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BB 366 - rockers clatter; oil pressure but no oil at rockers



 
 
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  #1  
Old October 17th 05, 09:19 PM
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Default BB 366 - rockers clatter; oil pressure but no oil at rockers

Hi - I'm working on my farm's chevy 87 c-70 w/ 366 v8 (which came out
of an early 1970's era truck). The motor runs and has good oil
pressure (according to the gauge) but there is no oil coming out of the
pushrod tubes and the valves are very noisy as a result.

What would cause this to be? There is only a little trickle of oil
coming out the pushrods for the number 1 piston (the front one on the
drivers side), none at the rest. I'm noticing it now because I just
had the head off the drivers side to fix a broken exhaust valve and
once it was all put back together the noise was terrible; before taking
the head off there was no noise but still hardly any oil coming out the
tubes.

I pulled the oil pan off and the pump looks fine - no plugged screen or
damage. I also pulled off the bearing cap on a couple of the pistons
and that looked ok - no visible problem. A local motor shop told me
that if the cam or cam bearings were bad we might have oil at the back
(closest to firewall) tubes but none torwards the front. SO - I'm at a
loss.

All and any help is greatly appreciated.

  #2  
Old October 17th 05, 09:23 PM
Chas Hurst
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Default BB 366 - rockers clatter; oil pressure but no oil at rockers

Distributor 180 deg out?
" > wrote in message
oups.com...
> Hi - I'm working on my farm's chevy 87 c-70 w/ 366 v8 (which came out
> of an early 1970's era truck). The motor runs and has good oil
> pressure (according to the gauge) but there is no oil coming out of the
> pushrod tubes and the valves are very noisy as a result.
>
> What would cause this to be? There is only a little trickle of oil
> coming out the pushrods for the number 1 piston (the front one on the
> drivers side), none at the rest. I'm noticing it now because I just
> had the head off the drivers side to fix a broken exhaust valve and
> once it was all put back together the noise was terrible; before taking
> the head off there was no noise but still hardly any oil coming out the
> tubes.
>
> I pulled the oil pan off and the pump looks fine - no plugged screen or
> damage. I also pulled off the bearing cap on a couple of the pistons
> and that looked ok - no visible problem. A local motor shop told me
> that if the cam or cam bearings were bad we might have oil at the back
> (closest to firewall) tubes but none torwards the front. SO - I'm at a
> loss.
>
> All and any help is greatly appreciated.
>



  #3  
Old October 17th 05, 09:28 PM
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Default BB 366 - rockers clatter; oil pressure but no oil at rockers

I don't know - how could I tell?

  #4  
Old October 17th 05, 11:04 PM
Chas Hurst
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Default BB 366 - rockers clatter; oil pressure but no oil at rockers


" > wrote in message
oups.com...
> I don't know - how could I tell?

No oil to the lifters.


  #5  
Old October 18th 05, 01:32 AM
shiden_kai
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Default BB 366 - rockers clatter; oil pressure but no oil at rockers

Chas Hurst wrote:

> Distributor 180 deg out?


Right.....the motor runs, but the dist may be 180 out?
Where do you guys come up with these guesses?
Even with the dist 180 out, what does that have to
do with the oil pressure?

Ian


  #6  
Old October 18th 05, 02:47 AM
Chas Hurst
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Default BB 366 - rockers clatter; oil pressure but no oil at rockers


"shiden_kai" > wrote in message
news:eoX4f.218877$1i.108812@pd7tw2no...
> Chas Hurst wrote:
>
> > Distributor 180 deg out?

>
> Right.....the motor runs, but the dist may be 180 out?
> Where do you guys come up with these guesses?
> Even with the dist 180 out, what does that have to
> do with the oil pressure?
>
> Ian


It's not a guess but a foggy remembrance of some engine that has a
distributor body that impedes the flow of oil to the lifters if fitted
correctly. If fitted incorrectly it blocks the flow of oil completely.
Now do you have some advice for the OP?


