Valve Catastrophe?

[Kaiju Senso]

So it looks like my timing chain must have broken. Car was idling fine for maybe 20 min then cut out at the end of the driveway and wouldn't restart. Didn't hear any serious "stuff breaking" noises when it happened, it just died. Cranking sounded funny, tried to see into the oil fill hole, decided finally to just pop off a valve cover.

http://youtu.be/S6U4ByodHB8

Comp 26986 Valve Springs
WOT Tech Strip Cam
matching custom length pushrods

everything else stock 2005 LNJ 3400 (Chevy Equinox, transplanted into Pontiac Fiero) maybe 2000 miles on the engine when in the Equinox, another 1000 in the Fiero with stock valvetrain, and less then another 1000 miles with this valve train before something broke.

Worth it to try and open the timing cover and fix what's broken while in the car or is it definitely (probably) screwed so needs to be pulled for a rebuild?

[Superdave]

chain or the cam dowel pin.. i'd pull the cover while it's in the car to take a quick look.

[1988GTU]

I'd guess the pin. If the chain snapped it'd most likely have bound up around the crank sprocket and started to make some noises.

[Kaiju Senso]

I'm just worried some of the valves might be toast.

[1988GTU]

a comp test would help you figure that out once you find out and fix the rotational issue.

[ericjon262]

good thing you have a DRTC on the way. or at least, as long as the Fiero isn't your daily driver...

[Kaiju Senso]

No Fiero isn't a Daily, especially in Winter. And actually this problem occurred a while ago and helped persuade me to get in on the Double Roller Timing Chain group buy.

The cam bolt loosening seems more plausible to me then the chain breaking. I thought the timing might have been a tooth off when I first started it so pulled the cover and realigned the marks, but had a bit of trouble getting a good angle to torque the bolt down while keeping the gear from spinning. If the dowel pin is sheared off, it'd probably be near impossible to put a new one in with the engine in the car, there is barely enough room to get the timing cover off.

I'll probably just drop the cradle again, and I'm still expecting some broken valves. I've seen some nice pictures... Might be time for another upgrade, cylinder head porting with 3500 valves sounds like a plan...

[TGP37]

I'd guess the pin. If the chain snapped it'd most likely have bound up around the crank sprocket and started to make some noises.

+1 though funny sounding crank, might be the chain.

The engine will run with chain off by one tooth. It is either 12 or 7 degrees difference adv or ret. It won't run it's best, but it would run.


I wonder if the oil pump shaft snapped, no oil pressure is no fuel pump? (in case of accident)?

[1988GTU]

Could be a snapped cam shaft. If the oil pump section snapped, it'd still start.

[TGP37]

Could be a snapped cam shaft. If the oil pump section snapped, it'd still start.

Yeah, the stock ones snap but they have WOT cam which I believe are solid. I doubt it would snap unless something seriously went wrong somewhere else.

[Kaiju Senso]

Engine cradle came out this weekend, should have pictures of what happened to the engine by next weekend. I'll remember to use locktite on the assembly, but which color?

[Mars]

Yeah it's a solid cam, so I bet it isn't broken.

I've wiped a locating dowel off on my 3500, i suspect that happened. It sucked. Motor was in bad shape after that, bent all the valves, ect. I'm pretty sure you toasted some parts in there.

I always LOCTITE red that bolt now. and torque to spec.