skep419
5.9 Magnum 4 speed afficionado
kdadadadaudthdathada at the top of the rev
Wow, pretty easy to hear it there!
post 180 edited
that's a 10 hr drive, man!
I would still check the end play. Maybe the crank is just rattling back and forth at this point.
And I would still put ears on the oilpan.
Hey, I noticed you were driving the car for this test,lol. Does it not do this in neutral?
--------------------------I bought a new 1969 440 4 speed coronet rt back in the day. It made the same noise, turned out to be the heat riser , I wired it open and the noise quit.??????????Well if it was a manual trans, I would have a better answer for you, but hmmmmmm. Ima guessing you looked for an exhaust leak already,so I'm kinda out of ideas.
It almost sounds like it's too slow to be crank-related, and it seems not to be in sync with the rpm in each gear. If it was crank related, we should be hearing it slow down to 59% on the 1-2 shift. Say from 4000 to 2400.
And too seems to be too fast to be in sync with the driveshaft.
So that just leaves the cam,which turns at half engine speed; so it would slow down from 2000 to 1180, on a 4000rpm upshift into second. Yeah that kindof sounds right.
Or maybe a header leak? which if just one port was leaking,would be at same as cam speed.
But man that is so sensitive to the gas pedal; have you got power brakes?And do they work properly? Have you tried disconnecting the Vcan?(I'm thinking diaphragm flutter, or not dropping out fast enough). What's your timing at the test rpm, say 2200? with and without the Vcan.
One thing I have noticed is that your carb is not responding properly to gas pedal inputs; almost like it's running very rich, at the test rpm and conditions.Yet it has a hesitation when slammed open,indicating lean on the accelerator pump.I'm trying to tie all that together, but it's not coming to me.......yet. Nice sounding mufflers tho, mine just scream when I get on it (Dynomaxers).
What carb?
So back to being at cam-speed......It doesn't sound like rocker arms,or valve train,and you said,IIRC, that it seemed to be coming from deep down in #8. So what's down there? Windage tray,oil pick-up,dipstick,collector,Tunnel pinchweld. What else? Pan evacuators?
oh.......trans dipstick tube. You got that secured?
Well if it was a manual trans, I would have a better answer for you, but hmmmmmm. Ima guessing you looked for an exhaust leak already,so I'm kinda out of ideas.
It almost sounds like it's too slow to be crank-related, and it seems not to be in sync with the rpm in each gear. If it was crank related, we should be hearing it slow down to 59% on the 1-2 shift. Say from 4000 to 2400.
And too seems to be too fast to be in sync with the driveshaft.
So that just leaves the cam,which turns at half engine speed; so it would slow down from 2000 to 1180, on a 4000rpm upshift into second. Yeah that kindof sounds right.
Or maybe a header leak? which if just one port was leaking,would be at same as cam speed.
But man that is so sensitive to the gas pedal; have you got power brakes?And do they work properly? Have you tried disconnecting the Vcan?(I'm thinking diaphragm flutter, or not dropping out fast enough). What's your timing at the test rpm, say 2200? with and without the Vcan.
One thing I have noticed is that your carb is not responding properly to gas pedal inputs; almost like it's running very rich, at the test rpm and conditions.Yet it has a hesitation when slammed open,indicating lean on the accelerator pump.I'm trying to tie all that together, but it's not coming to me.......yet. Nice sounding mufflers tho, mine just scream when I get on it (Dynomaxers).
What carb?
So back to being at cam-speed......It doesn't sound like rocker arms,or valve train,and you said,IIRC, that it seemed to be coming from deep down in #8. So what's down there? Windage tray,oil pick-up,dipstick,collector,Tunnel pinchweld. What else? Pan evacuators?
oh.......trans dipstick tube. You got that secured?
The last time I heard noise like that (3 cyl two stroke outboard mercury) it turned out to be piston slap. At idle was quite off idle at about 1500 on up accelerating could here it no problom. Also could here it decelerating until back at idle again. I figured it was #1 due to scoffed piston (oil injection failed) even with new piston & rings at TDC I could rock the piston with an all or screwdriver back & forth alot! & if I did it fast enough could almost duplicate the noise. #2 & 3 were notably tighter in there bores. Id make sense because it would make a "rattle" every time that offending cylinder would fire making p.s.I. spike rocking itIin its bore. Is it any worse cold or hot?
Yeah marine pistons are pretty sloppy in the holes,lol. The first time I ever took an outboard engine apart, I was very surprised that so much could be normal. Old air-cooled sled engines were set sloppy-loose too. And I have heard that certain aircraft engines were also pretty loose.No power brakes
I have another set of header gaskets I could try. You're going too fast; that's a lotta work to just try. I'd wanna prove it first.
