What make springs? Carquest? I think I would replace them all. Real lucky that valve didn't drop and I wouldn't trust the rest of them. With such a mild example you would never expect that and surely be suspect of the quality of the parts. Sorry to see but glad not a catasrophe.

Good video showing viewers how to diagnose a cylinder having issues

I've had new springs break, the thing is Alan diagnosed it and fixed it for Joe, he should be a happy customer 😊

I recommend swapping all the valve springs to quality Crower dual valve spring. It’s not worth the gamble running unknown brand springs.

Well that's frustrating. Thanks for sharing. If one went bad, I'd replace them all, intake and exhaust. Relatively lucky once, it's not worth pushing one's luck further.

Throw all those Chinese springs away and install some PAC springs. And also do not install those OEM oil shields, they just add weight to the valvetrain and are not needed if the seals are any good. They were designed for the original o-rings that were used way back when.

Appreciate you sharing. Those springs and the retainers looked stock. Just put all new of both and go down the road....If your not careful and the spring unwinds itself from the valve, then when the valve kisses the piston , its all over. $200 bucks is cheap insurance.. thanks

Despite machine shop checking, springs are unknown mileage? Change them all.

Check the pushrod to see if it is bent.

crower makes a very good spring for stock install height pontiac heads #cro 6804-16

I would replace them all. I know it sucks but it will probably happen again. Might be a lot worse the next time.

Great video guys!

Valve springs can also break when the RPM's go north 😂. Just joking. I'm glad that's all it was . Another GREAT video

Probably should change them all! Dropped valves destroy engines! He got lucky once! I’m sure you checked coil bind & made sure the retainers are not touching?

I’d buy the springs that match the cam and change all 16.. Sounds like these are mystery springs and possibly used springs.. PAC makes good springs. Dodged a bullet on this one for sure, it’s usually catastrophic when the valve does drop..👍🏻

Thanks for posting. Casting my vote for all new springs Im sure Joe has already decided to. The problem with springs today is where the wire is coming from. Having manufactured springs and setup spring coilers wire quality can be and issue today. I enjoy your videos. Bill reminds me of my late uncle. So more content from him please.😊

Great episode!

thank you for the video

When a spring breaks near the 1st couple coils then there might be coil bind or fatigue. When it breaks towards the center coils then it's a manufacturing issue/ poor quality.. thank you for your knowledge and videos.

Hey AG, Tim here, from ur description, while you were drivin there, i felt, hmmm, erratic comp, no fire, poppin thru carb, GOTTA be a spring..and THERE you have it.........ok, we both have been doin this a long time, but the erratic comp test, said valve spring to me LOUDLY!!....i hope Carquest does right, and you guys can move on.....LOVED the vid (well its a Poncho engine, so i'm a bit biased) haha, but, YES, NICE job of deductive reasoning.....you having him do the comp chk, and then results being erratic, told me what it was......again, lets hope Carquest, makes good on it all......or at least makes an effort to help you guys.....NICE BIRD btw.........another smart, enjoyable Gold Garage vid!!....TY sir!!!...PEACE to you!!

Film guy pay attention 😂. Bouncing around and drifting.. Thank you for your knowledge and videos. Must appreciate.

Springs might be close to binding...I've had that on an engine where the math noted enough clearance before bind, but in practice, it kept breaking springs...

From, your description of the the symptoms. I, knew it was broken valve spring. I've, dealt with that before.

An IR thermometer reading while idling would have been interesting. Probably useful for an early diagnosis to isolate the cylinder.

i Have rebuilt many engines big and small.. one large engine was a Bedford 466 a 11 liter diesel I fitted new valve springs. 4 weeks later the driver was reversing up to a loading bay being directed by the boss. A valve spring broke the valve dropped piston split engine stopped dead cracked block and head. complete right off. The valve springs went back to manufacturers they had been harden but not tempered! they paid compensation!!

I was thinking valve not sealing. Didn't think the problem would be the spring though. I'd replace "all" of them.

