The Stovebolt Site Forums The Shop Area Engine Shop Bad engine noise - video.

I had a reputable machine shop rebuild a 283 SBC for me. Upgraded parts and wasn’t cheap.
I broke the engine in on my run stand with 30W Lucas high zinc break-in oil. No issues at all.
Then in the truck for some gentle driving. Got about 600 miles on it and then it started making a bad noise.
Here’s a video link. VIDEO LINK.
Machine shop pulled the oil pan off and said the bearings looked fine. They suspected it was a bad fuel pump making noise but I tested that fuel pump (see video) on a good engine (another 283 SBC) and it checks out ok.
I suspect the fuel pump lobe on the camshaft went bad. The shop is gonna tear it down and tell me what they find.
Ideas?

How does the engine run with the fuel pump and the pushrod removed, with gas supplied by an electric pump? What is the stroke of the fuel pump pushrod, measured with a dial indicator? A disassembly would be a last resort if the engine came to my shop with that noise, and only after some detailed diagnosis. I'd check the flywheel bolts for the proper torque as one of the first tests.
Jerry

Shop has the engine. It’s under warranty.

Uncle Rodney came to visit for Christmas?

Thank goodness for that.

I removed the flywheel myself and none of the bolts were loose.

I can't remember when I had my 283 torn down if there is a threaded 7/16" bolt hole inline with the fuel pump rod, I know on the 350's that hole goes through to the rod cavity and if you install a bolt that is too long it will pinch the rod. I wonder if a bolt is in that hole that is just slightly binding the pump rod and not allowing it to follow the cam, especially with the softer spring in that particular pump.

Would it wait 600 miles to start making noise?

That Sir, I can't say, stranger things have happened. The machine shop will certainly find out if that is the case. I don't think I have ever heard of the cam lobe going bad for the fuel pump.

That's a 3/8-16 bolt, not 7/16. It's one of the ones that were used to mount the bird leg motor mount brackets onto the early engines. The hole is intentionally drilled all the way through- - - -it's supposed to be used with a long bolt during a fuel pump change to keep the pushrod retracted.
Jerry

Yes, that is why my mind wandered to that thought, easy to change the pump by pinching the rod with a longer bolt. I apologize to all if I may have misled you with the wrong bolt size. I should have remembered that dang near every external fastener on the V8's can be turned with a 9/16". Thank you HRL for clearing that up.

I have only seen the fuel pump push rod fail on one engine. It was worn down so far that it wouldn't make contact with the cam lobe. It wasn't making any noise, just would actuate the fuel pump.

For a lot of years I kept a modified bolt in my tool box, with the first 1/4" of threads ground off, leaving a small diameter tip that didn't have to fight the sludge built up at the bottom of that hole. It made fuel pump changes a very quick job. Just barely snug the bolt against the pushrod and swap the pump out in a few minutes. Flat rate mechanics were an innovative bunch, as they got paid the standard labor for a job, regardless of the actual time it required. A good flat rate man could get 60 hours' worth of pay or more in a 40 hour week.
Jerry

I would have liked to hear the rpms change slowly up and down. And I would have used a stethoscope to listen to different areas. Sounded like a soft lifter to me.

A loose flywheel quiets down when an automatic trans is pulled into gear, or a Fred Flintstone manual transmission is loaded down by slipping the clutch a little. The noise goes away, or at least changes pitch, when the bolts have a little load on them.
Jerry

I used a piece of old garden hose as a stethoscope and the noise was hard to pinpoint but sounded loudest at the timing cover. I did not think to listen to the fuel pump.

Rather than a piece of garden hose, I think using a long, heavy screwdriver to the engine and putting the screwdriver head on your forehead is a better way to transmit the sounds for you to do your investigation.

Cheers, Dean

Have you checked the crankshaft pulley bolts for looseness? That noise is way too fast and erratic to be camshaft-related. The cam runs at half crankshaft speed. I bought a Corvair once for pennies on the dollar when it had loose rivets holding the crank pulley onto the damper. The noise sounded just like a rod knock. I had a welding shop tack the pulley to the loose rivets, drove the car for six months, and sold it for four times what it cost me.
Jerry

I've used a broom handle before, for detecting strange noises.

