Ad Radar
12 Last
Item Posts    Sort Order

Rod bearing

 
74novaSS-#002
V-6 Camaros rule!
Posts: 71
Joined: 03/10
Posted: 10/23/12 11:03 AM

Just wanted a second opinion. this was my first build complete build and i screwed it up. SBC 355. After completely building the whole engine, i started it up for the first time for cam break it with out the oil galley plugs in, so zero oil pressure for about 30 seconds until i realized i messed up. i changed the cam just to be on the safe side. however after about 500 miles or so the engine developed a ticking sound. been months since ive had time to work on it but yesterday i broke the motor down.

This is the rob bearing from cylinder#6 totally scorch and the black marks are bends. not round at all
2012 10 22145318

This is cylinder#2- the black on this one is from grease on my hands.
2012 10 22150155

main bearings look fine. the machine shop said i can get away with only resizing the rod that are not perfect and replace those bearings. does that sound right or should i just do them all? im trying to get the motor back together and sell the car but i dont want to sell someone a time bomb. thanks for any input.  
"Brakes are for quiters"

Post Reply
connorIROC
V-6 Camaros rule!
Posts: 42
Joined: 05/11
Posted: 10/23/12 11:47 AM

Did you actually spin a bearing? or just wear a few down quite a bit? What does the crank look like, any meat taken off?  

Post Reply
74novaSS-#002
V-6 Camaros rule!
Posts: 71
Joined: 03/10
Posted: 10/23/12 12:08 PM

Didn't spin the bearing. was just making a ticking sound. crank looks fine, still very smooth from where it was machine .010 down. only number 6 cylinder looks like this. im guessing it wasn't perfectly round when it went in? checked the machine shops work. dry assembled with plasti gauge to check clearances but i guess i was off.  
"Brakes are for quiters"

Post Reply
connorIROC
V-6 Camaros rule!
Posts: 42
Joined: 05/11
Posted: 10/23/12 12:55 PM

oh alright. I would mic the rod journals and make shure they are still in spec, very very important. Then I would get new rod bearings all around (for my own peace of mind) and use a dial bore guage to measure bearing clearances.. dial bore guage method is the most accurate, but plastiguage could be used as well.. and you said your crank was ground? I just want to make sure you have the .010 undersized bearings for it.

This guy helped me with my build as far as dial bore guaging goes, copy and paste:

http://www.youtube.com/watch?v=qU5YOIT8Htw  

Post Reply
supersport66
V-6 Camaros rule!
Posts: 49
Joined: 01/08
Posted: 10/23/12 06:08 PM

Make sure you use some assembly lube on those bearings.It can run for a couple of minutes without oil pressure and wont harm the bearings.  

Post Reply
pepsi1
I mow my lawn and find Chevys
Posts: 1718
Joined: 09/11
Posted: 10/23/12 08:48 PM

Who sized the crank bearings for you?  
  Unless you had crap under the bearing inserts.If that was the only one I would think that is what happened. Engine assembly is like doing surgery. The room or area should be as clean as you can get it. If someone walks in your area cover everything up!
  If you can't MIKE the crank atleast use some Plasti Gauge. Use something to take some measurements.
 www.cartechbooks.com

Bob  

Post Reply
pepsi1
I mow my lawn and find Chevys
Posts: 1718
Joined: 09/11
Posted: 10/24/12 03:33 PM

I don't know of any assembly lube that will protect main and rod bearings for 2 minutes. You need to prime the oiling system prior to starting any engine. As soon as it fires that compression, and power stroke is trying to beat that bearing to death....

Bob  

Post Reply
redneckjoe69
I mow my lawn and find Chevys
Posts: 2337
Joined: 03/10
Posted: 10/24/12 03:53 PM

that bent bearing would really concern me.    i wonder if you have a cracked rod cap?   id get the rods checked out and possibly just buy a new crank, or have it turned by a compitent machine shop.   i would not do 1 rod or have 1 journal turned.   if you already have it apart, why not do it right?  

  i give you credit for not trying to sell a "time bomb."  

Post Reply
redneckjoe69
I mow my lawn and find Chevys
Posts: 2337
Joined: 03/10
Posted: 10/24/12 04:09 PM

Icon Quotepepsi1:
I don't know of any assembly lube that will protect main and rod bearings for 2 minutes. You need to prime the oiling system prior to starting any engine. As soon as it fires that compression, and power stroke is trying to beat that bearing to death....

Bob


Bob, i know you have way more experience then me.   but i use motorcycle chain wax when assembling motors.  it comes in an aerosol can.    if it can hang on to a streetbike chain at 150+mph, i think it will hang on the bearings, timing chain, and pistons for a few.    never had a problem using it, but i do prime motors as you stated.   i know its a little off the wall about the chain wax but it works for me.   gonna drain the oil anyway after cam/engine break in.     another thing i wouldnt be scared to use for assembly is teflon gel.   that stuff is super slippery and wont fall or drip off if the motor sits for a long time before start up.   arent they coating pistons with some form of teflon now?  

Post Reply
skyeking
I mow my lawn and find Chevys
Posts: 2738
Joined: 08/09
Posted: 10/24/12 04:12 PM

HI Guys!!  
skyeking

Post Reply
waynep71222
I have an SS396 tatoo
Posts: 448
Joined: 03/12
Posted: 10/24/12 04:38 PM

you may also want to scope out a bunch of the articles on this sister magazine engine tech site..


http://www.circletrack.com/enginetech/


there are several articles also there on how to read the parts to diagnose what failed..



there is an interesting article about crank straightness..  one top alcohol racer kept trashing main bearings... anther racer told him to take the crank to this specific crank shop near where the track was...   when the racer got his crank back.. he was stumped..  called the other racer over..  thought his indicator was broken as it did not move when he rotated the crank..   his indicator was not broken.. the crank was NOW STRAIGHT...  