  #7  
Old October 19th 05, 12:00 AM
shiden_kai
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Default BB 366 - rockers clatter; oil pressure but no oil at rockers

Chas Hurst wrote:

>> Right.....the motor runs, but the dist may be 180 out?
>> Where do you guys come up with these guesses?
>> Even with the dist 180 out, what does that have to
>> do with the oil pressure?
>>
>> Ian

>
> It's not a guess but a foggy remembrance of some engine that has a
> distributor body that impedes the flow of oil to the lifters if fitted
> correctly. If fitted incorrectly it blocks the flow of oil completely.
> Now do you have some advice for the OP?


Yes, I just gave him advice...hopefully he'll take it and
not fool around with his distributor hoping for more
oil pressure.

Ian


  #8  
Old October 19th 05, 03:14 AM
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Default BB 366 - rockers clatter; oil pressure but no oil at rockers

I'm back with an update. Thanks for all the help so far. I tried
losening a couple of the rockers with the motor running as suggested
but it didn't work; still no oil even after 30-60 seconds of running
like that. I also hooked up a trusted mechanical oil pressure gauge
and found that I do have 50psi at cold idle, so I'm ruling out oil pump
and any serious bearing trouble.

Here's a little background that may help the experts. This all started
when I took the truck on a trip much longer than we normally use it.
Typically, on the farm, it doesn't run for really more than 30minutes
at a time, but I was helping my brother move and had to drive it on a 3
hour trip, including some highway. On the way, after about 2 hours, I
started hearing a ticking in the motor. It's hard to describe the
noise; it was louder than the tick that comes from a loose rocker, but
not as loud and deep as a connecting rod problem. It's frequency was
dependant on RPM, but the noise did not get louder if the motor was
revved up; it just ticked faster. I had no idea what the cause was,
and since I was far from home anyway I figured the motor was toast and
I tried to make it as far as I could. It made it the rest of the way
to his house and back, running the same way.

I started working on the motor and found the spark plug on the #5
cylinder was smashed flat on the end, and that with a new spark plug
the piston was not working right; it skipped and removing the spark
plug wire from that spark plug made no difference in how the motor ran.
I pulled the valve cover and found only a tiny amount of oil flowing
down the rockers when it was running, went farther and pulled the
drivers side head and found the exhaust valve on #5 was broken - 1/2 of
the outer ring of the valve was gone and the piston dome was pretty
lumpy. No pieces inside.

I had the head checked and fixed, put it all back together. Now the
motor runs very smooth, but the loud ticking is still there. With the
motor running, I loosend the rocker on the #5 exhaust valve, and the
noise got less and less; with no tension on the pushrod tube (it just
going up and down but not compressing the valve, it was almost gone -
the loud ticking noise (normal valve ticking was going on though cause
it was loose). As soon as I slightly tightened the rocker the ticking
started again. I pulled the intake off but everything looks ok, but
what do I know?

So - what does this mean? Can hydraulic lifters go bad and cause this?
Could a bad lifter keep oil from going to the top of the head?

Oh, and by the way - when I took the distributor out I think I know
where the idea about the distributor came from. The channel in the
rotor housing that passes oil from the pressure port behind it to the
lifter ports on the side is not a consistent shape; one side narrows
down and is much smaller than the other side. I think if it was in 180
degrees backward it could impede the oil flow, but it didn't look like
it would block it completely on my engine. It was in 'wrong' from what
I could see - the narrower restricted side was towards the oil pressure
port in the block.

Tomorrow I will replace the lifters and spin the oil pump with a drill
to make sure oil is getting up there. If that doesn't work I do not
know what to do next.

Thanks again.

  #9  
Old October 18th 05, 03:34 AM
Bob
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Default BB 366 - rockers clatter; oil pressure but no oil at rockers


"shiden_kai" > wrote in message
news:eoX4f.218877$1i.108812@pd7tw2no...
> Chas Hurst wrote:
>
>> Distributor 180 deg out?

>
> Right.....the motor runs, but the dist may be 180 out?
> Where do you guys come up with these guesses?
> Even with the dist 180 out, what does that have to
> do with the oil pressure?
>
> Ian


That guess is so far off it can't even be described as "wild assed"
Bob


  #10  
Old October 17th 05, 09:46 PM
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Default BB 366 - rockers clatter; oil pressure but no oil at rockers

Had this happen more than once .Try backing them off while it's
running one at a time and see if the oil will come through . Sometimes
they get partially collapsed and won't pump up after they've "sat" for
a bit .

 




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