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Cam break in is done, time to tune. ** Uh-OH !!! #1492824
08/30/13 01:05 AM
08/30/13 01:05 AM
Joined: Feb 2010
Posts: 15,920
Granite Bay CA
Frankenduster Offline OP
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Frankenduster  Offline OP
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The Lunati cam swap is complete and the break-in is done.
I will admit that this has been a bit of a nerve wracking job. I have dragged my feet through most of it because much has been just a smidge outside of my experience. This is my first solid lifter cam and my first time degreeing one. I read everything everyone wrote in all of the posts I have put up. I read the Mopar Action magazine article on "First Fire" in this months issue. I didn't want to be in the position where I skipped a crucial step that led to another cam failure.
The engine started up within 2 seconds. Jeff ( My brother-in-law) brought it up to 2600 rpms and held it there. There were no leaks anywhere which was nice to see. The exhaust note from the back sounded great and actually smelled cleaner than before. I changed the jets yesterday from 85/92 to 86/93 and the power valve from a 3.5 to a 6.5 unit. The engine didn't make much of a "clack" noise like I expected from a mechanical cam, but it sounded great. oil pressure was at 80 cold, dropping to 58-60 when up to temp. Fuel pressure was between 7-8 lbs.
At the 15 minute mark, the fuel pressure dropped fast to about 3 lbs. The engine started to stumble. The fuel filter was almost dry. I had jeff shut it down. We let it cool for 2 1/2 hours and got back to it.
During the second run, as before it ran great and smelled clean, but at 10 minutes the fuel pressure dropped again, requiring shutdown. The pump is a Holley mechanical, part # 12-440-11 rated at 110 GPH. The pushrod is the same length as others I had here... I checked before reassembly.
This pump has been fine before. I've driven at freeway speeds, 2600-3000 rpms and haven't had a fuel starvation problem before. At idle it stays between 7-8 lbs. The lines are not kinked and the clamps are tight.
The cam sounds nice at idle, but not as radical as I had expected. To refresh, it is a Lunati Solid 316/326 with 261* intake 271* exhaust with .558 INT .578 lift on a 106 C/L. I didn't get to drive the car because I am curious about whether the fuel pump will be a problem or not. Here come the questions:

* Is it possible that the bigger cam pulls more fuel to the point where I need a higher rated pump?
* Has anyone here had a similar fuel starvation problem during a break-in process?
* If so, do you have a suggestion for a reliable mechanical pump?
Thanks everyone. I may take it out for a drive tomorrow anyhow. I won't be driving at 3000 rpms for 15 minutes straight, so I hope that it doesn't conk out on me!

Last edited by Frankenduster; 09/05/13 05:04 PM.
Re: Cam break in is done!....Now more questions! [Re: Frankenduster] #1492825
08/30/13 04:01 AM
08/30/13 04:01 AM
Joined: Aug 2003
Posts: 12,291
Kent, Wa
340SHORTY Offline
Truck Nut
340SHORTY  Offline
Truck Nut

Joined: Aug 2003
Posts: 12,291
Kent, Wa
Hard to believe it smelled cleaner with larger jets.

Possibly the sock in the tank is clogging up..

Did you have good airflow to possibly prevent vapor lock.

Cams dont set the requirements for fuel..


I am truckless..
Re: Cam break in is done!....Now more questions! [Re: 340SHORTY] #1492826
08/30/13 04:38 AM
08/30/13 04:38 AM
Joined: Feb 2010
Posts: 15,920
Granite Bay CA
Frankenduster Offline OP
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Frankenduster  Offline OP
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Granite Bay CA
Quote:

Hard to believe it smelled cleaner with larger jets.
Wouldn't a bigger cam require bigger jets just to stay equal in terms of A/F ratios?
Possibly the sock in the tank is clogging up..
Well, the tank and sending unit were new in 2003. I've never had anything but clean looking fuel go through the filter.
Did you have good airflow to possibly prevent vapor lock.
Good question. I had a cheap "Target" 20" box fan in front of the grille.
Cams dont set the requirements for fuel.. [/quote)




Hmmmmm......

Re: Cam break in is done!....Now more questions! [Re: Frankenduster] #1492827
08/30/13 09:18 AM
08/30/13 09:18 AM
Joined: Mar 2008
Posts: 5,741
Ontario, Canada
Dodgem Offline
master
Dodgem  Offline
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Ontario, Canada
the cam don't need bigger jets but 10% ethanol fuel requires 2 jet sizes
as ethanol fuel burns lean.

Sounds like a tank vent problem. Try running it with the gas cap off and if it does not run dry you are creating vacuum in the tank??

