350 crate motor - a little valvetrain rattle?

[mcintyrederek]

I've a Goodwrench 350 crate motor in an '86 C10..  The engine has about 20K miles on it.  I don't know the history of the engine before I rescued the truck.  I don't assume it's been mistreated, but don't know for sure.  I have a little valvetrain rattle, it sounds like the classic lifter noise.  It's certainly not worth taking apart, and it's not that noticeable.  It does NOT go away when the engine heats up either.

Any of you guys have a favorite crankcase additive that I might try to help it out or is all that stuff pretty much worthless?  I found a bottle of two-part "bars" engine oil treatment that looked like it had good reviews on it, but it didn't make any difference and that was 1000 miles ago.  Your comments please?

Thanks.

[454Man]

If you have valve train noise id at least pop the valve covers off start er up and watch the rockers. Check the lash and such.. Lifter noise isn't a good thing for a cam. It will wear that cam out quick

What's under the hood??? If you have to ask maybe we shouldn't race...

[rich weyand]

Does it have headers on it?  Have you had headers before?  Headers, which are very thin walled, make mechanical noises that heavy manifolds don't, and if you aren't used to it, it can sound like valvetrain noise.

[Engineer]

Is it possible your rockers a rubbing the valve covers?

I've seen it too many times to count on a perimeter bolt valve cover engine with aftermarket valve covers.

[mcintyrederek]

Thanks for the replies..  I have checked all those things and I don't see anything noticeable under the valve covers.  Looks like I'll go ahead and start now with the lifters, that's about all that's left I suppose. 

While we're at it, any good suggestions for a mid-range performance cam for this engine?  This is the 350 CI 260 HP model that came from Jegs (I think?)  Looking for something strong at 2500 - 3000....  Something torquey.. 

Your thoughts?

[OldsFan]

I know the mechanic-in-a-can stuff isn't popular amongst those who know their engines (and even I don't like them)...  But when I got my truck, it had a horrible valve tick at all times.  I put a third of a can of Seafoam in it and drove it around about 30 miles.  After changing the oil, it was gone completely.  Sadly, I think I still hear it now and again, but only when the engine is cold and I am working under the hood.  Once it is warm, the noise is gone.

I'm not saying it is going to fix a collapsed lifter or something (in other words, YMMV), but it seems to have worked great for me.  I couldn't tear into the motor when I first bought it, so I was amazed what a few bucks worth of Seafoam did.  I am planning to pull the valve covers and check things over the winter, though... 

[VileZambonie]

Describe what you call valve train rattle. When do you hear it, what's it sound like and does it get worse when operating under different circumstances?

[454Man]

Might be time for a valve lash adjustment

What's under the hood??? If you have to ask maybe we shouldn't race...

[rich weyand]

The cam you want is probably the Comp 12-235-2.  You can dyno simulate it with the Comp Cams Camquest software.
http://www.compcams.com/downloads/register.asp

This is the cam Sean Murphy at SMI recommended to me, and he knows what he is doing.

You will need to change the lifters as well -- they bed into the cam within the first hour or so of operation -- and you should change the springs as well if they have more than, say, 10,000 miles on them.

[mcintyrederek]

I hear it coming from the passenger side of the hood but it sounds deeper into the engine, like the crankcase.  I only hear it when it's idling.  It doesn't get worse when driving, or at least I don't notice it getting worse.  The repetition of the "ticking" noise I am hearing is definitely at valvetrain speed.  When you fire up a cold engine and hear one collapsed lifter, it sounds like that but only more subtle and gentle.  But even after running for miles and miles, when I get out and put it in park, it's still there.  I am leaning more toward lifters..  but then again it's not bad enough to fret over, but when and if I change the cam, I guess I'll find out.

Thanks again.

[VileZambonie]

Well you should easily be able to identify it. Pick up a mechanics stethoscope. If it's an exhaust leak you will hear it using the hose end if it's mechanical you can pinpoint it with the probe end.

http://www.autozone.com/autozone/accessories/OEM-Mechanic-s-stethoscope/_/N-26gd?itemIdentifier=70131_0_0_