Bent push rods

JasonMiller94SC

Registered User
So I found a couple of bent push rods when I took the intake off today. What the heck causes them to bend? Car was still running ok but noticed the plugs on the drivers side getting oil on them so I figured I better take the head off and check it out.
Any tips?
 
Got VERY hot, valves got stiff in the guides with the heat.
Seen it on many other engines.

Were the rockers ever worked on? Valve springs ever removed and worked on?
 
Got VERY hot, valves got stiff in the guides with the heat.
Seen it on many other engines.

Were the rockers ever worked on? Valve springs ever removed and worked on?

They are after market springs that I got from Dave Dalke to go with the cam. I'm running the Harland Sharpe 1.8 roller rockers with push rods to match.

I suppose it could have gotten hot on one of the nitrous passes. Motor has been sealed up for a couple of years since it was last opened up. I'll know more after I get the heads off.
 
You can't run 1.8 rockers with that combination, so your bent pushrods are the result of coil bind. That doesn't explain oil in the cylinders though, more likely that is because of broken piston rings or other nitrous damage. Look for any deformity of the piston tops but if you don't find anything there, the next thing is to pull some pistons out and check rings.
 
You can't run 1.8 rockers with that combination, so your bent pushrods are the result of coil bind. That doesn't explain oil in the cylinders though, more likely that is because of broken piston rings or other nitrous damage. Look for any deformity of the piston tops but if you don't find anything there, the next thing is to pull some pistons out and check rings.

Well there you go! Straight from the guru!

don't you just love it when someone asks a questions without giving you all the info...

Non stock rods, 1.8 rockers, different springs, AND Nitrous... YUP SOMETHING IS GONNA BEND!
 
Well,

I could have sworn I told the perons I order the cam from that I already had the 1.8 rockers in the car. Oh well. I guess it's a good think I kept the factory parts.

Could it be that the nitrous is just too much for it? Would the combo work without the nitrous?
 
Last edited:
Well, I got the drivers side head off. No marks on the tops of any of the pistons that I can see and the cylender walls still show a nice cross hatch all the way around. The valves in the head are pretty sooty so I can't tell much. I guess the next step is to take the heads to the shop and have them cleaned and checked for cracks.

As long as the motor is not hurt what kind of valve train combo should I be running if the 1.8 rockers won't work?

Here's the cam specs:

cam%20specs.JPG
 
Well,

I could have sworn I told the perons I order the cam from that I already had the 1.8 rockers in the car. Oh well. I guess it's a good think I kept the factory parts.

Could it be that the nitrous is just too much for it? Would the combo work without the nitrous?

I am that "persons". Whether or not it was my oversight or not I can't say anymore since it has been 5 years since we did this, but based on the cam grind specs, I know that the cam was ground with 1.73 rockers in mind.

When running stock valves you are very limited on valve lift. If I had known you already had 1.8 rockers I would have gone with less lift. My suggestion now would be to have aftermarket valves and beehive or dual springs installed. That is my recommendation, but if you don't want to go that route then you'll have to get some 1.73 rockers. You can use stock rockers if you want to. Since you have been running the springs into coil bind, you need to have them all checked for damage and for proper pressures. Most likely they should not be re-used.

Nitrous has nothing to do with the valvetrain. But if you are getting oil fouling on spark plugs, then you have another issue unrelated to the valve springs. Look for damaged valve seals or guides. If you can't find anything wrong with the heads then the next stop is pistons. Just because the cylinder walls look good doesn't mean you don't have broken rings or piston ring lands. I see that all the time.

I'm not trying to make you do extra work, but you have to find the source of the oil or you'll be taking it apart again later.
 
Thanks for the good info Dave.
Was not tryign to throw you under the bus about the cam thing. I can't say for 100% that I told you I had those rockers. Strange thing is I had the heads off a couple of years ago and never saw any bent rods then after 3 years of use. Also it's not all of the rods. Of the 6 I took out only 2 of them were bent. The other 4 are ok. Looks like the same deal on the other side but can't be 100% sure till I take them out.

What's the best way to check for binding coils? Can I rotate the motor around with the other head on and when the lifter is on top of the cam check for space between coils?

Unfortunaly if there is much wrong with the motor the car is going to sit for a long while as right now I don't have any extra money to spend. :(
 
Had the day off and was able to go out and confirm what Dave said. The coils do bind in the springs with these 1.8 rockers.

Next question is can I do anything to keep using the rockers? Shims, different springs or different legth push rods? If not I guess I'll be digging the stock rockers out of the shed unless someone wants to trade me some 1.73 RR for my 1.8's. :D
 
Had the day off and was able to go out and confirm what Dave said. The coils do bind in the springs with these 1.8 rockers.

Next question is can I do anything to keep using the rockers? Shims, different springs or different legth push rods? If not I guess I'll be digging the stock rockers out of the shed unless someone wants to trade me some 1.73 RR for my 1.8's. :D

You're going to need different springs. Unless you want to get a smaller cam. :D
 
Back
Top