Will not crank

[wishihadas14]

Just finished an engine rebuild and have tried all the recommendations in other people's threads. Setup is all new: pistons, cams, plugs, wires, etc. Cranks till the battery dies, steady with no hiccups but with an occasional loud backfire. All underhood fuses check, all in car fuses checked. Fuel lines hooked up correctly, all plugs spark, double-checked dizzy timing, compression numbers all right around 165. Thought it might just be flooded, so I cranked it a couple times without the fuel pump fuse in to clear out some of the gas, then replaced fuse and tried again. I know there's a million of these threads but I've spent 2 days and nights doing everything they recommended and I just don't know what to do. Please help! Any questions/suggestions are welcome if I forgot something please let me know. I just want it to run.

[Thamm]

check the battery or starter?

[wishihadas14]

Rechecked the dizzy timing, manually turned crank, TDC at compression stroke on #1, pin lined up on the crank pulley, then messed with the dizzy, ended up moving it one tooth. Had someone rock it between full advance/retard while cranking, no noticeable difference.

New problem has come up and I'm not feeling happy. When I was checking the compression, my dip**** friend never pulled the fuel pump fuse like he said and so I wrecked the tester after #3, it just stopped reading more than like 5 psi on any of the cylinders so I just postponed testing #4 since I figured the likelyhood of 1,2,3 being fine and 4 being ****ed was pretty slim, and that it would at least fire on the other 3 cylinders even if #4's comp was off. But today I had someone crank it while I held my hand over it without a plug and it felt mad weak, like it didn't even raise my hand off the valve cover. So I did the same to #3 for comparison and it blew my hand off hard. So now my car won't start and I'm having compression issues on a freshly rebuilt motor and I don't have time or money to tear it all back down or to have someone else do it for me. Someone please tell me that my cam timing is off by a tooth or something and that even though it's gonna be a *****, it'll all be fine tomorrow...

[wishihadas14]

Well its not my cam timing. Set the crank to tdc on 1's comp stroke and took off the valve cover. Looked right as per fsm and jwt so I gave them a call at brian crower and after checking every lobe's position we determined that the cams are in 100% correct. So I guess that leaves me with bad rings (but they're brand new, never been run), a somehow otherwise ****ed up valve, or massive headgasket failure.I'm gonna leave out every plug except #4 and see where the piston is pushing that air. It can't be the rings, because they push a little bit out the plug hole when the hole isn't sealed, but when it is sealed you feel no pressure (the air just takes the path of least resistance). This blows. I think that I either have a valve that isn't seating right (bent, missing something, fell in, I don't even know) or I'll find air leaking around the hg. This really blows. Yeah, car's in K-dale, address to anyone who wants to help will be given in PM form (not my house). And did I mention this blows?

[wishihadas14]

Took off the valve cover and verified that cam timing was dead on, But was still not getting any compression on #4. Figured it had to be a bent valve but didn't know how it could be if the cams were in right. Turns out the guy I bought the partially built engine from had the block machined 10/1000ths and gave me to thin of a gasket. intake cams on #4 were bent as **** when I took the head off and you can see little half moons on every piston where they were just touching the valves. Brought my head to HRT in Durham and they're gonna tear it down and double check everything when they replace those valves. Meanwhile, I've gotta measure my deck clearance so I can get the right gasket and get everything back together.

The question still remains, "if timing was right on the cams and 3 cylinders had fine compression and correct spark, wouldn't it have still cranked but just ran like ****?"

[neverlift]

even then it didnt sound to be trying to fire. I'm in a similar situation right now. just rebuilt the engine and everything is lined up perfect, now the car is gettign spark and fuel but still wont fire off.

[cmoody2006]

I put a head gasket spacer on mine and it solved my problem I had the half moo shapes after re-installing the head. Put the spacer in and it fired right up didn't bend my valves

[OldmanPurdy]

The question still remains, "if timing was right on the cams and 3 cylinders had fine compression and correct spark, wouldn't it have still cranked but just ran like ****?"

Yes even with low compression if you have fuel,spark, and timing you should have ignition, lots of cars are running around out there with worn rings and low compression. You obvously have fuel sans busted compression tester and you have tested for spark on all plugs so that really only leaves a timing issue.......when you put the 1# piston to TDC are you sure its on the compression stroke? and the 1# position on the dist. should be facing towards the front of the car? I hate to ask those questions because you sound like you know whats up but I can't think of anything other than the timing chain not set right that would cause this.

[wishihadas14]

Cams were dead on before I pulled the head. Yep compression stroke and #1 on distributor cap on front of car. I don't know either, maybe it's just too many little things and it was the first time trying to crank it. I'm just gonna set it all up fresh (not that I have a choice since I had to tear some of it back down) and hope that it'll fire right up.

[OldmanPurdy]

I'm not sure what to suggest beyond what you are planning to do anyways, it may help to post a link to this thread in 240sx Tech or in Nissan Online Mechanic subforums, NISTECH will probally have a useful suggestion for you, good luck.