Joined: Dec 01, 2008 Posts: 64 Location: Lexington, KY USA
Posted: Sun Mar 28, 2010 8:25 am Post subject: Engine Clatter
Lately I've been trying to pin down and fix the abnormal noises coming from my M38A1's engine bay. So far my dad and I have replaced the rocker arm shaft and rocker arms, and removed the house cat. That cleared up most of the noise. However, there is still one distinctive clatter, and it seemed to be coming from the fuel pump.
Now, I know these old mechanical pumps make some noise, but I've heard healthy M38A1s running and didn't hear anything as loud as this.
A little background, first, though.... The pump is a fresh rebuild of the original, done by Then and Now. Superb job. So far as functionality goes, it's perfect. I recommend them highly.
But there is a noise. My grandfather says that it sounds like the pump arm and cam lobe aren't making good contact, and there's some space between resulting in the clatter. My question is, if this is the case, how does one fix it? Is this a problem that's going to result in a larger problem if left alone? Is it even a problem at all?
Thanks for any input. And no worries, I was just joking about the cat.
- Deino
Ed. It is not the fuel pump after all. _________________ - Dan
You did install the pump with the original spacer between it and the block? _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
My question is, if this is the case, how does one fix it? Is this a problem that's going to result in a larger problem if left alone? Is it even a problem at all?
If Zane's idea is correct then the only risk is an eventual loss of fuel pump pressure and continued wearing of the cam pump lobe. The bad cam pump lobe usually comes from running the pump without the spacer. Once the light hard facing is penetrated on the lobe the ensuing wear is rather rapid. One other note is this wear metal has to go somewhere and that somewhere is the oil and that oil delivers that wear metal to the entire rotating mass of the engine.
So to answer your original question, "to fix it" new cam. "Will it result in a larger problem?" Yes.
Any other options? Remove pump. Install a bolt on cover plate with a gasket and install an electric pump and regulator.
Of course if you know me at all I don't advise using bandaid fixes. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
Joined: Dec 01, 2008 Posts: 64 Location: Lexington, KY USA
Posted: Sun Mar 28, 2010 9:08 pm Post subject:
Luckily I have a spare cam. However, I'll have to wait until after the 10th to check this out more thoroughly. Military parade; here's hoping for good weather! _________________ - Dan
Joined: Dec 01, 2008 Posts: 64 Location: Lexington, KY USA
Posted: Sat Apr 03, 2010 10:23 am Post subject:
Was running the jeep yesterday and noticed some things....
One, when I held the brake and let out on the clutch to put some torque on the engine, the clatter nearly vanished. That is, it got so quiet it was difficult to hear. I'm assuming if it was the fuel pump lever on the cam lobe, it likely would have just slowed down with the engine, but remained nearly as loud....
Two, the noise reduced after running the engine for about 5 minutes, and was about half as loud around 10 minutes.
Three, listening to it from the engine bay made me second-guess myself as to where it's coming from. Sounds higher than the fuel pump. When my dad and I had the head off during inspection some time ago, we checked for any scaring from pinging and whatnot, and checked the piston wrist pins for slop. Everything seemed fine.
I'm kind of at a loss here. _________________ - Dan
Loading the crank and reducing the clatter points to an issue with crank end play. If the last engine assembler forgot the oil slinger behind the crank drive gear then your crank may be slamming forward / aft too much and the washers or shims are rattling. Check crank end play by relieving belt tension and pulling and pushing on bottom pulley. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
Joined: Dec 01, 2008 Posts: 64 Location: Lexington, KY USA
Posted: Mon Apr 05, 2010 10:21 am Post subject:
Will do, Wes.
I think we've decided that, after the parade this weekend (it's only 3/4 mile long) we're going to pull the engine and do a complete check of everything. From previous inspections, it looks like the engine was recently rebuilt, though they only did what was absolutely necessary (i.e. honing the cylinders, new pistons, decking the block, changing the bearings, etc.) They did nothing to the valves, tried to fix the distributor, and lost some parts out of the carb. Well, so much for what was necessary, eh? The engine ran only after fixing all of what someone had screwed up. We'll see what else happened next Sunday.
Thanks for all the suggestions. I'll update when I figure something out. _________________ - Dan
Joined: Dec 01, 2008 Posts: 64 Location: Lexington, KY USA
Posted: Sun Apr 11, 2010 5:20 pm Post subject:
We removed the engine this weekend and tore into it on a stand. What we found was somewhat unexpected, though at this point I can't really say I was shocked.
First thing we did was check for end play in the crank and we measured 16 thousandsth at the thrust bearing. Book specs call for 4 to 6 thousandsth. Oil slinger was there. Either it was improperly shimmed, the thrust bearing is worn, or the crank itself it worn...we think.
We're still going to check the wrist pins since we've got it down this far.
Any suggestions or posed questions would be appreciated. _________________ - Dan
Joined: Jan 09, 2009 Posts: 34 Location: Newnan, Georgia
Posted: Fri Apr 23, 2010 6:41 pm Post subject: noises
My F head was noisey when I purchased the jeep, the noise would quiet down around 1500 rpms, and was qiute noisey at idle. During overhaul I found it was the exhaust valve guides worn out and the play allowed the valves to rattle around in the giude.
This noise sounded high in the block too. _________________ '53 CJ3B Hurricane, 5.38s, lockrights, koenig PTO winch. M606 conversion in progress.
In the land of the blind.... the one eyed man is king
Joined: Dec 01, 2008 Posts: 64 Location: Lexington, KY USA
Posted: Sun Apr 25, 2010 5:03 pm Post subject:
Turns out there were a whole bunch of problems. Long story short, I'm basically rebuilding the entire engine, including honing out the cylinders (true-ing them up to 40 over as the pistons indicate). It needs a new crankshaft; the one in it was rebuilt incorrectly. New cam. Might as well re-do it all and get it right now. _________________ - Dan
Joined: Jan 09, 2009 Posts: 34 Location: Newnan, Georgia
Posted: Fri Jun 04, 2010 2:37 pm Post subject:
I forgot to mention, I found the previous shadetree mech had left the oil slinger off the crank- .056 of end play, probably causing most of the noise. He put it in the oil filter housing for future install in the proper location. So I have an extra one now. _________________ '53 CJ3B Hurricane, 5.38s, lockrights, koenig PTO winch. M606 conversion in progress.
In the land of the blind.... the one eyed man is king
Joined: Dec 01, 2008 Posts: 64 Location: Lexington, KY USA
Posted: Fri Jun 04, 2010 2:43 pm Post subject:
It's nearly fixed now. Having some set-backs (4 of the connecting rod bolts stripped when torquing them down to spec...sheesh). I've got .050" of end play now, though, so I think my noise should be taken care of once we get the engine back in. _________________ - Dan
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