Hi,

355 Blue Print Crate, Flat tapett, maybe 6-8K miles. oil is 10-30 valvoline racing

I have a slight valve tap on cold start up, can't always hear it, kind of depends on where the car is parked and if the noise bounces off something like a car parked next to it. I heard it when I got it last year but you just don't always hear it. I heard it yesterday and investigated with a hollow rod, I can hear it on the manifold runner for #8. It is not audible after the engine has run for maybe a minute and its really only audible around 13-1500RPM, but you can pick it up with the rod even when hot. I kept the oil filter from my last change, about 2500 miles so I cut it open. You can't see any metal with a good light and the naked eye but I have a strong magified and bright desk lamp. You can see tiny glints of metal, way to small to see on a magnet and not very many but they are there.

My concern is I got this car from a none car guy who didn't do much. The oil was very thin and I just thought he put the wrong kind in so I changed it right away and then again in 500 miles, with zinc. I have no sense of smell but my son in law was around and I had him smell the oil after 2.5K and he said fuel smell. Turned out to be fuel perculation and I've fixed that but I wonder if the cam/lifters got damaged from the diluted oil...? I put a magnitized drain plug in today...will run it abit and change the oil..and check again.

What do you think.. Thanks!

60

 

If this were mine, I would warm it up. Pull the passenger side valve cover. Start grabbing rockers & checking for looseness. Jog the IGN key and check some more. One more time jogging the key and checking rockers.

If you find one loose, jog the key and put its partner valve fully open and set the lash on the "closed" suspect valve.

 

Agreed, I would start with checking, adjusting the valves. If it persists, time to drain the coolant and pull the intake.

 

If it goes away in a minute.....it is piston slap.
There are one million LS powered Chevy pickups running around that do the same thing......
Valvetrain noise typically does not go away in a minute.....it is usually noisy for either a few seconds after startup (Lifter pump up) or it just persists......
A damaged cam will just make noise...and it will just get louder.....sometimes within minutes.....I doubt that is happening here.....

Jebby

 

Thanks all,

I took it for fuel last night, about a 15 mile trip and I paid close attention.. I was a little optimistic on my initial post, when I can hear it, it gets a little louder as you go from 1200 to about1600 and then goes away or the engine noise drowns it out but I think it diminishes to the point you can't hear it. My electric choke clicks off real fast and the car idles at 800-9 even cold and it's not noticeable at that RPM, maybe an occasional tap After about 4 min warm up, the H20 gauge is halfway and it's pretty quiet-(you have to be **** to hear it-LOL). When I got back (15 miles) I could not make it do it but if you put my hollow tube on #8 you can tell it's different from the rest, very slight tap. I only hear it on the manifold, valve cover and header are quiet/normal.. I guess Piston slap would be Ok but I'd like to eliminate the valves, doesn't the fact that it gets quiet when things get hot mean that as things expand the tolerences get closer?.

I'll probably order valve cover gaskets, center bolt, and spark plugs since I might remove them to turn the engine over easier, plan on doing it by hand if I can. I've adjusted valves on Old VWs, Harleys, but not hydrolic's on a V8, I just want to check them and it's always good to learn. I plan to run it a few hundred miles and check the drain plug for metal before I do anything.

What do you guys think about those tiny flecks in the filter? Funny thing they were pretty much only on one side and not every fold.. I've never opened a car filter before so I don't know what to expect..

60

 

I have to agree with Jebby on this.
I just built a 496 and the builder encouraged me to have the pistons coated to prevent the slight slap of the pistons when cold.
It won’t hurt anything.
My new Chevy and Ram pickups have all done the same thing.
A good test would be to take it for a nice long drive, then stop for lunch or coffee.
When you start the engine warm and get back on the road listen for the noise.
If you can’t hear it, it’s probably just the pistons.

 

I had a Explorer V6 that was my 3rd car that didn't get driven very much. After a oil change, I noticed a valve clatter when first started that went away in a few seconds.
Long story short, it was a Fram filter that had a leaky anti flow back valve. I had used the readily available AZ Fram's for years with no problem. This was probably a combination of long periods of time between starting and the leaky filter. Fram filters were getting a lot of static on line about that time, so I changed it. Problem solved.
A filter change doesn't cost much.

 

You can check the valves......but they would have to be very loose, and just the right amount of loose for this to make the faint noise you describe. Hydraulic lifters are just that, the lash is taken up by hydraulics....and if it is lashed, then relashing is not going to do anything....verify they have lash and move on. I doubt very much that Blueprint would get this wrong. To make a hydraulic lifter make noise then have it go away when hot is kinda not probable.

