New car, slipped chain, broke valve hole in one shot....

[Quick6'n'-K.C.]

Thought i would share...

Here is what happens upon startup when using a off the shelf timing chain from advanced auto and the tensioner snaps.

I could deal with all the bent intake valves and marring on the pistons, when i found this i am a tad worried if the piston will hold up now...hmmmm

Anyway, its a hole in one shot right in the middle of the spark plug when i pulled the head off the block...
The threads look fine, not too much damage except for way too much carbon buildup after 15,000 miles on these heads.
Anyone run their piston after something like this?

BW

 

[Quick6'n'-K.C.]

head

 

[Quick6'n'-K.C.]

piston

 

[bison]

6 years ago i had a chain jump on me and it bent all the valves. The pistons were ok though. Ive seen people run pistons with more damage than yours. Hopefully the rod isnt bent. I wouldnt run a tensioner on a replacement chain unless it was a new chain and tensioner from GM. What head gaskets were on there? Looks like you have a carbon ring on the deck from a bigger bore gasket. The graphite ones leave almost nothing on the deck around the cylinder. Definitely to much carbon buildup for the low miles though. Maybe you should plate hone and re-ring it to be safe.

 

[Quick6'n'-K.C.]

Actually, it seems the damage really did happen upon start up and didnt do alot of carnage to the pistons....
I purchased the car with this issue and was hoping to leave the shortblock in the car... I guess i will spend some more time with it and redo the shortblock along with the head work....
1/2 -3/4 of the replacement timing chain metal gears were WORN OFF!!!
I wonder where that metal went???
Well, at least i dont have to worry about flattening this cam.. :biggrin: I never had a car with a roller cam before, cant wait to pull the cam out and take a peek at it
BW

 

[Quick6'n'-K.C.]

Headgaskets appear to be felpro 1000's...
I need to find out if thats the correct gasket for the 3.8 109 block, and if jason cramer sells a gasket with the same thickness..

thanks
BW

 

[vader87]

I guess your "lucky", if you want to call it luck. I had a 70 GTO that broke a valve but the valve was verticle when the piston slammed it into the head. When I took the head off, it was a permenent part of the piston. Of course this inturn cracked the block. I would rebuild the short block also. Like you said, "where did all the metal go" from the timing gears?

 

[NJVetteGuy]

Pull the motor. Last one I worked on that looked like that, the skirt was out of round by a few thousandths and ruined the bore because the owner just stuck new heads on the shortblock.

 

[turbofrank]

Happened to me too no broken valves did have bent pushrods. A couple
of pistons had were marred like yours engine builder notched all pistons
so if it happens again it won't be as bad

 

[TurboDave]

That's some massive carbon buildup for so few miles!!!

You might also want to take a close look at the chip you're using or the general state of tune. Looks like a lot of very rich open loop running!

 

[QKRNYRS]

That's some massive carbon buildup for so few miles!!!

You might also want to take a close look at the chip you're using or the general state of tune. Looks like a lot of very rich open loop running!

I disagree. Even a stock engine or a non-performance engine will have carbon on the tops of the pistons after several hundred miles. However, it does look like it may have some oul carbon indicating that it was burning some oil.

 

[Quick6'n'-K.C.]

That's some massive carbon buildup for so few miles!!!

You might also want to take a close look at the chip you're using or the general state of tune. Looks like a lot of very rich open loop running!

I agree thats a whole buncha carbon buildup for very little miles on the heads, but the damage was done before i purchased the car. Ive only had the car for less than a week. I bet i could get a teaspoon full of carbon out of each cylinder,
Anyway, after looking at the dinged piston and the advise from everyone here, the motor is coming out tonight, i will assess what all needs to be replaced and figure out what all this motor is getting.

I just got out of work from a 72 hour work week,glad to be home and get right back into tearing it apart.

I dont know whose chips were in the car before, but i guarantee its getting one of erics chips burnt for the champion heads and 61 turbo.
Here is what it looked like after i washed it at the car wash. :biggrin:
BW

 

[Steve V]

I thought that all roller cams required a double roller chain set-up not the stock type? Could the extra spring pressure be enough to snap the stock chain....

 

[Quick6'n'-K.C.]

I thought that all roller cams required a double roller chain set-up not the stock type? Could the extra spring pressure be enough to snap the stock chain....

i guess dls should have supplied the chain with the cam for the previous owner, maybe they informed him about using a double roller and he didnt take the advice???

BW

 

[ttypewe4jim]

:biggrin: man your all about the limiteds aren't you lol :biggrin: Sweet car man thats going to be a fun ride once you rebuild the motor or whatever it needs. If you don't mind me asking how much did you end up picking it up for?

 

[Quick6'n'-K.C.]

Fair market value :biggrin:
I got a great deal on it... all it needs is a pressure washer to the underside of the car, detail the engine bay, rebuild the motor,powdercoat a few parts and its ready to go!
Hell yes, i really do like limiteds :biggrin:
BW

 

[Quick6'n'-K.C.]

Pull the motor. Last one I worked on that looked like that, the skirt was out of round by a few thousandths and ruined the bore because the owner just stuck new heads on the shortblock.

YOU are the winner....

Guys, go back up and look at the dinged piston at the top of the page. That damage to the piston did the following...
The ring is pinched in place and the PISTON does not float with ease.. see pic, the piston should fall down on its own, but stays rigid....Not a huge issue... till......

 

[Quick6'n'-K.C.]

It does this and now its a paper weight.

I knew something was wrong when i got antifreeze from draining the oil, i thought to myself.. cracked block or previous owner forgot to drain coolant before removing the front cover...

The only part that ticks me off is this was the original vin matching motor for the car...
BW

 

[QUIP'6']

if originality is an issue just sleeve the damn thing. sorry to see this sort of thing happen especially the stuff that you cant see from the outside goodluck on your decision

 

[Quick6'n'-K.C.]

Yeah, i could sleeve it, but could find another motor and go with it cheaper then paying labor to get the correct block back into this buggy.

I think im just going to run another motor i have sitting, now i plan to swap out my flat tappet cam for this roller cam setup and t&d rockers, after these parts are cleaned and inspected...

Not what i was hoping for!
BW