Stock pushrods ?

**km346** · 03-05-2010, 08:13 PM

My 98 SS has currently has 55,000 miles on it and i am not the first owner. I was just wondering how many of you guys have bent the stock pushrods? I haven't missed any gears and have only bumped the rev limiter a few times since ive owned it, but ive been thinking about my push rods lately... do you think i should be worried about having any bent push rods? my valve train seems fairly quiet however i sometimes get a little bit of "lifter tick" when cold. opinions?

Thanks in advance
-Kyle

**67CamaroRSSS** · 03-05-2010, 08:19 PM

I over revved the 02 trying to manually shift the A4 when I 1st bought it. It hit the rev limiter HARD! I bent 2 of the pushrods. Not real bad but they wern't straight when rolled on a flat surface.

Now that I know better I let the comp do it's thing (It's programmed for max effort)...

**Mr. Luos** · 03-05-2010, 10:05 PM

I had 1 really bad one and 3 with very slight bends in them.

24K miles when they came out.

**bills98ta** · 03-06-2010, 02:55 AM

Bent push rods come from the valves hitting the pistons when they float out. You should consider heavier valve springs too. The comp 26918 springs would be a good investment. The stockers are to weak.

**Mr. Luos** · 03-07-2010, 12:59 AM

Stock valvetrain???
If so....replace with stock parts.

The stockers give....for a reason.

**km346** · 03-07-2010, 07:49 AM

Yeah, im planning to buy some used stock push rods to replace any pretzels i may find. It would be nice to upgrade springs and push rods... but that seems overkill to me with the stock cam.

**squirlnutz** · 03-07-2010, 01:53 PM

Originally Posted by km346

Yeah, im planning to buy some used stock push rods to replace any pretzels i may find. It would be nice to upgrade springs and push rods... but that seems overkill to me with the stock cam.

I dont think used pushrod would be good. Not much for good new ones.

**km346** · 03-07-2010, 02:45 PM

Originally Posted by squirlnutz

I dont think used pushrod would be good. Not much for good new ones.

Well I would be replacing a stock bent pushrod with a stock strait pushrod. I can get a set cheap that have less miles on them then my engine has... Why do you think that would be a bad idea? As long as they're strait they should serve there purpose, no?

**allbaugh_04** · 03-08-2010, 12:54 PM

Yeah but some nice hardened push rods don't cost all that much. I personally try and upgrade everything I change out.

Who knows when you miss a shift and bend the stockers again, right after you changed them.

The stock ones are weak.

**El Toro Loco** · 03-08-2010, 01:03 PM

Originally Posted by Mr. Luos

Stock valvetrain???
If so....replace with stock parts.

The stockers give....for a reason.

SO u dont think that there is justification for putting in better push rods and sprigns wit the stock cam. how come?

**km346** · 03-08-2010, 01:48 PM

Originally Posted by allbaugh_04

Yeah but some nice hardened push rods don't cost all that much. I personally try and upgrade everything I change out.

Who knows when you miss a shift and bend the stockers again, right after you changed them.

The stock ones are weak.

From what ive been reading the past few days the stock push rods are more then strong enough for the stock cam and valve springs. The only reason they bend is because the engine is mechanically over revved (downshifted into wrong gear, etc) The valves float causing PTV contact. Knowing that it wouldn't be smart to upgrade to chrome moly push rods because if i ever over revved again i would now be bending valves instead of the weaker push rods.

**allbaugh_04** · 03-08-2010, 02:11 PM

Originally Posted by km346

From what ive been reading the past few days the stock push rods are more then strong enough for the stock cam and valve springs. The only reason they bend is because the engine is mechanically over revved (downshifted into wrong gear, etc) The valves float causing PTV contact. Knowing that it wouldn't be smart to upgrade to chrome moly push rods because if i ever over revved again i would now be bending valves instead of the weaker push rods.

That's why you should do a cam swap and replace it all...silly

**02fbody35th** · 03-08-2010, 02:27 PM

QUOTE=km346;2261821]From what ive been reading the past few days the stock push rods are more then strong enough for the stock cam and valve springs. The only reason they bend is because the engine is mechanically over revved (downshifted into wrong gear, etc) The valves float causing PTV contact. Knowing that it wouldn't be smart to upgrade to chrome moly push rods because if i ever over revved again i would now be bending valves instead of the weaker push rods.[/QUOTE]

You hit the nail on the head man. that is exactlly why mr. luos said the factory put the weak pushrods in for a reason.

