305CID vs. 350CID Engine

[rereaves]

305 Engine issues

Thanks vmnate1, the truck has a Delco HEI distributor and I set the plugs at 045. I plan on increasing the timing a bit, from 10 to 14 and see what it does. I'm planning on driving the truck on a 650 mile round trip this weekend, it will be interesting to see how it runs along with the oil consumption.

 

[vwnate1]

Proper Ignition Timing

Before hitting the road , take the time to do a ' Throttle Ping Test ' :

engine fully warmed up and going along @ 35 MPH or so in top gear , windows closed , radio OFF , tramp the throttle to the floor and listen for any ping or knock ~ if you hear one , back the timing off by one degree and try it again ~ this is GM's factory method of peaking & tweaking the ignition timing for max power and safety .

It works on all ENGINES , OLD OR NEW .

 

[rereaves]

305 Engine Issues

Thanks again Nate for your reply. I will follow you suggestion with the timing. Today I did just about what you suggested. I advanced the timing a bit (not sure of amount, used the old ear) and took it for a drive. It was better but still had a stumble and a ping. I backed it off but still need some more work. It's better but not a home run. I leave for the trip to Charlotte to attend the Good-Guys Event on Friday Morning sure hope this old truck makes it. I'm packing a few quarts of oil.

Ron

 

[ol' chebby]

Look me up! I'll be at Goodguys. I'll definately be running the autocross this year. Come hang out with the Retarded Sparks.

 

[Zig]

Hey, Russ~ I hope the twisters you all had weren't around your place. What I saw on the weather channel could have been that road you ran down.

 

[ol' chebby]

Nothing at all at my house. They were in the northern section.

 

[vwnate1]

Traveling

Thanks again Nate for your reply. I will follow you suggestion with the timing. Today I did just about what you suggested. I advanced the timing a bit (not sure of amount, used the old ear) and took it for a drive. It was better but still had a stumble and a ping. I backed it off but still need some more work. It's better but not a home run. I leave for the trip to Charlotte to attend the Good-Guys Event on Friday Morning sure hope this old truck makes it. I'm packing a few quarts of oil.

Ron

Sounds good , I just ran my 292 I-6 to Queen Creek Az. and back , it ran _flawlessly_ (of course ) but it did use more oil than my '49s 235 would have .

I hope you had a good run and took lotsa pix for us to look at .

Remember : a 1/16" twist of the dizzy is a couple of degrees so go easy and keep testing it ~ ping is very VERY bad so take your time and keep at it until it runs right and should be easy to start too .

 

[rereaves]

305 vs 350

Hi everyone, sorry for the delay in posting. The trip to Charlotte was outstanding, the weather was great and lots of cars and trucks. My smoking 305 47 Chevy made the trip from Virgina Beach however she used a bunch of oil and did not run the best. The total round trip is close to 700 miles and I used 4 quarts of oil. While at Charlotte I spent some time with the Edelbrock folks, based on the way the truck was running they suggested trying to lean it out. I installed a set of metering rods which helped but still stumping. Prior to the trip I went to a leaner jet 095 vs 098 which did not help. Soooo, I think the smoking is oil rings and not sure what is causing the stumble but will keep talking and working to find the solution.

I have one other major issue, when I start up the truck I get a TON of moisture and black carbon out the exhaust. It is so bad that I have to put cardboard behind the exhaust pipe to prevent blowing black wet stuff all over the wall in my garage. It is not oil but it is a ton of wet black carbon, any suggestion? I thought it might be a head gasket issue but it is out of both sides of the engine.

If you get a chance take the trip to the Good-Guys, great show.

Ron

 

[ccharr]

You mit as well get ready to rebuild it or do a quick over the weekend ring and inserts.

 

[vwnate1]

Ron :

The smoke is telling you :

Black , carbony wet smoke is _unburned_fuel_ it's simply running too rich .

Oil smoke is blue until it gets really bad then it turns into dense , choking clouds of white smoke .

This means : your head gaskets are not bad else it'd have overheated and puked out coolant etc. .

Fix the carby problem before touching the engine's internals .

I don't know what carby you're running , mayhap it's simply too big for this engine .

 

[ol' chebby]

You were at Goodguys and didn't find me????? I was the one with the one blackwall....

 

[rereaves]

You were at Goodguys and didn't find me????? I was the one with the one blackwall....

Hi ol'chebby, hope you had a great Thanksgiving. Sorry I did not run into you at Goodguys would have enjoyed meeting you. We had a great time and had a lot of fun on the way down from Virginia Beach. My old 47 made the trip but she sure did not run very well and I went through several quarts of oil, about 4 (one every 150 miles). Looks like it's time to drop in a new bullet or rebuild the current one. From my limit knowledge it appears that I can purchase a new 350 long block crate motor for about the same or less than rebuilding my 305. My 305 really has all the performance I need in this little truck however she is tired. I have been looking at the GM performance site and they offer a 350/290hp long block for about $2000. I'm assuming I can transfer my plated water pump and drive along with the flywheel, balancer, HEI etc from my 305 to the 350?