Post Reply
pepsi1
I mow my lawn and find Chevys
Posts: 1718
Joined: 09/11
Posted: 10/24/12 05:51 PM

If you talk to 6 engine builders 6 will have their way of preping engine bearings, but 6 out of 6 will tell you all the parts must be clean.
  Purchase a 7 to 10 power magnifying glass and really look at the bearings that came out of your engine and investigate the reason why that bearing failed. I think the wbe-site that Wayne posted will show you what different bearing failures and what usually causes them.
  Your at the beginning of a long long  road if you want to become an engine builder. You may Mock up an engine 6 times or more before your final assembly.
  Just remember take your time and be clean....Good Luck...

Bob  

Post Reply
skyeking
I mow my lawn and find Chevys
Posts: 2738
Joined: 08/09
Posted: 10/25/12 04:00 PM

Hi People,
 Have YU tried using STP when assembling a motor?
 Never had a problem..I only used as little as needed..
  All the best at the Bar and Grill guys..  
skyeking

Post Reply
waynep71222
I have an SS396 tatoo
Posts: 448
Joined: 03/12
Posted: 10/25/12 10:27 PM

now that i have my thinking hat on...

that sure looks like either a random undersized journal.. or a improperly sized rod bearing..

can you flip the rod bearings over and see if the sizing stamped in all match..

do you have a micrometer.. or a dial caliper.. they are cheep now a days..

can you measure the thickness of the rod bearings ???? compare??? post the stamped sizes.. the part numbers and the Thicknesses you measured..

there are bearing thickness specs you can extrapolate from a bearing catalog...

i have seen in my days at the engine builder.. several cranks come through that had one throw that was smaller than the others... i don't know what happened... somebody took a break.. somebody sneezed..


lastly... carefully cut open the oil filter.. examine the element for broken pieces...

are all the main bearings in the proper locations...

is there a chance that the block oil galleys are mis drilled.. so the main bearing shell opening is partially covering the oil galley restricting the oil flow...

could there also be debris stuck in the crank...

do you have a set of oil galley brushes.. long ones for the block... and short small ones for the crank openings..

as for what to put it together with... people have used STP for decades...  people have used motor oil.... people have used white lithium grease...  people have used several brands of liquid assembly lube...

i personally use stay lube moly graphite assembly lube in a squeeze tube..

i also pre oil fresh start ups in several different ways...

put a quart or 2 of 10W30 in the pan...  disable the ignition.. with the filter off... and a drain pan under the filter area... i crank the engine with a remote starter switch... once i get oil flow .. usually in about 3 to 5 seconds.. i screw a filter on.. crank for another 8 to 10 seconds ...

i then connect the ignition.. top up the oil.. and start the engine.. since i have preset the distributer.. the engine is ready to run..  so i can break in the cam..

you can also.. rent or buy a chevy oiling tool.. this has a thick aluminum section to replace the missing distributer housing.. as the oil pressure flows around the housing just above the gear..

there are more ways to prime the motors.. but its late... and i can hear people yawning all over the forums...  

Post Reply
pepsi1
I mow my lawn and find Chevys
Posts: 1718
Joined: 09/11
Posted: 10/26/12 02:04 AM

Icon Quotepepsi1:
I don't know of any assembly lube that will protect main and rod bearings for 2 minutes. You need to prime the oiling system prior to starting any engine. As soon as it fires that compression, and power stroke is trying to beat that bearing to death....

Bob


Icon Quoteredneckjoe69:
Bob, i know you have way more experience then me.   but i use motorcycle chain wax when assembling motors.  it comes in an aerosol can.    if it can hang on to a streetbike chain at 150+mph, i think it will hang on the bearings, timing chain, and pistons for a few.    never had a problem using it, but i do prime motors as you stated.   i know its a little off the wall about the chain wax but it works for me.   gonna drain the oil anyway after cam/engine break in.     another thing i wouldnt be scared to use for assembly is teflon gel.   that stuff is super slippery and wont fall or drip off if the motor sits for a long time before start up.   arent they coating pistons with some form of teflon now?

I like your thinking Joe:

  What we want is a very sticky substance that will still be a liquid, and LUbricate during that harsh initial start up. When all the parts are trying to mate. The White Lubriplate doesn't do that. Back in the day before an assembly lube I mixed a 50/50. Of STP and 50Weight Racing oil. It worked fine. Joe are you talking about a Bar Chain Oil?  
  I've seen engine with that "White" Lubriplate grease used in an engine build up. That will dry up and you have NO Protection when you go to start the engine for the first time. Thats when most of bearing failures occur.
  Joe I had a guy bring in a Jeep 4 Cylinder engine a machine shop used that crap. Well it was 6 months before the engine was to be started. The White Lubriplate grease actually froze the piston skirts to the cylinder walls. On all 8 Skirts...The builder told them to just break it loose. Confused  
  They did just that. Our shop guys destroyed the 4 pistons, getting it apart. The engine was torn down, and rebuilt. It was a stack up of all the tolerances(Joe you heard me speak of stack up tolerances before) that cause all the parts to fuse. Grin  Cool
  From engine bearings, cam and lifters, valves, and valve guides all stuck together because the white lube dried up....

Bob  

Post Reply
12 Last
TO TOP