**Firebirdjones** · 03-08-2010, 03:01 PM

Originally Posted by allbaugh_04

Yeah but some nice hardened push rods don't cost all that much. I personally try and upgrade everything I change out.

Who knows when you miss a shift and bend the stockers again, right after you changed them.

The stock ones are weak.

This is true. The stock valve springs are weak, after some use they are lucky to have 60-70 lbs. seat pressure.

When you bend a pushrod, it's not because of the rev limiter, it's because there is some sort of piston to valve contact due to a weak spring. That can only happen if the spring is not controlling the valve properly. Most valve float occurs when the valve returns to the seat, and bounces off the seat.

The only other way to have piston/valve contact on a stock engine, would be if the timing chain jumped teeth.

If you have bent pushrods on a stock engine, more than likely the springs are weak allowing the valve to bounce. This more than likely occurs on the exhaust valve/spring. They see the most heat and those springs fatigue as a result.

I would pay close attention to which pushrod is bent and what hole it came from. Then check that corresponding valve spring for seat pressure. Chances are it's under par.

Your best bet would be to swap the pushrods for good quality ones, and replace the valve springs while the rockers are off. Good insurance. With the valves controlled properly, you could bang the motor on the limiter all day without issues.

**Wesman** · 03-08-2010, 05:10 PM

Originally Posted by Firebirdjones

This is true. The stock valve springs are weak, after some use they are lucky to have 60-70 lbs. seat pressure.

When you bend a pushrod, it's not because of the rev limiter, it's because there is some sort of piston to valve contact due to a weak spring. That can only happen if the spring is not controlling the valve properly. Most valve float occurs when the valve returns to the seat, and bounces off the seat.

I honestly don't believe any PTV must occur to bend the pushrods. If that were the case, I think we'd be seeing a lot more people with bent valves.

What is most likely happening is excessive lash in the valvetrain due to valve float, and the extra clearance causes a hard shock to the pushrod as the RPM's drop and the clearance is taken up.

Your best bet would be to swap the pushrods for good quality ones, and replace the valve springs while the rockers are off. Good insurance. With the valves controlled properly, you could bang the motor on the limiter all day without issues.

I agree. When I found out mine were bent, I swapped them for some Comp Cams hardened pushrods.

**El Toro Loco** · 03-08-2010, 06:55 PM

good info

**Firebirdjones** · 03-09-2010, 06:35 AM

Originally Posted by Wesman

What is most likely happening is excessive lash in the valvetrain due to valve float, and the extra clearance causes a hard shock to the pushrod as the RPM's drop and the clearance is taken up.

For that to happen, it would have to be some pretty flimsy pushrods. Doesn't say much for the stockers. All the more reason to yank those suckers and replace with something better.
Funny thing is, with the rev limiter set to 6,000 on these stock engines, and to already be into valve float at that point is not saying much for the valve springs either.
Shouldn't be seeing valve float that early if the engine is equipped with proper springs to control the valve action.

Short answer, upgrading the springs are a good idea.

**km346** · 03-09-2010, 10:54 AM

From what i understand ls6 springs are a direct swap over, may go that route depending on what i find when i open the valve covers... My luck ill buy new springs and chrome moly push rods and all my stock stuff will be fine when i open'er up. We'll see when i pull it out of storage...

**Wesman** · 03-09-2010, 06:04 PM

Originally Posted by Firebirdjones

For that to happen, it would have to be some pretty flimsy pushrods. Doesn't say much for the stockers. All the more reason to yank those suckers and replace with something better.
Funny thing is, with the rev limiter set to 6,000 on these stock engines, and to already be into valve float at that point is not saying much for the valve springs either.
Shouldn't be seeing valve float that early if the engine is equipped with proper springs to control the valve action.

Short answer, upgrading the springs are a good idea.

I agree, upgraded springs are always good.

However, I don't think the issue is happening at 6,000RPM. I think it is a result of an overrev situation (missed shift) or too much pounding against the rev limiter over time.

Either way, the stock pushrods are not very strong.

**blackbirdbrain89** · 03-09-2010, 07:12 PM

hell im running stock push rods and shifting at 6400 and some times hits 7k and no bent rods

every one note that i have 918 springs on my car and do not hit the limmiter @7k
the worst thing ive done is tossed a belt off my car