Bent pushrod, good compression??

[PlayingWithTBI]

I've never set valve lash on anything, ever. Never had a need to. Even my 76 Rot Box has hydraulic lifters, so no need to set valve lash.

But you do need to set lifter preload.

 

[DeCaff2007]

But you do need to set lifter preload.

I don't remember doing that, either, but it's likely that it happened. Here's why - and I'm referring to the Pontiac 400 that I build on my own - there's a book on rebuilding Pontiac 400's from the ground up. Step by step with color pics and all sorts of tips and tricks along the way. Setting preload with hydraulic lifters was LIKELY part of that book. So, if it was in there, I performed that step.

FWIW, said engine runs excellent to say the least. If I had a mint chassis to drop it in.... there's my daily driver... all 350+ (estimated) horsepower of it.

 

[grey wolf]

Interesting! I've also got a truck with the 4.3 that ticks, mostly noticeable at idle. I also have to replace the valve cover gaskets one of these days (I keep telling myself that I'm eventually going to do a junkyard LS swap, so I've been putting it off). I wonder if I'll find bent pushrods as well...

Just curious, any reason why having a manual transmission truck would affect this?

 

[0xDEADBEEF]

Just curious, any reason why having a manual transmission truck would affect this?

The infamous Money Shift.

Usually going from 2-1 instead of 2-3. 3-2 instead of 3-4 happens a lot too.

 

[PlayingWithTBI]

Years ago (IIRC in 81), stupid me, building a 360 for a 77 Dodge 3/4T full time 4X4. I installed the cam, lifters, push rods, and rocker arm bars. Went to turn the engine and it would only go about 1/2 turn, then get real hard. Went back the other way and same thing, WTF? Well, I forgot to install the timing chain BEFORE doing the top stuff. I bent 8 push rods doing it! Had to go get more push rods.

 

[DeCaff2007]

The infamous Money Shift.

Usually going from 2-1 instead of 2-3. 3-2 instead of 3-4 happens a lot too.

So just like I've read on lying google, other forums, and a few IRL buddies that I've talked to, the answer is the same: Over revving the engine.

Just got back from the junkyard. There's a 93 C1500 5.7L, automatic, no A/C, and the engine looks very, very clean. I don't have the financial resources at the moment to bring that engine home, so I took two of the push rods. V6 and V8 pushies (lol) are NOT the same.
Local parts stores are no help in this matter.

Rock Auto (SIGH.............), here I come.

 

[DeCaff2007]

Interesting! I've also got a truck with the 4.3 that ticks, mostly noticeable at idle. I also have to replace the valve cover gaskets one of these days (I keep telling myself that I'm eventually going to do a junkyard LS swap, so I've been putting it off). I wonder if I'll find bent pushrods as well...

Just curious, any reason why having a manual transmission truck would affect this?

Uhhmm... I HIGHLY advise against that. Here's why: If you have a PRE-OBDII vehicle, you're going to run into too many problems swapping over the OBDII system, as well as the dinosaur V6 to LS swap. IMO, it's just not worth it unless you are infinitely in love with the GMT400 body style.

It's more efficient and probably less expensive in the long run to just buy an LS equipped truck.

 

[Frank Enstein]

Flat tappet pushrods are 7.794" long and hydraulic roller pushrods are 7.195" long.

V8 vs. V6 isn't the issue.

 

[Dropped88]

Since it's a manual I'm betting it was over revved. Being slightly bent and been running fine other then the tick.

I'd just throw some used push rods in it and run with it

 

[DeCaff2007]

Flat tappet pushrods are 7.794" long and hydraulic roller pushrods are 7.195" long.

V8 vs. V6 isn't the issue.

You nailed it.

So Rock Auto actually called me (that's a a first) and said the push rods I ordered were out of stock. Whatever. I'm just going to throw it back together and run it until it dies.

The whole point of even starting this thread was that I wanted to know what may have caused it in the first place. Now I know.

Thank you all for the replies.