Engine wont start. Could use some help and ideas.

Hi Guys, I'm about at wits end and need some ideas please.

History;
I have a 32 Ford that I put a 350 vortec crate engine in a couple years ago after re-wiring the entire car. It ran great. I had an issue with a intake manifold leak (tip; Dont use Edelbrock gaskets, use Felpro on vortec style heads.) and replaced the gaskets. The engine started and ran fine but developed a serious bog off the line over time. I rebuilt the Edelbrock 600cfm I had on it with no effect. I was using a very old Mallory dual points distributer that had a Pertronics IgniterIII in it and thought the shaft bearing may be bad so I replaced it with a new MSD. The car would not start. I put the Mallory back in with same result. I have tried 3 carbs including a brand new Holly 670 street avenger which is now on the car, both distributers, two coils and new plug wires. I have tested for voltage at coil and at MSD's suggestion, put a jumper from the battery's positive terminal (battery is in trunk) to the coil's + terminal. All with same results.

Symptoms;
Car cranks as normal. Sometimes it will backfire but wont start. I have (tested with old plug outside engine and inductive timing light works when cranking.) spark. Fuel pressure gauge shows correct (6-7psi) pressure. I can see gas from accelerator pump so engine is getting gas. When I crank the engine I can see (by using inductive timing light) timing is at 10 btdc. I ran a compression check and all cylinders have good compression and are very close to each other in PSI reading. I have verified TDC using a finder tool and the marks on the harmonic balancer were right on. I have verified the firing order with the plug wires. I have tried turning the distributor as the engine is cranking from 10ATDC to 30 BTDC.

My thoughts;
I have spark or it wouldn't backfire. inductive timing would not show if spark wasn't happening.
I have gas for same reason, it backfires and I can see it via accelerator pump shot and through the sight glasses.


I'm not a pro but have worked with SBCs for a long time. The engine cranks, has spark, has gas and is at least close on timing but wont start at all. I'm 100% lost and out of ideas. Any help would be greatly appreciated.
Thanks,....

maybe you are 180* out on the dist

I agree with Jerry, the distributor sounds 180° out causing the backfire.

The bog however is a different problem, have you considered that you may still have a vacuum leak at the intake manifold? The leak may be on the oil side and not visible from the top. Once you get the distributor corrected you can check for vacuum in the crankcase with pcv disconnected.

Sometimes the surface angles between the head and the intake are out of alignment, check with clay to see if gasket surfaces are even (top to bottom and length wise). If the angles do not match, it will cause all kinds of trouble that a gasket can not fix.

Quote:

---

Originally Posted by 36 sedan

I agree with Jerry, the distributor sounds 180° out causing the backfire.

The bog however is a different problem, have you considered that you may still have a vacuum leak at the intake manifold? The leak may be on the oil side and not visible from the top. Once you get the distributor corrected you can check for vacuum in the crankcase with pcv disconnected.

Sometimes the surface angles between the head and the intake are out of alignment, check with clay to see if gasket surfaces are even (top to bottom and length wise). If the angles do not match, it will cause all kinds of trouble that a gasket can not fix.

---

Question. I considered this originally. Only have 2 vacuum hoses; One to PCV and one to modulator on TH400. Can the modulator develop a leak and can it be replaced separately without pulling the trans? I tried running the car without it connected once and tranny would not shift correctly so I couldn't tell much but it did seem not to bog. I figured that since the tranny didn't like it when the modulator wasn't connected it must be working? The vacuum reading on engine was around 14 as I recall last it was running which I always thought was low but it was like that from the first time I fired the engine.

Quote:

---

Originally Posted by jerry clayton

maybe you are 180* out on the dist

---

I'll double check for this but with the timing marks lining up and rotor pointing at #1 and the timing light showing 10* BTDC, I would think this would indicate proper timing? I also believe my problem to be a timing issue but cant see how this could be? Maybe that's my issue, not being able to understand how I could be off 180*?

Quote:

---

Originally Posted by Duece coupe

I'll double check for this but with the timing marks lining up and rotor pointing at #1 and the timing light showing 10* BTDC, I would think this would indicate proper timing? I also believe my problem to be a timing issue but cant see how this could be? Maybe that's my issue, not being able to understand how I could be off 180*?

---

There is easy confusion here, as you must make sure you are on #1 compression stroke and not exhaust stroke. If on exhaust you will be 180° out. Easiest way to check this is to pop compression on #1 (have someone bump it over while your finger is over #1 spark plug hole, when on compression stroke it will blow your finger off). Line up the timing marks and go from there (there are also some excellent posts about finding absolute TDC on this site).

