I need a bit of advice from the 300 experts. I've built quite a few engines so but this is my first 300. Heck they never wear out....The only reason I did a rebuild was oil pressure problems persisted after a pump and screen change. It had 355,000 on it and it spent most of its life pulling heavy loads. The mains and rods were worn out, so it was time.
After break in, my problem is sounding like rod knock in number 1 cylinder, I think. I took the plunge and installed a Cloyes 81014 timing set. Its their best and I have heard that they can be noisy. So here's my question, Do these gears make a clanking sound? The supposed rod knock seems to be very concentrated toward the front of the engine? Its also not constant like a rod knock would be. It starts after everything is well warmed up and isn't present when the engine is cold. That's the confusing part, in my previous encounters with rod knock its there from the moment the engine fires until its turned off. I plan on dropping the pan this weekend and seeing about the rod bearings. If their good I guess that leaves the timing set? Anybody ever have a clanky gear set from Cloyes?

 

It could be in the timing set. I had a knock in the front of my new rebuilt engine and it was the timing set. My re-builder replaced it and it was good to go.

 

How did you diagnose it? When I was assembling mine I thought I heard a clank but checked the rods at that moment and they seemed fine. I was unable to duplicate it so maybe you're right. But its going to be hard to tell for sure without opening her back up. Luckily I can drop the pan without an engine pull. I have the cam gear puller so maybe I can get the set out without too much work. Cloyes does have a lifetime warranty or should I use another brand?

 

It was determined by my mechanic when the engine was first fired up. The engine was pulled and sent back to the machine shop for the fix.

 

I have about 1000 miles or so on my new long block with the Cloyes gear set. It's as quiet as a mouse..to my surprise. I can tell there is sort of a "whir" perhaps but not really any noise.

I DID have a similar knock in the old engine though. turned to have a cam lobe going flat and the crank shaft had some main bearing issues..(I had only changed the rod bearings when doing an i-frame re-ring). I had NOT pulled the lifters or checked the cam for lift.

I'd have a hard time suspecting the cam gear if it is a new 8-1014 alum/steel set.

 

Knocking in a new set of gears is not usual but isn't unheard of either. The noise was hard to isolate. It sounded like it was between the #1 and #2 cylinder. When my mechanic called the machine shop they told him it was probably the gear set and to send the engine back. I also have a bit of whiring noise but it doesn't bother me.

 

I had the same problem as harte3. I thought it was rod knock the second time I started up a newly rebuilt engine. The rebuilder diagnosed it as the timing set. The gears came with rebuild kit, rings, gaskets, etc. The machine shop who reground the cam had also made the base circles too small so the lifters sounded like a machine gun (exageration, but loud.) I swapped the cam with an Isky, new lifters, new gears, and I'm still driving it.

That was engine #2, after the first failed within 1k miles due to falling oil psi. My opinion of mechanics dropped with the oil pressure. Many machine shops may as well be in Tijuana. Research pays off.

Keep us posted. I would very much like to hear whether or not it is the Cloyes set making the noise. They have a tremendous reputation.

 

My 82 has steel gears, and knocks. More of a thunk. But it is definitely the gears

 

I have the Cloyes timing gear and my engine just started to sound like I have timing gear drive its not so loud though

 

I won't be pulling the pan until this weekend but I'll sure keep you guys posted. I have used the same machine shop for years and the owner knows me by name. However, the history on this job is bad. I took the block head crank and piston/rods in with all my new parts. The only parts I didn't buy were bearings as the crank was most likely going to need ground and polished. Well they did everything up and he told me since I was a regular and this was my personal vehicle he would assemble the bottom end for me. I said sure sounds good. This guy builds most of the drag motors around here and does work for RHS. So I figured cool. I went happily and picked up my assembled short block and took her home. I mounted it on the engine stand and slid a new damper on and went to give her a roll over. I couldn't even turn it over with an 18 inch breaker bar. I pulled number 4 main. it was full of crank turnings. I pulled number 2 it was jammed full and had gouged the bearing. I was pi$$ed. I loaded it back in the wifes suv and drove right back there. I left the main caps loose. When I got there I just unscrewed the two shells and showed him. Then I asked for a clean paper towel I stuck it down bore number 2 and wiped. It came back black with honing dust. I asked him "do you send them all out this way or am I special". He was completely embarrassed. He said he had an employee that was working his last day when mine was assembled and he already had two come back from the same day and said he would assemble mine personally. Well when I got it back it was spotless. I checked everything and pulled each bearing. It was right as far as I could tell.
Believe me, if its got a scored bearing I'll be making another trip to his shop and we'll be "discussing" it. It has been through 20 minutes of break-in and about 46 miles. It was broke in with comp cams oil additive and the oil dropped and filter changed. I did it like every engine I've built in the past 20+ years and he has done all my machine work. I have never had one like this. That's why I'm hoping its a noisy set of gears. Its also a whole lot easier to change a timing set then pull the engine and change the crank.

I guess my old ways of being paranoid and wanting to blueprint every engine I build was right. I've never had this problem before until I let a "pro" do the sub-assembly work.

 

Just curious: Was cam end-play within specs? ...jack

 

yep! It sure was. Measured at .003 with a dial gauge.

 

Well I discovered the problem. With the help of a long phillips head and some listening, I isolated the knocking to the camshaft drive gears. Like I said, I have a Cloyes 81014 set. It has an aluminum cam gear and a steel crank gear. It also has 3 key ways to adjust the timing. Mine was in stalled "straight up". After pulling the timing cover, I was just dumbfounded. There was a small amount of aluminum on each side of the pan gasket. So I started to turn the crank and see if I could find a chipped tooth or some kind of wear. All the teeth looked good. Then my drop light slipped and I caught a flash off something shiny. Well, getting a mirror and turning the crank so I could line up with the cam retaining plate bolts, it was as plain as day!!!



That's why it took so long to show up. The engine would have to heat up for a while. Apparently the cam gear, being aluminum would swell enough to hit the bolts. The right one was even closer and that's where the knock was coming from. This is what you get when a "pro" assembles your stuff. I pulled them both and ground about .060 off of them. and put them back. There is plenty of clearance now, but I have a question. In the factory manual the bolts are not listed as Cap screws. They are shown as 2-grade 8 hex head bolts. I think the mod I have done will work, but should I exchange them for 2-hex head bolts? I don't think I have room to do the swap as I would not be able to get a socket on them through the gear. I'll have it back together tomorrow as I tore the timing cover gasket. Needless to say, I dropped the oil and ran it through a couple of strainers looking for stray aluminum. I didn't find any. I then, with the oil pan drain plug out, flushed out my oil pan with about 2 quarts of gas, followed by about a gallon of soapy water, followed by about an hour of compressed air to dry everything back out. It's sitting air drying now until I get the timing cover gasket tomorrow.
Any suggestions?? I don't think I'll have any more problems as I have a full 1/16 of an inch between the ground cap screws and the back of the cam gear. This engine will have had three oil changes within 50 miles..... And thanks to everybody who helped me think this one through. When I get her back together I'll give a final update.......hopefully.

 

wow, i'm glad u found the problem. headboltsdotcom sells the thrust plate and the bolts is u need them in the future.

 

Cap screws are easier to install in limited access areas, probably why they were used...but gotta be careful due to the extra clearance needed. I'd replace them with what's supposed to be there if they will fit without taking the whole thing apart-you can more accurately torque a hex bolt. Use a magnetic socket to install. ~Bill