[MEJ1990TM]

Yesterday we put the inner springs in the '70. It had just about a thousand miles on it since getting it running again. We figured it was about time that the inners got put in. The engine was kept at a safe max RPM of 5,000 all the while driving it with just the single springs and dampeners. The first cylinder we found that the exhaust push rod had the tip broken off of it, and the rocker arm had started to crack around the point where they met. That was quite a surprise. Then on #8 cylinder the intake push rod had started to do the same thing. These were Pro Form 3/8" one piece rods. I called a friend of ours and asked if he had two spare one piece push rods. He did, so we went up there. While we were there he was showing me what some of the real good one piece push rods look like. After seeing what the real good ones are like I feel like an idiot for picking the ones I did. They look ,and feel, like cheap Chinese junk compared to these Trend rods he showed me. The quality of the two just does not compare. He let us borrow a set of pretty decent rods to put in there until we can get a replacement set.

I didn't order the cheapest ones, but I didn't really find it necessary to spend over $130 on push rods in a pretty mild engine. Perhaps I should have. The ones we got were about $80. I'm going to call Summit tomorrow and send these back. I'm afraid it's not acceptable for push rods to start coming apart at just under a thousand miles while not seeing above 5,000 RPM. I'll tell them I want to order a better set and I'll just pay the difference. It will be my dad actually paying for them ,since it's his car, but I am the one with a Summit account.

 

[Heckeng]

That sucks. Pro form anything pretty much seems to have a bad rap. I used the Trick Flow pushrods which I believe are made by Trend. Compared to my original GM pushrods that were in my crate motor, the new ones were WAY heavier duty and nicer construction.

 

[BillK]

Michael,
I wonder if you have another problem that is causing the pushrods and rockers to fail ?? Mercruiser uses the cheap ($1.50 ea) ball end pushrods in most of its engines and they have absolutely no problems with them, even on the hydraulic roller 502's. They run 120 lb seat and close to 380 lbs open pressures.

Personally, I would never turn an engine with just the outer springs much more than 3000 rpm's maybe not even that. Certainly not 5000 ! I wonder if things were bouncing around and caused the problems ? Summit will probably replace the pushrods, being that that seems to be thier policy, but I dont think its fair to say anything bad about them at this point. I would be looking more at the valve train and the possibility it was "floating" in my opinion.

Also, I dont think comparing the Trend pushrods to the Summit ones is fair either. Two diffferent animals. I dont know what camshaft you are running, but I would bet that the stock GM 3/8 pushrods or the Melling replacements would work just fine and they are about $50 a set, if that.

Just my opinion,

 

[MEJ1990TM]

I'm not knocking Summit in the least, Bill. I've had nothing but success with them. I have experienced valve float with this engine once before. That was long before the engine was pulled out. This was not the case. Prior to the engine being rebuilt it was running just the outer LS6 springs. We thought the inners were in there, but they weren't. Then we were unable to locate the inners. Before I realized how important the proper spring pressures are I had it buzzed up to 6500 occasionally on just the outers with dampener. It was one of those times the valves floated. None of the things I experienced when that occured happened while driving it these last couple of months.

 

[The Old Reliable]

Perhaps this thread contributes to a possible explanation:

http://www.chevelles.com/forums/showthread.php?t=347556


Plus, a one-thousand mile cam break-in period, w/only outer springs, might be a weeeeeee bit beyond what was necessary.


Somehow, (overly long) "cautious cam break-ins" & "burnouts" don't go together.

 

[MEJ1990TM]

Really? I mean really? Those feeble attempts at trying a burnout happened with about 750 miles on the car. At no time did the engine see more than 5,000. The valve train had more than enough time to get aquanted with one another during that time. Just a quick shot to the 5,000 mark in low gear than I let off. Now if this thread was about the M22 taking some teeth off of 1st gear maybe that "burnout" would have something to do with it.

 

[white68]

My bro-in law had the same thing happen to his ProForm set of Rocker Arms, luckily he caught it before serious damage there too.

He also bought the "nicer" Chromoly ones instead of their cheapest ones.

But you know what they say about polishing cheap chinese turds...

 

[MEJ1990TM]

http://www.summitracing.com/parts/PRO-66407C/

Those are the ones that were in there. The only reason for not putting the stock pushrods back in is the small possibility of those balls coming undone. The guy we are borrowing these ones from had that happen. It is probably extremely rare, but why take the chance?

 

[Elcoman]

How long have you been on this site? Have you heard any good stories about proform? Why are you buying Chinese parts?

 

[charbilly2001]

Michael,
I wonder if you have another problem that is causing the pushrods and rockers to fail ?? Mercruiser uses the cheap ($1.50 ea) ball end pushrods in most of its engines and they have absolutely no problems with them, even on the hydraulic roller 502's. They run 120 lb seat and close to 380 lbs open pressures.

Personally, I would never turn an engine with just the outer springs much more than 3000 rpm's maybe not even that. Certainly not 5000 ! I wonder if things were bouncing around and caused the problems ? Summit will probably replace the pushrods, being that that seems to be thier policy, but I dont think its fair to say anything bad about them at this point. I would be looking more at the valve train and the possibility it was "floating" in my opinion.

Just my opinion,

X2. Just because you can't hear popping through the carb or the exhaust doesn't mean you don't have valve float or valve bounce. Particularly around 5000 RPM. That single spring doesn't necessarily prevent the valve from bouncing on the seat which shocks the entire valve train. Running a single spring for the purposes of camshaft breakin is supposed to involve running your engine at 2000 to 2500 RPM for 20 minutes or so to establish a proper wear pattern between the cam and the lifters. Beyond that you are just asking for issues.

You made a mistake. Man up and take ownership. Stop blaming others.

 

[MEJ1990TM]

So then how do you explain running the engine much harder with single springs and GM pushrods and no problems whatsoever? If I made a mistake I will own up to it, but when I've got a person who has been building high performance engines since the early 60's telling me that there isn't anything I did that caused this I am going to tend to agree with that.

 

[MEJ1990TM]

How long have you been on this site? Have you heard any good stories about proform? Why are you buying Chinese parts?

I don't remember reading anything about Pro Form one way or the other.

 

[charbilly2001]

Ya. I go back that far too. Been building engines since then as well.

 

[MEJ1990TM]

That still doesn't answer the question I threw out there.

 

[69bu]

I would be taking a hard look at the valvetrain geometry. Did anyone look at this before it went together? If that checks out I would look at the quality of the parts used or the lack thereof.....

 

[estherkilledfred]

Man, that will stand for all eternity as the World's Record for Longest Cam Break In!!

:yes:

Plus extra points for the burnout trials to test the outer springs!

 

[Georgia69]

Burnouts and 5,000rpm on single springs...wow...

 

[mr 4 speed]

Hey...I have done 4000 rpm burnouts with stock big blocks that have..what 90 lbs. on the seat from the factory?

 

[MEJ1990TM]

Burnouts and 5,000rpm on single springs...wow...

The part number for just the outer spring/dampener is 805-DO. What is the part number for Isky's stock big block spring you ask? Oh ,gee, it's 805-DO. So don't talk down to me like I'm some kind of idiot. The springs that were in there are their factory replacements for a big block. A big block that would have had a factory red line of 5500 RPM. The highest I took the thing was 5000.

 

[mr 4 speed]

Michael...I don't think Mike is out to sound like he is talking down to you.
We're all a bunch of big block guys having some fun with our rides :thumbsup:
Get it back together and keep an eye on everything.
Everything should be pretty much drama free...3/8 pushrods,stock rockers and a reasonable spec solid lifter cam w/matching springs shouldn't cause any issues.