Engine noise help

[mrsprite]

OK.....I have a '59 Austin-Healey Sprite with a Datsun A15 engine that has been in the car for 20 years now (I've owned the car for 5). It was running just fine, but the clutch was slipping (has been for a year now), so I decided to do a clutch job and replace a leaky rear main seal. I've had this engine out 3 or 4 times previous to this and have swapped cams, etc, so I am familiar with it. All I did was remove the engine, pull the pan, remove the old seal, install a new seal, install pan (w/new gasket, of course!) and install a new clutch. That's it....nothing else. When I got it all back together I had a noise. It sounded like valves rattling so I readjusted the valves (even though I never touched them or even removed the valve cover). Still there. Friends suggested I may have spun a bearing......against my better judgment I pulled off the pan and removed the main & rod caps. Bearings look pretty darn good for a 20 year old engine rebuild.....nothing wrong at all. I put it all back together again and, of course, the noise is still present.

I am curious of anyone can help identify this noise. I even went so far as to remove the valve springs to see if I broke a valve guide or had a busted spring......everything I can see checks out. I also removed the belt to make sure it wasn't the water pump or alternator.....still there. My only thoughts are:

- a loose valve seat (unlikely, but possible)

- bad lifter(s) and/or camshaft

- rocker arm assembly binding up (I did remove all the rockers from the shaft and inspected everything....all looked good)

- ???


I'm at my wits end. I wish I just left in the slipping clutch! My next move is to pop off the cylinder head and have a look. Any thoughts before I do this would be great.

Listen to the video and give me your opinions/ideas.


Thanks.


https://www.youtube.com/watch?v=9J-IlIKCZoA

 

[Deleted member 8987]

You had good oil pressure, and rockers were oiling? Does the noise change with pressure on the clutch pedal?
I am thinking the pressure plate may be slightly differently shaped, or a plate bolt not all the way down, something it hitting the bell housing. You didn't bend the pickup tube, did you? Might be hitting a rod. How often is the noise? Once per rev, or once every two revs?
Use a timing light, look at the strobe flash on the inner wing, see if it's one flash per noise or two noises for one flash.
That'll tell you upper end or lower end (and clutch).

 

[mrsprite]

I forgot to mention......a solid 50-55 psi oil pressure. I don't have the electric fan hooked up, so once the engine hits 190* I shut it off, but oil pressure is good. The rockers are getting oil too. No change in noise with clutch in or out.

The pick-up tube isn't bent.....I removed it when I took off the pan and looked it over when I reinstalled it. (not hitting crank/rod). I will have to check the noise again tomorrow with the timing light to see how often the noise occurs.

It is possible that it is clutch related......that is the only other thing I messed with, so logically if the engine checks out it has to be the clutch. It's conceiveable that I failed to double check that the bolts were tight. It's weird because it really sounds like an upper end noise.

 

[Deleted member 8987]

Upper end will be half crank speed, or, at 700RPM will be 350.

 

[nomad]

Another trick is to use a piece of heater hose up against your ear and searching for the source with the other end. Replaced a water pump because I though the bearings were squealing this spring. When the replacement did the same thing I got out the hose and found it was a vacuum leak!

Kurt

 

[Gerard]

I don't know why it would show up after the things you've done, but your description sounds a little like piston slap.

 

[aeronca65t]

Or timing chain? (does it have a spring or hydraulic chain tensioner that's stuck?)

 

[TraceZ]

I bet the crank is contacting the inside of the oil pan somehow. Maybe the new gasket on the pan is a different thickness than the old one so clearances have changed?

 

[Deleted member 8987]

I bet the crank is contacting the inside of the oil pan somehow. Maybe the new gasket on the pan is a different thickness than the old one so clearances have changed?

awwhhhhh.......nah, Don't think so. Lots of clearance usually....never seen anything close enough to hit. Stethoscope or hose on the pan will tell you....bell housing and Timing Cover, too.

