I built my first motor (350) and am having some problems

[Waylan_Yass]

I built my engine over the summer and replaced alll of the required parts, or had them rebuilt . . .all except for the actual block. It seems that I should have had it bored because I'm left with the same noise that forced me into the rebuild. I found so many poroblems that I overlooked the source. Now, along with the faint slapping noise, I have a vaccuum leak. I'm wondering if this is because of the piston slap. And this is causing my brakes to weaken, escpecially when I'm coming to a stop or idling. HELP!

[abaird]

so,what kind of work did you do to this motor? Just a re-ring, or did you get any machining done? Did you just decicde to tear the motor apart and put it back together again with some new parts?(some blocks are not worth rebuilding) Engine building can be very complicated. If your main bearing bores aren't perfect and they weren't machined, this could cause problems. Poor vacuum can be caused by many things. Bad compression for one. Make sure the engine is timed correctly. Then I would run a compression test. If some cylinders are bad, do a cylinder leakdown test.

[wrightz28]

if you didn't stagger the ring gaps, you just learned a very tuff lesson.

[jveik]

Originally Posted by wrightz28

if you didn't stagger the ring gaps, you just learned a very tuff lesson.

what do you mean by this? is it just placing the gaps in the rings in different spots around the piston? does it distribute force better that way or something?

[directory]

the rings on the pistons aren't all complete circles. they seem to be "cut" . what you want to do is stagger these "cuts" around the piston itself. if not--oil can leak, vacuum issues, etc.

[directory]

it is fun rebuild an engine. it's alot to know--but can be well worth the knowledge and time. you just need to read up and take your time doing it.

it's especially fun on an engine that isn't needed--like one that you have yo put back together for your daily driver.

[wrightz28]

You should 'stagger' from each others openings to prevent compression loss, oil/fuel leak down, and blow by. The exact orientation o fthe stagger may cause some debate. Some say simply 180 from each other, so the top compression rings gap would be at 12 o'clock and the lower ring at six. Some will say anywhere between 90-160 degrees dependent on crank angle.

[TLBLZER]

Originally Posted by Waylan_Yass

I built my engine over the summer and replaced alll of the required parts, or had them rebuilt . . .all except for the actual block. It seems that I should have had it bored because I'm left with the same noise that forced me into the rebuild. I found so many poroblems that I overlooked the source. Now, along with the faint slapping noise, I have a vaccuum leak. I'm wondering if this is because of the piston slap. And this is causing my brakes to weaken, escpecially when I'm coming to a stop or idling. HELP!

What is the specs on the cam shaft you are using.Lots of times to much cam will cause you vac. problems with this kind of set up.