Help! What has happened here?

[HO455]

Back story. Installed budget rebuild 350 in my Burban this spring. 2600 miles later it has failed. Was running fine till last week when it started a slight backfire out of the passenger side exhaust. It got some what more annoying over the next couple of days. I pulled the plugs and found #6 was covered in black fluid (Photo 1) I cleaned the plug off and swapped it with the #8 and went for about a 20 miles test run over two trips. The backfire went away for the most part. I chalked the slight misfire up to still having the fouled plug installed. I picked up a new plug and replaced the fouled one. Upon start up there was a slight ticking coming from the passenger side valve train I went for a drive to see if it would go away when hot. I went about four miles in stop and go traffic turned around and headed back. Then I started noticing smoke from the exhaust ad could smell burnt oil. The idle got rough and pickup was poor. I got home and the inside of the exhaust pipe was coated in oil. I popped the hood and now there is loud valve train noise.
This morning pulled the valve cover and found the #6 intake rocker arm at a 45* angle and jammed into the exhaust spring. (Photo 2) When I loosened the rocker nut (about 1/3 turn) the push rod dropped into the valley. I pulled the intake and found the push rod mangled and in two (almost 3) pieces in the valley (Photo 3) There was no indication that the intake gasket failed and was sucking oil from the valley. (Photo 4) The lifter was free in the bore.
The next step I took was to remove the cylinder head to see if there was a scar in the cylinder wall of damage to the piston. With the head on the bench I can see no signs of oil in the intake passage. The head gasket seems to be OK. There is no scoring on the cylinder walls and I am unable to see any damage to the piston. (Photo 5) The #6 intake valve is not stuck as I can push it down by hand. The tip of the valve has a strange wear pattern on it that the others do not have. The rocker stud has a slit in it about 1/2 of the way through. I believe that it is from the rocker arm.
The oil was changed at 500 miles, the filter cut open and nothing of concern was found. 500 miles later I checked the oil and found it a 1/2 quart below the add line. I filled it and watched it closely, but it never dropped like that again. I did add 1/2 quart about 1200 miles later. I knew I had two leaks that could have accounted for the loss of oil. When I got home yesterday the oil was below the add mark but this morning it was just below the full mark. I don't see any smoking gun for the high level of sudden oil useage. Yet to be seen is if there are broken rings.

[HO455]

It doesn't appear that the rocker stud has pulled out and the rocker adjustment nut wasn't backed off to a noticeable degree compared to the others. Once again no smoking gun as to why the push rod went awry.

[sweetk30]

please edit the 1st post with paragraphs to read it easy .

made it hard to read but i think i got it .

1st who built the engine ? warranty ? deal with them 1st if so .

2nd the oil is more than likely from that cylinder not getting any fuel and burning and the oil was being sucked up past the rings if i had to guess . kind of like fuel getting past the rings with a non firing cylinder does .

and that intake valve wear pattern could be looking funny from not moving right or not getting washed clean from air/fuel mix if i had to make a pic based guess .

the cam / lifters should be checked for damage . and the head needs a stud in it if not cut / machined for screw in to fix that if it wont repair correctly .

i have seen some heads get worn in the push rod hole / guide area and cause slop in the area and bend or kick a push rod out . years ago my dads old truck bent a pushrod and we put in a new one . 5 miles later bent again . found guide hole was egged out . fixed it with a chunk of new brake / fuel hard line as a oversize sleeve . lasted another year or so till the engine was replaced from tossing a rod from no oil .

hope my info helps you get a idea on what happened . good luck .

[HO455]

More photos in hopes that someone sees something I don't. Last one shows oil spattered on side of truck from the exhaust

[HO455]

Originally Posted by sweetk30

please edit the 1st post with paragraphs to read it easy .

made it hard to read but i think i got it .

1st who built the engine ? warranty ? deal with them 1st if so .

2nd the oil is more than likely from that cylinder not getting any fuel and burning and the oil was being sucked up past the rings if i had to guess . kind of like fuel getting past the rings with a non firing cylinder does .

and that intake valve wear pattern could be looking funny from not moving right or not getting washed clean from air/fuel mix if i had to make a pic based guess .

the cam / lifters should be checked for damage . and the head needs a stud in it if not cut / machined for screw in to fix that if it wont repair correctly .

i have seen some heads get worn in the push rod hole / guide area and cause slop in the area and bend or kick a push rod out . years ago my dads old truck bent a pushrod and we put in a new one . 5 miles later bent again . found guide hole was egged out . fixed it with a chunk of new brake / fuel hard line as a oversize sleeve . lasted another year or so till the engine was replaced from tossing a rod from no oil .

hope my info helps you get a idea on what happened . good luck .

