If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
|
#1
|
|||
|
|||
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
|
|||
|
|||
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
|
|||
|
|||
BB 366 - rockers clatter; oil pressure but no oil at rockers
I don't know - how could I tell?
|
#4
|
|||
|
|||
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
|
|||
|
|||
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
|
|||
|
|||
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
|
|||
|
|||
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
|
|||
|
|||
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
|
|||
|
|||
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
|
|||
|
|||
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 . |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Starting Problems | McNick | Jeep | 12 | October 1st 05 03:58 AM |
Low oil pressure | Papa | VW water cooled | 30 | July 12th 05 01:56 AM |
2000 TJ: Low Oil Pressure After New Oil Pump | Josh | Jeep | 8 | June 21st 05 07:15 PM |
Oil pressure gauge sticking on start-up in cold weather? | Azfreeflyer | Ford Explorer | 6 | December 27th 04 03:22 PM |
'99 Explorer Fuel pressure problem | Tim South | Ford Explorer | 2 | December 20th 04 05:49 PM |