Time for me to be a Noob

[Chezedik]

Here is the deal, I just finished my engine (again) and am going nuts on my KA-t spree so I need to get this thing running.

The engine makes 90+ pounds of compression cold, never ran. When I crank on it, after a few seconds it will start spitting fire from the exhaust ports (no mani on it), the longer I do this the closer it sounds to an idle. When it sounds just like an idle, I let of the key, and it stops. So I have a serious no start condition. When I spray it with starter fluid, it sounds like it's going too rich, and the starter whirs higher, when it vaporizes, then it starts pumping again. I keep the throttle half open when doing this.

Is this normal for a rebuild? Also, what suggestions do you have to help me get this ***** started?

[crzycav86]

Your compression seems pretty bad. Is it like that across all the cylinders?

If it's not anything more serious, it seems like your timing is off.

[Chezedik]

Yeah, but I am told it is normal for what it is. I have never ran the motor and this test was done cold with the rings unseated.I was thinking timing, but didn't want to plant a seed. I wanted to be sure that I got your opinion not my own. I have that ASP pulley, and I timed it using those marks. I am told that they are incorrect. But if anyone else has anything please butt in.

[TheOne]

do you still have the stock crank pulley? try marking the asp pulley along with it, i've been told that they made some crank pulleys with wrong timing marks on them too.

am thinkin its timing also as it is tryin to fire up but its just too out of timing to idle.

[Chezedik]

That is also my thing. No, stupid me gave the stocker to a guy who ended up keeping it in a closet (for who knows what reason), Does everyone think/know if KAE is the same? There is a shop two houses down that has a SOHC that I could use for comparison. I think I will set the engine at TDC using the old ratchet extension method and then back it off a bit. I will take measurements at the distributor and determine what 20' is, then mark the crank pulley. Does that seem acceptable? Anyone else have any other ideas?

[Edub1]

Why not set the crank pully to TDC and have a look at your cam position. Perhaps the way the cam mates to the pully can give an indication of position if you compare it to pictures in the service manual. Or look on another car.

[C-Kwik]

Assuming the compression tester is functioning properly, the compression does appear low. You're cam timing may be off. The exhaust valves may be opening too soon. Perhaps to the extent that it does so before TDC. This could cause both the compression to drop significantly and burning mixtures to shoot out the exhaust ports.

[Chezedik]

I think the flames were just unburnt gas, I am not too worried about that. I am thinking it normal. Also, I am pretty certain that I got cam timing right, because I went back to stock cams to do it. But maybe I will check and see if they are not S14 cams. It should be obvious by looking for the one with the bigger lobes which is exhaust, correct?

[C-Kwik]

What cams are you running? You should be looking at the cam gear positions when setting the chain. And even then it's easy to make a mistake as the KA has no markings on the heads or cam towers to match these to. It wouldn't hurt to be sure.

I'd also check to see if the injectors seals might be leaking...

[Chezedik]

I used the method as described in the FSM, aligning the dots on the sprockets with the colored links. I think I am using S13 cams, I cannot be sure because I had to buy them when I snapped my old intake cam. If they are S14 though, then they need to be switched. Any good idea on how to be sure? Also, could this be just distributor timing?

[C-Kwik]

I followed the FSM as well. Like I said, it's not hard to be off a tooth on either.

As far as S14 cams, it should still allow good compression and run correctly. The S14 cams are milder, but the ECU should have no trouble compensating.

For it to be distributor timing, you'ld have to be way off the mark. If you're close it should still run. And compression would be okay.

[Chezedik]

I've been told this is a fine compression number for a motor that has never ran and was tested cold. Is that wrong, for sure? Also, from what I have been reading the ASP pulley's timing marks are something like 20 degrees off. Finally, If I installed green on intake and brown on exhaust then having the cams in backwards would change cam timing too. Where should the lobes be at TDC on #1, does anyone have a pic. I am not trying to shoot down all of your suggestions C-kwik, I just really want to get to the bottom of this once and for all.

[Edub1]

They should be positioned so both valves are totaly closed. I've never worked on that motor but typically you won't have too much room to rotate before a valve starts to open.

Plus, this might sound crude, but stick a thin piece of tie wire or a tiny nut on a string through the plug hole and use it as a feeler if you have to. Of course it's not percise but it will get you into the ball park.

[Chezedik]

To feel for what? Also, I meant should they be about to open or about to close or what, that is why a pic would help.

[C-Kwik]

As with any internet diagnosis, it's difficult to tell what's going on. Best thing to do is get down and dirty and actually check everything. We can sit here and discuss it all day long, but you'll only find a problem by getting in there and methodically eliminating the possibilities. Compression should not be terribly far off even for a fresh motor. It's not like brand new cars at the dealer lot aren't making close to it's rated HP when you test drive it. Normal compression should be at 179 psi with a minimum of 151. 90 is really low even for a new cold motor. You can always test if this is a problem by pouring a little bit of lightweight oil into the spark plug hole to see if it bumps up compression.

I's say it's a relatively easy process to check cam timing. Simply remove the valve cover and inspect it.

AS far as Edub's post, he was referring to using a thin wire to check the piston position. As you turn the crank by hand, you can watch the wire or whatever long thin object you choose and see when the piston hits TDC. Make sure the wire is long enough and stiff enough that it doesn't fall in.

