Tappet noise?

[Gary Gregory]

Ok....replaced crank gear, Alum timing gear, new valves...guides, springs and I still get a very loud tapping noise. Engine was rebuilt several years ago..runs great..uses no oil. It been makng this noise since I bought it 3 yrs ago so I figured the valves, guides and tappets need replaced. I thought I would find the adjustable tappets with worn devits but they were flat and making good contact with the valve stem. The valves and guides were in good shape but I replaced them anyway. Any ideas as to why im still getting this loud noise..it seems louder toward the front of the engine.
How close can I set the valve clearance and without harming anything? Im thinking of setting them tighter than what the manual says.

[1931 flamingo]

Did you replace the cam tension spring in the front cover??
Paul in CT

[johnsor]

I have one of my Model A's with the same type of noise. After listening to it, I'm told by a very experienced mechanic that it is a piston slap and to not be concerned about it. Well I am concerned as it's not normal. I'll be interested to see where this post goes.

[James Rogers]

Piston slap and, it WILL sound like a very bad valve tap.

[Gary Gregory]

Yes...replaced the spring. What causes piston slap....bad pins?

[James Rogers]

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Originally Posted by Gary Gregory

Yes...replaced the spring. What causes piston slap....bad pins?

Excessive wear between the piston and cylinder which allows the piston to rock in the bore. There is usually no cure except a re-bore of the cylinders and replace the pistons and rings. Probably the only way to find out if it is slap is to pull the pan and inspect the pistons from below. If the piston skirts are smooth and not scarred you can run the pistons to the top and try to fit a feeler gauge between the skirt and cylinder to figure the clearance. In an engine like you describe, I would figure someone set it up too tight and scored a piston early on. Sounds like it is due for a tear down and inspection.

[Gary Gregory]

James...wouldn't the engine have lots of blow by and smoke if this was the problem?

[James Rogers]

Some but if it is just one piston and it is slight it may not show much. This may not be your problem but I would guess it is by the symptoms and the work you have done.

[Duffy1]

I had a 54 chevy that did the same thing . Replaced all the lifters still did it . Checked the cam and found one lobe had a small piece of metal gone . Replaced cam and noise was gone .

[Kurt in NJ]

Does the noise change with engine temperature? ---is there a change from when it is first started and warmed up

[Mike V. Florida]

What are the lifter gaps?

[Gary Gregory]

Sounds same hot or cold. Gap is about .012

[johnsor]

In my one "A" with the supposed piston slap, that experienced mechanic advised that I might go to a heavier oil like straight 40 weight Diesel engine oil. He said then if it doesn't get worse, "don't worry about it". Due to his knowledge and experience, I'll take his advice. Worst case, I eventually may have to tear it down.

[afuncar]

My new engine with stipe ib330 cam adj lifters strait valves one piece guides adj. to 012 clacks like hydraulic lifters when I first start and goes quiet after a few minutes of running, except for one valve or lifter that still seems to clack. mine I think is caused by a tight guide.Won't know till I take down to check, I'm very sure It's in the valves.

[PC/SR]

Short out the plugs one at a time and see if it goes away. That might provide a clue, narrow it down, but is not conclusive of anything. Since you have rebuilt the valve train, it is probably piston related as James notes.
I once had a tappet sounding noise on a fresh rebuild. Tried lots of things, finally tore it down after about 1200 miles, and measured everything. Found #2 cylinder was barrel shaped from the machinist, and the #3 rod end play at the crank end was .022. (Added: That same rod had only .004 clearance at the piston when it was all the way over to one end on the crank.)Take your pick. I lean to piston slap.

[James Rogers]

A compression check and a Vacuum test would tell a lot.

[KR500]

A piston which has excessive piston to wall clearance should be able to Knurlized. You can run less clearance on a knurlized piston, you haven't changed it's weight, and the knurlizing holds oil better.

[columbiA]

When I was at trade school in 56,I had the pistons knurlised when I o-hauled the engine in my 32 Chev coupe.It eliminated the piston slap & the engine used no oil in the 10,000 miles I drove it.

[Chuck Sea/Tac]

Originally Posted by afuncar

My new engine with stipe ib330 cam adj lifters strait valves one piece guides adj. to 012 clacks like hydraulic lifters when I first start and goes quiet after a few minutes of running, except for one valve or lifter that still seems to clack. mine I think is caused by a tight guide.Won't know till I take down to check, I'm very sure It's in the valves.

You might try marvel mystery oil in the gas. It stopped a slight ticking I had when my engine was new.

[afuncar]

thanks,I've done that and hoping it solves problem. Engine only has 500 miles on it. I've started to notice slight improvement when engine is warm.

[Gary Gregory]

Is it possible the can bearings could cause this noise?

[Tom Wesenberg]

Originally Posted by Gary Gregory

Is it possible the can bearings could cause this noise?

I also was wondering if the center camshaft bearing isn't too worn?