1969mach1man 11 Report post Posted June 21, 2009 Ok... I have a 351w 408 Stroker. I recently installed a new carb.. I drove the vehicle around for about 5 min to check her power. "ran like crap btw" Brought her back to the house and advanced the timing a bit. I proceeded back up the road. i punched it and the motor immediently started knocking bad. and ran like shit knocking all of the way home. I then cleaned the carb and flushed the fuel and put in some higher octane fuel in and backed off the timing. Now the car kinda idles like crap. and there is a tapping sound on acceleration that sounds like someone beating on a valve cover with a screw driver. Could it be a head gasket . Cause i pulled all of the rockers and cant tell if there is any bent push rods. I don't really know how to tell anyways I cannot figure it out Quote Share this post Link to post Share on other sites
superduty69 11 Report post Posted June 21, 2009 A couple of questions... New motor or just new carb. What was the timing before and after adjusting. Was carb. installed ootb or or set up for your motor. I only run my junk on premium gas to eliminate any detonation problems. A quick way to check push rods is to roll them on a flat surface. Do you have headers and are they leaking. They can and do sometimes sound like that. Any more detailed info will help us give you detailed responses. Hope this helps John Quote Share this post Link to post Share on other sites
S code 69 13 Report post Posted June 21, 2009 Lots of things it could be, do you have solid or hydraulic lifters? First I'd check for vacuum leaks and pull the plugs, check for a dead or toasted cylinder by looking at the plugs . running like crap is one thing to fix, running like crap with a new loud noise sounds more serious. Quote Share this post Link to post Share on other sites
1969mach1man 11 Report post Posted June 21, 2009 new Used carb motor only has like 600 miles on it like 15btc then i went to like 25 btc and thats base timing The headers could be leaking slightly The plugs are just black as hell. I rolled a few of the push rods and the tips don't look quit as center as they should be. But not really bent I have solid lifters and roller rockers A fairly high lift cam too I'm just about to pull the heads and take them to a machine shop to make sure everything is in spec I think that i am also going to pull the timing cover and inspect the Timing gears and such. If this is just something stupid Atleast all of the gaskets are geting replaced. Quote Share this post Link to post Share on other sites
Jayru 17 Report post Posted June 21, 2009 25 degrees of base timing is WAY to high. Most likely the tapping you heard was actually pinging from the cylinders detonating (pre igniting) like hell! The black plugs/running like crap is most likely from your new carb being out of tune/way to big. I would NOT start pulling it apart till you completely diagnose the problem. If it is something in the bottom end, you'll rip it apart, check the heads/tchain, put it back together and still have the problem (and waste time/money)! Quote Share this post Link to post Share on other sites
superduty69 11 Report post Posted June 21, 2009 I agree with Jayru, 25 base timing way to high, I would start 12-14deg. base. Carb needs tuned, Holley or Edelbrock? Do you know how to tune the carb yourself or know someone who can? Myself, i would not tear the motor down for no good reason until i sorted out the carb. If plugs are black I would start at carb. John Quote Share this post Link to post Share on other sites
S code 69 13 Report post Posted June 22, 2009 I have to agree, rule everything out before you get to far into tearing it down. swap the carb back to one you know isn't screwed up and set your timing to a decent starting point. I'm guessing you checked you valve adjustment, so if all this doesn't clear it up then it gets down to pulling the head making the noise. Quote Share this post Link to post Share on other sites
1969mach1man 11 Report post Posted June 22, 2009 I know im going to have to figure it out. and i feel like an ass for saying this but.. Can i have a freebee. Ive never really adjusted valves before. I'd like to know the process from you experienced veterans Quote Share this post Link to post Share on other sites
S code 69 13 Report post Posted June 22, 2009 It's easy, just bring it up to TDC on compression on #1 and set both valves to spec, I'm not sure what they reccomend for your set up but just get the proper feeler to slide through with a little resistance. Then rotate the crank 1/4 turn and do the next cylinder in the firing order until you get them all, there are a few shortcuts you can do but this is the best way. some guys prefer to cut a valve cover in half to catch oil and do it at an idle, this only works if your adjustment screw is not the jam nut style, this works good but way to messy in my opinion. Quote Share this post Link to post Share on other sites
