Tuning question

[nickjames138 15]

I have a 351 with 302 heads. A bigger cam and dual magna flow exhaust. I just put on a 600cfm 4barrel holley and MSD ignition and distributor. My car is dieseling and it's hesitating off the start. I asked my mechanic to back the timing off and add to the air/fuel mixture. He told me that he doesn't want to take anything off the timing because it will make the car sluggish. He suggests it's the carburetor (that it's too small and I should've gotten a 750 double pumper). I'm getting frustrated. Thoughts? 

[barnett468 418]

ok, EASY deal so lets figure this out, however, i can guarantee you that the timing can be modified so it can be retarded for starting but still have plenty of advance for acceleration.

 

please answer all these questions one at a time?

 

can you do minor mechanical work?

 

do you have a timing lite?

 

what is your water temperature when it diesels?

 

does it diesel when it is cold?

 

do you know what the compression is with a gauge?

 

do you know what the static compression is?

 

what octane gas are you using?

 

what is the spark plug number?

 

what distributor do you have?

 

does the distributor have points?

 

.

 

.

[1969_Mach1 333]

A 351W with 302 heads is an odd combination.  Anyway, yeah overall a 600 cfm Holley vacuum secondary carb is a little small and not the best choice for a 351W.  Also, the 600 cfm vacuum secondary is not one of Holley's better carbs.  Myself, I wouldn't invest time and money on that carb.  But it shouldn't diesel because of it.

 

Is the base timing advanced far enough?  A common starting point for base timing on a 351W is 10 to 12 degrees BTDC.  One cause of dieseling is timing is too far retarded and the throttle plates are open too far to obtain an idle.

 

I guess the engine is not over heating, it wasn't mentioned.

 

Lastly, a 750 cfm double pumper carb is a little large for a 351W, stock or mild.  If you are going double pumper, 650 to 700 cfm work good on a 351W motors.  Keep in mind the only Holley double pumper carbs setup for Ford auto trans kick down linkage are the Ultra Double Pumpers.  Any other and the primary throttle shaft will need to be replaced.  I'm partial to double pumper carbs, I'm sure others will have input for vacuum secondary carbs.  The best vacuum secondary carb I am aware of is Holley's old original List 3310 or List 3310-1.  Those were 4150 series 780 cfm carbs that seem to work great on small and big block mild and stock motors.  To my knowledge those are still a highly sought after carbs.

 

If you have a timing light and some basic tools and can follow barnett468's instructions, he can probably sort out the issues.

[MikeStang 247]

Yep ask him what the timing is and if it's 8-10 take it to 12 degrees initial and then readjust the carb and idle it down... Sounds like combination of timing to low and carb idled to high..

You may need to recurve the distributor depending on total timing but it's and Msd so it's easy and almost anyone can do it... I have done it in the dark with a friend holding his cell phone for a flash light LOL.

[nickjames138 15]

ok, EASY deal so lets figure this out, however, i can guarantee you that the timing can be modified so it can be retarded for starting but still have plenty of advance for acceleration.

 

please answer all these questions one at a time?

 

can you do minor mechanical work?   Yes

 

do you have a timing lite?   No

 

what is your water temperature when it diesels?    Not sure. I think around 190

 

does it diesel when it is cold?     No, but the electric choke stopped working after he installed the Distributor. So, now I have to hold the gas to warm it up before I put it in gear in the mornings. It only diesels when I've driven a decent amount. 

 

do you know what the compression is with a gauge?    No but I can find out. 

 

do you know what the static compression is?      No 

 

what octane gas are you using?     91 usually go to Shell and get the V-power

 

what is the spark plug number?  I believe I gapped them at 35

 

 

what distributor do you have?     Summit Racing Ready to Run billet http://www.summitracing.com/parts/SUM-850312-1

Also have MSD Blaster High Vibration Coil http://www.summitracing.com/parts/MSD-8222

 

does the distributor have points?   Yes 

 

 

I really appreciate your help. I wish I would've listened to my dad everytime he went into the garage to work on the cars. Now, I really want to get into doing it all myself. The biggest thing i've done to my car is replaced the plugs and gapped them. I know that's not the hardest thing to do. I'm definitely a fast learner and a DIY'er

.

 

.

[barnett468 418]

ok, xlnt

 

yes the compression test would be helpful.

 

do you have a tach or vacuum gauge?

 

can you rent or borrow a timing lite?

 

does it turn over more slowly on a hot day or after you have driven it a little then turned it off for a few minutes and tried starting it again?

 

do you ever hear any pinging/detonation when you accelerate?

 

do you know the spark plug part number?

 

where does the vacuum hose for the distributor connect on the carb?

[SA69mach 39]

When I first bought my Mach 1 I drove it 600 miles from Penn to Mich.  PO was looking worried that I was going to do that, but I went anyway.  It dieseled like crazy at every gas stop.  30 seconds one time.

 

It had a bog off idle. 

 

Timing light revealed zero degrees advance.  I had the car Dyno tuned for distributor and carburetor, and it runs and starts perfectly at 12 degrees BTC, and the off idle bog completely gone.  Carb tuned up nicely for 35 hp increase from base, and perfect Air/Fuel ratio to 5400 revs.

