Okay, I just got my F-head 161 finished and ran it on an engine stand (thank goodness). It started and ran after a balky attempt or two. A total of about 3 minutes (three starts due to stopping oil leaks) Anyway, at about three minutes it sounded a little different and started knocking, evidently from the bottom end and seemed to be coming from the front of the engine. I shut it off right away. I did have one cylinder (#2) that was not firing due to a loose plug wire. Since then, I've taken it apart and other than end play on the #2 rod on the crank end(.013 instead of a max of .009)I haven't been able to find anything wrong. Bearings all look good, clearance was right on target when I put it together. The first assembly was 40 over, new rings, reground crank, 10/10 crank and rod bearings, reground cam and new bearing. Plastigaged main and rod clearances. Piston to cylinder clearance was correct. Ring end gap checked and corrected to spec.
Edit to say..Oil pressure was 40lbs while running and 20 at idle, and everything inside seems awash in super slippery Brad Penn oil. Carefully drained and let the oil run through very fine paint filters (it's all I had handy) and nothing of interest was in the filters.
So, got any suggestions? or would the generous end play on the rod sound like that?

Thanks:
Paul

I don't think the end play would do anything other than let a little oil slip out the sides of the bearings but I don't think .004" is a big deal.

How do the cam bearings look? Does the bottom side look squished out? Even with the cam in?

At lower RPM's especially, the crank thrust or cam thrust can start banging back and forth if its excessive. Have you checked either one of those. Does the cam have a thrust plate on it. Did you check the endplay of either when you assembled the engine.

Beater:... Thanks for the input. I'm having a hard time making that noise and the rod end play come together. I have another set of rods to choose from and when it goes back together I'll get a better fit.

tlowe: I'll look into the bearing on the cam today. I was hoping to avoid taking the cam out but... Out it comes.

CNC Dude: The crank was right on the numbers for end play when I assembled the engine, and I'm pretty sure the cam was as well although my memory isn't giving me an answer at the moment. I can't imagine I wouldn't have checked it. And yes, the cam does have a thrust plate. I'll recheck the cam end play this morning before I pull it out.

Thanks everyone for the help and ideas:
More as news develops
Paul

Fuel pump?

The end play for the crank and cam measure as they should as does the lash on the timing gear. Cam bearing looks good. I measured the lift for the exhaust valves at the valve and they are with 1 thousandth. (the head is off so I cannot measure the intakes)But doing a stare and compare, the lobes for the intakes look fine and do not appear to be damaged.

Gearhead1:.. Fuel pump is next, and I'm running out of parts to check. I'm going to order a rebuild kit for the pump Monday as well as a new gasket kit for the motor.

I'm baffled..
Paul

You can probably tell if the pump is making the noise by simply removing it and actuating the lever. There should be no slop in the lever arm.
(I'm assuming a lot because I don't know anything about this engine.)

I chased what I thought was a lifter/rocker noise on my 270 GMC for years. I adjusted and readjusted several times. I checked the cam, changed lifters, push rods, and rockers. I finally decided to live with it and just wait for something to break. Nothing ever did. While doing an "update" I switched from tube to cast headers. The noise disappeared. I hate that kind of crap.

Oh, that's an easy one. Header wobalator valve.

Great I was afraid it was the fleeber housing gasket. The wobalater valve is a lot easier to get to.

Right now, I'd settle for either one. Fuel pump doesn't seem to be hurt, but I did order a rebuild kit for it along with new gaskets for the motor...

I have not found anything out of spec inside so it's going back together. Double checking everything as it goes back together. I really don't like not knowing what caused the noise I was hearing but lacking anything turning up, it goes back together.

Thanks for the replies
Paul

Timing knock? Too much advance. I'm thinking something simple. That's why I told the header story. I just sounded like a knock. At least you know several things it is not.

Thanks Beater.. I'm going with that. Something happened, but so far, left no trail. I'll know by next week one way or the other.

Thanks again
Paul

I assume that a Willys ? I rebuilt a F four Hurricane and it had a slight knock from the from that cleared up after about 20 minutes.....I never checked but I bet mine was the new fiber timing gear...It's been fine for several years...

Wristpin to piston clearance opening up on one perhaps?

Xerxes...any updates about the problem??

Xerxes...any updates about the problem??

Xerxes...any updates about the problem??

Xerxes...any updates about the problem??

Update. I've been going over everything, checking, measuring, cleaning.. It's going back together now and I have found nothing that would explain what was going on as far as fit or clearance. All the bearings are good, end play is where it's supposed to be on the crank and rods. Lash on the timing gear is correct. I had one cylinder that was not firing as the others were (as evidenced by the lack of soot on the exhaust valve or piston top) so I'm going with one dead cylinder (plug wire) and timing as the likely culprits. It'll be a few days before I have it closed up and back on the run stand. (I've got a few real life things that keep popping up) I'll post the results, good or bad when it happens.


