[DeTomaso] Valve cover sound, strangest question of the day?->new developments

Sun May 11 08:07:31 EDT 2014

I do believe the mail below didn't get to you guys, picture too big.
Resending, because now I've fixed the issue and come to a conclusion after
several detours.

-My valve train was binding after replacing lock nuts, even though rockers
are Comp Cams and locks are also Comp Cams with smallest possible OD
(0.600"). Go figure. Had to buy Crane Cams lock nuts, they're 0.550", no
binding
-Metallic sound had nothing to do with material of valve covers, it was the
binding
-For reasons I still don't understand, the binding valve train produced a
lot better idle, maybe less lift and thereby less overlap. Doesn't matter,
can't drive around with binding stuff
-I've always adjusted rockers between 1/2 and 3/8 turn, now I use 1/8 to
1/4, modern hydraulic lifters don't have that much play in them as in the
old days  

Idles fine now, just waiting for a no rain day...

Mvh/Regards
Mikael
+45 31770747
mikael_hass at mail.tele.dk

-----Oprindelig meddelelse-----
Fra: Mikael [mailto:mikael_hass at mail.tele.dk] 
Sendt: 29. april 2014 22:25
Til: 'Mike Thomas'; 'detomaso at poca.com'
Emne: SV: [DeTomaso] Valve cover sound, strangest question of the day?->new
developments

Prepare for a long mail... Again ending with probably the strangest question
of the day. Cleveland specialists, please read on.

So, see the previous mail below.
--
So based on the mail below, I was happy, well, not really. The grinding
engine sound was definitely reduced, but not gone. If I remembered
correctly. Did I? Couldn't really sleep, next day out and diagnose some
more. I noticed that some pushrods were very loose, but since I hadn't a
tick tick, I thought it must be lifters collapsing when engine is not
turning. But when I turned the lock nut slightly, the rocker banged down,
and now the pushrod was not loose any more. My valve train was binding! How
could it? The only thing I had changed during winter were the lock nuts.
A-ha! So I took one off, and yes it was deeply scratched, so was the rocker.
But why, I got the ones Comp Cam recommends? Here's why. The original locks
were .600 OD except the lower 2mm which were .550. The new I got (correct
according to Comp Cams catalog) were .600 all the way up and down. And
that's too wide for my rockers. Couldn't understand, I have pretty standard
Cleveland alu heads and the 1.73 red Comp Cams rockers, I think a lot of us
have, right? I called Comp Cams, and while I could hear that they in no way
wanted to admit to a problem, they said that the lock nut with only .550 at
the bottom was discontinued, and that they didn't have anything smaller than
.600. So no help there. I told him that Crane has them in .550 all the way,
he said, so use them. So I ordered a set, and put them on tonight. No more
binding. Isn't that wild? These red rockers are used by so many people, and
they produce locks that don't fit? Am I missing something?

See attached picture. Grind marks visible on rocker both top and bottom.
Lock nuts from below:
-Original with .550 bottom 2mm
-New for this winter .600 all the way, grind marks at bottom -Just bought,
.550 all the way

---
So now all should be fine, no binding, no unpleasant engine noises. But oh
no, now it gets complicated. First a little history. Ever since I got this
Pantera with its 600HP 408 MME engine, I've had a challenging idle, with max
10-15 vacuum if all was adjusted perfectly. I thought, wild cam, that's just
the way it is, right? But this spring, I've had a much better idle, above
20, idling like a daily driver. I never understood why, the only thing I
could think of was that I had had the intake off and on, maybe I had fixed a
vacuum leak, but I've had that intake on and off several times, and this is
the first time I've had this perfect idle. Couldn't explain it, and still
can't. Here comes the problem. Since my valve train doesn't bind anymore,
the idle is back to around only 10. How is that possible? How can one set of
locks produce a perfect idle (and bind) and another set produce a lousy
idle?

I have a theory. Since the locks I put on this winter were binding, when
adjusting the rocker lock height, it must have pushed the rocker down "too
early", and when the engine then got started the valve spring force etc
quickly ground off some of the rockers and locks and allowed the rocker to
move up slightly, just like a very loose setting. In theory it could work.
To prove my theory and to get back to a 20+ idle, I therefore tried
loosening the rocker lock nuts in 1/4 turn increments. Idle got a bit
better, but never near the 20+, and then when I continued, they started to
tick, so too loose I guess.
---
Q1: Anybody else had binding problems with standard Comp Cams valve train
parts?

Q2: Any ideas why I had perfect idle with binding lock nuts? And how I get
back to perfect 20+ idle?