And, yes your transmission's modulator can leak vacuum (as well as the hose going to it). If the bog was gone with the modulator disconnected, you have probably found your leak. And yes, usually it can be changed without pulling the tranny (depending on clearance).

Let us know if the distributer is in right.

does`nt someone make a 180 degree rotor button .. i`m reaching here .. i had a 289 motor 40 years ago i couldn`t get to fire . a friend put a different rotor button on it and it fired right up ..he said it was 180 out ..

Ok,... looks down and kicks dirt with toe,... You may now number me among those who are not able to install and time a distributor correctly..... ~blush / feels like a tard~ Yes, I had it 180* out. Yes I was able to get it to run. Now still have same stumble that started the whole thing. I'm happy for now though and will just be content the damn thing starts and runs,.... for now.....

Thanks guy for pointing me in the right directions and taking the time to post replies. Its good to have another set of eyes at times like these. Thanks again.

Wouldn't that be cool HOSS!
Glad it starts now!

Quote:

---

Originally Posted by HOSS429

does`nt someone make a 180 degree rotor button .. i`m reaching here .. i had a 289 motor 40 years ago i couldn`t get to fire . a friend put a different rotor button on it and it fired right up ..he said it was 180 out ..

---

Ive known guys that cut the index pins off of the rotor so they can spin it around, it works until someone changes the rotor. You could do this to test it, then reset the distributor if it works and replace the rotor.

Quote:

---

Originally Posted by Duece coupe

Ok,... looks down and kicks dirt with toe,... You may now number me among those who are not able to install and time a distributor correctly..... ~blush / feels like a tard~ Yes, I had it 180* out. Yes I was able to get it to run. Now still have same stumble that started the whole thing. I'm happy for now though and will just be content the damn thing starts and runs,.... for now.....

Thanks guy for pointing me in the right directions and taking the time to post replies. Its good to have another set of eyes at times like these. Thanks again.

---

Don't be too hard on yourself, you are not the first to do it!

Oohps, can't believe I double posted!

Hoss-on those era Fords you could raise the points plate and remove a snap ring under the felt oiler under the rotor and reverse the advance system, reinstall the snap ring and 2 breaker plate screws and the rotor would be turned 180* of course the amount mech advance will be changed------

First, replace the vacuum line from the manifold to the modulator. That's normally where the problem is, the line has chafed against some part of the car and over a period of time has worn a hole in the line. Take vacuum off the manifold. There's usually at least one threaded plug hole you can use.

Secondly, the 14 inches of mercury manifold vacuum tells me that you have cammed the motor. When you do that, the motor needs more initial ignition timing at the crank. I think you said you have L31 heads on the motor. The combustion chamber of those heads likes 34 degrees total (initial and centrifugal) ignition timing. The cam, depending on cam timing, will want from 14 degrees to totally locked out at the crank. If it were mine, I'd dial in 16 at the crank and modify the centrifugal for 18 degrees, for a total of 34 degrees, all in by 2800 rpm's. If the motor wants to kick back against the starter with this much lead, interrupt the hot wire to the coil and run a wire to the drivers compartment to feed a switch, then back to the coil. I like a normally-closed push-button switch, but any good-quality 15 amp switch will work fine. Mount the switch so that you can operate it with your left hand. Cut the power with your left hand while you operate the key switch to start the motor. The motor will wind up pretty good with no fire to the plugs. Once she's wound up, let go of both switches and the motor will be idling. With this modification, the starter will likely outlast the vehicle. With more initial lead at the crank, the motor will be more responsive, particularly to the air/fuel screws at the venturis and you'll likely see more manifold vacuum.

Finally, replace the vacuum advance cannister with a Echlin #VC-1810 advance can, also known as GM PN 88924985 and AC-Delco #D1312C (aka "B28")
__________________

.

Vacuum line is good to modulator. Motor is 350 HO votec crate engine with the cam that came with it; 212*intake, 222*exhaust @.05 lift duration, 109 ATDC intake and 116*BTDC centerline. .435 intake and .460 exhaust lift. Instructions call for 10*BTDC for timing but I have found in the past it likes a lot more. I have a MSD pro billet PN8360 distributor that I have removed the vacuum advance on. It has the 21* bushing installed. I have the heavy springs still in it and needed to get it running first before starting to tune it but I think I will bringing in the advance in faster in the future. I am running a Holly 670cfm Street avenger carb with vacuum secondaries and again have not started tuning on this.

Interesting idea with grounding the coil as you crank. I've never seen that before. I have a high torque starter and normally have no issues with cranking or speed.

Thanks for your thoughts and ideas.