When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I don't want to get in a conversation about oil, but I don't like wimpy weight oils that could also run a 4 cylinder, because of the sheer mass of the moving parts of a V-8.
Interesting technique! I never tried that one! But I have ran plenty a bore scope down a spark plug hole!
That's really an old, old troubleshooting technique - the theory is without the plug firing the load on the suspect cylinder will be less and the knock should lessen or disappear
Here's my vote for the satisfaction of keeping the original engine in your Vette. To me it feels right to have the born-with engine in one's car. That's what I did a few years ago with the original 327/350 in my 67. Storing the original engine on a stand in your garage until you die seems pointless. The only way to make sure the born-with engine stays with the car is to install it in the car.
I bought a BluePrint 383 last year and put a 700R4 behind it in my 1962. Couldn't be happier. I like the one piece rear main seal, too.
Randy, I'm glad it's worked out for you.
To clarify my statement; I have a NOM, so I'm not inclined to chase my *** having it rebuilt when I can drop in a motor that's 50lb lighter (alum heads) and makes way more HP.
Being active duty, I move every couple years and the warranty is peace of mind knowing I can drive ~ 8k miles a year.
If the mill ran good...and it IS a rod knock...you know you don't HAVE to go crazy. Yank it..flip it over , pull the pan and find the issue, certainly it's not 'spun' Either get a crank kit or have the original turned. Do an oil pump while pan is off. Measure big end of the rods, if good put it back together. Whole job $1500 tops...
Sometimes you guys spend money for no reason at all.....
Ugh, hate replying with my iphone...lots of errors hitting the wrong keys lol
the shop that I talked about before is saying 3200...not 4200. But that is everything.
Hot tank, magnaflux, bored, new pistons, rods, bolts, freeze plugs, crank turned and polished, all new bearings, cam, lifters,timing chain, oil pump, gaskets, and heads completely refinished and assembled.
I think I am going to stick with the original engine. Doesnt feel like a screamer being a 300 hp, but then again driving a stock 62 with a stock suspension and steering, I would be fine with the stock rebuild. Only thing I am debating is a cam, and maybe giving it a bump over stock.
Who knows, machine shop is saying 2 months. I might just say screw it and get a crate motor, and if the machine shop called and said "yeah, theres a problem" I could still go that route. After owning the car two months yeah, I could just pull the crank and lower assembly...but since I am going in this far, might as well start with a clean slate engine wise and not worry about it in the future.
Rebuild the original and do it right. If you're thinking of upgrading the cam, the L79 grind would be a good choice. Crate motors are great for cars that are NOM.
Had a dull deep knocking sound when warmed up, heard only at idle. My wrenching buddy arm wrestled me to drop the pan (327)...easy peasy to do. Disconnected a rod from the crank and confirmed the bearings were a copper color. Pulled the motor, leaving the top end intact. Rotated it on a stand, pulled the crank and had it turned down .020. Purchased a set of .020 undersized main and rod bearings. Replaced the oil pump with a standard Mellings. Torqued all to specs. Replaced pan gasket (1 piece Felpro). Shell Rotella T 15-40 oil and a Baldwin filter. While on the stand used an electric drill to verify 55 psi of oil pressure. Drained and replaced the oil and replaced the filter (to clear any possible debris, saw none).
Think I had less than $700. into this (bearings, machine shop labor to turn crank, oil pump, oil, filter and gaskets and my time.
If the mill ran good...and it IS a rod knock...you know you don't HAVE to go crazy. Yank it..flip it over , pull the pan and find the issue, certainly it's not 'spun' Either get a crank kit or have the original turned. Do an oil pump while pan is off. Measure big end of the rods, if good put it back together. Whole job $1500 tops...
Sometimes you guys spend money for no reason at all.....
It is too early in the diagnosis to determine you need a complete rebuild. Do a few easy things first:
You say it was recently rebuilt (right)? Do you have receipts from the PO? Find the shop that did the machine work and ask what was rebuilt. Was it just a valve job, or a complete overhaul? Don't be judgemental, and let them know you may be looking for more work to be done (honey buys honesty, vinegar gets nothing).
Pull a valve cover and look at the oil and grunge in the drain back holes and over the intake heat riser port. Is oil cooked to the heads? Does it look like it was recently hot tanked and cleaned inside (does it need hot tanked, again)?
Find the cylinder where the sound goes away with the plug wire pulled, and feel the rocker arm and pushrod free play at TDC. Is there any visual and touch/feel indication the noise can be valve train related?
Thinking that until you isolate the cylinder with the knock, you may have a main bearing knock (you said dull thump that goes away at speed). Does the knock clatter immediately on engine coast down? Does the knock continue on chop throttle but dissipate like slowly turning down the volume with each revolution (indicating a wrist pin or rod journal), or just go away (more like a main journal)? Does the crank walk forward and back on light acceleration (indicating a main journal thrust bearing)?
All of the above diagnosis can be accomplished without special tools or crawling under the car. The findings may turn up nothing better than what you already know (it knocks), but it might close out a few options.
Best case:
1. bent pushrod, or bad rocker arm or pivot ball, bad cam lobe/lifter.
(replace & drive)
2. bad main bearing, thrust or un-spun bearing shell.
3. bad rod bearing, un-spun bearing shell.
(replace, emery cloth to dress journal, and drive)
4. spun main bearing shell.
(crank comes out)
5. spun rod bearing shell, wrist pin seized, broken piston or ring.
