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Question for all 3.1 owners - Please Read by Cplensdorf
Started on: 10-05-2003 04:39 PM
Replies: 76
Last post by: Pyrthian on 10-13-2003 08:30 AM
Cplensdorf
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Report this Post10-05-2003 04:39 PM Click Here to See the Profile for CplensdorfClick Here to visit Cplensdorf's HomePageSend a Private Message to CplensdorfDirect Link to This Post
As many of you may have noticed, I have been attempting to diagnose a detonation/mechanical noise on my rebuilt 3.1 for some time now. Well, Pyrthian and I hooked up this morning and we noticeed that he too has the very same problem with his 3.1. He was unaware until I pointed it out to him. As I mentioned in several previous posts, the problem is this:

At approx. 1800 rpm in both neutral and drive, the engine exhibits a knock type noise that appears to be coming from the top of the engine. Neither of us can discern whether the noise is mechanical or detonation. The noise continues through 2800 rpm and appears again coming back down through this range from 2800->1800. The engine has a noticeable lope/miss through this range, also. This fact alone makes us both believe that this is more fuel related than mechanical. Our thinking is that if is in fact a "piston slap" (highly unlikely to happen on both cars, though) type noise, the engine should not noticably miss through this range, it would simply be a mechanical type noise and would not be pronounced only through this range. Here are the specs for both cars (Pyrthian, correct me if I speak incorrectly):

Mine:
88 2.8 stroked to 3.1 with less than 5 miles.
2030 compucam
Brand new upper end from intake manifold up including heads.
Stock springs/valves/heads
Gasket matched upper intake.
New 15# injectors
New distributer and Accel cap and rotor
New delco coil
Automatic transmission
Stock PROM
New throttle body

Pyrthian's:
94 Lumina 3.1 bottom end.(brand new crate motor)
2030 Compucam
1.51 roller rockers
Bored throttle body and intake
automatic
Accel cap and rotor
MSD ignition and coil
17# injectors
Hyper. pistons
Aftermarket chip
Roughly 3000 miles on build.

We are thinking this may be related to the 2030 cam. We are asking that anyone with the Compucam 2030 installed to please respond to the following:

When holding your engine steady between 1800-2800, do you too notice any considerable miss? If so, do you also notice it when coming back through the range 2800-->1800?
If you have the same problem, do you have similar setups as the two of us? Can you please post comments, noting any similarities that you may have? Thanks in advance.

[This message has been edited by Cplensdorf (edited 10-05-2003).]

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Report this Post10-05-2003 09:28 PM Click Here to See the Profile for CplensdorfClick Here to visit Cplensdorf's HomePageSend a Private Message to CplensdorfDirect Link to This Post
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Report this Post10-06-2003 03:54 AM Click Here to See the Profile for edheringClick Here to visit edhering's HomePageSend a Private Message to edheringDirect Link to This Post
Have you tried using a mechanic's stethoscope to try to pinpoint the source of the noise?

My first thought--which is a W.A.G. of course--is that you're hearing some kind of harmonic noise or something. If both engines seem to work fine, it might just be that.

Ed

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Report this Post10-06-2003 08:16 AM Click Here to See the Profile for PyrthianSend a Private Message to PyrthianDirect Link to This Post
well, I've been worried about my motor, now that I know I have a problem. Some funny things about this knock. It only shows up at a narrow RPM range - roughly 1800 to 2500. Funny things about this range, thats basicly where the tach is for city driving. either idling at the light, or 1800-2500 driving. Dont always hear it while driving, in fact, have to strain the ear & work the peddle to hear it clearly. I'm beginning to beleive it really is spark knock, and am going to do 2 things - drop the timing back to 8 - maybe even 5 degrees, and try higher octane. We did use a stethescope, and it seems to be loudest near cyl 2, maybe 4. Thats reminded of what people say about removing the EGR (which I have done...) that pistons 2 & 4 burn - why them 2, I dont know.
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Report this Post10-06-2003 08:36 AM Click Here to See the Profile for CplensdorfClick Here to visit Cplensdorf's HomePageSend a Private Message to CplensdorfDirect Link to This Post
Thanks for chiming in Pyrthian....BTW - it was great meeting you.