Thanks agian,
Ron

 

[rereaves]

The smoke is telling you :

Black , carbony wet smoke is _unburned_fuel_ it's simply running too rich .

Oil smoke is blue until it gets really bad then it turns into dense , choking clouds of white smoke .

This means : your head gaskets are not bad else it'd have overheated and puked out coolant etc. .

Fix the carby problem before touching the engine's internals .

I don't know what carby you're running , mayhap it's simply too big for this engine .

Hi Nate, hope you had a great Thanksgiving and thanks for the reply. I have a Edelbrock 1406 (600) carb. I have replaced the jets and metering rods to try and lean it out but it still spits black wet carbon, and a lot of it out of the exhaust at start up and a small amount after the engine has warmed up. Since I have a small garage, I have to back the truck into the garage and use a sheet of cardboard behind the exhaust pipe to prevent spitting wet back carbon on the garage wall and door.

While at the Goodguys event I talked with the Edelbrock folks and they gave me a different set of meter rods which they said would lean it out more, well it appears to have leaned it out but it stumbles so bad during early acceleration that I'm going to have to go back to the old rods. So, currently I'm burning oil (I assume oil rings since compression is good) and it runs terrible. The engine ran better with the larger jets and metering rods still had a stumble but not as bad, looks like it's time for a new bullet, maybe a 350 long block.

Ron.

 

[vwnate1]

Egine Running

Hi ol'chebby, hope you had a great Thanksgiving. Sorry I did not run into you at Goodguys would have enjoyed meeting you. We had a great time and had a lot of fun on the way down from Virginia Beach. My old 47 made the trip but she sure did not run very well and I went through several quarts of oil, about 4 (one every 150 miles). Looks like it's time to drop in a new bullet or rebuild the current one. From my limit knowledge it appears that I can purchase a new 350 long block crate motor for about the same or less than rebuilding my 305. My 305 really has all the performance I need in this little truck however she is tired. I have been looking at the GM performance site and they offer a 350/290hp long block for about $2000. I'm assuming I can transfer my plated water pump and drive along with the flywheel, balancer, HEI etc from my 305 to the 350?

Thanks agian,
Ron

As much as I don't like (yawn) SBC engines , they're very good with nice power to weight ratio and last a long time once properly set up .

I'd fix the carburation issues before doing anything else , I'n not familiar with the # 1406 carby but most that use meterng rods are adjustable & the the rods are typically way to far _up_ making the engine run rich no matter what.

The off idle flat spot isn't a metering rod issue .

Once you have this sorted out , drop the pan and yank the heads , measure the bores for excesive taper and it they're O.K. , I'd say overhaul it in situ , replacing the cam & lifters unless they're *perfect* , using only all metal cam gears and of couse a new chain , new pistons and either crome moly or better yet , full circle piston rings (you have to try this to believe how well it works) , retain the old oil pump unless it was bad as new ones are all over the map quality - wise .

New bearing shells and seals through out of course .

Up grade the old oil filter to a spin on typ or is that far too old tech ? I dunno abot these newer SBC's , older ones leaked profusely from the oil filter base but FRAM has a nifty , _cheap_ upgrade kit for it . (it's in the paper catalog in the footnotes)

Anyways , DO NOT put in any engine or internal work until you've sorted out this black soot problem as too rich will prevent the new engine from bedding in correctly and it'll burn oil forevermore and have a short life to boot .

I hope this helps , baby steps , remember ! .

 

[rereaves]

305 vs 350

As much as I don't like (yawn) SBC engines , they're very good with nice power to weight ratio and last a long time once properly set up .

I'd fix the carburation issues before doing anything else , I'n not familiar with the # 1406 carby but most that use meterng rods are adjustable & the the rods are typically way to far _up_ making the engine run rich no matter what.

The off idle flat spot isn't a metering rod issue .

Once you have this sorted out , drop the pan and yank the heads , measure the bores for excesive taper and it they're O.K. , I'd say overhaul it in situ , replacing the cam & lifters unless they're *perfect* , using only all metal cam gears and of couse a new chain , new pistons and either crome moly or better yet , full circle piston rings (you have to try this to believe how well it works) , retain the old oil pump unless it was bad as new ones are all over the map quality - wise .

New bearing shells and seals through out of course .

Up grade the old oil filter to a spin on typ or is that far too old tech ? I dunno abot these newer SBC's , older ones leaked profusely from the oil filter base but FRAM has a nifty , _cheap_ upgrade kit for it . (it's in the paper catalog in the footnotes)

Anyways , DO NOT put in any engine or internal work until you've sorted out this black soot problem as too rich will prevent the new engine from bedding in correctly and it'll burn oil forevermore and have a short life to boot .

