used engine-problems

1875 Views 50 Replies 6 Participants Last post by markmitch, 6 mo ago

markmitch

Discussion Starter · 7 mo ago

OK so I bought a used 350 a while back and it's all back in my Astro, but when I try to turn the engine over to start it, it turns a few times, and then it makes a loud squeaking sound and acts like the battery is dead, but it isn't. I tried three times to get TDC and nothing has changed after each time. Could it be the torque convert not seated right? Any ideas, please feel free to post. I need to get this van on the road asap! Thanks , Mark

Save

1 - 7 of 51 Posts

Rod's Trucks

· #6 · 7 mo ago

Can you pull.plugs and try turning it over with the ratchet?
If it is a mechanical problem, it should be no different.
If it is a compression issue then it should turn freely.
I would not attempt to use the starter until you know it will spin all the way around without binding.
I am assuming you could turn it a full revolution before the installation.
That would probably point to either a mechanical issue with the transmission, or a hydraulic lock in one of the cylinders, due to water or oil.
Was the cooling system filled?
On some motors, a stuck.ppen valve cam jam a piston, but I do not think older Chevy V-8's are built that way (so called 'interference motors' like many foreign makes).

Rod J
Issaquah, WA

Save

Reactions: 1

Rod's Trucks

· #8 · 7 mo ago

markmitch said:
Its raining here so I can't do much till it stops, I will do what you posted and let you all know. Thanks, Mark

I misread your previous post.
It sounds like it was turning over with the starter, so the hydraulic lock idea probably will not be the case.
I have forgotten the history of your project. Did you ever have the bottom of this used motor opened up to check main and rod bearings etc?
Would it rotate normally with a wrench, before it was installed?
Sorry for the questions?
I am just trying to get a better mental picture of the situation.

Rod J

Save

Rod's Trucks

· #17 · 7 mo ago

Good information...now I think you can assume the motor is not the issue. That is good to know.
Is it possible the torque converter was not quite lined up on the flex plate correctly? ( pure speculation)
It has been so long since I have seen how those fit together, I cannot visualize the mating surfaces or how the mounting points are set up.
I recall seeing an old Ford, on which somebody had tried to use a couple of bolts that were a bit too long to attach a torque converter. The bolts tightened up just fine according to the owner, but they had bottomed out against the torque converter housing and not held the flex plate tight. It causes a lot of strange noises, and finally damaged the flex plate before the problem found.

Rod J
Issaquah, WA

Save

Rod's Trucks

· #30 · 7 mo ago

Mark,
For peace of mind; a leakdown test is pretty easy to do on a non-running engine, but.
I think you stated earlier that you heard this one run. If so, then there probably is not much to be concerned about internally. The only thing that might show up could be an oil consumption issue. You stated this was going to be a temporary motor in your van, so again, probably not a significant issue.
"temporary" a fix that is implemented until a more permanent solution is found...or until it breaks permanently and irrepairably!
Rod J
Issaquah, WA

Save

Reactions: 2

Rod's Trucks

· #40 · 6 mo ago

Just an observation, but I am wondering if the tweaking of the oil pickup, to better fit the modified oil pan, may have generated an air leak, so there is no suction at the pickup.
There is not much else between the oil pickup tube and the pump itself, that can leak. I have never installed any oil pump (new or used) without priming it or putting light grease in it before installation. That just sounds like a recipe for trouble later.
Rod J
Issaquah, WA

Save

Rod's Trucks

· #42 · 6 mo ago (Edited)

markmitch wrote:
"What I am going to try is I will remove the oil pressure switch assembly and add a piece of hose to it and turn the engine over to see if oil comes out without making a huge mess."

You could also use a small garden sprayer tank, and put oil in it. Use the tube to the spray wand to hook to the oil pressure port., pump it up and let the air pressure lube the motor.
When I had a shop, we had one of the old style galvanized metal garden sprayers ( yes, that was manyyears ago) . It was rigged up with an air pressure regulator set to about 5psi, and used specifically for the purpose of pressurizing oil systems on rebuilt motors.
One day, somebody 'borrowed' the air pressure regulator off that tank.
One of my mechanics was not paying attention, and hooked the shop air line directly to the tank, which had about two gallons of oil in it. That blew a seam in the bottom of the tank, and it became a rocket; spewing oil everywhere as it went through the shop ceiling and into the attic.

What a mess!

, and nobody hurt!
When we replaced that system, we made sure there was a pressure regulator attached in such a way that it could not easily be removed.

Rod J
Issaquah, WA

See less See more

Save

Reactions: 1

Rod's Trucks

· #45 · 6 mo ago

Yes! , proving oil pressure to the sensor is a big step forward . That has to be a relief.

Rod J
Issaquah, WA

Save

Reactions: 1

1 - 7 of 51 Posts

Top Contributors this Month