 

Because you have both of those issues, and dont have the timing, I suggest you consider that and find out the timing.  Timing by ear is near impossbile.  Timing by vacuum works, but it works best in conjunction with recommended factory timing settings, and only in small increments outside of those.

Please do yourself a favor and get a light, and see what you have right now.

My vote is  that you will find your engine has very low advance numbers. 

 

Good luck.

[nickjames138 15]

So, I'm watching videos on how to set timing and I don't have a timing marker. Also, this looks like a bigger job than I'm capable of right now being that I don't have any markers. I just don't know what shop to trust with an older car in Los Angeles. I've already struck out on a shop. I definitely don't mind paying a little extra to get solid work. I just don't want to keep double paying. 

 

That being said...Barnett if you think I can do this myself...then I'm always down for a challenge. 

 

I don't have a vacuum gauge. 

 

I can get a timing light.

 

I can't figure out the pattern of it ignition. I definitely have to pump the gas 3x before starting it in the morning. Once it's warm I can turn it off and turn the key and it starts right back up. If I let it sit for an hour after running it I turn the key and it takes a 3-4 seconds to start and I usually have to push the accelerator down and it fires right off. 

 

I never hear any pinging. However, if it's in first there is a whistling if I accelerate in first and then let off as it's slowing down it whistles. 

 

I don't know the Spark Plug part number, but I can find it. I can also take a photo of the engine/hoses/etc. 

[barnett468 418]

ok . i guarantee you can do this yourself and you will not likely find a shop that can do what i am going to have you do and others here will be able to help . . this happens to be one of my specialties just have faith.

 

 

COMPRESSION TEST

 

i do not "need" the compression but it might be a little helpful i really cant tell unless i have it but i and others can still tell you what to do without it . . you can just take it on number 1 and 5 cylinder.

 

1. remove the coil to distributor wire.

 

2. prop the throttle open by opening the throttle then putting a screw driver in the venturi.

 

3. turn the engine over for 4 seconds.

 

 

CARBURETOR GAS LEVEL

 

we need to know if you have inspection holes with screws or sight windows in them in the right side of your carb float bowls . . if they are windows, what level is the gas at as soon as you turn the engine off.

[barnett468 418]

IGNITION TIMING

 

 

 

Connect timing lite to number 1 cylinder

 

you need some liquid white out or white liquid shoe polish and a tape measure if you use a timing lite which will make this a zillion times easier . . they are $20.00 from some shops and autozone or a similar shop may rent them or loan them.

 

 

VACUUM ADVANCE AND FRONT THROTTLE BLADE POSITION AND IDLE SPEED

 

As someone mentioned, if your idle is too high or your throttle is too far open, it can diesel when you turn it off.

 

we need to know where your distributor vacuum is connected.

 

until you get a timing lite, you can let your engine warm up then remove the hose or plug from the vacuum port from on the right side of the carb located near the top then put your finger over the fitting feel if it has a light amount of vacuum feel . . if the distributor is connected to it listen for a drop in engine rpm. when you remove it.

 

next suck on the hose going to the distributor . . if you can suck a little air the vacuum can is bad . .. if there is no vacuum at this port at idle your idle setting is probably not the cause but we will still check that.

 

if the distributor hose is connected to this port and the rpm drops when you remove the hose, your throttle is open too far . . do not touch the idle screw yet, but turn the car off and see if it still diesels.

.

[Guillaume69 150]

Sorry to interrupt here. Silly question: what is this phenomenon you guys keep calling "dieseling"?

 

G

[barnett468 418]

Sorry to interrupt here. Silly question: what is this phenomenon you guys keep calling "dieseling"?

 

G

 

the engine continues to idle poorly after the key is turned off.

[Guillaume69 150]

Thanks Barnett. We call it "self-ignition" here. Why is it called "dieseling" in the US?

[SA69mach 39]

Because it runs with no spark

 

And I guess it also sounds like a bad diesel engine

[1969_Mach1 333]

So, I'm watching videos on how to set timing and I don't have a timing marker. Also, this looks like a bigger job than I'm capable of right now being that I don't have any markers. I just don't know what shop to trust with an older car in Los Angeles. I've already struck out on a shop. I definitely don't mind paying a little extra to get solid work. I just don't want to keep double paying. 

 

That being said...Barnett if you think I can do this myself...then I'm always down for a challenge. 

 

I don't have a vacuum gauge. 

 

I can get a timing light.

 

I can't figure out the pattern of it ignition. I definitely have to pump the gas 3x before starting it in the morning. Once it's warm I can turn it off and turn the key and it starts right back up. If I let it sit for an hour after running it I turn the key and it takes a 3-4 seconds to start and I usually have to push the accelerator down and it fires right off. 

 

I never hear any pinging. However, if it's in first there is a whistling if I accelerate in first and then let off as it's slowing down it whistles. 

 

I don't know the Spark Plug part number, but I can find it. I can also take a photo of the engine/hoses/etc. 

