Bent pushrod!! Need some advice please

I have a replica Shelby Cobra running a 429 with police interceptor heads, a flat tapet cam and roller rockers with hydraulic lifters, and built by a race shop with all the bells and whistles. I turned it loose a few months back and started hearing a tapping sound (which is hard to hear with side pipes) and started getting smoke from the collector pipes that was filling the engine compartment. There is oil and smoke spitting up from the collector pipe on the failed pushrod's cylinder. The failed rod is on the intake valve, so I wasn't getting fuel, but why am I getting oil and smoke?? Is the vacuum from the downstroke causing the intake valve to open enough to suck in oil and spit it out the exhaust where it's burning in the header?? That being said, what kind of damage should I be looking for?

Is the cam/lifter damaged from being slapped around by the cam whenever the lifter decided to fall back down the sleeve?

How did that rod get bent?

Some of the pushrods (especially the failed one) are getting chaffed up to .06in by the valve guides, whats happening there?

Just spitballing but...


You sure your builder used hardened pushrods with your guide plates?

I have no idea what kind of rods he used, I just gave him money... All of the rods are chaffed, some worse than others.

Take the motor back to the guy who built it and give him more money to fix it .. Tell him to fix it right this time ..
Money Fixes everything. Just throw more at it.



Dan

Cobbcfi wrote:I have no idea what kind of rods he used

See if you can scratch the pushrod with a file, if it is a hardened pushrod, a file won't scratch it. Also can you post a picture of the heads and pushrods?

if you are getting oil smoke from the bent cyclinder your valve may have it the piston and damaged the piston.how high of rpm was you turning when it bent sounds like the wrong pushs rods.Get with the engine builder but most of the time a engine builder want do anything about a high preformance engine but I would still quistion him about it.

IcallhimGeorge wrote:Just spitballing but...


You sure your builder used hardened pushrods with your guide plates?

if the intake valve aint opening it'll pull oil by the rings too.

cool40 wrote:

IcallhimGeorge wrote:Just spitballing but...


You sure your builder used hardened pushrods with your guide plates?

if the intake valve aint opening it'll pull oil by the rings too.

And , if there is no combustion there is no pressure to make the top ring hook up.

for whats its worth scorpion brand pushrods are sold as hardened but they are just coated. i threw one set out and have a second set collecting dust

If the pushrods are being chafed by the guide plates they are not hardened.

Now you have an oil pan full of filings from all those ground up pushrods.

Pull the engine check, clean, replace as required and try again with the correct pushrods.

dkp

A couple things will cause the pushrod to bend. One is the valve hit the piston and another is if the pushrod is too short and the geometry is all out of wack. Regardless you need to find the problem before just throwing new pushrods back in. If the valve hit the piston the valve could be hit and the guide could be damaged causing the oil smoking. If they put different valves in the head (like SCJ valves) they are a different length requiring a longer pushrods.

If the pushrod is chafed .060 like he said there isnt enough column strength left to open the valve.

dkp

The lifter on the failed rod has been thrown into the intake area somewhere.. Where the rod failed the pushrod has a wall thinkness slightly more than 1/32in or half of 1/16in. The rod scratches easily with a file as well. I had it wound up pretty good when it started knocking.

My question is, if the pushrod is supposed to be tight in the rocker how can they fly around and get chaffed up on the guides? Are the springs not strong enough to keep pressure on the rod and rocker or at high rpm's do rods normally fly around and that's what the guides are there for?

Are these the rods I should get?
http://www.summitracing.com/parts/CCA-7948-16/

Also, the "COMP Cams" rods from Summit don't look like mine on the ends, mine have round balls and COMP are different looking. I assume that means nothing right. What is the difference between "End A" and "End B"??

Another question since ya'll have me worried about metal flake in the oil pan. What kind of oil should I use. I still have Joe Gibbs break-in oil in it right now and it's time for an oil change. I have a relocated oil filter and an oil cooler up front. How much oil would the stock 429 hold? I also am not sure if I have the right dipstick in this motor, will any 429 dipstick work so I know my oil level is right or do I need to find one specific for this motor ( which I am really not sure what it came out of, i think it's a early 70's truck motor)..

thanks again for any help, sorry about the pics, only have a cell phone to take and upload pics

I believe I'd be having a discussion with an "engine builder"

crittersf1 wrote:I believe I'd be having a discussion with an "engine builder"

for damn sure! pull the intake and check all the other lifters out while your at it.a hard pushrod will work however you put it in,they're hard all over.the metel off those went to the pan then the pump and should be in the filter.i'd drop the lifter back in,put some good rods in it and fire it up.change the oil first tho,lol,then change it again real soon.

