So you think you know how to diagnoce a dead motor???

Skyetone

Kinda crabby latley
Location
East side
Well I got a few peoples attention. :cool:
Here is the scenareo....
1970 chev truck 2wd (camper mobile / tow rig) 3/4 ton. 145k on the ticker.
JUST got the stock carb rebuilt prier to a road trip to vegas. This motor and truck has been with me and my mom for 6+ years.
The motor has always been a clean block.It has a gooey film on the front of the blockbetween teh head and block on pass side, but thats been there for a long time. Started getting gutless over the years. So I got the carb (Quadrajet) rebuilt and the dwell set right. Runs tons better. More spunk same fuel economy. I throw it a tach and disconect a manual oil pressure guage. Hook it back up when the tach is in (it all goes in the guage cluster in the dash so i needed to pull the oil to remove the guages) and it doesn't work right anymore. It goes down to medium and the truck turns on and the pressure goes all the way high. I think that it may be air in the system???
Truck runs great to las vegas. Runs good through city streets. We get a little trailer wiring done to go with the new trailer that we were there to get. I helped install some of the wiring.
We hitch up and try to get out of town. We run some arrands to gas up and get beer and stuff. We had a slite belt sqeal on the way down at 80-85MPH and roughly 3500rpm. So I tighten the alt and power steering belt a little. Power steering belt didn't like that and decided to go away. We stop on the side of the highway and replace it with the spare.
There was an ocasional stutter that I beleive was spark related. So at the time of the power steering belt I check and see on drive side that the two back spark plug wires were close to the exaust and really hot. So i tie them away from the exaust. They are unmelted. I then turn the carb mixture in one revolution on both sides to help with altitude and possible stutter / backfire.
It seems to be running good.
We drive for a couple hours Twards SLC. We get about 20-30 min from meskete(typo) and hear an occasional "vibration" from araound the tranny tunnel area. It sounded like a part of the metal dash was vibrating, or maybe the tranz shifter with u-joint issues. Subtle but there. It vibrates for maybee 30 seconds and goes away for 5ish muinets. Then it comes back Cant seem to get it to put our hand on it to make it stop vibrating.We have all done it. "whats making that noise?" Put your hand on things untill you figure it out. Mom tells me she has heard it before on road trips and wondered on the manual tranz. It goes away and comes back a few more times. Always really quiet for a truck with a decent amount or road noise and regular vibrations. Then out of no where.... Clank... Clank, stall. (still not horribly loud [ I have thrown two rods in toyota motors out the side of the block due to crank bearing falure)

White smoke like hell out from under the truck.
We pull off the road on an uphill slant to pass side.I get out to see WTF. There is white smoke pooring out the exaust on both sides. After a second there is antifreeze drizling out the pass side tail pipe, drive side runs slightly uphill.
I look under the hood and see no real smoke except in the exaust. The carb has milky oil all over the top when I pull the air cleaner. There is gas leaking out of the pass side linkage for cold choke ext. NO visible points of block rupture.
I am thinking head gaskets or something in the head. Maybee valves. So I pull the valve covers off, there is a little milky oil on the covers inside but not any on the heads themselves.I then try and look at the valves and rocker arms. Looked ok. So I get mom to rotate the motor(coil off) so I can watch the rockers. We get about 1/2 a revolution and the motor stops / ceases. Try a couple more times.Tried to crank with clutch in and out. Nothing. So I break out the breaker bar and try and hand crank. NOTHING. :mad2: Tried to go backwards NOTHING. I check the oil on the dipstick(1.25 quarts low before we left, put one quart in before hitting the highway) and it looked black and was REALLY high on the stick. I checked it 2-3 times with the same results. The truck was sitting for roughly 10 minutes by now. We have leaked at a pee stream pace about 1/2? gallon of antifreeze out pass tailpipe. I pull radiator cap and the 4 core radiator is down a ways, Maybee half, but is still green.
This weekend I will start teardown to see what went wrong. Really weird that I had no warning.... What went wrong? I'll update... Are you smart? I'm kinda stumped.

Sorry so long winded, but thats details...
 

Shawn

Just Hanging Out
Location
Holly Day
Skyetone said:
There is white smoke pooring out the exaust on both sides. After a second there is antifreeze drizling out the pass side tail pipe, drive side runs slightly uphill.
I look under the hood and see no real smoke except in the exaust. The carb has milky oil all over the top when I pull the air cleaner. There is gas leaking out of the pass side linkage for cold choke ext. ..