What car??

Re: Cam break in is done!....Now more questions! [Re: Frankenduster] #1492828
08/30/13 11:28 AM
08/30/13 11:28 AM
Joined: Jan 2003
Posts: 4,974
Pikes Peak Country
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TC@HP2 Offline
master
TC@HP2  Offline
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T

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Pikes Peak Country
Assuming you are sitting in the garage or driveway running it up for break in, are you getting enough airflow over everything? You could be heat soaking everything under the hood and boiling the fuel.

Re: Cam break in is done!....Now more questions! [Re: TC@HP2] #1492829
08/30/13 01:13 PM
08/30/13 01:13 PM
Joined: Nov 2004
Posts: 2,493
Oregon City, OR
Baxter61 Offline
top fuel
Baxter61  Offline
top fuel

Joined: Nov 2004
Posts: 2,493
Oregon City, OR
Are you sure its not just out of fuel?

Re: Cam break in is done!....Now more questions! [Re: Baxter61] #1492830
08/30/13 01:43 PM
08/30/13 01:43 PM
Joined: Jan 2003
Posts: 16,347
D
dogdays Offline
I Live Here
dogdays  Offline
I Live Here
D

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Vapor lock.
R.

Re: Cam break in is done!....Now more questions! [Re: TC@HP2] #1492831
08/30/13 03:13 PM
08/30/13 03:13 PM
Joined: Feb 2010
Posts: 15,920
Granite Bay CA
Frankenduster Offline OP
Moparts proctologist
Frankenduster  Offline OP
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Granite Bay CA
Quote:

Assuming you are sitting in the garage or driveway running it up for break in, are you getting enough airflow over everything? You could be heat soaking everything under the hood and boiling the fuel.




Last night during my sleep, I thought of this very thing.
It was 94 degrees during the break-in. The car does not have a fan shroud. The helper fan I had wasn't very big. The clear fuel filter showed bubbling as the guage reading was falling.
I might try rerouting the line from the pump to the carb. Mine is run in a path similar to stock. It runs up from the pump between the alternator bracket and water pump housing, between the distributor cap and water pump housing then into the filter.
Does anyone ever slip a rubber hose over their steel line to reduce heat soak?

Re: Cam break in is done!....Now more questions! [Re: Frankenduster] #1492832
08/30/13 07:24 PM
08/30/13 07:24 PM
Joined: Dec 2008
Posts: 2,780
USA
J5440 Offline
master
J5440  Offline
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USA
Are you using aluminum heads and intake? I had this problem before, solved it with a small carb spacer/insulator.

I don't think you can just slip a hose over it...it will still hold heat. What you want to do is displace the heat to aid in cooling, such as the use of fins in and air cooled engine. I don't think routing is the problem. What did your water temp reach?

Re: Cam break in is done!....Now more questions! [Re: dogdays] #1492833
08/30/13 10:07 PM
08/30/13 10:07 PM
Joined: Jul 2005
Posts: 1,933
Blairsden, CA
T
Triggerfish Offline
top fuel
Triggerfish  Offline
top fuel
T

Joined: Jul 2005
Posts: 1,933
Blairsden, CA
Quote:

Vapor lock.
R.



I agree. I bet the fuel is boiling after a few minutes with only
a box fan to cool the radiator. How close is your fuel line to the
lower radiator hose & the intake runners? My Hemi did the same
thing as the Shaker kept the heat right where it shouldn't be.. &
the fuel lines got too hot to touch. Krppy ethanol laced fuel here
is a problem. Factory vapor separator w/ return line solved the
problem. On my 71 Power Wagon's 383 mag, I ran the fuel line &
filter too close to the bottom radiator hose & the heater hoses as
well on the top of the block. Vapor lock left me stranded twice.
Re-routed the lines & shielded the filter. Huge difference in temp.
The heat shield blew off the filter & the temp rose seconds later.
Maybe heat is boiling your fuel after 10 minutes. Are you running a return line?

Re: Cam break in is done!....Now more questions! [Re: Triggerfish] #1492834
08/30/13 11:22 PM
08/30/13 11:22 PM
Joined: Feb 2010
Posts: 15,920
Granite Bay CA
Frankenduster Offline OP
Moparts proctologist
Frankenduster  Offline OP
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Granite Bay CA
The water temp guage read dead center, but I am not 100% sure of its accuracy. When out driving, it usually stayed left of center. Center looks to be about 170 degrees.


No return line on the carb. I'm starting to think I might need to install one.

