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

Daniel C Jones daniel.c.jones2 at gmail.com
Sun May 11 12:23:16 EDT 2014


> Speaking of Comp Cams - the latest delay on getting 5332's engine finished
> was due to Comp Cams roller hydraulic lifters.  They wouldn't hold pressure
> and bled down.  Will be run on the dyno tomorrow with Crane lifters.

Was this the issue I've mentioned before with Comp's OEM oil band location being
exposed due the chamfer at the top end due to the large lifter bore chamfer or
some other issue?  It varies from block-to-block and depends upon the
size of the
chamfer at the top of the lifter bore but, on many 351C blocks, the oil band is
exposed at maximum lobe lift when the cam has a standard base circle.

Also, are you running a reduced or standard base circle cam?  If so, watch for
intereference with the block and the tie bars when the lifters are on the base
circle.

> They quote the inlet opening (@ 0.05) 3 degrees BTDC, and the exhaust closing -4 ATDC.

I don't see the problem.  For the 114 LSA cam installed on a 109 ICL, I get
timing of 3 deg IVO, 41 deg IVC, 54 deg EVO and -4 deg EVC at 0.050" lift.

Why the wide 114 LSA?  Is this a low compression engine with open chamber heads?

Dan Jones

On Sun, May 11, 2014 at 8:36 AM, Stephen Nelson <steve at snclocks.com> wrote:
> Speaking of Comp Cams - the latest delay on getting 5332's engine finished
> was due to Comp Cams roller hydraulic lifters.  They wouldn't hold pressure
> and bled down.  Will be run on the dyno tomorrow with Crane lifters.
>
> I get the idea that Comp Cams is having some challenges.  Check out the
> attached cam specs - They quote the inlet opening (@ 0.05) 3 degrees BTDC,
> and the exhaust closing -4 ATDC.  When queried Comp Cams indicated the sheet
> was in error.
>
> Makes one feel all warm and cozy, eh?
>
> Stephen Nelson
>
>
>
> -----Original Message-----
> From: DeTomaso [mailto:detomaso-bounces at poca.com] On Behalf Of Mikael
> Sent: Sunday, May 11, 2014 5:08 AM
> To: 'Mike Thomas'; detomaso at poca.com
> Subject: Re: [DeTomaso] Valve cover sound,strangest question of the
> day?->new developments
>
> 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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