These are all signs of top end. White smoke is oil burning, antifreeze leaking out the pipes comes frome the heads, Carb and air cleaner,, signs of back fire...


Top end.
 

SuperRunner

Turbo is my middle name
Location
Orem, Utah
Shawn said:
These are all signs of top end. White smoke is oil burning, antifreeze leaking out the pipes comes frome the heads, Carb and air cleaner,, signs of back fire...


Top end.

Motor is toast. A blown HG doesnt make a clank sound. Probably a rod, but it just didn't puncture the side of the block.

I had something like this happen, but it was a screw in the intake. Friend took his truck to Jiffy Lube, and they put a new air cleaner on it. THey didn't tell him, they broke off the screw and dropped it down the carb. Well, three months later, that screw finally made it through a valve, while I borrowed it one day.

It went something like this.....rattle, rattle, rattle, rattle, rattle, crunch, clank, bang, then poof, white smoke galore out the tail pipe. Drove it back home(was only about 40 feet from the house.

Pulled the head off, and found the screw smashed into the head, and #1 cylinder had two 4" cracks down the front and back of the cylinder. I wasn't too happy with Jiffy lube.

Oh, by the way, this was a motor I had just rebuilt. Port and polish on the head, and a few other things. He could run this thing at 100mph. Only had a few thousand miles on it.
 

harkinoff

something to do...
Location
Sandy
Shawn said:
oohhh,,,

Good point.

Its a chevy we are talking about here... It could slip time and not even come close to hitting a valve...

Sounds like it threw a rod and went through cylinder is my guess.. to get that much water that quick it's a cylinder puncture...
 

harkinoff

something to do...
Location
Sandy
Shawn said:
These are all signs of top end. White smoke is oil burning, antifreeze leaking out the pipes comes frome the heads, Carb and air cleaner,, signs of back fire...


Top end.

white smoke is WATER ..... blue smoke is OIL :D
 

RockMonkey

Suddenly Enthusiastic
harkinoff said:
white smoke is WATER ..... blue smoke is OIL :D
I'm enginetarded, but... Every time I roll over on the passenger side, and oil gets into the cylinder, the generous amounts of smoke that come out look very white to me. Seen lots of oil exit the engine through the exhaust during my four wheeling career, and it always looks white to me. :confused:
 

harkinoff

something to do...
Location
Sandy
RockMonkey said:
I'm enginetarded, but... Every time I roll over on the passenger side, and oil gets into the cylinder, the generous amounts of smoke that come out look very white to me. Seen lots of oil exit the engine through the exhaust during my four wheeling career, and it always looks white to me. :confused:


Basic engine 101 states that Black is GAS ,Blue is OIL ,White is WATER

when oil dripes on hot exhaust is will look white, but when burned under combustion its blue....


When your washing cylinders when running rich it will tend to have a blackish blue tint to it also...
 

RockMonkey

Suddenly Enthusiastic
Sorry, I skipped engine 101. Practical experience tells me that when oil gets into the cylinders it comes out the exhaust in the form of white smoke. Anyone who's ever been to a UROC event can back me up on this.
 

Floppy Hat

mbryson's hairdresser
Location
Lehi, Ut.
Here is an idea of what RockMonkey is talking about:

attachment.php
 

harkinoff

something to do...
Location
Sandy
RockMonkey said:
Sorry, I skipped engine 101. Practical experience tells me that when oil gets into the cylinders it comes out the exhaust in the form of white smoke. Anyone who's ever been to a UROC event can back me up on this.


Practical experience tells me that the oil isn't being burned under combustion, but from being pushed onto hot exhaust since the cylinder is full of oil... not all cylinders we fill up with oil at the same time...a cylinder full of oil will not fire...
 

harkinoff

something to do...
Location
Sandy
Floppy Hat said:
Here is an idea of what RockMonkey is talking about:

attachment.php


I know what he is talking about, there happens to a cylinder not firing is all..

When engines are on there side they don't run smooth like they do when upright...its because they are not firing properly, because cylinder is full of oil, sure its still running but not smoothly...
 

Shawn

Just Hanging Out
Location
Holly Day
Water doesn't creat smoke, it creats steam. White smoke is an abundance of oil not completly burning away. Thus, the above pic...



Only time will tell what went wrong...My new guess is.......





Sky worked on it..... there ya go ;)
 
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