Q3: How should I adjust these rocker lock nuts? Here's how I've always done
it: TDC, cyl 1, tighten until pushrod starts to bind, +1/2 turn, tighten
counter hex bolt, turn lock nut and hex bolt at the same time to tighten
approx. 1/16, then turn engine 1/4, next cylinder, do it 8 times.
That has worked for me for years, but, I must admit, produced the less than
perfect idle on my Pantera. Is there a better way? Tonight I also tried the
Chevy SB way, covers off, idle, turn loose until tick tick, tighten 1/2
turn. Didn't give me a better idle.

I'm confused. And I want my perfect idle back! Or I'm buying a Porsche!

Mikael

-----Oprindelig meddelelse-----
Fra: Mikael [mailto:mikael_hass at mail.tele.dk]
Sendt: 13. april 2014 15:10
Til: 'Mike Thomas'; 'detomaso at poca.com'
Emne: SV: [DeTomaso] Valve cover sound, strangest question of the day?

Wise words. Took the fabricated covers off, and yes, there had been contact.
Found out that the local fabricator that I got to install a plate to avoid
oil at PCV etc., I asked him to raise max 15 mm and he raised 17 mm. So I
dented and grinded (ground?) that off so there was no contact. It sounded
like a Pantera again. But I had also tried my previous very high "Ford
Racing" covers, and they sounded best, least valve train noise, most exhaust
noise.

Mvh/Regards
Mikael

-----Oprindelig meddelelse-----
Fra: Mike Thomas [mailto:mbefthomas at comcast.net]
Sendt: 12. april 2014 18:16
Til: 'Mikael'; detomaso at poca.com
Emne: RE: [DeTomaso] Valve cover sound, strangest question of the day?

If you are talking about the cast aluminum valve covers with DeTomaso on the
top, and you are running a set of aluminum roller rockers, you may be
experiencing interference between the rockers and the baffles in the valve
cover.  When I had my motor built in '07, I had my builder install a set of
aluminum roller rockers (don't recall the brand without digging out my build
sheet) which were a rather blocky casting.  Mine are blue (not sure if that
means anything, FoMoCo?), but have seen the same from other manufacturers.
There was quite a loud ticking that I thought to be much more serious than
the truth.  What was happening was that the corners of the rockers were
contacting the angled portion of the oil fill and vent baffles in both valve
covers, and I had to remove the covers, remove the baffles, relieve that
area of the baffle with a slight peening, and reinstall them (never just
take them out and toss them!!).  You can check easily by removing the valve
covers and looking at the baffle, or the corner of the rocker, and you'll
see a wear spot.

The strange part about this one is that you don't hear the noise at first,
likely because the rocker doesn't leave contact with the baffle until there
is a little wear in the softer aluminum material on the rocker, and the
baffle is scratched a bit, then the noise is much like a stuck lifter or
bent push rod as it's coming from the top of the motor.  Also, trying to
peen or relieve the baffle while it is still in the valve cover is very
difficult as it is very easy to bend the baffle so it no longer stays seated
in the cast lip in the cover meant to keep it in place.  You could possibly
do this with a Dremmel tool with a small grinding head.  I'm not sure if
polishing off the corner of the rocker is a good idea for balance or
strength issues with the rocker.

One local member recently had a bunch of us up to pull his motor.  Said
there was this horrendous whacking noise coming from his brand new build.
The builder, located in California, told him the only way he'd check it out
was if the owner pulled the motor and shipped it back to him.  So, we have
the motor out an on the pallet, just before we were going to strap it down
and wrap it, and I mentioned to the guy "let's pull a valve cover and take a
look".  Sure enough, that was all it was.  He pulled the manifold later to
be sure there were no valve lifter issues or other obvious problems, but all
else seems to be in good order.  He was completely embarrassed to have had
pull his motor for such a simple fix.

Good luck.
Mike Thomas
VP, POCA
VP, Panteras Northwest
Yellow '74 #6328

-----Original Message-----
From: DeTomaso [mailto:detomaso-bounces at poca.com] On Behalf Of Mikael
Sent: Saturday, April 12, 2014 8:49 AM
To: detomaso at poca.com
Subject: [DeTomaso] Valve cover sound, strangest question of the day?

This may seem like a strange question, but has anyone experienced a change
in the mechanical sound of an engine by switching valve covers? I replaced
the Ford Racing chrome covers this winter with fabricated alu valve covers.
Man, they look good. But at idle, now I hear more valve train noise than
exhaust noise. Can this be? I can of course have a valve train issue, but I
don't think so.

Mvh/Regards
Mikael

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