I think if you just follow barnett468's instructions you can get the motor tuned yourself.  It's not difficult.  After, you'll wonder why you ever paid a shop to do the work. 

[1969_Mach1 333]

Thanks Barnett. We call it "self-ignition" here. Why is it called "dieseling" in the US?

I think in the US the technical term we use is "engine run-on".  At least that's what I was taught.  After you shut off the ignition switch the engine tries to keep running.  It sounds terrible which might where the term dieseling comes from.  Self ignition does describe what is happening.

[MikeStang 247]

Yes

Dieseling is "Engine Run On" in the US lol...

 

Lets not forget the wiring diagram Barnett showed above is Correct Per Ford However his may not look like that because as a lot of us know you can put number 1 where ever you want to on the cap, provided the #1 Cyl is at TDC and the rotor is pointed to the same post that the #1 wire is on...

 

I'm just saying this because if he had someone else do it for him and the timing is this far out of whack, the guy could have put the #1 in a different location on the cap, and it may confuse him trying to get it all straight..

Just something to think about...we never know what someone elses handy work might look like LOL

[barnett468 418]

Yes

Dieseling is "Engine Run On" in the US lol...

 

Lets not forget the wiring diagram Barnett showed above is Correct Per Ford However his may not look like that because as a lot of us know you can put number 1 where ever you want to on the cap, provided the #1 Cyl is at TDC and the rotor is pointed to the same post that the #1 wire is on...

 

I'm just saying this because if he had someone else do it for him and the timing is this far out of whack, the guy could have put the #1 in a different location on the cap, and it may confuse him trying to get it all straight..

Just something to think about...we never know what someone elses handy work might look like LOL

 

 

lol, yes, xlnt point.

[barnett468 418]

.

number 1 will be on the front left as you face the front of the car.

 

follow the wire up to the distributor cap then put a piece of masking tape on it or put a small dot on the cap with white out where the wire plugs n.

 

the wiring sequence will be the same from that starting point UNLESS they installed a 289/302 cam, in which case the sequence will be 1 5 4 2 6 3 7 8 but will still go in a counter clockwise position so verify the firing order first.

[Guillaume69 150]

I think in the US the technical term we use is "engine run-on". At least that's what I was taught. After you shut off the ignition switch the engine tries to keep running. It sounds terrible which might where the term dieseling comes from. Self ignition does describe what is happening.

Got it, thanks!

[nickjames138 15]

ok . i guarantee you can do this yourself and you will not likely find a shop that can do what i am going to have you do and others here will be able to help . . this happens to be one of my specialties just have faith.

 

 

COMPRESSION TEST

 

i do not "need" the compression but it might be a little helpful i really cant tell unless i have it but i and others can still tell you what to do without it . . you can just take it on number 1 and 5 cylinder.

 

1. remove the coil to distributor wire.

 

2. prop the throttle open by opening the throttle then putting a screw driver in the venturi.

 

3. turn the engine over for 4 seconds.

 

 

CARBURETOR GAS LEVEL

 

we need to know if you have inspection holes with screws or sight windows in them in the right side of your carb float bowls . . if they are windows, what level is the gas at as soon as you turn the engine off.

Ok, So I've been super busy the past few days. Just reading all of these. I'm so appreciative of your help! I love that you want to help out and I will do everything in my power to follow your steps. I just don't want to be a burden because Some of the questions i'm a little dumbfounded over. My knowledge of engines is very small! I honestly don't really understand what to do to get the compression tests. I know the gas level is 3/4 estimate from what I've seen after unscrewing the inspection hole. I still have to do the compression test. Im going to start googling videos and hopefully get a good understanding by this weekend. 

[nickjames138 15]

So, update....I just drove 5 mikes down the road, Stopped and let it sit for 4 mins. Came back and it's leaking gas from under the hood (there was a soccer ball sized leak under it. I'm also blowing through gas too fast, so....

[1969_Mach1 333]

Stop driving the car and look for the fuel leak and fix it before a fire starts!

[barnett468 418]

you are not a burden . . these types of forums are for people that need help and the fact is that when people help others it makes them feel a little better about themselves so you are simply helping others feel better about themselves so it is we who are indebted to you for providing this opportunity for us lol . . as far as knowledge goes you dont need to know anything as long as you have basic mechanical skills . . . i or others will patiently answer all your questions . . as far as any tests i suggest the must be done in the order i list them . . just rerad one test at a time until you understand it . if you read the entire page it can be confusing and overwhelming . . detailed answers are critical . your commment about the gas levrrl is confusing . . do you have clear inspection covers? . . is the gas 1/4 below the top of the glass or 3/4 from the top etc? . . the level must be near the bottom of the glasd . . if it has a screw it must be just below the bottpom of the screw hole . . both these measurements are with the car idling or right after you turn it off.

[barnett468 418]

if the carb has a screw in the float bowl inspection hole the gas must be almost touching the bottom of the hole when the car is idling or right after you turn iy off . . if it is li 1/4 inch below the hole it is too low . . if some gas comes out when you remove the screw the level is too high