(engine comes out, replace/resize rod, piston, crank, etc.)
The car is new to you. Doing the above diagnosis is like dating. Do it slow, and with your complete attention (and it's too late to call off the wedding, you bought it , so make the best of it and think where you want the relationship to be in ten years).
And then of course there's people like my crazy brother who has been driving his F-150 truck for a decade to haul construction supplies and trailer his boat around with a rod knock which he refuses to fix. He won't even switch to a heavier oil
Another vote for diagnosing the problem and repairing it, keeping the matching numbers engine in the car. Disable the ignition to each cylinder one at a time to determine which rod is the culprit. It could be a fuel pump, as previously stated. If you pull the engine and disassemble the lower end, it could just need a crank turn and new bearings.....as stated, not expensive or particularly time consuming.
1955 Copper is right, a hunk of carbon sounds just like a rod knock, but a rebuilt enging shouldn't have any copper.
Put the car in the air, take a long screwdriver or better yet a stetoscope or even better yet a set of chassis ears [look 'em up] and locate the noise.
You said it was a rod knock,
I mean a rod knock is a rod knock.
I'm guessing you may don'tt know what a rod knock really sounds like. Pretty distinctive..Any decent old time hot rod guy can call it.
Maybe it's not a rod knock at all. Honestly, only really BAD knock, is a rod knock. Most everything else is pretty drivable. Some degree of noise is really fairly normal, don't go chasing rainbows here..
1955 Copper is right, a hunk of carbon sounds just like a rod knock, but a rebuilt enging shouldn't have any copper.
Put the car in the air, take a long screwdriver or better yet a stetoscope or even better yet a set of chassis ears [look 'em up] and locate the noise.
You said it was a rod knock,
I mean a rod knock is a rod knock.
I'm guessing you may don'tt know what a rod knock really sounds like. Pretty distinctive..Any decent old time hot rod guy can call it.
Maybe it's not a rod knock at all. Honestly, only really BAD knock, is a rod knock. Most everything else is pretty drivable. Some degree of noise is really fairly normal, don't go chasing rainbows here..
BTW how is the oil pressure?
Agree with all this.
Today's modern engines don't knock, click, clack or clunk. They just don't make any noise. I'd have someone with experience on yesterday's SBC engine to listen to the engine before I did anything else.
I also agree with changing rod bearings IF they are worn and IF the crank is still round and IF the rest of the engine appears sound.
Changing a bearing USUALLY is a very temporary fix. Often the reason the bearing is wiped is from foreign matter or lack of lubricant. USUALLY there is corresponding damage done to the crank surface, the boogered up crank will is often short time wipe the new bearing.
I have successfully replaced a bearing ONCE, rest all failed in short time, conversely I've re-cranked maybe 10 time always with success...
Had a dull deep knocking sound when warmed up, heard only at idle. My wrenching buddy arm wrestled me to drop the pan (327)...easy peasy to do. Disconnected a rod from the crank and confirmed the bearings were a copper color. Pulled the motor, leaving the top end intact. Rotated it on a stand, pulled the crank and had it turned down .020. Purchased a set of .020 undersized main and rod bearings. Replaced the oil pump with a standard Mellings. Torqued all to specs. Replaced pan gasket (1 piece Felpro). Shell Rotella T 15-40 oil and a Baldwin filter. While on the stand used an electric drill to verify 55 psi of oil pressure. Drained and replaced the oil and replaced the filter (to clear any possible debris, saw none).
Think I had less than $700. into this (bearings, machine shop labor to turn crank, oil pump, oil, filter and gaskets and my time.
Motor sings all the way to 6,500 r's
Here's some pics:
My experience.
Jim
In God We Trust!
If you would have done all of that without removing the engine, I would really be impressed! Just joking and giving you a hard time! Honestly good job!
Changing a bearing USUALLY is a very temporary fix. Often the reason the bearing is wiped is from foreign matter or lack of lubricant. USUALLY there is corresponding damage done to the crank surface, the boogered up crank will is often short time wipe the new bearing.
I have successfully replaced a bearing ONCE, rest all failed in short time, conversely I've re-cranked maybe 10 time always with success...
I edited my post above and took out the word I mistakenly said, "just replace bearings". I meant fix/check the crank too.
You're correct that if the bearings are gone, there's probably something wrong with the crank as well.
I once spun a rod bearing in a SBC. I pried off the crank that it welded itself too. Took a file to the crank and then a long strip of emery cloth and shined the crank up. Installed a new .001 OS bearing, put it back together and drove it for another six months until I had the bucks to buy a new 327 engine. Don't recommend anyone else do this. Just did what I had to do.
I struggled with the same decision on my 65 project. I even went to the trouble of figuring out how to make a new crate motor look like an original 327. In the end, I rebuilt my stock engine. The machine shop bill came to $2,000. That included a hot tank on the block, bore the cylinders, turn the crank, rebuild both heads with all new valves, valve springs, and valve seats. The rest of the parts were less than $1,000. I put it together myself. An honest shop will assemble a small block chevy for a few hundred dollars. In the end, your car will be stock and a lot more valuable. In my experience, having a crate motor in the car with the stock un-rebuilt motor in the garage is still a big hit as far as market value. I am not an NCRS kind of a guy, but my personal preference is an all stock car. I hope that it turns out to be something cheap and you can get back to enjoying the car.
10-05-2016, 03:51 PM