Holy Smokes, those sure ain't hardened pushrods.

Besides talking with your engine assembler about the pushrods maybe you should ask what the maximum engine rpm should be with your hydraulic flat tappet cam and set your rev limiter about 200 rpm lower ~ 5700 rpm or so.

It looks like there is a braided line coming out of the rear oil port behind the intake manifold. That's a convenient place to read oil pressure but be aware it typically reads a little low there.

I know you dont want to hear it but that engine needs to come out, be completely stripped down and cleaned. Then any damaged bearings replaced, crank journals polished etc, etc, yada yada yada. Personally I would not bother with the original engine builder. I simply would not trust him to assemble my lawnmower after that.

Find someone else who really knows what they are doing and have everything rechecked. Pretty simple deal that you have to use hardened pushrods with guide plates. A lesson I learned the hard way on my first 351C. Tried the just replace the pushrods deal. Lost the bottom end pretty quickly bearings full of ground up pushrod material.

Tough lesson. Sorry for your loss.

dkp

Like the last 2 guys said the push rods are chewed up because they're not hardened.The guide plates are harder then the push rods that's why the push rods got chewed up.

Later Mark.

These guys are so right .It sux ,but your engine will have to be torn down ,cleaned and inspected thoughly. You'll never believe how much metal is going to be all over the inside. Oil galleys ,bearings and anywhere else it can get into. You'll never get it to live without taking it apart . The engine builder doesn't know his stuff,that's for sure..I'd be pissed over that deal.Anybody with any experience in performance engines would've known better than to use those pushrods with hardened guide plates. Sorry you had to learn this way. Good luck!

OK, here goes..... I took my replica Shelby Cobra to a shop that had a well known race engine builder knowledgable with BBF's. I wanted a full tune and some other work. 3 years later, my Cobra had robbed the space of one bay in a 5 bay shop. They had lost any money they ever would have made losing that single bay in the shop. At this point with my years of restoration in an auto-body shop in my youth, I said screw you, I'll rebuild the damn car myself. I wanted a performance tune, they tried a frame off restoration and complete engine rebuild and failed. To make a long story short, the engine builder did the guts and I fabricated the components, not to mention re-do the entire car cosmetically. I must say I did enjoy learning leather work and carpeting etc. but this was not my plan. This old engine building bastard had my car for 3 years and still wanted $3,400 in labor. I told him to sue me and get outta my face. He didn't sue, but he did get out of my face. But he has now retired and so did our contact. I cannot go back to him or the shop since it has now gone out of business. I have receipts and such of what I paid for but have no idea the valve lengths are, much less what they are. Although somehow, knowing the engine was knocking, I still got it tuned, timed 16 BTDC at idle, and running good thinking it was only a valve adjustment and I didn't care to dig in until a few weeks back and saw the level of calamity that had occurred. This is why I have asked for your help, I am engine savvy and very knowledgable around the car, what are my next steps??

I know I cannot measure the valve length without pulling the head (and I'd rather not if I don't have to) I don't know if the valve springs are marked for strength or anything. What else do you fellas need to know so I can head in the right direction... BURNING RUBBER

Oh, and I am still worried about whatever dip stick has been put in my engine.. I would like to know how to figure out which stick I need and where to get it...

Thanks a bunch guys for you help!!!!!

56Tbird wrote:These guys are so right .It sux ,but your engine will have to be torn down ,cleaned and inspected thoughly. You'll never believe how much metal is going to be all over the inside. Oil galleys ,bearings and anywhere else it can get into. You'll never get it to live without taking it apart . The engine builder doesn't know his stuff,that's for sure..I'd be pissed over that deal.Anybody with any experience in performance engines would've known better than to use those pushrods with hardened guide plates. Sorry you had to learn this way. Good luck!

I just saw your post after writing 3 of my own... ARE YOU SHITTING ME?????????????? ARE YOU SERIOUSLY @&%*ING SHITTING ME?????