Good information thanks. The wear pattern on the valve tip and a possibly of a push rod hole being out of shape seem to go hand in hand. I hadn't thought about oil being pulled past the rings with the intake being closed. The bottom of the lifter looks good and I glanced at the cam through the bore and saw nothing bad.

[HO455]

Some more photos to follow sweetk30's lead.

[68gmsee]

Looks like a combination of problems from my experience with the symptoms your engine has. The spark plugs coated with oil indicative of badly worn valve guides. I had a 350 that would foul the plugs fairly frequently.

The cylinder walls do show signs of wear and the oil ring/rings seized or worn. A major overhaul without shortcuts is in the works. Might be better off with a crate motor cost wise.

[cadillac_al]

The first thing I thought of was that the valve got stuck. It could just be a bad push rod though. We would need more info about the "budget build" to rule out some stuff.

[Chevyrestorerman]

Drill out the holes in the head where the push rods go. Install screw in studs with guide plates. This will fix your problem as far as why the push rod issue. Seen this several times on sbc where the push rod is “guided” thru the head. Once the push rod wears the hole in the head the push rod binds the rocker arm.

[homemade87]

I have seen this several times with people using used stock rocker arms . I had it happen to me . The stock rockers used are bad to do this or excessive wear on an oem motor . The rocker is put on a different stud and the wear is different and will go sideways and saw the stud in half . This is why the push rod broke . Get a new set of rockers and push rods and replace that stud and you should be fine . I dont see enough damage on the push rod bore to be a problem . As mentioned above the oil consumption is most likely from weird cylinder vacuum pulling oil in .

[Chevyrestorerman]

You still need to address the wear in the head that is used for the push rod guide. Being able to say there is not enough wear from your chair at home is really good. New rockers with screw in studs along with guide plates is the true fix. If not the problem will never be fixed right. My opinion only. If more debate needed we can get more into this if you like. Drilling out the hole in the head that is used for the push rod guide is a must allowing the bolt on guide plate to do the work of keeping the push rod aligned with the rocker.

Just to add to this:
Was a leak down test performed prior to tearing engine down ?

Was a compression test performed ?

benchmark information to highlight weak areas in the engine, reason "why" perform tests would assist in repairing your engine === Full rebuild or fix what is broke based on test performed before tear down ======
Heads are already off, send heads over to machine shop and have what I mentioned above done or redo this again in 2600 miles.

[Chevyrestorerman]

As far as the meaning of a “budget build” what does this term mean in this forum ?

[HO455]

Took my sad story and broken stuff to the machine shop today. They are going to tear both heads down and inspect and get back to me on Tuesday. As far as the " Budget Build" this local machine shop sells rebuilt Chevy long blocks for $1500 plus core. They don't provide an oil pump at this price. Not being naive I know that this means not every part is new but I have low requirements for the engine.( Plus being local I can drive down and talk with them. That's the number one reason I didn't go with one of the many crate engines available.) I expect it is better than some of the engines I built in the trunk of my car back in the day. I can't speak at this time as to parts were used. I do know that it has a Melling cam (CCS2) which is a copy of the old 300 HP 327 cam and the head gaskets are Victors. I will say I generally have more confidence in used GM parts than lots of new overseas parts.
Thanks to everyone who replied. I will post more as I know more. Still undetermined at this point is the source of the oil from the original fouled plug. If they don't find something in the head I may fabricate a plate to bolt on the cylinder and do a sort of leak down test before I have to pull the short block.

[sweetk30]

not to sound like a A$$ but for 1800.00 shipped to your door it gets you a ready to drop in long block 290hp vortec roller cam 350 brand new from gm . https://www.ebay.com/itm/GM-OEM-NEW-...4AAOSwysRas9qX

rebuilt engines at local machine shops have been hit and mostly miss these days anymore .

i got the vortec 350 for my current build . spent 250 on a nice edelbrock intake could have went super cheepy if i wanted to save 50ish bucks . then a 30ish buck new flexplate and dist gear to work with the roller cam and she is ready to run .

good luck on the local guy and hope he stands behind his work .

[Tom]

Why does it look like the rocker stud is cut half way threw? Like someone with a dremel and cut off wheel went into it....
Top of the piston has a crap ton of carbon buildup for a new engine. Also don't see any oversize markings on piston so just exactly what does rebuilt mean to the shop?