Today I went for a drive. The timing was set to a "safe" 30 degrees total timing. It pinged on the first full throttle run, so I backed it off a few degrees. It still knocked, so I backed it off a 3rd time. Now it idled so low it stalled. I had to raise the idle by the set screw. It ran weird, really lazy from idle to 2500. At home I checked the total timing at 2900...20 degrees! The headers were glowing red too. Do you think the detonation could be caused by an excessively LEAN mixture? I just changed jets and the PV from 85/92 to 86/93 and from a 3.5 PV to a 6.5.
What the heck happened? Wouldn't a higher PV give a richer condition at part throttle?

I bought an AEM wideband guage kit last winter. I also had bungs welded into each collector. Maybe Sunday I'll install the guage and wire it. I had figured that there would be some tuning needed to optimize all of this.

Re: Cam break in is done!....Now more questions! [Re: Frankenduster] #1492835
08/31/13 03:01 AM
08/31/13 03:01 AM
Joined: Dec 2008
Posts: 2,780
USA
J5440 Offline
master
J5440  Offline
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Joined: Dec 2008
Posts: 2,780
USA
A lean mixture will burn hotter, and the more heat you introduce into the chamber the more volatile the fuel mixture becomes. Did you plug the vac advance when you checked the timing?

Re: Cam break in is done!....Now more questions! [Re: J5440] #1492836
08/31/13 04:28 AM
08/31/13 04:28 AM
Joined: Feb 2010
Posts: 15,920
Granite Bay CA
Frankenduster Offline OP
Moparts proctologist
Frankenduster  Offline OP
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Granite Bay CA
The vac avdance has been plugged for several months. I was trying different things to stop the detonation when I had the other cam in there.

Thinking about power valves: There appears to be several sizes and types. I see listings for Standard flow, High flow and 4 window. I put in a used 6.5 PV from a parts stash, but now I wonder if it is bad. Can a defective power valve open but not flow well?
Also, do Barry Grant Demon carbs use all the same bowl and metering block gaskets as Holley 4150 carbs? I know I'm reaching here but I'm trying to make sense of this. I used gaskets that came from the same stash as the power valve. They looked like all the various holes lined up with the old gaskets holes. I'm wondering if a passage is blocked off.

Last edited by Frankenduster; 08/31/13 05:18 AM.
Re: Cam break in is done!....Now more questions! [Re: Frankenduster] #1492837
08/31/13 10:11 AM
08/31/13 10:11 AM
Joined: Jan 2003
Posts: 5,210
Indiana
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YO7_A66 Offline
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YO7_A66  Offline
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Posts: 5,210
Indiana
""No return line on the carb. I'm starting to think I might need to install one.""
- With todays gas, this is almost a necessity with a street car.

""At the 15 minute mark, the fuel pressure dropped fast to about 3 lbs. The engine started to stumble. The fuel filter was almost dry.""
- It sure seems to be a fuel delivery issue. The existing pump may be big enough but maybe it has an issue.

""The car does not have a fan shroud.""
- Adding the shroud will help keep it cool once you get the fuel issue figured out.

If your headers are glowing red, and you have a fuel starvation/vapor lock issue, then the carb tuning at this time will not fix it. Concentrate on the fuel lines, fuel pump, fuel vent as mentioned.

-------------------------------------
""I bought an AEM wideband guage kit last winter. I also had bungs welded into each collector. Maybe Sunday I'll install the guage and wire it.""
- You will find that a wideband kit is an excellent tuning tool and carb-tuning learning tool. Once you have this installed, the tuning process should go smoother for you. You could then give us A/F numbers and since we are all on the other side of the keyboards from you, we can give you better suggestions on where to start if this is a carb problem during your tuning process.

""I see listings for Standard flow, High flow and 4 window.""
- What carb are you running? I would suggest using the style of PV that the carb manufacturer suggests. At 2600rpms, you should have enough vacuum to keep the PV closed.

Last edited by YO7_A66; 08/31/13 11:02 AM.
Re: Cam break in is done!....Now more questions! [Re: YO7_A66] #1492838
08/31/13 05:54 PM
08/31/13 05:54 PM
Joined: Jul 2007
Posts: 1,450
North Carolina
cjskotni Offline
pro stock
cjskotni  Offline
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Joined: Jul 2007
Posts: 1,450
North Carolina
A few comments I have so far from what I have read:

You are causing more issues by retarding the timing so far! You need to advance the base timing back to at least 10*. Having the timing so far retarded will cause the glowing headers and hot condition among other things. 10* is a good place to start but you will probably end up running 14-16* base for a total of 36* or so but get to at least 10*!