I hope this helps , baby steps , remember ! .

Thanks Nate I will try to solve the Carb problem first. I just posted a couple pictures of my truck in a "new post" Ron's 47. Thanks again for all your help.

Ron

 

[ol' chebby]

Is your carb an electric choke? That may explain the rich conditions at startup. The 290 hp smallblock is a great engine, hotrod mag dynoed one and got around 315hp with just carb/intake and tuning.

 

[rereaves]

305 vs 350

Is your carb an electric choke? That may explain the rich conditions at startup. The 290 hp smallblock is a great engine, hotrod mag dynoed one and got around 315hp with just carb/intake and tuning.

Hi ol'chebby, the carb has an electric choke. I checked to see if the choke was open once the engine reached temp and it was open, guess I will check again. I keep receiving "mixed signals" based on the way the truck runs. When it is cold, with the choke on the stumble is minimal however once the engine is warm the stumble is terrible. The engine runs fine and sounds great until you put it in gear and under a load. With the engine in neutral and you increase the RPM it sounds great. When you RAP the engine you get the smoke. So I do not know if it needs more gas or less. It runs better when cold with the choke on however I have a ton of black wet stuff blowing out the exhaust. The exhaust smoke is what I call a very dark blue, some black some blue and I'm definitely burning oil. So as you can see, the engine is giving me screwed up signals. My next step is to get a good fuel pressure reading along with a good vacuum reading and try to determine which way to go, I'm also going to perform a "leak down test". When I drove the truck to Charlotte, NC my son was driving and I was riding with a buddy in his car so I could see the exhaust smoke. Running at 60/65 you could not see any smoke and just a small amount when he backed off, you could also see smoke at acceleration. I do not have access to sophisticated equipment so that's about the limit of my ability. I'm almost convinced that the oil rings are the problem with the oil consumption and smoke however the stumble and black stuff is another issue. I'm loosing faith in the Edelbrock carb.

Ron

 

[federale]

Re:Stumble and smoke

Hi ol'chebby, the carb has an electric choke. I checked to see if the choke was open once the engine reached temp and it was open, guess I will check again. I keep receiving "mixed signals" based on the way the truck runs. When it is cold, with the choke on the stumble is minimal however once the engine is warm the stumble is terrible. The engine runs fine and sounds great until you put it in gear and under a load. With the engine in neutral and you increase the RPM it sounds great. When you RAP the engine you get the smoke. So I do not know if it needs more gas or less. It runs better when cold with the choke on however I have a ton of black wet stuff blowing out the exhaust. The exhaust smoke is what I call a very dark blue, some black some blue and I'm definitely burning oil. So as you can see, the engine is giving me screwed up signals. My next step is to get a good fuel pressure reading along with a good vacuum reading and try to determine which way to go, I'm also going to perform a "leak down test". When I drove the truck to Charlotte, NC my son was driving and I was riding with a buddy in his car so I could see the exhaust smoke. Running at 60/65 you could not see any smoke and just a small amount when he backed off, you could also see smoke at acceleration. I do not have access to sophisticated equipment so that's about the limit of my ability. I'm almost convinced that the oil rings are the problem with the oil consumption and smoke however the stumble and black stuff is another issue. I'm loosing faith in the Edelbrock carb.

Ron

I'm not sure about the smoke issue,but the stumble may be something as simple as the vacuum advance. Make sure you are plugged into a vacuum port above the throttle plates,not at the bottom of the carb. Just a random thought.

 

[vwnate1]

Flat Spots

Also known as the misnomer stumbles off idle .

@ idle , connect a vacuum gauge (cheapo fuel pump tester) to manifold vacuum ~ it *should* be 18" ~ 21" and be _steady_ if it varies or drifts up and down, there's a vacuum leak you must fix .

If it jitters , bad valves or improper timing , gaps too close on the spark plugs .

As in any engine you must do the basics or you'll wind up chasing your tail .

Stop worrying about the blue smoke ntil it starts easily and runs smoothly and has good pep, minor missing under load due to excesive oil buring , no worries , you'll fix that later .

You DO NOT need expen$ive tools here ! just a dwell tachometer and an inductive strobeoscopic timng light .

Under $100 at ay pwn shop or swap meet . DO NOT pay for used tuneup tools until -you- personlly hook them up and test them .

 

[rereaves]

I'm not sure about the smoke issue,but the stumble may be something as simple as the vacuum advance. Make sure you are plugged into a vacuum port above the throttle plates,not at the bottom of the carb. Just a random thought.

Thanks, I will double check but I think it is connected to the correct port.