[HO455]

Originally Posted by Tom

Why does it look like the rocker stud is cut half way threw? Like someone with a dremel and cut off wheel went into it....
Top of the piston has a crap ton of carbon buildup for a new engine. Also don't see any oversize markings on piston so just exactly what does rebuilt mean to the shop?

The stud looks like a cutoff wheel was used, but the center is not cut. Its like a groove that goes half way around the stud. The rocker arm did that to the stud. I was able to wiggle the rocker around and get it to fit into the groove. The only piston picture I posted was the problem child. Here is the one next to it showing .030 oversized.

[HO455]

Originally Posted by sweetk30

not to sound like a A$$ but for 1800.00 shipped to your door it gets you a ready to drop in long block 290hp vortec roller cam 350 brand new from gm . https://www.ebay.com/itm/GM-OEM-NEW-...4AAOSwysRas9qX

rebuilt engines at local machine shops have been hit and mostly miss these days anymore .

i got the vortec 350 for my current build . spent 250 on a nice edelbrock intake could have went super cheepy if i wanted to save 50ish bucks . then a 30ish buck new flexplate and dist gear to work with the roller cam and she is ready to run .

good luck on the local guy and hope he stands behind his work .

The whole needing to buy $500 dollars worth of extras to install a Vortex made it not worth doing. I discussed getting one from them but it was going to be $2700 by the time I was done.
The interweb is full of crate motor horror stories and the best way to avoid them is to buy local. E-Pay and wallmart do not get my money. I try to support local businesses and I know these guys have been around for years. I have never done business with them before now but, I have seen them at numerous swap meets over the years. (Archie Somers is my go to guy for engine machine work, but his wait list is months and I wanted to get the Burban back on the road after the old 305 lost a main bearing.)
If it blows up in my face so be it, but after talking to them today I don't believe that is going to be the outcome. Either way I will post it.

[cadillac_al]

Ahah, It still may have stuck a valve if they replaced valve guides and didn't check clearance. Stuff happens and they probably know that. It is nice that they are standing behind their work. I'll bet they get you a good engine this time. I'm pretty sure my local friendly machine shop would do the same. That's the way it's supposed to be.

[HO455]

Originally Posted by cadillac_al

Ahah, It still may have stuck a valve if they replaced valve guides and didn't check clearance. Stuff happens and they probably know that. It is nice that they are standing behind their work. I'll bet they get you a good engine this time. I'm pretty sure my local friendly machine shop would do the same. That's the way it's supposed to be.

The sticky vavle guide theory is starting to gain traction in my head. The initial indication of problems was after I had the rear end gone through and in the process went from 3:07 gears to a 3:73 ratio set. The new higher cruise RPM would cause more valve friction for longer periods than before.

[Chevyrestorerman]

take the keepers and retainer off along with the spring for that one valve that had the broke push rod. Take close up pics of the valve stem please. thanks.

[HO455]

I wish I could but the machine shop has the heads now. They are tearing them down and said they would get back to me on Tuesday.
Once again. Thank you for your interest.

[Chevyrestorerman]

I would think if the valve was sticking it would have some markings on top of the piston where the valve may have came in contact with the piston but per the pics you provided I do not see any indication of such markings on the valve or the piston. Even if you do have a sticky valve and no markings on the piston/valve I would still address / fix the push rod guide in the head.

[DieselSJ]

Originally Posted by Chevyrestorerman

I would think if the valve was sticking it would have some markings on top of the piston where the valve may have came in contact with the piston but per the pics you provided I do not see any indication of such markings on the valve or the piston. Even if you do have a sticky valve and no markings on the piston/valve I would still address / fix the push rod guide in the head.

Unless you have very high compression (small chamber and/or domed piston) and a wicked high lift cam, these are not interference engines and you can easily hang a valve open and not have it contact the piston.

[Chevyrestorerman]

In the very first post, it was indicated the valve was not stuck. Only going by what is being told per the story of "HELP, WHAT HAS HAPPENED HERE" but I know its a forum, anything can happen.

[mattfranklin]

What length intake manifold bolts did you use? Some sources call for 1 1/4" long bolts. I tried that with mine with Edelbrock Performer intake and got a slight binding on one of my push rods. (It would not rotate.) I wound up switching to a 1" bolt and then was fine. This was on the passenger side near the exhaust crossover of the intake. I forget if it was hitting a push rod on #4 or #6 cylinder. This was with high-performance stock replacement Manley hardened push rods.

If intake bolts are too long they will dig into the push rod and wear into it until it's so weak and then it bends in half and/or breaks. Luckily, I caught mine before it was an issue.