 

[Billm]

Dave
Actually on the A15 you do need to use the proper A15 pan- it has extra clearances to allow it to work, the A12 & A14 pans hit.
Tracez may be on too something here!
Mike do you have the correct A15 pan on there?
BillM

 

[mrsprite]

I've used the screwdriver & hose trick and the noise appears loudest in the middle of the block where the mechanical fuel pump resides. I use an electric pump so the old one is plugged off. I did remove the mechanical poump and started it up....the noise is still there, so it isn't the pump itself. It probably is a bad lifter ot two......will have to check that out later in the week. It has only been a week since I last started the engine, so it would be strange if I did fry a lifter on start-up......I've started it up afetr its been sitting for 2 months and it fired right up without knocking, so it just seems odd (and very bad luck) that it happened this time (if it is a bad lifter due to oil starvation).

BTW....I thought about piston slap too. That would be something coincidental to the work I've done, but is certainly possible.

As for the pan gasket.....I used another Fel-Pro one that I used last time I had the pan off. They're the same thickness, etc.

The timing chain is a possibility.....at least the tensioner, but I doubt it. The car idles & revs without sputtering, Wouldn't the timing be messed up if the tensioner caused too much slack?

Anyway......I am taking a breather from it today and will tear back into things tomorrow. I'm going to check valve clearances again then prepare to pull the pan & timing cover to get the cam & lifter out. The lifters are solid, BTW, so a collapsed hydraulic lifter isn't possible.

 

[TraceZ]

middle of the block....


Going back to the oil pan... is it possible a baffle or something inside the pan got bent while it was removed from the engine and is now causing a rub?

 

[mrsprite]

Bill......it's the same oil pan that's been on it for 20 years, so it has to be the correct one (never had this issue before). It has been modified to fit around the Sprites very wide lower cross brace (it's been notched), but it is the correct A15 pan.

It is a good thought though as the A15 has a longer stroke than the A12/13/14, etc.

 

[mrsprite]

middle of the block....


Going back to the oil pan... is it possible a baffle or something inside the pan got bent while it was removed from the engine and is now causing a rub?

All baffles were intact and positioned correctly when I had it out of the car. I suppose I could drop the pan and start it up to see if it makes the same noise or not (I wouldn't leave it running, obv.).

I'm looking at pulling the cam out anyway and the pan is the first thing that needs to come off so it's worth a shot.

 

[58Custom]

What about the clutch?

Maybe a loose spring on clutch disk or PP. Maybe the TO or fork is loose. Pilot bearing? Noise change when you engage the clutch?

 

[mrsprite]

I changed out the disc due to oil fouling from the leaky rear main seal......the pressure plate & TO bearing were in good shape so I reused them. It hasn't been that long or that many miles since I swapped clutches and they weren't making any noises before. that isn't to say it couldn't be the clutch, but I'm leaning towards a bad lifter. I'll know more this weekend when I start pulling it apart again.

Also, the noise doesn't change at all with the clutch in or out.

 

[Deleted member 8987]

Bill- I know about proper pans, but it worked before....and having this just occur is a bit of a puzzler, especially since the old PP and T/O bearing were used. Middle of the block is something to think about.
Is this a constant rattle or a rhythmic "bang-bang-bang"?

 

[mrsprite]

It's a constant noise.....when you rev the engine it sounds "chirpy" (how's that for a technical term?). I did the timing light trick and it seems like it's one flash per noise.

With the screwdriver I can hear the noise pretty much everywhere.....it must be echoing pretty good, so pinpointing the exact spot is difficult. Again, it appears to be strongest between the distributor & mechanical fuel pump which is pretty much where the camshaft & lifters are so I'm leaning strongly in that direction.

 

[RickB]

I listened to your video file and it sure sounded like rod knock.
What are the chances you developed a bearing problem right when you did the other work? I'm sorry to say that's just what it sounded like to me.
I hope not, but hey you will be tearing it down somewhat anyway so you might as well...

 

[Morris]

oooch... I am sorry for your troubles... but I hate to admit I enjoy the mystery. Have you run it with the valve cover off? I had a horrible noise not long ago that turned out to be a valve clearance adjuster slamming into the top of my valve cover. Though that explanation seems unlikely given the other factors.

Ps. That A15 looks real good in your car!