Possible mechanical problems?

[S10xGN]

Hi all,

Man, I'm completely and totally lost - everything I ever thought I knew about engines over the past 30 years must have disappeared on a major brain f@rt.

As some of you know, I cannot get my engine to start: No start thread so now I'm thinking, could it actually be a mechanical problem? I have fuel and spark, but no start. The spark tester was set at 20kv - about 1/4" gap - the spark was there, but kinda puny in my opinion. I did a compression check and have (decent) compression.

So if I have a good compression check, could there be any other mechanical problem(s) causing my grief?

TIA,

 

[REDS HOT AIR]

are you saying it will only jump fire 1/4 inch??

heck mine will jump a good 3-4 inches

 

[Joe 1320]

A few things that come to mind.....

Cam sensor set incorrectly
Not enough spark energy
timing chain jumped a tooth
incorrect fuel mixture

 

[Buick T]

here's a crank sensor pic, gotta be cam or crank sensor, or timing off a tooth or two or thee...

http://www.engraver1.com/pics/cranksensor.jpg

 

[S10xGN]

are you saying it will only jump fire 1/4 inch?? heck mine will jump a good 3-4 inches

Only? I don't know, as I set the plug tool for 20kv, which is about 1/4" or so. It *may* jump a longer gap, I figured 1/4" would be plenty. I can try a longer gap if you feel it would help...

A few things that come to mind.....

Cam sensor set incorrectly
Not enough spark energy
timing chain jumped a tooth
incorrect fuel mixture

Cam sensor has been set correctly (several times) and even rotated a few degrees either way while the engine was cranked.
Don't really know "how much" spark energy is required, do you?
Timing chain has been checked and found to be spot on.
I've now tried the MSD 50#'s with chips from 2 different people, and the stock injectors and chip combo - same scenario.
None of it made any change...

here's a crank sensor pic, gotta be cam or crank sensor, or timing off a tooth or two or thee...

<LOL> I still can't see the crank sensor in that pic - too much oil! Mine is in the groove furthest from the electrical terminal - if I were to use the closest groove, the end of the sensor would touch the crank balancer and there wouldn't be enough of the sensor left in the bracket for the clamp bolt to "pinch" on.

Timing marks are lined up. I "degreed in" the cam on initial installation, and just removed the gears to do an oiling mod WITHOUT moving either the crank or the cam. Naturally, the gears went back on A-OK, and the marks were lined up.

I may try a different battery tomorrow, as some folks here have great disdain for the Optima (in fact, my current red-top is a replacement for one that went dead after a month of sitting).

Thanks!

 

[REDS HOT AIR]

for fir test i just pull the wires off the coil pack and you should get fire jumping down to the bolts holding the coilpack to the module..looks like a little lightning show..

 

[SubZero350]

To get back to the basics, pull out all the plugs and make sure they are clean and dry. Put them back in if you are sure they are good. Next, disconnect power to your fuel injectors, (i.e. unplug them). Now spray some starting fluid, and I mean actual starting fluid, into the engine and crank. If it doesn't even seem to want to fire, you are almost guaranteed to have a mechanical problem. Starting fluid is so volitile that even the weakest spark should set it off. If it fires, I would think you have bad gas. Just a thought.

 

[S10xGN]

Well, today we tried a new crank sensor and coilpack/module with no change. Then pulled the battery from my son's MCSS and tried it - still no start.

I didn't think about the gas... it was about 9 months old, but I just put 10 gals of fresh 93 Chevron in it last week. Anyways, it's too late now, as we started pulling the motor down to long-block form today.

If it looks like the cam is snafu (most likely), I'll prolly be looking for a flat tappet hydraulic to put back in. The roller is just too complicated for me (I believe I can trace ALL of my problems to the roller cam). If I can't even pull the timing set off it without screwing up the timing, I don't want it!

So if my heads flow 205/176 @ 0.500" lift, what should I use for a flat tappet hydraulic?

Thanks!

 

[dpok69]

Gas thats 9 months old?.....Thats bad news.

My lawn mower did not start after sitting a while with old gas. I changed the gas and then if immediately fired up on the first pull. Not to say that a lawn mower is a GN

 

[SubZero350]

Oh, i see you have fallen victom to the roller cam-in-gn motor fiasco. I have heard many bad things about these roller cams for you guys. Why can't aftermarket manufacturers use steel billet cores like OEM roller's?

 

[S10xGN]

Oh, i see you have fallen victom to the roller cam-in-gn motor fiasco. I have heard many bad things about these roller cams for you guys. Why can't aftermarket manufacturers use steel billet cores like OEM roller's?

Speaking of that, I talked to Tim Cole at Comp Cams today. He told me last year (June, when I bought the odd-fire nosed billet roller) that Comp should have a true even-fire billet roller out some time around Feb of this year. He went on to say they were having some problems with the cam bolts that delayed the cam until at least mid-summer.

We talked some about the problems I'm having with the odd-fire nosed cam. He said "you do realize the cam is 180° out when the dots are lined up?" I got a chill when he said that because it seems I do remember hearing that once, but I've just spent 30 minutes looking through all my on-line sources (along with the factory manual) and cannot find any reference to it. Everything I can find indicates that with the dots lined up, the motor is on #1 cyl TDC firing stroke. Remember, I didn't move the cam or crank and the motor was running before... So, what exactly is CORRECT?

 

[fly89gta]

wouldn't a bad coolant temp sensor sometimes not allow a car to start?