1969mach1man 11 Report post Posted June 24, 2009 Ok found the deal I pulled the Drivers side head cause i thought i saw a crack in the valve guide. And vuala Check out what i found So whoever said not to tear it down :hammer: anyways heres what i saw Quote Share this post Link to post Share on other sites
Jayru 17 Report post Posted June 24, 2009 A broken head gasket wouldn't cause the motor to knock or tick though. Regardless of the Head Gasket (which is obviously busted), you have other issues somewhere else... Most likely you blew that gasket apart by having your base timing way to high causing insane detonation in the Cyl's. Quote Share this post Link to post Share on other sites
1969mach1man 11 Report post Posted June 24, 2009 Head gasket being blown can knock or tick.. It was blowing compression between cylinders. It was knocking before due to running lean with a hot motor.. The ticking was either the compression going between cylinders or the crack on my valve guide .. Its ok though cause they are pressed in valve guides. The shop that built the motor is only charging me for a resurface.. :shifty: Quote Share this post Link to post Share on other sites
superduty69 11 Report post Posted June 24, 2009 Damn..... Sorry to see that. You were leaning towards the head gasket in your first post and that was it after all. That is one bad thing about doing this stuff over the internet, you are there, you ran it,and you heard it. We can only offer advice or insight as to what to check or test by what info is given. For piece of mind i would also check that the deck surface is flat in the area that the gasket gave out. If it was lean and hot i would check it just to be sure. I hope this gets fixed up and you are back on the road before to long. There is never any fun in finding something like that. Good Luck John Quote Share this post Link to post Share on other sites
1969mach1man 11 Report post Posted June 24, 2009 ahh dont get me wrong I love posts You guys are always my heros in many cases I had the head re surfaced . My block looks just fine. Im going to pull the other head also cause i think that i heard spitting coming from that side two Quote Share this post Link to post Share on other sites
Pakrat 1,043 Report post Posted June 24, 2009 I still think the advice given was sound. More often than not folks tend to replace every possible part they can instead of troubleshooting and they are left with a bunch of new parts they didn't need and out a lot of cash with still the problem to tend to. I have seen more than one person with a bad header gasket go tearing into the heads to look for a ticking sound so when giving advice on an unseen unheard problem it's best to start with the basics and eliminate them as suspects as a general rule. Quote Share this post Link to post Share on other sites
S code 69 13 Report post Posted June 24, 2009 Definetly check your timing, you said your plugs were black so being lean didn't have anything to do with it. Is #7 as oiled up as the picture looks? if it is I would check your guides and stem seals while the heads are off. I have fought oil consumption on brand new rebuilds due to a little stem clearance and those worthless teflon positive stem seals. be sure to change your oil too since you know you're going to have a little antifreeze in the crankcase. Quote Share this post Link to post Share on other sites
1969mach1man 11 Report post Posted June 25, 2009 yea I see what you mean.. I was just being coy. I did check everything one by one while tareing down though. Most ticks from a high horspower engine can be bad. especially when ever part installed on it I would assume was bullet proof. Mabe this time i shoud get a cometic head gasket. So when i run lean Ill just melt a forged piston. I did check the header gaskets then I pulled the valve covers then the intake. then what elce to pull but the head.. . Me personally Id rather spend 150 bucks on gaskets then 3500 to 10000 on a new fresh motor.. I just know that this time Im not sticking that crappy Barry grant bolt on carb on it.. Quote Share this post Link to post Share on other sites
klevor 10 Report post Posted June 25, 2009 How are the heads? Did they survive the ordeal. Hope so sounds like a smooth setup. Bet it sounds nasty to hear it fired up not to mention the pull. Quote Share this post Link to post Share on other sites