Just so everyone is aware, I have a fully functioning EGR system that tests out fine. Like Pyrthian says, the noise on his appears to be from #'s 2 & 4... Mine, it is not discernable where it is coming from...

Pyrthian, just so you know, I too retarded the timing to about TDC and still heard it...I also am running 94 octane with 108 octane boost additive and still hear it! ARGH!!!!! Gotta be mechanical.....
I read last night that Jazzman had recognized some binding in his dampeners when he used the 2030 and modified them prior to running his....I wonder if he can chime in and elaborate...

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Report this Post10-06-2003 09:04 AM Click Here to See the Profile for CplensdorfClick Here to visit Cplensdorf's HomePageSend a Private Message to CplensdorfDirect Link to This Post

Cplensdorf

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OK....the engine shop just called and stated that the noise IS a mechanical noise and is coming from the top end of the engine...he suspects valvetrain....In fact they felt it so severe that they shut down the engine relatively quickly...

Now Pyrthian and myself can't be the only ones with this cam and having these problems!!!!!

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Report this Post10-06-2003 09:04 AM Click Here to See the Profile for m0sh_manSend a Private Message to m0sh_manDirect Link to This Post
MY 3.4l Fiero has a miss between 1800-3200 RPM im going to take the intake and injectors out this weekend and put in mustang 3.4L injectors and a bored throttle body on it and see what happens. Ive had this problem scince ive purchased the car, and it started with a 2.8L 5 speed, then i swapped it out for a 3.2L 5 speed and now it has a 3.4L 5 speed, all the engines have had this problem, ive tried two different wiring harness's changed countless injectors, replaced all gaskets, even tried different ECM's nothing seems to want to fix the problem.

makes me frustrated.

matthew

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Report this Post10-06-2003 09:11 AM Click Here to See the Profile for PyrthianSend a Private Message to PyrthianDirect Link to This Post
 
quote
Originally posted by m0sh_man:

MY 3.4l Fiero has a miss between 1800-3200 RPM im going to take the intake and injectors out this weekend and put in mustang 3.4L injectors and a bored throttle body on it and see what happens. Ive had this problem scince ive purchased the car, and it started with a 2.8L 5 speed, then i swapped it out for a 3.2L 5 speed and now it has a 3.4L 5 speed, all the engines have had this problem, ive tried two different wiring harness's changed countless injectors, replaced all gaskets, even tried different ECM's nothing seems to want to fix the problem.

makes me frustrated.

matthew

what cam do you have Mosh? is it a miss or knocking noise? if its a miss, it may just be the coil.

[This message has been edited by Pyrthian (edited 10-06-2003).]

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Pyrthian
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Report this Post10-06-2003 09:19 AM Click Here to See the Profile for PyrthianSend a Private Message to PyrthianDirect Link to This Post

Pyrthian

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quote
Originally posted by Cplensdorf:

OK....the engine shop just called and stated that the noise IS a mechanical noise and is coming from the top end of the engine...he suspects valvetrain....In fact they felt it so severe that they shut down the engine relatively quickly...

Now Pyrthian and myself can't be the only ones with this cam and having these problems!!!!!

oh no....
maybe it was a bad batch of lifters...
how recent is your cam? mine was from early this spring. It doesnt sound like a failed cam (I've done 2 of them already...) It sounds alot like a bad rod bearing. Except that its only there for that short RPM range. Well, I guess I'll pull spark plugs wires one at a time, to see if goes away on a particular cylinder.

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Report this Post10-06-2003 09:22 AM Click Here to See the Profile for CplensdorfClick Here to visit Cplensdorf's HomePageSend a Private Message to CplensdorfDirect Link to This Post
P,

Lifters are about two years old...like I mentioned yesterday, I really do not know the details of the lower end other than the date of the balancing, which was done some time in 2001. I will check when I get home.