Regards:
Paul

I would try another set of timing gears. I once built an engine that sounded like it had a bottom end bearing knock. I changed out what looked like a perfectly good set of gears and the noise went away.

crank throw scuffing the oil pan? this happened to me once on a Rambler six, a seemingly-insignificant dent on the pan caused a crank weight to scuff, made a terrifying sound on a new engine.

if none of the usual suspects are causing it, a stethescope might locate it. my father (g*d rest his miserable soul) used a long screwdriver for that; handle on the bone behind his ear, tip on suspect location. surprisingly precise.

FTF.. I hope it's not the timing gear, because I just closed it back up. But as you said, it looked really good and I double checked the lash and end play. But I haven't found anything else to blame either...
Tom.. I did check the crank throw a couple of days ago. I wondered about that possibility but there is ample clearance.

Thanks:
Paul

Wasn't there a video for this at some point? I thought I remembered there was.

One possibility... does the transmission happen to have a PTO on it? If it does... is it engaged but not hooked up to anything? When the trans spins, the PTO would spin as well... and the u-joint could be hitting up against the trans body. I know you said it sounded like it was coming from the front of the engine... but its a possibility that hasn't been explored (but happened to me the other day)

Okay, update...

Back together and on the run stand...Cranked it up tonight and no knocking. Compression check was good. 125 to 130 psi on all six. Had one cylinder not firing...new plug wire and it came to life. Running really rich. Closed down the idle circuit and it cleaned up. Still not happy with the mixture (Carter YF) but a new carb is next. It's sitting on the shelf and I'll get it on in a day or do. It's a Holley Webber and I have to make an adapter to clear the valve cover.
Never did find a reason for the knocking on the first run. But I am very glad it didn't reappear this time. A few tweaks, a few shiny pieces need to be made and back into the truck it goes.

Needless to say, I'm a happy camper and I'll sleep a lot better tonight.

Paul

That's great and though you spent extra time it is time well spent just for peace of mind.

I don't know about your engine but Chevy stamped rocker arms can make knocking sounds sometimes. I know this for sure because I've watched the noise come and go as the pushrod revolves. Slight out-of-true pushrod moves the rocker alignment around and the noise comes and goes with the alignment shifting around.

And Again...

The latest update.. I got the new carb on it. A Holley Weber 32/36. Had to make an adapter for it. It needed to up and out to the side so to speak. A $20 block of aluminum and several hours on the milling machine (I'm a rookie)and some time polishing it (had to have something shiny) and it worked. Before I changed the carb the motor didn't seem very crisp. Sounded sort of like an aircraft engine running up with one mag instead of two. I took the ballast resistor out of the circuit (per instruction sheet from Pertronix) and between that and the new carb it's like a new motor (Newer than new)I still have a random miss I'm pretty sure is the number one cylinder. I gave the distributor cap a good look and cleaning, as well as the rotor. Cap was a little oily but otherwise seemed okay as did the rotor. Ran it until warm and set the intake valves. (exhaust valves were set cold per the manual).I installed a vacuum gauge on the run stand control panel for the next run. Overall, I'm really happy with the build. It's really cool to see the change in this motor. Can't wait to get it back in the truck.

Pics of your machined block of aluminum would be cool to post.

MBHD

Sure... Here are a couple of pics of the adapter I made to fit the H/W carb to my motor.

first rough fit. old vacuum line will be re-routed. (lots of crap in the shop)


a little more cleaning up and another angle..


after a few (too many) hours polishing


Anyway, it fits and works...clears the valve cover. And it was fun to do.

And this one is waiting in the wings..It'll have two Carter YH carbs.








But first, I'm making new side covers and a new valve cover..More to follow. Progress is slow.

WOW, I was thinking of a flat plate with holes in it. Home made hot rod stuff in the best. I can do holes in flat plates.

Very nice work.

MBHD

WOW! I wish I had access to machines like that and the skill to go with it. Very nice! Jay 6155

About the machines.. The big milling machine, a Bridgeport, belongs to a friend of mine who has been very generous with the machine and patiently trying to teach me how to perform the most rudimentary tasks and not hurt myself or the machine in the process. I have a smaller Chinese type ( available at a variety of discount tool stores ) which was well used before I got it. But as you can see, even a well used import machine, used carefully, can be very useful. Takes a while to learn how to use these things and given my current age, I may have gotten about as far up the learning curve as I'll likely get. :-/ It is fun though.