Vortec Test

[FreeBeeTony]

Re: Vortec Test

backfire is gone........only did it a fwe times first time out.....<br /><br />going to take compression numbers this week and try to get a set-up for a leak down test.

 

[rodbolt]

Re: Vortec Test

get the leakdown numbers. think of that motor as 8 little motors with a common crank.

 

[FreeBeeTony]

Re: Vortec Test

I can get my hands on a compression gauge, not to sure about the leakdown equipment. Can I put the leakdown set-up together myself?<br /><br />I just rechecked the timing: 8* BTDC.<br /><br />By myself on the boat I was able to get to about 3400RPM before the miss occurs.<br /><br />If the timing chain did jump a tooth, would the vacuum readings be normal at idle?

 

[Don S]

Re: Vortec Test

You're not off a tooth on timing or your engine would run rougher than S#%@ at low speed also.<br />There is more to timing than initial timing, like I asked (and never got answered last year) are you getting the correct advance.<br />As far as the leakdown tester. Read this.<br /> http://vmaxoutlaw.com/tech/leakdown_tester.htm

 

[RubberFrog]

Re: Vortec Test

Have you inspected the distributor? Have you checked the advance mechanism?

 

[lilmandavis]

Re: Vortec Test

its a sticky valve or the valve seat buddie!!

 

[FreeBeeTony]

Re: Vortec Test

I did check the advance. I put a piece of tape on the vibration damper and it was defintely advancing. And like I said I tried another ignition module with no change.<br /><br />I will look for a leakdown tester. Would a portable air tank work?

 

[tommays]

Re: Vortec Test

the portable tank would be to small i could lend you a hand held 1 Hp if the guys think its enough<br /><br />I am in amityville everyday <br /><br /><br />tommays

 

[FreeBeeTony]

Re: Vortec Test

tommays, you mean a handheld 1hp compressor?<br /><br />That would be great. I will let you know when I get a leakdown tester.<br /><br />Thanks alot. Have you ever done this test before?<br /><br />Also, do you know of a good mechainic in our area?<br /><br />I am in Babylon.

 

[tommays]

Re: Vortec Test

Ya i lot a lot of motor head friends BUT there all car guys and most of us have been fixing machinery instead of motors for so LONG its distant memory at this point<br /><br /><br />tommays

 

[paulie0735]

Re: Vortec Test

Tony, a couple of questions if I may; <br />1) Does the engine start and idle as it should?<br />2) Other than the heads, what else have you changed to do this conversion and from where did you source the parts

 

[FreeBeeTony]

Re: Vortec Test

1) Starts at the click of the key and idles smooth.<br />2) Changed the heads and intake manifold. Heads are new from GM.

 

[KaGee]

Re: Vortec Test

I'm inquiring here for my own knowledge... valve adjustment on Vortec heads is fixed, correct? i.e. you torque the rocker nut down to spec and thats it, unlike pre-Vortec, where you tighten until the pushrod has no play and then add another turn on the nut?<br /><br />Just wondering Tony, about your valve adjustment??

 

[coalbucket]

Re: Vortec Test

The Vortec heads compared to what you original heads will require less total advancement due to the fast burn design of the cylinder heads........I know this from dealing with them on hot street/strip engines.

 

[John_S]

Re: Vortec Test

Tony,<br /><br />How do your plugs look? Anything unique looking with #2 ? Completing the compression/leakdown, and then systematicly going through Don's list should be done. Some of them, can be prioritized, based on some of the prior work done, but can't be eliminated, since it is not guranteed that this is not part of the new changes. Could be same symptom, but different cause. <br /><br /><br />

Exhaust is not restricted.

I assumed, since you had water injestion evidence, that you changed exhaust manifolds, but it wasn't on the list. I do remember a recent thread where you talked about a ticking noise, near the back of the engine. Are you sure that the exhaust flappers are in place, and none have fallen down in the Y-tube, etc? I have seen a number of pictures where this has happened. A partial restriction would be hard to detect at idle.

 

[FreeBeeTony]

Re: Vortec Test

Thanks for all the inputs............<br /><br />Valve adjustment is the same as pre-Vortec.<br /><br />Exhaust Flappers are in-tack. I checked them when I had the engine out.<br /><br />1) Bottom is freshly painted and clean.<br />2) Outdrive ratio is 1.5:1.<br />3) Checked fuel pressure last year and it was fine, even replaced the pump. Even ran it off a seperate tank to eliminate bad fuel or a restriction.<br />4) Oil is clean and at the correct level.<br />5) Removed the flame arrestor with no affect.<br />6) Throttle plates and secondaries open fully. <br />7) Dist. cap, rotor, sensor, coil, plugs and wires were replaced.<br /><br />I don't think I forgot anything.

 

[searay3]

Re: Vortec Test

I think Rodbolt is on the right track. Runs good to the mid rpm range and falls off. With the new heads and other life support, the carb needs tuned. If you had vacuum issues, timing chain, etc, it wouldn't idle at the proper rpm. See what the plugs look like after you put the full load on her. That's full load and then shutdown. Do not idle back to the dock. Something else to try...have a partner at the helm and with the carb uncovered, close the choke a little and see if it picks up. If it does, your running lean...

 

[paulie0735]

Re: Vortec Test

Tony, a couple more,<br /><br />1) Did you find out why the water was being ingested into the engine in the first place?<br />2) Will the engine rev out without load on it?

 

[FreeBeeTony]

Re: Vortec Test

Thought the coolant was coming from a cracked head or bad head gasket. Did not see any coolant in the cylinder, assumed it was getting there by the condition of the top of the piston.<br /><br />Engine will rev w/o a load.

 

[lilmandavis]

Re: Vortec Test

try backing the rocker nut off a turn or two and see what happens there