engine question

[K5XLR8R]

This maybe a stupid question. But whats the difference between a small block and big block??...Also,I have a 350 supposedly new or rebuilt??(just bought from a girl that didnt know much about cars-or that she was getting ripped off)wich leads me to suspect that the thing was even put back together right!Or even really "rebuilt" One main reason being that it uses about a quart of oil every 250 miles..the other being that when I accellerate quickly I notice smoke thats sort of whitish colored coming from the tailpipe..it isnt blue like oil so I'm just wondering if its normal exhaust being expelled from the pipe??..So I guess what im asking, is that if anyone knows of any other reasons a motor would use oil and not overheat or give any real signs or head dammage etc. i.e. overheating???Any and all input would be greatly appreciated to help me figure out whats wrong! thanks!

 

[JimmyDie6.2]

you have alot of questions let me see if I can help you??
firstly, a small block (otherwise known as a mouse motor) and a big block (otherwise known as a rat motor), refer to two things firstly the sheer physical size of the motor, a small block has 4 bolts holding the valve cover down and a big block has 7 bolts holding down the valve cover. there are many many other differences though, but just so you can tell by looking at the motor thats an easy way. secondly the cubic inch displacement, a small block is usually smaller than 400 cubic inches , a big block is usually bigger, there are exeptions, (396 big block) and a .030 over 400 would be bigger. typical small block CHEVY inches are 265, 302DZ Z-28 camaro,307,327,350,400 there are others. you should really consult a good engine book. big blocks are genI 348-409 (long gone, these motors were basically the first) 366-427 tall deck blocks from big trucks and the most popular 396,402,427,454, and now 502. there are others also.........
as for your oil consumption, is it really consumption or a leak?? white smoke is a head gasket, blueish tinted smoke is oil. black is your running to rich. see if the valve covers are loose. start with easy things, read as much as you can about engines and ask questions, something to keep in mind about all motors, always be careful and not careless, because inevitably you with hurt yourself or blow it up. good luck!!!

 

[jimmyjack]

Check your compression, it should be fairly even on all eight cylinders. Also check your intake manifold,I just replaced my intake manifold gaskets. Now I use no oil, no water, and no more smoke. Its 100 % better. Good luck.

creepin' and crawlin'

Jim

 

[sosamantx]

I am going to try this again. Fyi, I had an oil leak on a motor that someone else put in for me on a warranty job. Well it turns out that they pinched the intake manifold gasket on the backside by the distributor. I guess six months later it started leaking and it washed down the transmission and down the sides of the tranny. I never saw it leaking, because it did not get on the exhaust and smoke. I also did not see anything when I parked the vehicle. I only noticed when I was looking at the distributor and I saw the top of the transmission covered with oil. - Steve

Steve Sosa a.k.a. "sosaman"
http://sosaman.home.texas.net/carpics.html