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Report this Post10-06-2003 11:17 AM Click Here to See the Profile for CplensdorfClick Here to visit Cplensdorf's HomePageSend a Private Message to CplensdorfDirect Link to This Post

Cplensdorf

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Pyrthian,

Are you running stock springs under your roller rockers? When reviewing Crane Cams site, they have an interesting article on spring issuse that talks about a "harmonic" vibration that occurs in all springs. It goes on to say that this noise is commonly misdiagnosed as a fuel/ignition problem as it too causes significant misfiring throughout a range of rpm. It also leads to significant cam damage and eventual failure....Sound familiar?

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Report this Post10-06-2003 11:34 AM Click Here to See the Profile for PyrthianSend a Private Message to PyrthianDirect Link to This Post
nope, Crane springs from the Fiero Store.
It would suck if theres a "Harmonic Vibration" right in the middle of the most used RPM range.
One of the things thats buggin me is how much louder the knocking is it is when the motor is unloaded. That makes me think lower end. When I pull the plug wires tonight, one at a time, I'll see if it particular to one cylinder (like #2....).
Maybe I really did wreck a rod bearing at the Waterford Track day, and its not fully gone yet. But it went so nice to & from Virginia, thru the mountains, over hill, over dale (who's dale?) and the oil's clean. and it runs the exact same now as then. except now I know how make the knocking, and what/when to listen for.
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Report this Post10-06-2003 05:54 PM Click Here to See the Profile for PyrthianSend a Private Message to PyrthianDirect Link to This Post

Pyrthian

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well, pulled plug wire from #2, and the knocking got alot quieter, and the rpm range to make it happen was alot smaller. I think I got a bearing about to go or gone already. It still sounds more like upper end, like a lifter hitting the cam, but pulling the spark plug wire wouldn't affect that at all. It's amazing how well the car runs on just 5 cyl's.
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Report this Post10-06-2003 07:11 PM Click Here to See the Profile for Every DetailSend a Private Message to Every DetailDirect Link to This Post
I just built a 3.2 with a phase 2 cam from ari. I noticed pinging,cherping sound that sounds like its coming from the valvetrain I have comp cams 1.6 roller tip rockers. I think my water pump might be going bad because it looks like it is wobleing could that be the sound?
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Report this Post10-06-2003 07:24 PM Click Here to See the Profile for CplensdorfClick Here to visit Cplensdorf's HomePageSend a Private Message to CplensdorfDirect Link to This Post
Pyrthian,

Just got home with my car from the shop.....I was told that the noise is definately from the upper end and more specifically from cylinders 6 & 4. The noise appears faintly when cold but much louder when warm (he used a stethoscope that you can tune out some noises and focuses on others) .....the mechanics take on all of this...he was pretty confident that the noise is valve related and questioned whether this cam can run with the stroked engine...he stated that many people will stroke an engine and run with a non-stroker type cam....the result ->>the nuts on the rod caps will hit the cam and give the same exact noise that he is hearing...apparently he is all too familiar with this sound as in his younger days did the very same thing...twice...on a stroked motor....I am going to verify this info with Crane tomorrow...He was VERY confident that the bottom end was NOT to blame for the noise....so don't go tearing your engine out, yet....he wanted to take mine down to the cam and show me, but I did not want to part with the $300 he would charge...

...I will start my teardown tomorrow and see what I find....

He kept pointing at valves remaining open as the culprit here, be it because of spring binding, crimped/bad valve seals, etc...

this whole thing just sucks!!!!

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Report this Post10-06-2003 09:36 PM Click Here to See the Profile for L44_87GTSend a Private Message to L44_87GTDirect Link to This Post
I had the same knocking sound your descirbeing with my 2.8.One day I was drivign down the road and KABANG the motor started knocking and chattering all the way home.I pulled the oil dipstick and it looked like acrylic enamel.

------------------
87 Fiero GT with a few mods

blew another 2.8....looking for a 2.8 long block.

