Nasty sound - wot's 'appening?

Mopar Big Block Talk
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Per
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Re: Nasty sound - wot's 'appening?

Post by Per »

Operation aborted, oil leak from one of the brass fittings in the lid. Depending on which thread the pump may have to come out again. Grrrrr :evil:
Per
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Per
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Re: Nasty sound - wot's 'appening?

Post by Per »

Oil leak was clumsiness on my part (dislodged O-ring beneath lid).

Problem persists, although at a lightly higher temperature and needle does not flicker quite as wildly. (Hardly flickers at temp below 70C.)

Ran it on the starter today with valve covers removed, there is oil at all rockers, although a bit more at the RH next to rearmost one and a bit less in the rearmost one.

My guess is that the momentary drop is when the camshaft bearing alignes with the roker arm feed channel. But does that indicate too much wear in e.g big ends/main bearings or elsewhere?

It is getting closer to overhaul :x
Per
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slotcarone
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Re: Nasty sound - wot's 'appening?

Post by slotcarone »

I would not worry about the oil gauge fluctuation as long as you find out what is making the noise. Does the engine run quietly before the noise starts?
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Per
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Re: Nasty sound - wot's 'appening?

Post by Per »

It runs smoothly without untoward noises as long as the temp is below 80C.
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Re: Nasty sound - wot's 'appening?

Post by Per »

Back on the case again. After a local run to get it up to temp I did not nurse it home. This time I gave it a full welly. And lo and behold the higher the rpm the worse the power loss. Thus I believe the theory of oil starved lifters is proven.

The lifters are fed from the main oil galleries. The camshaft is fed from the RH oil gallery. The rocker shafts are fed from camshaft bearing no 4.

The oil pressure gauge is fed from the cross feed from RH to LH oil gallery.
Per
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slotcarone
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Re: Nasty sound - wot's 'appening?

Post by slotcarone »

Your original post was about noise from the engine. In your last post you are talking about power loss at high RPM's. Most likely unrelated problems and IMO certainly the power loss is not from lack of oil pressure to the lifters. I have never seen or heard of anything like that. If the lifters collapsed it would take quite a while for them to pump up again and the valve noise would be ridiculously loud from all 16 rockers. If I was there to see what is happening it would be easier to figure out what the problem is with your engine. I have never been to Norway! :)
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Re: Nasty sound - wot's 'appening?

Post by Per »

The noise is still very loud and clattery. But only in conjunction with the vibrating pressure gauge and now proven power loss.
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RockyUSA
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Re: Nasty sound - wot's 'appening?

Post by RockyUSA »

Running the car wide open is an expensive way to diagnose an engine problem...

I wish you the best.

Suggestions:

1. Mechanical Gauge in stock sender location (even of only temporary)

2. Trip to a mechanic in Norway familiar with Mopar V-8s.

3. Big glass of "Isbjorn" or "Aass" while you consider your options.

Rocky
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RayR
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Re: Nasty sound - wot's 'appening?

Post by RayR »

I agree with Rocky.

Weird problem, hope the answer is simple. Couple of suggestions/questions.
1. Sounds as if the power loss is significant, how do you know?
2. If it really is significant what are the spark plugs telling you?
3. Is one cylinder bad? if so change the lifters? and see if it changes.
4. If I understood your comments correctly you are still getting 'enough" oil pressure, even if it does fluctuate - it should be enough to keep the lifters pumped up?
5. Have you tried the Mopar chat lines for the problem? some good help on there.

Good luck.
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Per
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Re: Nasty sound - wot's 'appening?

Post by Per »

Car will not accellerate. Plugs etc. all good. After a bit of cooling down starts, idles and runs very well indeed. All lifters replaced even though all old ones still good. And agree the pressure should be more than enough to feed the lifters.

One angle of attack can be to either cut open the valley pan and try to observe the lifters. Alternatively remove the valve covers once thoroughly warm and observe the valves. Very messy though :?

I have wondered if there is plug at the end of the LH main oil gallery and that it has become loose in some way. Then the lifters nearby may starve a bit but even then they should have oil enough. After all even an engine with 20psi hot will have oil enogh for high rpm feed to the lifters. If the feed to some lifters are partially blocked it ought to be worse when the oil is cold and thicker.
Per
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Per
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Re: Nasty sound - wot's 'appening?

Post by Per »

Turning crank by hand while running oil pump with a drill revealed that the oil pressure dropped from ca 75psi to 60psi each time LH and RH rocker shaft was fed with oil. So that is the fluctuation I see. As both were 60psi I tend to think they are OK'ish. BUT I found one dud lifter :-) That means one lifter was dud from new: The symptoms did not change when I replaced all lifters with new ones. (Sealed power btw.) The lifter sits next to camshaft bearing no. 4 which is the one feeding the rocker arm shafts. It makes sense as an overall picture.

Using a good quality oil pressure test instrument the vibration is barely detectable. So something srtange with the instrument as well. i'll blow the plastic tube free of oil and see how much that improves the situation.

It remains to be seen if all is well though as I am among other things replacing the failing starter. And even though the starter was supposed to fit the 383 it did not. And of course the bracket holding the centre bearing for the front prop shaft interferes with the new starter. Grrrr.
Per
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slotcarone
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Re: Nasty sound - wot's 'appening?

Post by slotcarone »

I can't imagine what starter you have as all the MOPAR 383 and 440 engines take the same starter. If my memory is correct even the small block engines are the same. I remember back in the '70's we had a Chrysler 6 cylinder and also a Chrysler 8 cylinder starter in stock at my shop and they fit them all. :)
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Per
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Re: Nasty sound - wot's 'appening?

Post by Per »

Bought from RockAuto (who hitherto have been very good in all respects). EDIT: Removing the elaborate electrical connection and just fitting the wires directly to the bolts on the motor body left about 4mm clearance to the block.

Next hurdle: After mucking around with the old oil pressure takeoff it leaked. So new tube and tight again.

Then (drumroll) wait for it....


NOW I HAVE AN EXHAUST BLOW AGAIN :evil: AAAARRRGGGHHHHHHH!
Per
Not only English cars these days, an Italian is part of the stable again 8)
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