you have another manual to look at? Quote Link to comment
onekickkawi Posted July 8, 2012 Author Report Share Posted July 8, 2012 I could look, but interference or not... timing is simple tdc, cam gear mark matches the one one the backing plate, same with the crank. The cam gears are on their perspective cam... right and left are different Quote Link to comment
bananahamuck Posted July 8, 2012 Report Share Posted July 8, 2012 Could there be something wrong with the tension-ing pulley assembly ?? Quote Link to comment
onekickkawi Posted July 8, 2012 Author Report Share Posted July 8, 2012 It was tight and right where I left it when I put it on... a big part of me want to get a vg30dett and have someonelse wire it... it will have plenty of power. I'm great with fabricating things, though I was good with motors (this is the first time I'm stumped), always hated and terrible with electrical. Quote Link to comment
Jesse C. Posted July 8, 2012 Report Share Posted July 8, 2012 Did you cam gears come loose during break in? Did you do a proper break in? Are the heads shaved? Just trying to narrow it down a bit. As for a VG30DETT, I would not do that. Too big and you can make the same or more power with a VG33E Quote Link to comment
onekickkawi Posted July 8, 2012 Author Report Share Posted July 8, 2012 Yea head was decke, cam gears were solid... break in procedures seem to vary a lot depending who you talk to.. but it was idled for a while, timed, and driven under 3k rpm ... how I have usually broke in motors. The vg33 is vary similar, and there are other reasons why I don't want it. If I an going to change to a new motor plus efi I would want the dett... gotta reasons, but I'm on my phone and its to much to type. Quote Link to comment
q-tip Posted July 8, 2012 Report Share Posted July 8, 2012 Did you set your valve lash? Quote Link to comment
DAT510 Posted July 8, 2012 Report Share Posted July 8, 2012 I thought you broke in motors at WOT :lol: 1 Quote Link to comment
onekickkawi Posted July 9, 2012 Author Report Share Posted July 9, 2012 Now that I think of it there was one thing I didnt touch personally. I had the block bored 40 over a long time ago and new poistons and rods put in. Makes me wonder if somehow though piston had the wrong vlave dipressons or maybe put in backwards? After some thinking I am starting to lean more towards a new motor. Scrap this one and start over on a clean slate. Quote Link to comment
bananahamuck Posted July 9, 2012 Report Share Posted July 9, 2012 I can`t type good enough to describe how to do this so i went and found a couple links for it,,,,pretty common method on big cammed engines... Using clay to check valve clearance http://www.racingheadservice.com/Information/Technical/PistonToValveClearance.asp http://www.centuryperformance.com/checking-and-setting-piston-to-valve-clearance-spg-144.html Seems like a caveman way to do it but it does give pretty accurate results.. 1 Quote Link to comment
ggzilla Posted July 9, 2012 Report Share Posted July 9, 2012 New Camshaft break-in is start the engine -- DONT LET IT IDLE -- and run it for 20 minutes at 2,000 RPM. Quote Link to comment
q-tip Posted July 9, 2012 Report Share Posted July 9, 2012 If you think the pistons were installed wrong there ill definite be some kind of marks from bending valves Quote Link to comment
onekickkawi Posted July 9, 2012 Author Report Share Posted July 9, 2012 I will look eventually when I pull it out. I am looking at pulling the motor within a week... I have now calmed down and stoped yelling at the car, remembering its a project. However I am planning on buying a SR20DET to install. I will start making a list of what needs to be done tomorrow. Quote Link to comment
onekickkawi Posted July 9, 2012 Author Report Share Posted July 9, 2012 So it looks like it will be the SR20DET bellow is a list of parts and my guess... also a preview of what I will be selling. Buy: SR20DET Motor, Trans, Wiring, & ECU $2,100 510 SR20DET down pipe 3" $320 t25/28 Turbo 3" vband $135 TURBO ON TOP MANIFOLD $450 May Not Need TURBO OIL AND WATER LINES $136 External fuel pump $150 Can-Am Wiring box $150 Ceramic Coating by RS performance $200 Misc Fuel Lines and fitings $200 Total $3,841 Piping the intake/intercooler $200? Resize Driveshaft $200? Sell: Lightend Flywheel $200 Clutch and preasure plate $200 Transmission rebuilt $600 VG30 Headers $200 Motor Mounts $100 VG30 Oil Pan $150 VG30 Carb Intake $200 Saudi Distributer $350 MSD 6-AL and Coil $100 $2,100 Anyone in the CA bay area good with wiring? Either shops or members, pay in cash and or beer 1 Quote Link to comment
Draker Posted July 9, 2012 Report Share Posted July 9, 2012 Wiring is simple.. Don't puss out on it. Quote Link to comment
onekickkawi Posted July 9, 2012 Author Report Share Posted July 9, 2012 Bahh I will look at it when I get the harness.. I still need to pull the motor Quote Link to comment
onekickkawi Posted July 9, 2012 Author Report Share Posted July 9, 2012 replied, i put a post up in the classifieds. SR20DET it is, i will slowly start to dismantle the motor this weekend... Quote Link to comment
Son_of_a_Datsun_Guy Posted July 11, 2012 Report Share Posted July 11, 2012 Bottom mount turbo manifold is cooler.... just sayin' Quote Link to comment
510T Posted July 11, 2012 Report Share Posted July 11, 2012 Bottom mount turbo manifold is cooler.... just sayin' Agreed. I have a cracked SR510 bottom mount that could be rewelded. OP if you need any assistance with your new setup I have a couple good contacts in Santa Rosa for fabbing and SR20 stuff. lmk... Quote Link to comment
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