max wedge engine troubles

[64savoyguy]

Ok guys. I got my engine put together and ran on the dyno. It made decent numbers. 520hp and 530 ftlbs torque at 4400. I have a comp roller thumper cam and all the necessary valve train components per comp and my engine builder ( who I would recommend to anyone building a mopar or any engine). Got the engine in the car and put about 170 miles on it. Rev limiter set at 6000 rpm and it's seen that twice. I go to start it two days ago and it fired rite up, ran for about 30 seconds and then started knocking. if u give it a little bit of gas it comes out of it. (Around 1200 rpm). But at a n idle it sounds horrible. I don't think it's anything in the bottom end but what do I know. Long story short I'm wondering if any of you have ever had problems with bad lifters causing this problem and what you did to remedy the issue. I like everyone else have heard good and bad about comp parts. Thanks in advance for any ideas.

 

[ozymaxwedge]

First question would be How's the oil pressure at idle and at revs ?

 

[64savoyguy]

Oil psi is between 70 and 75 psi both at an idle and with a little rpm to it. That's a cold start.

 

[hemlock]

Have you checked valve lash?

 

[NOSTRT980]

how old is the gas? what is the timing?

 

[64savoyguy]

I haven't checked anything yet cause I had to go to work. Gas is new and the timing is at 38*. I'm just looking for a direction. later today I was gonna pull the valve covers and see if any of the lifters have collapsed.

 

[moparsteve636]

You used a good break in oil with Zinc? And did the cam break in? If not you might have killed the cam! JMO

 

[64savoyguy]

The first time it was started was on the dyno with Brad Penn high zinc break in oil.

 

[Dodge 330]

You used a good break in oil with Zinc? And did the cam break in? If not you might have killed the cam! JMO

How?! It's a roller cam if I read correctly?!!

 

[64savoyguy]

Yes it's a hydraulic roller cam.

 

[383man]

Does the noise sound like a high end lifter tick or more like a lower end knock or thud ?? Ron

 

[64savoyguy]

Ron it sounds like a low end knock but if u Rev it up it goes away. I pulled the valve cover off of it seems like the lifters are losing oil pressure because with #2 up on compression u can depress the lifter down with the rocker arm and push rod by hand about a 3/16's of an inch

 

[super-bee_ski]

Pardon me fellas, but...isnt it plausible that a main bearing will knock untill it gets a load on it?
At idle, my Buds 4-2L in-line 6 knocks but when he applies RPM it smooths out.
I think he said it was a MAIN...
Just asking.
PS: the engine DID REV to 6K a couple of times...

 

[Hemi 354]

Check out the read....I've used it a lot of times. http://www.southernwheels.com/Feb_04Frame1Source1.htm

 

[Meep-Meep]

If you suspect a piston or rod then while idling (and making the knock) pull plug wires out one by one until the sound goes away or changes. That's when you found the affected cylinder. Tip: Loosen the wires from the cap with engine off and pull one by one from there so you are not holding a live wire.

FYI: I don't RPM a new engine that hard that soon. You want to load the rings at full throttle very soon but not max RPM and not lugging either.

 

[super-bee_ski]

To me,
6,000RPM is high for a long-stroke engine
But, I am convinced a "MAIN" will knock until LOAD, then it will subside.
PS: I'll never run any of my engines to 6K RPM except the Shelby GT500 and it has a REV limiter.

 

[lewtot184]

a loose race type piston with a straight pin along with a mech roller with a fast closing ramp will scare the bajibbies out of you when cold, especially with a mufflered car. if the oil pressure is ok and your sure nothing in the valve train is coming apart then let the engine warm up to 160-180 degrees and see if the noise decreases. try to distinguish between valve train clatter and piston slap/rock. piston slap will go away at operating temps; if they're clearanced correctly. mech rollers will always make noise even when warmed up.

 

[super-bee_ski]

Piston slap?
As was on the early RACE type engines?
Allowing extra tolerance for thermal dynamic "growth"
-I have heard of that, but: Did OP state that it happens when cold or goes away with RPM?

-I do not know enough about this thing as you do lewtot184
-I HIGHLY respect your opinion here on this forum.

 

[crossram 426]

I had a similar knock in my old 69 cobra jet a few yrs ago, wasn't there at idle but when you gave it a rev it started knocking ....spun a rod bearing and had to get the crank spray welded and machined etc, good luck hope it turns out ok.

 

[lewtot184]

Piston slap?
As was on the early RACE type engines?
Allowing extra tolerance for thermal dynamic "growth"
-I have heard of that, but: Did OP state that it happens when cold or goes away with RPM?

-I do not know enough about this thing as you do lewtot184
-I HIGHLY respect your opinion here on this forum.

piston slap is when the piston rocks in the bore as it changes direction. race type pistons have the pin in the center of the bore plus need more clearance due to the material and skirt design. the race/hipo type piston doesn't have the slotted oil ring groove and this transfers more heat from the top of the piston to the skirt requiring more skirt clearance. this causes the piston to knock until it's warmed up and fits the bore tighter. all passenger car/driver type pistons i know of have the piston offset in the bore creating some drag, and have a skirt design that isolates the skirt from the top of the piston reducing heat transfer allowing for tighter clearances and less to no noise. clear as mud? piston material plays a little part in noise.