I just bought a 350 to swap into my 1987 camaro. I took all of the fuel injection stuff off and put carb intake on. I cleaned the engine up and painted it. I wanted to check compression before I do the swap in order to make sure that the engine would run. I put the starter on the engine, hooked up jumper cables to it, took all the plugs out and put the compression gauge on. When I try to turn the engine, I get about 7/8 of a turn before the starter stalls and the starter gear won't retract. So I gave up on that for a while and took the oil pan off to change the gasket to fix a leak. When I got the pan off, I found a bolt in the oil. The bolt was from the front main cap. I made a tool to keep a drill on center with a 7/16 bolt and drilled the remaining bolt out. The threads are fine. I don't know if something is wrong. Why would a main cap bolt break? Is the crank bent? Would that cause engine turning problem? There is oil pressure and the motor turn fine when there are no spark plugs in the holes. As soon as I put anything in the spark plug holes I get the 7/8 turn and stall problem. Advice PLEASE

 

Judging by the lack of reply, I either asked a stupid or really hard question. Here's hopefully a simpler one. Lets just say that I took the distributer out of the engine being careful to mark where the rotor was pointing before and after lifting it. Then lets say I had a dumb*** attack and rotated the engine by hand without the distributer in. How do I get the distributer back into the correct place on the cam?

 

It's almost impossible to say remotely. The 7/8 turn thing doesn't make sense unless there is an internal problem.

Let's say you turn the engine over until you can feel pressure coming out of the #1 sparkplug hole as the timing mark comes up to the timing tab. When the timing mark gets to the "zero" on the timing tab, let's say you set the distributor back in, rotating the rotor counterclockwise about 20 degrees, so that the rotor points to the #1 spark plug terminal on the distributor cap when the distributor body drops all the way down. It's likely the oil pump shaft won't properly line up with the distributor, especially if the distributor was pulled out, let's say, when the engine wasn't on the #1 or #6 firing position. In that case you might have to turn the crank over some more to get the distributor to drop down - you'll have to turn the crank over past the timing tab and around one more time so you're back to the #1 firing position so you can verify the distributor is now in the right spot.

Just for the sake of discussion, of course.

 

line your timing marks up, the only problem is they line up on top dead center and 180 degree out, if you listen to the #1 cylinder and line the marks up on the compression stroke you will hear air rush out.Once the marks line up just point your rotor to #1 cylinderand drop the distributor in

 

what kind of internal damage should I look for?

 

Broken main cap bolt is a very bad sign. Bent crank, broken rod, broken piston - could be many different things.

I'd pull the engine apart and have it checked over very carefully.

 

A compression test would rule out broken piston and rod right? Then I just have to rule out bent crank. I don't want to got through all of the trouble of rebuilding this engine. But if I have to now is the time. If you could give me some ideas on how to rule some things out and do this the low budget way, I would appreciate it.

 

Bite the bullet and do it right. Pull the engine and find out what is REALLY wrong.

The old saying: "You can pay me now or pay me later" applies in these situations, except add "way more" right before later.

The person that rebuilt the engine "MAY" have overtorqued (stretched) the main bolts, then that particular bolt broke at a later time. Use a torquewrench to measure how much torque it takes to REMOVE the other main bolts. That may give a clue.

I've seen sbc cranks not be totally straight and be a little difficult to turn UNTIL all the mains were bolted and torqued properly.

In any case, do it right and pull the engine.

jms

 

take off that cap take off the bearing...buy your self a cheap *** dial indicator and magnetic base that goes with it. Put the needle on the journal of that main. Go to your flywheel take off a cover or something to get at the flywheel teeth and use a screw driver to turn the engine over...not plugs in the holes either. See what your run out is at that main. Do not turn at the front of the main those cranks have enough flex in em to give your a false run out. do not use the bloody starter to turn the engine over...disconnect the battery first. At least you can get an idea on your run out before you pull the motor. The reason you want the spark plugs out is 1 it makes it easier to turn and due with the compression force there maybe enough force with compression to deflect the crank via the con rod and again give false readings.

I do this on big engines with 3800 pound cranks and mains torqued from 2400 to 2800 foot pounds. I also use this experiance in small kiddy engines I call em

 

I may have misled youi guys a little somehow. This engine is not installed in my car. My car has a 305 LG4 that runs fine, it's just tired. I was getting ready to install this engine. Now I think that I will rebuild it. I will give the runout thing a shot as well. I was a diemaker before I went back to college, so I have a lot of precision measuring tools including a dial indicator and mag base. How much runout is too much. While I'm at it should I rebuild the 081 heads on my car and throw the 193's away. From what I have read, the 193 are junk.

 

You may want to have someone experienced look at it before you pull it completely apart. Once the pistons come out you're looking at new rings as a minimum and a re-bore while you're there. Your fix could be a easy as replacing a bolt, maybe bearings, up to a crank kit.

 

ok cool you have the engine out so its easier.I would touch base with an engine shop or gm dealer or a knowledgable person. I personally would problably go with not more than .0015 run out. On the big engines we can get away with up to .003 with bearing clearances ranging .005 to .012. If the crank is good then you need to get the crank line or bore checked. And you may get away with using a precision straight edge. On the big guys I've had machined up precision mandrels, laser siting or the piano wire method. If a guy is handy enough and got a few ideas up his sleeve and they work you can save a few bucks.Also you can check for cracks yourself using that three step system using a dye penatrante and developer which actuall works extremely well. I know the coast gaurd except that when I use that on thier engines or parts.good luck and have fun

 

As much as this will probably make you guys mad....I checked the runout and ended up with around .002 (my dial indicator only has .001 marks *cheap*). I put the pan back on and wired the starter up with actual battery cables as opposed to jumper cables BIG DIFFERENCE. Everything worked great. I had 180-190 PSI in each cylinder. I figure what the heck and stuck it in there. That took all weekend so I'm stuck riding the motorcycle for a week. I'll let you know how hard I'm kicking myself next week. Thanks for the info. I may still end up rebuilding another motor knowing that I'm on borrowed time with this one. The Motor is in, not running yet. I still have to hook up all of the wiring and hoses and cables and stuff.

 

hey bro how'd you make out with that motor