[Chezedik]

I would probably use an extension. But what should I be looking for on a cold motor with the rings unset, and where should the lobes be (roughly in degrees). I know the valves should be shut, but where should they sit. I have trusted your judgement in the past, and I could use your help. I don't mind getting down and dirty, but advice never hurt. This is, afterall, my first re-ring (sort-of). I put oil in once and got 240psi, but I may have used too much oil. I hate to keep bugging you, but I have never driven this car, and I need to know what to do next. I am about 10 min away from just buying a used engine. Please help.

[Edub1]

You know the valve sequence - just watch them as you crank. When the intake valve closes 100%, and the exhaust valves are closed, the piston should start to move up (compression). This is when you feel for piston position with the wire. Turn motor a bit at a time and keep feeling for TDC with the wire. When you get there all valves should be closed and remain closed untill BDC when the exhaust valves should be starting to open - then you will watch the valves through the exhaust stroke.

Just think about the engine cycle and it will start to make sense. If the all valves are not 100% shut when the piston starts to move up (durring compression stroke) you might have found your problem.

Say the piston has moved up 1/4 of its stroke before all valves are 100% closed. This accounts for low compression doesn't it?

So too, the exhaust valves need to open at the begining of the exhaust stroke. Just think of the sequence while you crank & feel.

While you are doing this, take note of where the ditributor rotor is. At TDC, it should be 15 degrees passed the #1 pick up. This should be easy to measure on a protractor.

Again, this will only get you into the neighborhood. BTW, You only need to do this on #1 piston. All the others will be likewise.

Whatever you do, don't panic. You might try the Nissan Mechanic forum or parish the thought, finding a local mechanic and biting the bullet.

Good luck...

[Chezedik]

Whatever you do, don't panic. You might try the Nissan Mechanic forum or parish the thought, finding a local mechanic and biting the bullet.

NEVER!!!! j/k

[slipnfall]

I have found the Jim Wolf cam install instructions to be the most helpful when dealing with the timing chain. Basically set the #1 to TDC(by either the crank pulled or the wire/extension method), then install cams so cyl 1 lobes are pointing away from each other. The exhaust actually positions to about 2:30, and the intake around 9:30.

FWIW, I re-shimmed my valve buckets last weekend: the markings on the sprockets and chain will *likely not be lined up*. Because of the cam/idler gear ratio, the colored links on the chain will move with respect to the cam gear markings. The only way to line them up is to rotate the crank a good many times.

http://jimwolftechnology.com/w...E.PDF

[Chezedik]

Thank you, that is exactly what I needed. I will check that out. So are we all in concensus that this is likely my problem?

[slipnfall]

After I finished my rebuild I couldn't get it to start, and it was a timing issue. I was off a tooth on the distrib, but it would sooorta fire... I didn't have the header off like you do, but I could hear the firing[inside the exhaust/mani] from the tailpipe of my exhaust. After I fixed my timing it fired right up.

[Edub1]

Not necessarily, but you can certainly rule out cam timing this way. Go to Wallgreens and get a protractor and measure the angle of your distributor rotor as well. If your timing is 15 BTDC, the rotar will have passed the #1 pickup by 15 degrees when at TDC. Kill two birds with one stone.

[Chezedik]

I will probably do that on Wed, after class since I am off. School keeps me busy!

[Chezedik]

I thought of something this morning... How if one of the cams is off, how do I tell which one. I know that they must be in relation to each other, but one must be the prob.Since I am not backfiring, but I am throwing fire, does anyone think that means I should turn the exhaust cam a little? And should I advance or retard it?

[Iamjohnhayes]

i know its a little late to say this but you hould not be firing an engine with no exhaust manifold. no brackpressure is not good for an engine. plus a friend told me it can possibly bend vavles if you keep it up. just something to keep in mind.

[slipnfall]

It's pretty easy to tell if you're off on the timing chain: the lobes will be way off from that picture above(with cyl1 at TDC). That's 1/2 the picture: now with the valve cover off(best to be sure your cams are in the right position), set your distributor. For reference, the [distrib] cap can only go on two ways(180* off). The breather on the cap should be 'upwards'. Then with cap off, install the distibutor. Place the cap over top and make sure it's close to smack-in-the-middle of the cylinder 1 plug connection.

HTH, still sounds like timing is off.Jamie

[Edub1]

Your cams should look just like the picture.

I was going to mention about running with no manifold. What can happen is cold air rushing in against a hot valve. This can crack the valve. I think you'll be ok just firing it up for a second though.

[Chezedik]

Well, I have never got it fired up. Also, I think the issue is that no backpressure can cause the valves to slam shut, and bend by falling improperly on their seats. But my deal was just a test. I still think it is fine, but I agree with you all. I will not be doing it again until I get my new mani.

[Chezedik]

Okay, here is the new story. I changed my cam timing two times, and each time the numbers got higher. The first, I got 115 and 150 wet. So I opted to try another change. This one still wet from the time before and I pulled 180! Now, I don't know if I am out of the woods yet. This seems a little high for a motor that has not been broken in. But the cyl was wet. And so I am asking, does this sound about right?

[Edub1]

I'm confused. You have a diagram of where the cam lobes should be. I would think that would make your cam timing a moot point. Am I missing something?