Yes....parts expand due to heat.....a larger than necessary piston to wall clearance will make noise until the skirt expands and takes up the difference......we are talking thousands of an inch too......
Will it hurt anything? Nope.

Jebby

 

This is an idea......if you do this, spin an HP4 Fram race filter on it....highest flowing spin on filter on the market and built much better than the standard Fram. But this is probably not what it is either.....since the noise is still faint when hot.

Jebby

 

Jebby,

The noise being faint when hot is when I put something on #8 and hold it to my ear, otherwise it's a struggle to hear it at all.. My Oil presure is almost 70 cold/1500, 60ish cold/1K and 45 Hot in neutral-800rpm. If that filter is better flowing does it filter as good as the NAPA or WIX..just wondering...

Thanks
60

 

Yes....20 microns. NAPA/WIX 1060 gold is 21.
When you get the filter.....compare it to your old one......the difference is eye opening. There is a lot of oil moving through a filter at 5000 rpm.....this takes the "filter restriction" question right off the table.

Jebby

 

I just want to add that the 22460 Moroso filter is an excellent piece too....but more money and not as easy to get....has to be ordered from the aftermarket. I keep the Moroso on the shelf when I remember to order some.
The Moroso is 27 microns......which I feel is ok but filter geeks trip out on it......20 micron particles wash right through the bearings...too small to be seen with out a microscope.

Jebby

 

Just a note about "Piston Slap".
More common with forged pistons than cast or hypereutectic pistons.

O.P. says this is a 355 Blue-Print Crate Engine. Those come with hypereutectic.

 

Yes they do, I'll have to google what that means..lol thanks.

I cant really use it, my header is right under the filter and the long ones are under an inch away, would get real hot I think.... What would running one of these due to my oil presure, I'm thinking lower it a little???

I thought I had an extra filter on the shelf but there was a used filter in the box from my first oil change, I cut it open but I have to let the media drain, you can't see anything with it soaked in oil... Curious to see if there are any of those flecks in there..

Thanks..
60

 

Dragging this back up...

My slight valve tap is still there and maybe a little louder, or I have become even more ****...It taps hot or cold but very slight. It's been 3K miles and I changed the oil every 1K, picture of the last two filters attached. You need a magnifing glass to catch even a tiny glint of metal and there are very few of them, maybe every 5-8 pleats has one microscopic one. The Magnet drain plug has a thin coating of metal mud, real thin, . Car runs good otherwise. I can't pin point the tap with a hollow rod or a scope but it seems to be on the right side. Took the valve cover off, verified all pushrods are turning-(both sides)-...#6 intake seems to be the tapper but it's really not definite... I did the loosen till it clacks, tighten till it stops and then half turn more lash adjustment, no change....

Am I correct that if the pushrods are spinning then the cam/lifters are OK-(flat tappet)?
Any ideas? -(I really don't want to take it apart unless I know what I'm after)

Thanks, 60

 

Header gasket? Pull the plug wire and see if it goes away.

 

Mechanical fuel pump? Put stethoscope on it..

 

I forgot about that, will check tomorrow...should have checked it before I pulled the valve covers... Thanks!

Thanks, I do have a scope, was using the rod to stay away from the oil being slung around...its really not that bad..lol, Electric fuel pump....

​​​​​​​60

 

Agreed. The modern performance engine has very short skirts and low tension rings. Both of these are a recipe for piston slap. If everything else is AOK then just run it. Doesn’t hurt a thing.

 

So, I took another look today, the odd side is pretty quiet, the even side has the tick/tap and #6 Intake seems to be it but the exhaust also has it,, either because it's right next to the intake or maybe it's something else with that cylinder. I used a stethoscope, 6 tapped with the same rhythm as the engine tap, I loosened it til it clacked and tightened til it quieted some then half turn more...no difference, another half turn and the noise changed a little but the engine also ran different because I had the valve too tight. Did the same with the exhaust, no change. Pulled the wires one at a time, no change, accessories are quiet, plugs all look good, no oil consumption or smoke, all pushrods are spinning and when I loosen the lash they really spin. I'm thinking about replacing the rocker arms and pushrods on #6 while its open or maybe switching them to a different cylinder to see if the noise follows...

Any Ideas?.
Thanks, 60