As mentioned previously, this sounds like a vapor lock issues. One thing you may check (if you haven't already) is will the car start again after it dies (fuel pressure drop)? If the issue were vapor lock, most likely the car would not restart until it cooled off or at least would be a bear to get going again.

I had an issue similar to yours last year into this past winter where my car would run for 10-15 minutes beautifully, and then idle down and cut off. It turned out it was a partially failed fuel pump! One of the delivery valves within had a chunk missing which would eventually cause the pump to cavitate and lose pressure...like a cutoff almost.

Also for the record, glowing headers is not necessarily from a lean condition, but can also be caused by an overly rich condition! Pull one of the spark plug wires and run the engine and watch that cylinder begin to glow! Not your issue here (yours is timing) but wanted to point that out.

I know you said you had pinging, but you need to pull that timing back up! Remember to re-adjust your idle screws on the carburetor once you do that. I am thinking the pinging is caused by/related to the fuel delivery issue you have and/or you have cruddy fuel...

Good luck!

Re: Cam break in is done!....Now more questions! [Re: cjskotni] #1492839
08/31/13 06:05 PM
08/31/13 06:05 PM
Joined: Jul 2007
Posts: 1,450
North Carolina
cjskotni Offline
pro stock
cjskotni  Offline
pro stock

Joined: Jul 2007
Posts: 1,450
North Carolina
Quote:

Thinking about power valves: There appears to be several sizes and types. I see listings for Standard flow, High flow and 4 window. I put in a used 6.5 PV from a parts stash, but now I wonder if it is bad. Can a defective power valve open but not flow well?




A mis-matched PV will usually result in a hesitation or stumble at part-throttle. Once you are at WOT, you will have lost enough vacuum where any PV will be open.

I highly doubt you have an engine that is pulling more fuel than a standard PV can deliver. If you want advice as to which one to use, you need to know what your idle vacuum is in gear. I had 6.5's in my 4150 but my engine responded better (crisper throttle response) from going to 8.5's. Let us know what your idle vacuum is in gear once you advance the timing back up!

Re: Cam break in is done!....Now more questions! [Re: cjskotni] #1492840
09/01/13 01:16 AM
09/01/13 01:16 AM
Joined: Feb 2010
Posts: 15,920
Granite Bay CA
Frankenduster Offline OP
Moparts proctologist
Frankenduster  Offline OP
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Granite Bay CA
Quote:

A few comments I have so far from what I have read:

You are causing more issues by retarding the timing so far! You need to advance the base timing back to at least 10*. Having the timing so far retarded will cause the glowing headers and hot condition among other things. 10* is a good place to start but you will probably end up running 14-16* base for a total of 36* or so but get to at least 10*!

As mentioned previously, this sounds like a vapor lock issues. One thing you may check (if you haven't already) is will the car start again after it dies (fuel pressure drop)? If the issue were vapor lock, most likely the car would not restart until it cooled off or at least would be a bear to get going again.


I know you said you had pinging, but you need to pull that timing back up! Remember to re-adjust your idle screws on the carburetor once you do that. I am thinking the pinging is caused by/related to the fuel delivery issue you have and/or you have cruddy fuel...

Good luck!




During yesterdays drive, I was retarding the timing as a means to see how far it needed to be backed off to stop full throttle detonation. I had no intention of keeping it at 20 degrees of total timing! I just wanted to get it home and get a timing light on it so I had a number to record.

It idled and cruised fine at 30 degrees total. It was only at 1/2 throttle and more that it made audible detonation.

Today I reset the timing to 33 degrees total and checked idle vacuum in gear....4 inches of vacuum? Really? This is with a 700 rpm in gear idle. I have not touched the idle mixture screws yet. Having the idle vacuum number lower than my power valve rating is obviously a problem.
I want to get the wideband guage in to have actual In my face evidence of what effect each change makes.
I have read the Mopar Action magazine articles on carburetor tuning. Rick suggests to jet the carb to achieve 14.7 A/F at cruise and 12.5 to 13.0 at WOT.

Re: Cam break in is done!....Now more questions! [Re: Frankenduster] #1492841
09/01/13 11:21 AM
09/01/13 11:21 AM
Joined: Jul 2007
Posts: 1,450
North Carolina
cjskotni Offline
pro stock
cjskotni  Offline
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Posts: 1,450
North Carolina
Quote:

During yesterdays drive, I was retarding the timing as a means to see how far it needed to be backed off to stop full throttle detonation. I had no intention of keeping it at 20 degrees of total timing! I just wanted to get it home and get a timing light on it so I had a number to record.