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Report this Post10-07-2003 07:46 AM Click Here to See the Profile for Dan010Send a Private Message to Dan010Direct Link to This Post
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Report this Post10-07-2003 08:26 AM Click Here to See the Profile for PyrthianSend a Private Message to PyrthianDirect Link to This Post
well, while thinking of what could be affected by pulling the sprark plug wires, one things came to mind - loose exhaust manifold bolt. Was to late to go out and look, but this is also a common Fiero thing, and tho I've never heard it before, it is described as simalar to what we are hearing, manifold flange smacking the head after every exhaust stroke.
The thing thats buggin me about this kocking noise, is you only hear it in a small RPM range. With the exhaust, this kinda makes sense, in the under that RPM, not enough pressure to push it away from head, and over the RPM, it gets held away from head.
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Report this Post10-07-2003 05:28 PM Click Here to See the Profile for CplensdorfClick Here to visit Cplensdorf's HomePageSend a Private Message to CplensdorfDirect Link to This Post
-P

...longshot, but at this point anything sounds possible. I have not had a chance to even pop the hood on mine since I got it back....I saw your reply on the other post about the "rod knock" ...

...can't help thinking that the moon is somehow in a phase that only affect Fieros!!!!

Keep the ideas flowing, we WILL figure this thing out!!!!

Anyone else.

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Report this Post10-07-2003 06:39 PM Click Here to See the Profile for PyrthianSend a Private Message to PyrthianDirect Link to This Post
well, I'm parked, and preparing to drop the oil pan. I'm assuming it to be a bad rod bearing. not a spun bearing, just badly worn bearing.
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Report this Post10-07-2003 07:08 PM Click Here to See the Profile for rogergarrisonSend a Private Message to rogergarrisonDirect Link to This Post
Just throwing something else out for ya. I had a 3.1 Transport. They did have a 3.1 recall in l990 for piston slap. If it was excessive you got a new motor. Mine had a slight noise, but it ran fine for 100k till i traded it off.
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Report this Post10-07-2003 09:27 PM Click Here to See the Profile for JazzManSend a Private Message to JazzManDirect Link to This Post
 
quote
Originally posted by Cplensdorf:
.....the mechanics take on all of this...he was pretty confident that the noise is valve related and questioned whether this cam can run with the stroked engine...he stated that many people will stroke an engine and run with a non-stroker type cam....the result ->>the nuts on the rod caps will hit the cam and give the same exact noise that he is hearing...apparently he is all too familiar with this sound as in his younger days did the very same thing...twice...on a stroked motor...

The issue of a stroked crank hitting the cam only applies to custom cranks and extreme lift cams found in V8 hotrods. The 3.1 crank is a stock crank meant to fit in that block. Though I don't know what the noise could be without being there to listen to it, I can say that a stroking issue is not the case.

JazzMan

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Report this Post10-07-2003 09:44 PM Click Here to See the Profile for CplensdorfClick Here to visit Cplensdorf's HomePageSend a Private Message to CplensdorfDirect Link to This Post
 
quote
Originally posted by Cplensdorf:

I read last night that Jazzman had recognized some binding in his dampeners when he used the 2030 and modified them prior to running his....I wonder if he can chime in and elaborate...


Jazzman.....whats up with this issue? More details please!

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Report this Post10-08-2003 08:59 AM Click Here to See the Profile for CplensdorfClick Here to visit Cplensdorf's HomePageSend a Private Message to CplensdorfDirect Link to This Post
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Report this Post10-08-2003 10:29 AM Click Here to See the Profile for Dave GunsulSend a Private Message to Dave GunsulDirect Link to This Post
 
quote
Originally posted by JazzMan:

The issue of a stroked crank hitting the cam only applies to custom cranks and extreme lift cams found in V8 hotrods. The 3.1 crank is a stock crank meant to fit in that block. Though I don't know what the noise could be without being there to listen to it, I can say that a stroking issue is not the case.