First thought is a bad valve spring

I just did my valve spring seals on my 1991 GMC , no more smoke at start up , i used that hose and a bigger hose and put it in my mouth and could feel the piston air coming up when the air stopped blowing I new I was at TDC , then I found number one TDC set the valves in its firing order every 1/4 turn or 90 degrees to set valves with the firing order . I just turned 72 but its in my blood .

I had one break on me once. I installed an Edelbrock Performer cam. Only had a .420/.442 lift. Single spring of course. I had iled my way up a logging road, during a weekend photo excursion and stopped to fix lunch, and upon restarting the engine it had a barely noticeable miss. Thinking a fouled plug, I pulled plug wires one at a time to discover it was the #4 cylinder. (SB350) I limped 120 miles home on Oregon coast hwy 101 to get home. The only time that I drove over 30 mph was taking it out of gear and coasting down hill. That was one l o n g 120 mile drive. 😁 The next morning i removed the rocker cover again to find the spring had broken a srcond time. 😱 Young, lucky and stupid. 😁

Carquest heads are junk. I don't know why in the world you would use 'parts store' rebuilt/reman heads on ANYTHING other than a bread and butter daily driver. At best you're getting a set of stock spec rebuilt heads. If you're a betting man. They aren't in any way or shape up to performance use. You get exactly what you pay for. Why did it break? Carquest isn't using any 'premium' or 'performance' parts. They're run of the mill off shore replacement parts. If they stand up to routine standard duty consider yourself lucky. You really need to pick your own parts, including the valve springs, instead of letting a mass rebuilder do it for you.

The Car Doctor makes a house call. Spot on diagnosis. Next the remedy...

Wonder if the inner spring breaking caused the outer one to bind. I read excessive friction between the inner and outer will do that.

Seeing how that wasn't your fault, how much would one charge for a house call like that?🤔👍

Steve Morris has had some springs break on some of his SMX builds lately. Of course he buys only the best springs for his big horse power builds but your problem could be just crappy parts. Should you replace all the springs? That's a tough one.

When you assembled the engine did you check for retainer to guide boss clearance based on cam lift? Check for coil bind? If those areas are all good and the unknown valve spring just broke, I’d fit a complete new set of springs. Cheap insurance in my opinion.

Nice looking rocker arms!! What brand?

Did you spin the valve ? Did it seem straight ?

they don't make metal like they used too , back in the day we had our own steel mills in the USA .

Joe! Buy some fender protectors !

If piston at TDC how can valve fall beyond reach?

I think I have it figured out.

New doesn't mean better, replace the one that failed, and leave the ones that are still working alone. If it happens again, on a different one, then replace all. Anything man made is apt to give problems.

Chinese springs?

Never use SBI Z28 al cheapo springs obl, use beehive by Isky etc

I would replace them all they must all be junk to brake in a mild application that does not RPM.

Stay away from any speedmaster part's.

Valve/lifter

I would love for you to build a motor for me whiling to pay

Inferior Chinesium parts?

I hope they are not from china. I have heard of copy cat springs that would not make it down the block.

Better hope it didn't coil bind and start to take out the cam

yeah lets put a 600 lift cam in and use weaker than stock valve springs from car quest cause we heard they use corvette valve springs! dumb meets dumber

I found the problem while driving to look at the pontiac you build the best engines on the planet and drive a ford?? LOL. I have seen this first hand the damage is catastrophic even at an idol LUCKY GUY .if it had droped a valve you would have been to blame even though you did not do the heads. stop starting the engine.

I cylinder looks bad , fowled plugbutcommresiongood,? Checked cylinders to left and right ruled out head gasket leak i 100 % find it to be abad card gasket or sealcausing a general over rich slight condition with just one plug and cylinder looking reallyfoweled replace carb gasket it solves the issue. Chevy guy here taught by my old man. This issue is also indicated by very little to no change in iddle mixture scews response even if botto.ed out. If its the rigjt mixture screw not making a change its the rihht plenum of carb to intake gasket withe issie, bad gasket and leak on right side or visa versa.