I'm sure you didn't want to keep it this way but I wanted to point out the retarded timing was most likely causing the glowing headers so you didn't chase your tail on that one. :-)

Quote:

It idled and cruised fine at 30 degrees total. It was only at 1/2 throttle and more that it made audible detonation.




What was the base timing when it goes to 33* total? What we need to know is how far (and when) does the dizzy advance. Most distributors will advance 20* or so from the base. The issues you have with low vacuum could be timing related...as in still not enough base timing but you are advancing too far it seems. What is the calculated compression ratio? What kind of heads?

Quote:


Today I reset the timing to 33 degrees total and checked idle vacuum in gear....4 inches of vacuum? Really? This is with a 700 rpm in gear idle. I have not touched the idle mixture screws yet. Having the idle vacuum number lower than my power valve rating is obviously a problem.




So two suggestions on the low vacuum here: I still think you need to give us you base timing here (as opposed to total). This engine probably wants 15-18* of base timing and will generate more vacuum with it. Once this is done, you should adjust the idle mixture screws for maximum vacuum. And yes, the vacuum being lower that the PV rating will potentially cause an overly rich condition. I wouldn't worry about that yet until we can achieve a better vacuum reading at idle.

It sounds like if you do advance the base timing like I suggest, your total will go too far and you detonate. We really need to know how far your dizzy is advancing. If you need to rein in the total timing there is a plate you can buy from FBO here part J685 . Other than that you will have to weld the slots to limit the advance.

Re: Cam break in is done!....Now more questions! [Re: cjskotni] #1492842
09/01/13 01:25 PM
09/01/13 01:25 PM
Joined: Feb 2010
Posts: 15,920
Granite Bay CA
Frankenduster Offline OP
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Frankenduster  Offline OP
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Granite Bay CA
Sorry if I left out some details. I had the distributor worked on in 2005 to have an advance curve limited to 14 degrees. 17 initial gave me 31 total. THAT was the setting I ran for 3 seasons with the '509 cam. Summertime I had to back it off 1 degree and stay out off the secondaries to avoid detonation. Heads are Edelbrock aluminum. 2" TTI headers. 10.73 compression. It had an average of 189 cranking compression with the '509 cam. The numbers should be lower with the Lunati cam I have now.
This new cam has a later intake closing so I expected to have less of a chance of detonation.
When I wrote 33 total, that adds up to 19 initial.

Re: Cam break in is done!....Now more questions! [Re: Frankenduster] #1492843
09/01/13 03:49 PM
09/01/13 03:49 PM
Joined: Jul 2007
Posts: 1,450
North Carolina
cjskotni Offline
pro stock
cjskotni  Offline
pro stock

Joined: Jul 2007
Posts: 1,450
North Carolina
Quote:

Sorry if I left out some details. I had the distributor worked on in 2005 to have an advance curve limited to 14 degrees. 17 initial gave me 31 total. THAT was the setting I ran for 3 seasons with the '509 cam. Summertime I had to back it off 1 degree and stay out off the secondaries to avoid detonation. Heads are Edelbrock aluminum. 2" TTI headers. 10.73 compression. It had an average of 189 cranking compression with the '509 cam. The numbers should be lower with the Lunati cam I have now.
This new cam has a later intake closing so I expected to have less of a chance of detonation.
When I wrote 33 total, that adds up to 19 initial.




You shouldn't be pinging with only 33 total timing. There is something else at play here because your logic with the cam is sound as the higher lift + duration should help bleed off some of the compression.

FWIW, my build is loosely similar to yours as I have a Holley 4150 on a 10.4:1 499 stroker, same heads and even the same fuel pump! The big difference between our builds is that I have much less cam then you as in 484 lift or so. My motor idles like a stocker and pulls 16" vacuum in gear. Even with my wimpy cam, my motor won't start to ping until I hit over 36-38* total timing (18-20* base)! I run my motor at 17* base right now -- the first limiting factor being hard cranking on the starter motor if I go beyond.

FWIW, I had my engine tuned on a chassis dyno and I settled on 82/88 jets with initially a 6.5 PV but going to 8.5 helped out a bit on throttle response. This was with o2 sensors and it gives a nice flat A/F right around 13:1 at WOT (4000-5500 RPM range)...closer to the 14.7 at lower RPM's. Keep in mind this is with a 499. If anything, I think you may be jetted a bit rich.

How is the gas there? I think you either have crud for fuel and/or you are battling an overheating condition to make your motor so temperamental with the pinging. Maybe that or a vacuum leak but you would probably be able to detect that pretty easily. I suppose you could always limit the distributor's mech advance even further but that seems like a band-aid.

Maybe somebody who knows more about this that I can chime in. Let us know if you find anything.

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