I just finished a 305 to 406. It fired almost right away, but ran rough. It acted exactly how the 305 did when I had the firing order wrong one time. Anyway eventually it stopped firing. Now it will just try to turn over but wont fire, it ends up killing my battery after so many attempts. Any suggestions would be great! It's carburated and the entire bottom end is brand new. Roller rockers, pink rods, Crowler Cam. Compression is 11:1 and the cam lift im pretty sure is .627 628.

 

Sounds like an ignition issue, need to go back over the firing order. Make sure you are TDC #1 on the compression stroke (there are two strokes), then make sure rotor points to #1 plug wire, then follow firing order clockwise.

Then, while cranking, you need to turn distributor until you get to a point where it starts and runs, then grab timing light and set a timing that the car will run at.

You are using a vac advanced distributor right?

Using the intank fuel pump with a return regulator, or using a mechanical pump with a carb pickup?

 

Thank you very much for you reply bud, but that's one thing I know I'm TDC and on the compression stoke and not the exhaust stroke, and firing order is correct. But ignition does seem to be the problem, maybe the ignition itself or something else? I am running a vaccuum advanced HEI but had a non vaccuum Accel that I took off. Guess the guy I bought the motor from said he welded the vendex so it was always advanced because there wasn't a lot of vaccuum. And a mechanical fuel pump...

 

Whats the duration of the cam? With that much lift, I'm assuming its a lot of duration. If so, that motor is going to want a lot of initial timing. I run a solid roller with only 236 degrees at .050" and I use 15 degrees intial timing plus vacuum advance. Winds up being like 35 degrees total timing at idle. I would also get the vacuum advance working right. My motor ran much better with it hooked up than without it.

 

Thank you for your reply! This thing is my daily driver believe it or not. Anyway, I am selective in what I know, I do have people helping me that will probably know what your talking about but I am pretty sure your right. Its dumb but I don't know the exact duration but when the motor was fired on the ground it was pretty lopey. I just don't know what a solid roller is... Again thank you, anything helps.

 

Of course go back to basics. Check spark and KV, remove fuel line from carb and see if it shoots fuel when you crank the engine. Look at a plug or two and make sure they're not fouled.

 

Just Carb jets are squirting and plugs are brand new, forgive me for I am selective in what I know but what is KV? I will try the fuel tip though thank you. Hey! Your from Arora, that's not too far from me just saying...

 

Just read your last post. That's a daily driver? I wont say you're not ambitious. This could end up being a hard lesson for you. 11:1 on pump gas? What rod/ stroke ratio are you running? What heads? I've seen 11:1 on pump gas but it's very tricky to do.

 

Haha, ports in the heads are drilled which brings down the compression a bit. Yes I know it sounds stupid, but its about a 10 minute drive to work so its not too big of a deal. Your right it is tricky but I should be able to pull it off

 

11:1 is pushing it for pump gas, but if he really is running a cam with over .6xx lift then his DCR is probably ok. I'm running almost 11:1 SCR but my DCR is ok because of the cam bleeding pressure.

 

Yes, the guy I bought the block from is very good with SBC and said premium with an occational octane booster will be fine. The engine was also broke in on pump gas...

 

WOW! A TGO fiend from my hood! We are definitely gonna have to meet at Woodburn this summer. I just need to get a helmet. By KV I mean Kilivolts of ignition voltage.

I understand the theory of using a larger cam to reduce DC. I'm still concerned though with DC going high as the engine reaches peak VE. Large cams work because they increase VE through their effective power band. It seems that detonation could be an issue in this area. I understand that this can be overcome through quench area design, fine tuning of ignition lead, and intake port velocity for good atomization. That's what I mean by tricky.

 

Hell ya bud, sounds good. If this thing ever runs...

I see what your saying, just hook a multimeter up to it? My dad says to bypass the ignition and force start the starter (getto style) Haha. Would I need a more powerful ignition? And sorry I don't know all the terms yet.

 

Tried bypassing the ignition, no go! Any other suggestions?

 

Can you put a timing light on it and see how much timing you have at idle? If not, you really need to do this.

 

I'm pretty positive its on, when I reverified the crank/cam timing it was at 10 degrees. I made sure it was at 10 degrees when I put the distributor back in and made sure it pointed at #1. It only turns over, but doesn't fire, doesn't it need to be running to get an acurate reading?

 

Side note: where'd you get that badass radiator cover? I've been looking for a chrome cover for a while!

Edit: I think I see now that is you radiator itself. Haha my on my phone I couldn't quite tell.

 

I'm going to go back through it today and look at everything. Ill post if I find anything out...

 

Yeah, thats the radiator itself. Its actually not really shiny. Its just an aluminum radiator.

It may need more than 10 degrees initial. You really need a timing light to see where its at, but yes, it needs to be running. I would loosen the distributor and move it around a little to see if that does anything. You can eyeball 10 degrees, but its not exact. It may actually be at only 5 or so.

I know my car ran like crap at 10 degrees. It needed more. If you can find out your cam specs it may help also. Make sure its not one of the cams that swaps two cylinders around. I forget which cylinders it switches, but the cam is ground to change the firing order.

 

I'm familiar with the altered firing order cam you refer to. It swaps cyls 4&7 to correct the inherent issues of having two adjacent cylinders fire in sequence. It has shown some benefit in racing applications.

 

Thank you all so much! It was the damned carb that was on the motor when I got it! Anyway I got it fired finally and the damn thing knocked pretty bad. Tore most of it down already and gonna find the problem. The dude that sold me the motor burnt me. At least I finally know why it didn't fire and know it will have a fresh new rebuild!