Ok, I bought a salvage yard engine for 100, and am having some problems getting it going. It is a vg30e. I am getting spark and fuel, however I think that the timing may be off. I did a compression check on five of the cylinders(number one is stripped and I don't want to take the plug out and put it back in) cyl 2=150 4=165 6=75 1=? 3=175 5=175....any ideas?

 

Cylinder #6 is 175 psi, Correct?

 

No, it is 75

 

sounds like you got problems with your rings or valves. did you get any infro from salvage yard about condition of engine befor they removed it

 

I just did a GA16DE swap with a j/yard engine and the cylinders had water in them due to condensation...It would not start until i got the water out of the cylinders....Purring like a kitten now..

 

if you don't want to rebuild it then you have a pretty good paper weight there.

 

maybe the timing belt broke and F.U.B.A.R.E.D your valves???
then maybe they replaced it with a new one thinking it would be ok??

 

I did the timing belt on it, and it was my first time. i was wondering if possibly the teeth are slightly off. Would those numbers indicate that. I think that it is wierd that one head seems perfect and the other is jacked.

 

if the teeth were slightly off all cylinders on one bank would be low. its likely valves, rings, or headgasket. to test if its the rings you can put some oil into that cylinder then do the compression test again. if the numbers raise at all its likely the rings. if not, then headgasket or valves.

might be able to inspect how the valves look by taking off the valve cover. if one of them got damaged you should be able to see it there.

 

That's why I'm wondering though. The bank nearest the front is low, 150, 165, 75 is a little low, while the other bank seems perfect.

 

The jump is too extreme though.

For instance:
I have an 85 Maxima VG30E that I've been working on to put into a 300ZX Turbo. I checked the compression of it and all 6 cylinders were around 120 and a couple at 90. I knew something was incredibly wrong as the chances of every single cylinder being low would be slim (unless the timing belt broke bending all of the valves, and I knew that hadn't happened on this engine.)

Turns out whoever worked on the engine previously accidentally put the cam gears on wrong. They had the left/front cam gear on the right/rear and vise versa.

If one of the gears were off a tooth on the timing belt, all of the cylinders would be something like that 120 on each cylinder. The timing seems right, there just seems to be a problem with cylinder number 6 on your engine.

 

Would that be enough to prevent it from firing up? I didn't get any type of response(sputtering, waterlock, backfire, etc...) out of it when cranking.

 

I would think with just one cylinder having low compression it would start up.

I'm thinking that maybe the injectors aren't putting any fuel into the engine or maybe spark timing is off. Was the distributor in the engine when you got it or did you have to put one on yourself?

 

I had to put that on, the old ones wiring was cut. I tried it in every position that it could go,nothing at all, and i was smelling fuel during the process.

 

Could be an ignition timing issue then. Turn the crank by hand/socket so that the timing mark lines up with 0 degrees (left most timing mark). That's top dead center of the compression stroke of cylinder 1.

From there, you'll want to line up the distributor so that the rotor is actually slightly past the number 1 contact (side note, very important: the contact for cylinder one in the distributor cap is actually on the opposite side of where the actual number is. Find number 1 on the cap, then look inside it. You'll notice a raised section that runs from that number 1, to a contact point that sticks out. That is your true number 1 contact point inside the cap. This one throws people off sometimes.)

Once you get that, like I was saying above you'll want to turn it slightly past the number one contact as the gear is curved. When you slide it in the rotor will move into place slightly past number 1. There actually should be a dimple on the gear of the distributor that lines up with a protuding indention on the housing right above the gear. That should like it up for top dead center but my memory is fuzzy at the moment.

 

If you're smelling fuel I'd check for leaks in the hoses. A bad enough leak and you wouldn't get any pressure to inject fuel in... although I would think if it were leaking that bad you'd have a pretty large puddle of fuel in there.

It could also be a vacuum leak but I would think it would at least try starting. I'd double check the distributor first and go from there.

 

My charcoal canister broke, so I removed that, and pluged the lines. I don't have leak, but I will redo the distributor to TDC. Thanks

 

Might want to find another charcoal canister. I think plugging the lines could potentially cause a problem.

 

Hello Guys, I'm teh Newbie here
But I was wondering with his problem could he be 180 deg. out of Time ?? (at the distrubutor)
That will cause an engine to not fire at all......

Troy.

P.S. I love this site !! Everyone is quite nice here, To the point too

 

Its very possible it could be 180 off. I don't believe his would be that far off (just depends on how he found top dead center), but you definitely are on the right track.

 

maybe the timing is advanced too much???? and your not gettign the right kind of fuel in the motor .. i dunno

 

doesn't 180* off cause it to backfire?
sorry, but that's how it works on my antiques with a dizzy

 

180 Deg. Out is the EXACT opposite of what the engine needs to ignite the gasses in the cyl. so the exact opposite would be just that...... No Ignition Evan with spark and fuel.....

Troy.

 

If the spark was off, I would still expect some kind of reaction. I'm really only worried about the compression results. My friend(who is a mechanic) said that it is possible that one of the gears is off by a tooth or two, so if that's the case I'll fix it, and if it's a ring, head gasket, or valves, then I'll just get one of those vg33e thingys and try that out. I won't really know anything until i try again Tuesday(my day off). Thanks

 

It'll be highly unlikely that one of the gears are off a tooth. The compression is too high for it to be that case.

When that engine I have was at around 120 psi compression, that was only at half a tooth off (the difference of the cam gears). A full tooth would likely make it even less. (granted you can be off a tooth advanced or retarded which will likely make thing differ, the numbers of the two good cylinders are still too high.)

It definitely wouldn't hurt checking it at all... I just don't see that being a problem. I think at one tooth off the valves are getting pretty close to hitting the piston and at two teeth off they definitley do. I'll have to double check but I'm pretty sure the clearances are that tight.

 

if you pulled the distributor..did you line the engine up prior to pulling it?

set #1 at TDC - take off the spark plug and stick a screwdriver in there. turn the engine BY HAND and watch where the screwdriver moves up and stop when it reaches the highest point. reinstall the plug and wire.

once that's done clock your distributor at #1 (at mtcook said roll it back a little before so when it goes it it will be at 1). from there try to start the engine. if it doesn't start try to see if it's close to starting...little back fire and it would sound like it's almost starting. if that's the case then set it back to TDC on #1 and reclock the distributor...back one tooth or forward one tooth and keep trying until it runs correctly.

this is bearing that the T-belt is installed correctly and the cams are right.

 

Ok, the engine was pulled and disassembled to make room for one of those vg33 things. I feel dumb, because whenever i did the timing belt, somehow, one of my 12mm sockets fell in the gearing and threw off the teeth, so it was timing.