JazzMan


I agree completely.
Besides that; the cams you guys are using were meant for all 60* V6 engines which includes the 3.1 and 3.4.
Interesting thread though.
Have either of you checked your plugs? If so; are they whitish colored?
Are either of you using an MSD box like the 6A?

------------------

Activities Director N.I.F.E.

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Report this Post10-08-2003 10:51 AM Click Here to See the Profile for PyrthianSend a Private Message to PyrthianDirect Link to This Post
yes, I'm using a MSD 6A box, and I agree the cam is made for the motor, so it shouldn't be hitting anything. I believe the knocking I am getting is a bad rod bearing, but every spun rod bearing I've ever had, you could hear at idle, and every valvetrain noise I've had was more a ticking than a knocking. It sounds more like a piston slap or predetonation, but hearing it both when you up in RPMs & down thru the RPMs would eliminate detonation, and both being fresh motors with different pistons types would make piston slap less likely. when I pull the oil pan, I'll see if the cyl wall is scored up (god I hope not...). hopefully I'll find a badly worn, almost paper thin rod bearing, still in place, with no damage to the rod, cap & crank (yeah..dream on)
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Report this Post10-08-2003 12:17 PM Click Here to See the Profile for Dave GunsulSend a Private Message to Dave GunsulDirect Link to This Post
Pyrthian; disconnect the MSD box and see if the noise stops or gets quieter. I'm betting it will.
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Report this Post10-08-2003 12:26 PM Click Here to See the Profile for PyrthianSend a Private Message to PyrthianDirect Link to This Post
well, like my post above says, I pulled spark plugs wires, and when I pulled #2, the knock got ALOT quieter, others - no change. #2 was also the loudest when checked with stethescope. But, I will switch to stock ignition right after I check the exhaust manifold bolts. What about the MSD box makes you think that may be the cause of the knocking? But, I'll take that bet, say for a 6 pack Labatt Blue

[This message has been edited by Pyrthian (edited 10-08-2003).]

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Report this Post10-08-2003 12:40 PM Click Here to See the Profile for Dave GunsulSend a Private Message to Dave GunsulDirect Link to This Post
Had a similar problem with my 3.2 and i have never trusted those things.
The box is putting out quite a bit of power and i suspect that it's making you run lean and spark knock. I would also bet that if you check your plugs you will find them to be whitish. Although you will have to go through a lot of tuning to get it right i hope that i am right because it would certainly be better then the alternative which is the engine being bad in some way.
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Report this Post10-08-2003 12:43 PM Click Here to See the Profile for CplensdorfClick Here to visit Cplensdorf's HomePageSend a Private Message to CplensdorfDirect Link to This Post
Dave,

I am running a stock setup (all new of course) with same issues.

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Report this Post10-08-2003 12:47 PM Click Here to See the Profile for Dave GunsulSend a Private Message to Dave GunsulDirect Link to This Post
 
quote
Originally posted by Cplensdorf:

Dave,

I am running a stock setup (all new of course) with same issues.

I was afriad you'd say that cp but it might be something similar in your case as well. Tuning a motor like this is difficult and it requires a lot of patience with the adjustable regulator. If the MSD box turns out to help him then it will point to a similar problem with your car. As in; not enough fuel. I certainly could be wrong but worth a shot. If it fixes or helps his engine then i think it will be something similar in yours. The box would make that problem more pronounced though. It's also the easiest thing to chech and if it does work it will point right to what i'm thinking. Again, i could be wrong, but worth a shot.

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Report this Post10-08-2003 03:04 PM Click Here to See the Profile for CplensdorfClick Here to visit Cplensdorf's HomePageSend a Private Message to CplensdorfDirect Link to This Post
OK...here is what I am seeing....it is on number 6 cylinder...do not see the same tracks on 4...but haven't looked at others...looks like the rocker is striking the rocker stud....it looks to be on only the pushrod side of the stud...what do ya think?

I will continue to look at the rest...and post as I do...

BTW - this is on both the exh. and int...the pic was taken prior to removing the exhaust...

[This message has been edited by Cplensdorf (edited 10-08-2003).]

