Timing?

[beanhead]

Okeedokee. Working on getting my freshly rebuilt 440 dialed in and the timing seems weird..at idle the rpms and vacuum don't start to level out until I get to around 35 degrees? The engine is now .060 over, compression is a hair less than 9.5-1 (it was about 8.8 before) cam is 231/237 @ .050 with .526 lift and it degreed in at 106.5..same 850 demon carb and RPM heads as before although the heads were milled .030. Before the rehab it liked 20-22 initial. I know it's a a bit different animal now, but I don't understand why it wants so much timing at idle. If I have it in the high teens or low 20s it runs a little bit rough and hotter than it should, it runs like the timing's too far retarded. Wires and firing order correct. I had the number one at true TDC when I put the distributor in and the rotor pointed to number one like it's supposed to. Maybe I need to run it with manifold vacuum advance now? I'm not getting why it wants so much more timing with increased compression I would have thought it would be the other way around. Thanks for any ideas!

 

[5.7 hemi]

Is the 35 initial?

 

[beanhead]

Is the 35 initial?

Yep! I drove it a little with it at 22 but it wants more. I don't want to load the engine with it advanced to 30+ at idle as I have the distributor set for 14 degrees of mechanical advance, but all that initial seems to be the only way that it runs well.

 

[oldbee]

Here we go, what kind of gas? I hate this new stuff.

 

[beanhead]

Here we go, what kind of gas? I hate this new stuff.

Same crap I been using for 2 years... would gas make that much of a difference if it was the same grade and octane?

 

[MoparLeo]

As with any diagnostics, Don't assume anything and start from scratch. Verify TDC and reset distributor to #1. Even if you say you didn't change anything. Step by step, one change at a time. Fresh fuel. Remove and recheck plugs. Proper number ? or did you change to something else ?

 

[beanhead]

I will re-do the basics just to be sure. Reset to TDC and start over and go from there. Just bugs me...I thought maybe the position of the oil drive gear? But that shouldn't matter. It would cause the cap to end up at a different spot but it wouldn't affect the balancer degree at which the idle cleans up if the wires are going to the correct cylinders. Oh, it's the 440 source balancer btw, which if I recall isn't able to 'spin' like the factory ones. (Fluidampr style)

 

[beanhead]

I just verified the light is good too...used a spare and got the same reading. It wouldn't be that easy anyway!

 

[cryplydog]

same cam or different? 106.5*

 

[beanhead]

same cam or different? 106.5*

Old cam was the comp xe274, very close to the same specs except for the lift. Unfortunately I don't know where the cam timing was, it was in the engine when I got it. When the builder disassembled it he told me he found it to be retarded but for the life of me I can't remember what it was..

 

[furryfrog]

My car idles at 30 degrees. I'm using a msd 6530 (programmable box)with a locked out distributor but essentially my initial would be 20 at idle and I'm adding 10 degrees advance because of vacume, so I advance timing at idle, it does run better, my vacume is 20-21 inches at idle, summit k6401 cam, 224/234 @.050, using rhoades lifters.

 

[Don Frelier]

Do you know for sure that the balancer mark is at 0 degrees?

 

[beanhead]

Do you know for sure that the balancer mark is at 0 degrees?

When the engine was out I did find it to be one mark off zero, so true TDC actually reads at 2°...not to shabby for an aftermarket piece! Even being that close, I take it into account.

 

[Cranky]

Know what your cranking PSI is? And if you haven't checked true TDC or know exactly where your cam is degreed, it's a crap shoot. If your PSI is low, it might like a lot of initial and total. Wouldn't be the first time I've seen it....

 

[beanhead]

Know what your cranking PSI is? And if you haven't checked true TDC or know exactly where your cam is degreed, it's a crap shoot. If your PSI is low, it might like a lot of initial and total. Wouldn't be the first time I've seen it....

Haven't checked the cranking PSI yet as I'm still tracking the engine's life by hours and not miles lol..I did verify TDC and the cam was degreed. Static ratio should be just about 9.5 or maybe a hair less, didn't CC every single chamber..
Pistons .060 below deck with 5.6cc notches, 79cc chamber aluminum heads, a .039 gasket. Block is .060 over. Intake valve closes at 61 or 62 abdc if I recall.

 

[beanhead]

Got some time before the kids ballgame so I'm going to pull the distributor out and check it as best I can for any trauma I might have caused it when it was out. There were some late nights in the garage so anything's possible...maybe I fudged it up somehow. If this new amount of timing is simply what the engine wants now, that's fine I can adjust, but it just seems 'not right' to me..I want to rule out any badness first.

 

[Cranky]

Haven't checked the cranking PSI yet as I'm still tracking the engine's life by hours and not miles lol..I did verify TDC and the cam was degreed. Static ratio should be just about 9.5 or maybe a hair less, didn't CC every single chamber..
Pistons .060 below deck with 5.6cc notches, 79cc chamber aluminum heads, a .039 gasket. Block is .060 over. Intake valve closes at 61 or 62 abdc if I recall.

Yup....getting 9.48 according to http://www.wallaceracing.com/cr_test2.php
I understand Wallace is a pretty decent calculator but knowing cranking PSI helps. Couple of engines I've worked with in the 8-1 range (and lower) liked a lot of timing which is usually the case unless it has an RV type cam in it. Those things have a really late intake opening event and raises cranking PSI making a low compression engine 'think' it has more. Not a bad thing in low CR engines but performance cams usually lower cranking PSI a bit......

 

[PRHeads]

I’d like to know what the warm cranking pressure is along with manifold vacuum with the timing at something normal-ish....... like 22-25*.

How many turns out are the mixture screws for highest vacuum reading with normal timing?

4 corner idle, right?

Front and rear blades open equally?

All 4 mixture screws set the same?

All 4 mixture screws affect idle speed?

Any idea what the lifter preload is?

“Normal” stock type lifters?

 

[5.7 hemi]

Since we are asking all the pertinent information, I’ll need your SS number as well. You can send that in a pm, lol!!

What is the springs set in the distributor, light or heavy?

 

[beanhead]

I’d like to know what the warm cranking pressure is along with manifold vacuum with the timing at something normal-ish....... like 22-25*.

How many turns out are the mixture screws for highest vacuum reading with normal timing?

4 corner idle, right?

Front and rear blades open equally?

All 4 mixture screws set the same?

All 4 mixture screws affect idle speed?

Any idea what the lifter preload is?

“Normal” stock type lifters?

Thanks! OK, 7/8 turn out on all four corners. They do have an effect.
Set it at 22°. Only enough time to check two cylinders, #8 and #7 both registered 152psi.
11 in. of vacuum (this is somewhat questionable, my gauge apparently starts at 3 now, not zero..it moves when it should
though and it read 14 so I'm calling that 11..)
This was at 800 rpm in neutral, not in gear.
I have standard hyd. comp lifters, new w/ the new cam, nitrided and broke in with inner springs removed.
Adjustable rockers set at roughly .040 preload.
The A/F meter bounces around between 13.5-14 also.
*Note* I blipped the throttle right before shutting down and it popped through the carb and died, if that means anything..

And she's shakin' like a dog poopin peach pits!!