Did the shop find the problem yet?

I’ve not received any report yet. I’ll be sure to report what they find.
I have $5 on a failed fuel pump camshaft lobe.

The news should come today or tomorrow!

In 60+ years of building engines, I've seen two- - - -count 'em- - - - -worn out fuel pump lobes. Both of them were on extremely high mileage engines.
Jerry

Remember when I thought I had a worn out pump lobe because two new fuel pumps wouldn't pump a drop of gas up to the carb? Nope. Not a worn lobe. Crappy Chinese fuel pumps were the culprit.

I’ve racked my brain (didn’t take very long = small brain. LOL!)
I have not been able to understand the noise.
Water pump has not been tested but it was new and turns freely by hand, so it passes my bench inspection.
Not a noisy fuel pump because it’s not making noise now on my other 283. It was pumping gas good enough to drive highway speeds all the way home the night I made the video of the noise.
Builder says bearings look fine. I assume he looked at both crank and rod bearings.

We will just have to wait and see.

Update!
My engine is ready for delivery. Warranty covered everything!
Builder says it was a bad lifter.
Oh boy! At least it wasn't something worse.

Lugnutz,

'That is fantastic news that the issue was covered under warranty.

Very glad to hear that they stood behind their work.

that's great.

Nice news. And who mentioned that?



Truckrolet Online
'Bolter
I would have liked to hear the rpms change slowly up and down. And I would have used a stethoscope to listen to different areas. Sounded like a soft lifter to me.

Last edited by Truckrolet; 21/12/22 04:02 PM.[u][/u]

I think we had discussed this a little early on. From watching the video that Jay sent me I told him I thought it was from the Top End and that a rod or main bearing would have sounded a lot more solid. I'm glad they found the issue and your getting the engine back.

You should be getting good at swapping the engine in and out by now.

Ya, did they compensate you for the time and travel to pull the engine and deliver it? What if you had to hire someone to do the installation and removal?

The struggle is real. I spent plenty of money on the Carolina Machine Engines 283. It's a 1965 283 bored 0.060 with a mid-level performance build with a slightly lopey cam (268H Comp Cams flat tappet). It ran fine for 600 miles and then went back to the machine shop for the noise. So I installed the OTHER 283 I have. It's a 1966 block rebuilt by Jasper years ago but it sat in a trailer on the shipping pallet wrapped in plastic. It's 0.040 over and I swapped the factory cam out for a GK930 cam that Jerry says is a bit nicer than the factory cam.

So I have driven the truck with BOTH ENGINES. I can't say that there is a noticeable difference in performance.

The plan was always THIS . . . . Test each on the run stand and then install the one I liked best. Then sell the other one.
Swapping the Carolina Machine Engines unit back into the truck means another Loooooong weekend of work. What to do, what to do . . . . . .

If I sell the CME engine, I will lose money. (I knew that was a possibility from the start.) If I sell the Jasper engine I will break even on the investment on that Jasper engine.)

Did they replace just a lifter or the cam as well?

Were both of these engines all prettied up in that nice gray paint? I remember the pictures. But not sure which engine(s) I was looking at.

The warranty doesn’t cover my work time and energy. They picked it up and will deliver back to me. Pretty standard warranty in my opinion.

Both were painted and looking good. I favored the lighter gray with the Corvette covers. I could swap them to the other engine if I want.

Just playing Devil's advocate here, is it costing you anything to keep both engines? You after all know what it took to find these 283's and the work you have in them is excellent. If storage is an issue I know a guy

That's good that they did the transport, at least.

Delivered back to me today. It has fresh breakin oil inside and I’ll do another break in run next month. Too busy to do it sooner.
It looks like they reassembled the engine as far as they could with a new gasket kit. There is a box of parts that indicates they replaced all rings, bearings and seals.

New cam and all new lifters?

Full rebuild. I’ll ask for details.