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Report this Post10-08-2003 11:47 PM Click Here to See the Profile for JazzManSend a Private Message to JazzManDirect Link to This Post
Use a wire feeler guage to check for clearance between the rocker stud slot and the stud while turning the engine to actuate the valves. I'd guess you want at least .060" clearance, maybe more, though I've never seen a spec for this. If the rockers are indeed hitting the studs that would be bad juju and you need to get that fixed asap, probably by elongating the slots ever so slightly.

JazzMan

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Report this Post10-09-2003 08:12 AM Click Here to See the Profile for PyrthianSend a Private Message to PyrthianDirect Link to This Post
by the hieght, that looks more like the half moon thingy under the rocker nut making that mark, not the rocker. what push rods do you have?
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Report this Post10-09-2003 08:40 AM Click Here to See the Profile for PyrthianSend a Private Message to PyrthianDirect Link to This Post

Pyrthian

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quote
Originally posted by Dave Gunsul:

Pyrthian; disconnect the MSD box and see if the noise stops or gets quieter. I'm betting it will.

well, disconnected the box, started up the car, and the knock was not there!

shut it down, hooked the box up again, started it up. still no knock.

wtf!? so I kept looking for the knock, then there it was. OK, doesnt knock when its cold. must be the thickerer oil. the box didnt make a difference once it warmed up.

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Cplensdorf
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Report this Post10-09-2003 08:51 AM Click Here to See the Profile for CplensdorfClick Here to visit Cplensdorf's HomePageSend a Private Message to CplensdorfDirect Link to This Post
The marks are under the fulcrum, indeed. Good eye! It clearly makes no sense unless I have a lifter that fails and provide enough slop to allow the fulcrum to rock slightly on the rocker stud...which seems possible when sliding the fulcrum on the stud and wiggling it...some of the others look like they have similar marks, but not as bad as this one. The noise only appears when the car is warmed up, yes. It seems like something is very close and when expanded by the heat actually contacts.....

P - have you started your tear down on the bottom end yet? Find anything?

I am calling Crane today to discuss.

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Report this Post10-09-2003 08:53 AM Click Here to See the Profile for CplensdorfClick Here to visit Cplensdorf's HomePageSend a Private Message to CplensdorfDirect Link to This Post

Cplensdorf

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P-

What springs are you using?

What weight oil?

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Report this Post10-09-2003 09:14 AM Click Here to See the Profile for PyrthianSend a Private Message to PyrthianDirect Link to This Post
crane springs, 10-30 oil.
nope - pans still on. just got the car jacked up & checked exhaust bolts. They're fine. The Rodney Dickman studs are doing their job. Also looked for crossfire in the spark plug wires & unhooked the MSD box.
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Report this Post10-09-2003 09:28 AM Click Here to See the Profile for CplensdorfClick Here to visit Cplensdorf's HomePageSend a Private Message to CplensdorfDirect Link to This Post
Just spoke with Crane...after explaining our dilema, he said to look at the following:

Coil bind issues and preload. He said that these are crucial for this cam....

He also said to break in with 10w40 non-synthetic oil....they have seen issues with lifters not behaving well on break in with synthetics....

I am off to find a dial gauge and feeler gauges to check some issues.....

He commented on the rocker stud and said it may be the lifters acting funky with the synth on break in and allowing the rocker to fall on the stud......

Did you do your springs or have a shop do them.....How did you check preload and height? Shims?

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Pyrthian
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Report this Post10-09-2003 10:35 AM Click Here to See the Profile for PyrthianSend a Private Message to PyrthianDirect Link to This Post
well, my springs are the ones recommened for the cam. The preload was 1-1/2 turns on the rocker nut, after zero lash, and break in was with 10-30 dino oil. I had a shop do my springs. They told me my max lift was 0.450, after my first 2 cams, 0.443 & 0.440 lift, both wrecking the high lobes only. The springs are advertised to be able to goto 0.500 lift. The preload is the same thing as the valve lash. many many opinions on this out there. there are no shims.
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