Okay now what ? Rod knock on a 50 mile engine /

[amceaglesx4]

Well my builder swung over to my garage to take a listen. I had the valve cover off as well. Good news he said it definitely isn't a rod knock or lower end issue. He thinks its a rocker problem of sorts. He took a hammer but and pressed on the rockers to see if anything quieted down. It didn't appear so. He said if the rockers are worn enough it could cause my sound. He also said that possibly the fulcrums on the rockers are basically trying to wear in a new groove. Either way he thinks its a rocker issue. So its not the lower end , new camshaft, or new lifters. Basically it leaves original pushrods and rockers. Yes pushrods are straight lol. And the noise is definitely louder with the vc on it for sure. He actually thought it was pretty quiet for a straight six. Rocker bolts at 28 lbs.

[optmaxx]

So it doesn't sound bad to him? It could be just the way that cam sounds like.

[amceaglesx4]

I think I'm going to try the pushrods from the 4.0 and possibly rockers idk. I think I used the ones off the 4.2. I did notice its strange torque for the rockers on the 4.0 are 28 and the 4.2 are sup post to be 18 !

[jsawduste]

Chris, your a dangerous man.

Why don`t you spring for the 15 bucks and order a pushrod length checker from Summit ? That way......If you follow the instructions.........you will know exactly what length of push rods you need. Not saying what you have now is wrong but you don`t know do you ?

For rockers, isn't this your second set as you bent up the other set by not unloading them ?

I still don't think your running the factory valve springs for very long. At least without checking the installed height and verifying that they are usable.

For the amount of time and money you pissed away on this you could have done it right the first time. Cause even after you patch these wounds the quench is still off and that anit gonna be something you band aid back together.





I can just predict it. 3 months, 6 months a year from now.........Your going to be one of the folks that bash 4.0 based strokers for being unreliable, expensive and hard to do. Not because they are, because of your (lack) (see, I offered you a little out there) experience with them.

Hell, your already doing it with your crate 4.0 comment.

[optmaxx]

I think I'm going to try the pushrods from the 4.0 and possibly rockers idk. I think I used the ones off the 4.2. I did notice its strange torque for the rockers on the 4.0 are 28 and the 4.2 are sup post to be 18 !

Good advice from Jsawduste to use a pushrod length checker first, follow it.

I had no idea you used the 4.2 pushrods, that's not a good way to start your build since the 4.2 pushrods are longer than the 4.0s, and I assume you're using a 4.0 head which is shorter too I think. So you have a bigger cam, longer pushrods and a shorter head, it does sound like a recipe for a noisy valvetrain. From what I remember, the torque for the the rocker arms are 19-21 ft lbs for the 4.0, unless something changed, but I don't think that's your problem? Your valvetrain geometry may be off, so I wouldn't drive it till you make sure that's correct.

Any reason why you went with the 4.2 rods? 4.0 and 4.2 rockers are interchangeable, they are the same. At least that's what I understood when I ordered new rockers for my Jeep. Are you using regular stock rockers?

[amceaglesx4]

Yea stock rockers. From what I found the pushrods are the same length. Lifters same size too. Hell... even bolt holes on both blocks are the same. So what is torque for rockers then ? Russ told me 28lbs so that's where I set em. Really doesn't matter because torque is basically how tight you make the bolts. Once two pieces of metal are flush then that's it. I will definitely look into the pushrod length now !

[amceaglesx4]

Looks like I'm wrong on that. Maybe the problem is the 1/16 difference in pushrod. I'll look into it tomorrow.

[jsawduste]

Ahh,
there are 5-6 different OEM pushrod lengths. Who knows what your cam base circle is or the overall stack up that determines your PR length.

There is a strange phenomenon called clamp force or if you prefer pressure.
It is achieved by providing a measured compression via a fastener. Sorta why bolts are tightened even if the mating surfaces are flush. Like a main cap or rod cap.

[amceaglesx4]

I see your still up too. Curiosity got in the garage. It just so happens all my 24 pushrods are the same length. The 81 4.2 and the 99 4.0. Shit thought a had something.

[amceaglesx4]

Yea I've got no play at all when the pushrods are torqued. Some spin but no up n down movement what so ever. Some rockers move a hair and others don't I noticed but no " oh shit that's loose ".

[jsawduste]

That doesn't mean they are the correct length for your engine.

[amceaglesx4]

That's very true. Even if they are slightly off don't the hydrolic lifters help with that issue ? Obviously solid lifters no.

[amceaglesx4]

My good friend Joel stopped over today with his stethascope. He said for the most part everything sounded pretty good but he did hear the noise I was talking about. He mentioned from front to rear the noise off the rockers were a little louder. I pulled the last plug and it was pretty carboned up and they got better moving to number one. If plugs aren't firing right they can cause a noise. What I'm thinking at this point is initially I was running a 280 FM two barrel and life was good. I decided to throw on a 500cfm four barrel and that's about the time I heard the ticking. I noticed under the 4bbl carb others was a puddle of gas which would explain extreme rich causing a possible spark plug failure. So a couple variables with initial start up had 87 octane and a 2bbl then to 89 with a 4bbl. Since higher octane burns slower and now bigger rich running carb instead of 87 octane and a leaner carb that could create havoc on a particular spark plug heat range. Anybody on the same page as me here ?

[jsawduste]

Higher octane does not burn slower

[amceaglesx4]

Well that's what was in the article I read online. It says lower burns faster.