Vac can is disconnected.That is part of the response problem. tip-in will be much smoother if you reconnect it.
Will have to get back to you on the timing. 15 initial 32 all in.Very good
Carb is a holley 750 street hp.4 corner idle screws. All just over 1/2 turn out. My combo with the 223/230/110 cam,very similar to yours,right? did not require any idle air bypass with 14* of idle timing, and consequently no idle-fuel in the secondaries.
A half turn on the front mixture screws means the T-port sync is pretty close.
I think your automatic could run a bit more idle-timing and that might/should help with the tip-in response. Unless it fudges the T-port sync too much.
Have you already tried it with;say 16 to 18* of idle timing, the secondaries closed up tight, the front screws at 3/4 to 1 turn out,and the Vcan hooked up? If yes, how was that? If no, that's what I would work towards and see if the tip-in improves. Then I would try to bring the PV in a little sooner. And finally I would work on the pump-shot.
Where does your TC stall at?
I would agree with the rich.In the long-run, not so good
No windage tray, Kevko 5qt pan, OK
Trans dipstick is tight (locking). No, I meant the tube;is it secured to the block at one of the bellhouse bolts, so it cannot rattle?
Ok then
Make sure the Vcan is hooked to the sparkport. With good combustion chambers, tight Squish, and/or aluminum heads; detonation will not be an issue. The Vcan will only work at part throttle, and will vary the timing according to the throttle opening. The harder you step on it the more timing will drop out, and it absolutely cannot work at WOT. At a cruising RPM of 2200, the timing will be fine with a minimum of 40/45* to a maximum of 55/60*, TOTAL. That's initial, plus centrifugal, plus Vcan. he crappy your chamber, the more it will like. The more your engine accepts, the leaner you can run it. Pretty soon you will be getting fuel mileage in the hi 20s. Ok; maybe not you, but I did,... with a double overdrive pulling like 1550rpm@65mph. That was a final drive of just under 2.0
Ok since you asked about idle-air bypass;
This is air you might need to introduce into the low speed circuit, to satisfy the engines craving for air,while maintaining the T-port sync.Click on the little blue M in my sig for a better understanding.
This air has to be introduced near to where the transfer ports are, so that it has time to mix with the A/F charge entering there, and be fully homogenized by the time it gets into the chamber.
The bigger the cam, the more bypass air it will want. My HE2430AL did not require any bypass air. So yes, closing up the secondaries tight but not sticking should reduce the rear idle fuel to zero.
If you advance the idle-timing, the idle speed will go up. The first response is to back out the curb idle screw. But doing that will lower the throttle blades on the transfer slot and that will reduce the fuel being delivered there. So then the next idea would be to increase the mixture screw opening so she will idle again. And that works. At idle. But as soon as you step on it, the beast goes lean, and she hesitates, maybe even stumbles; until the transfers come back on line. Sound familiar?
So, the transfer slots have a minimum operating relationship with the throttle blades. If a decent idle speed, and tip-in cannot be obtained at this minimum setting, then we have to figure out how otherwise to make it happen. This is where idle-timing and bypass-air come into play.
thanks
the spark port does nothing when hooked up to vacuum advance. (checking timing while reving in park) That would be normal. The sparkport requires the throttle blade to be in close proximity to it, and to remain there for a bit of time, as in running at part throttle or cruising. Blipping the throttle does nothing to encourage a timing change. And running the rpm up slowly might take a no-load rpm of over 4000 to get things synced up.
Ill try it on my lunch break. unless there is something else brought up to check about the noise.
No! That would just give you a snapshot of the Vcan's maximum capability at it's current adjustment, in conjunction with the centrifugal advance. This snapshot could endure for a limited rpm span, right around a cruising speed of *** which varies with the gear that you are in, cuz the signal at the sparkport also varies with the load. This advance can vary according to the can's design, and to the amount of signal, and to it's adjustment. One could call it a very sophisticated device. At any given moment, it could be contributing from no advance to whatever it's rated maximum is. They are available with various specs and I have seen from a minimum of 9 degrees to a maximum of 22 degrees. So if you are cruising at 2200 and your vacuum is sufficient to pull the can to it's maximum, then you could be cruising with as little total all-source advance of say 14* on a seized system(idle timing), to 55* on a well executed system. And the engine will love somewhere between 45 and that 55, depending on its design and chamber efficiency, and the environment in which it is operating.So you verify the timing using manifold vacuum port than just hook it up to ported and test drive?