Hi All, So... I've had my '49 back from the mechanic a while now and have just got around to rewiring, installing an exhaust, and upgrading to a MSD ignition system. When I fire up the engine, I hear a clacking sound from the passenger side head near the water outlet (number one cylinder). I did a timing light test and it appears to stay in tempo with the light (though slightly off from the flash) and putting a piece of wood to the engine definitely helped localize the sound. So I'm guessing I've got some kind of valve train issue. My question: since I'm a novice, is there anyone in the CA. SF south bay that may be able to help me sort it out? Or, does anyone have a recommendation of a shop in the San Jose area that they would trust with their flathead? After reading a lot of threads on this subject, I know its pretty much impossible to diagnose a problem via internet, so I figured I'd skip that step and move on to finding an experienced local. Thanks! -Stefan
A novice can remove a couple of rows of bolts and yank the manifold carefully without getting into anything complicated...give it a try. Betcha a nickel you simply have an adjustable lifter whose adjustment has gone walkabout. If so, you can diagnose it by eyeball, and we can walk you through the fixxit for the price of a tube of Loctite and a Sears feeler gauge. Either that, or vaporlock from a ruptured power valve has cracked your block and blown your gasket, and you need to swap in an LS-10 with digital fanbelts to get away from all that evil old junk.
The good part is the flathead is a easy one to work on. Taking a look at the valve lash is easy and dosen't take a lot of time and a good way to increase your mechanical education.
Thanks guys. Off with the intake manifold! (At least no one asked me to check the timing chain or pushrods.) -Stefan
If the gasket is ruined, spray down the new on on both sides with WD 40 twice. That will make it reusable several times. There is no fluid going through it, if everything is clean, it works.
Thanks, Don. Will do. Ok, the manifold is off and it does appear that there adjustable lifters in place. (Skipping ahead, if the gasket is intact, can it be reused, or should I replace it?)
Next step, look to see if someone drilled 1/8" holes in each of the lifter bosses. If they did you can use a drill bit to hold the lifter from turning while you adjust the clearance. If no holes, then you need a special tool to hold the lifter while adjusting the clearance. Wally
You need the special tool that catches the holes in the top of the lifters while you adjust the hex. Sorry, I can't give you a source. Try searching for the "Johnson Lifter" tool.
Set of adjustable lifter wrenches has been ordered. Hopefully I'll be set to tackle all of this next weekend. In the meantime, I'll need the low down on properly setting the lifters and I should be set! Thanks guys, -Stefan
Off the top of my head the clearance should be 0.014". Seems like Intake might be only 0.012". If you have noise, I'm guessing you have a lot more than 0.014". Wally
QUOTE=49 Custom]Thanks for the encouragement, Bruce. I've seen your post help quite a few novices, so I'm happy to have your input. I can handle pulling the intake, but what would be the next step in sorting the problem? Think about how you detach stuff to save trouble...disconnect fuel lines and linkage so intake come off as one lump, no fiddling needed. Get a 7/8" socket an rotate the engine...you have the area located so eyeballs on that area, base of valves/tops of lifters. With noise you are probably going to see one gap visibly much larger than the other 15 as you turn...most likely just an adjuster bolt that was too loose in its threads, but just possibly a failed cam lobe probably due to mechanical error by grinder. Once loose lifter is spotted, get small caliper or good steel rule, measure lift on a good tappet by rotating engine to high and low, then measure same on loose lifter (mark the rule so you don't have to read 64ths in the valley). Again, not a precision thing...if cam has failed, lift will be missing a very visible amount. If lft looks normal, screw out lifter screw as far as you can and clean screw repeatedly with spray brake cleaner...next step will be readjusting it with a drop of loctite to end the foolishness! Clearance spec is specific to the cam, assuming aftermarket gasket can be reused if nothing stuck or tore.
Ok, wrenches are on order- next question is about the lash. Apparently, depending upon A) whether or not I have an early or late '49 engine affects the gaps: .012 intake .014 exhaust on an early, .014 and .018 on a late. B) whether I'm using stock lifter or adjustables (it looks like it all goes to .014 if they are adjustables. I don't know whether I have an early or a late, but I DO know that I have adjustable lifters: does this mean that I should be gaping at .014 for all? Thanks, Stefan
I'd find the smallest gap of all intakes and all exhausts and go from there. If the smallest intake is 0,012" it may be an early.
Update: I pulled the intake, got my feeler gauge out and measured the lash on the lifters. All but one sat between .014 and .018 with the intakes sitting at the lower value and the exhausts at the higher. The one oddball was the #5 exhaust which was around .020. I reduced the gap, buttoned the whole thing back up and started the engine. The clacking is still there. Same spot near #1 exhaust. Is it possible that I'm hearing sparking between wires since they are all bunched up near the distributor? I still suspect it is within the block because I can feel the vibration on the passenger head, but I'm trying to consider all possibilities. -Stefan
Since noise is at front...start by removing belts, taking a bunch of things out of operation. Next suspect might be loose timing gear.
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