I just built my first engine. It is a 350 in a 67 chevelle. I tried to fire it up for the first time but no luck. I checked the timing at least a dozen times and the timing light shows that the spark is in the right place. I tried adjusting the valves but when I do the come out of adjustment. I tighten them and after turning the engine a few times a few become so loose that I run out of threads on the stud and they are still loose. The other thing that concerns me is that fuel blow up and out of the carb. Any suggestions?

Thanks!

Are the studs coming out from the heads??

yes!

studs pulliing out is a sign of couple of things... valve sping bind or cam timing being off valve hitting piston.. it takes a lot of force too pull those studs from heads

sorry, I misunderstood. No the studs are not pulling themselves out of the heads!

Are you adjusting them in the correct order?

I'm pretty sure. I think I will remove the intake and re-lube all of the lifters and try to start over again and see if that helps. Also something that concerns me it that the spark plugs don't smell like fuel at all and there was little compression coming out of the #1 plug hole. Also the fuel being spit out of carb into the air. can the lifter and valves cause these problems?

If you have fuel being forced back up thru the carb,then there is definately a problem with either timing or valve adjustment.I would set everything back to top dead center on #1 and doublecheck that the distributor is in right and readjust each of the valves from here.I forget which ones you adjust at each rotation position.Do this and make sure you don't get them too tight.It WILL NOT start if the valves are too tight and you don't get any kind of compression.

I just pulled the valve covers and in fact the studs are pulling out. I don't know why this happened. I know I lined up the crank and cam dots. My dad came in and started to just tighten every rocker arm old school style. Should I do a complete tear down?

How big is the cam you're running??

well to tell you the truth I have to run down my spec. sheet because it has been so long since I have looked at it and didn't bother memorizing it in the first place. But i bought the one recommended for my head application. At the risk of sounding stupid, I just took off my rocker arms on one head. The exhaust studs are higher than the intake studs. Is this normal? If so then I don't think they pulled out!

Maybe try to TAP them with a deadblow hammer & watch if they go back it..

I had a buddy whose engine had exactly the same symptoms. Did you use a timing set with 3 keyways?

it has been months since I have laided eyes on the cam so I don't know if it was 3 keys but it allows both the exhaust and intake to close fully when #1 is TDC. would it allow that if the cam is off? I just pulled the intake and I re-lubed everything and I will try to adjust the valves with the intake off so i can keep an eye on the lifters rising!

If a burst of air came out of the top of the carb your distributor is probably 180 out. The same thing happend to me when I did a cam swap.

I'd put a stright edge across the tops of the studs in the head .... if their not even ....... you've pulled em up ..cam maybe to large for springs .. or you've got the cam timing off... with it back fireing thru carb & loosing the lash every time you reset it ... I"m betting on the cam timings off did you degree the cam or just stick it & line up the dots ..& which dots 4a - o -4r my christal ball is cloudy from here but ... I see bent valves & push rods in your future .... I hope I'm wrong

Gerard,

You did not say if this is a hydraulic cam or not. If it is, and it has been sitting a long time, it is quite possible that you have collapsed all of the lifters. I would back all of the rockers off, and tighten them slowly while checking for end play on the pushrods. And whatever you do, don't check pushrod loosness by spinning them; move them up and down and stop about a quarter turn after they no longer move up and down.

this is hydraulic. I adjusted the valves twice with the intake off watching for the lifters themselves to move. I went through the whole process twice. I buttoned everything up and try to turn it over but no luck.

I too, am thinking that your timing is 180* off. This is very common, because when the dots on cam and crank sprockets are correctly lined up (cam at 6 o'clock and crank at 12 o'clock position) the engine is at TDC/compression stroke of #6 cylinder, NOT #1 cylinder.

I'll try the timing again but I brought the #1 up to tdc and felt it with a screwdriver then made sure the distributor was at #1. Why would the rocker arms keep coming loose after adjusting them so many times?

Gerard... it this point I'm sure your having a Very bad time .. so I'll just ask if you just don't want to read my posts or don't want to belive them ... I've told you twice whats going on.... its the CAM timing ... pull front timing cover & check it out for yourself ... then pull heads & get them repaired ... check valves while apart more then likely you bent a few .. same for push rods.. If it was me I'd have heads cut for screw in studs & guide plates while their at machine shop ....BUT first start by checking cam timing

a compression check is a lot simpler and cheaper than pulling the front and heads off. gerard, can you post a note on how exactly you're adjusting the valves? what it is you're using to decide when exactly to adjust which valves? If your hydraulic lifters are not prefilled it can be a little tricky adjusting the valves.

Here's the deal: the valves can't de-adjust themselves in a few turns of the engine with the starter. if they're turning up loose after a few revolutions they probably were not on the base circle of the cam when they were adjusted.

if you dropped the distributor to point he rotor at the #1 plug wire while the dots on the timing gears were together, 6:00 and 12:00, then the distributor is 180* out. this will cause the backfiring through the carb you've mentioned.

there's several methods for adjusting the valves, tell us how you are doing it. There's another simple check to find out if you're in the ballpark on this stuff but fill us in on what you're doing.

well, I decided to take some advice and I spoke to the machine shop and they will machine the heads for screw in studs. While they are doing that I will make sure everything else is fine and make sure the timing is dead on. I will keep you posted and let you know if the studs are the problem which I think they are. I found the spec. sheet on the cam and it is .477 on the intake and .480 on the exhaust. There should be no reason it is pulling the stud out other than I got a bad set of heads.

The heads are off and it looks like all of the exhaust valves hit the pistons and caused a scar. But it is only on the exhaust valves.

HUMmmmmmmmmmm I guess that christal ball gets a better picture then I thought .... check which keyway you used when lining up cam timing ... also when heads are at machine tell them how much cam you have .. so they check springs for lift limits ... you never said if they were new or not ... good to hear you found problem .. keep us posted on how it goes :)

yes, the springs are new, in fact the heads are too. I bought the modified vortec heads from skoggin dickey.

I've had expercence with that setup........ I know you've got the self centering rocker arms with the kit ... BUT ... with the amount of cam you've got I'd put a set of LONG slot rockers .. with the stock pushrods & rockers the chances of running into a stud to rocker arm slot problem is VERY posible.... also those springs are right at their limit besure Machine shops knows so they don't shim to much .. seat presure is LOW to start with & the shop may try an shim to bring up ..

I found out that I do have a 3 key way timing set. Is there any way of tellinhg that I put it on the wrong slot without going through the hassle of pulling the timing cover? I all ready have the heads off and can see what the lifters are doing.

I've been following this but haven't responded. You shouldn't be having these problems. What technique are you suing to set your initial valve lash???

Cam

I turn the crank until the #1 exhaust valve begins to open then set the intake valve. then I turn until the intake fully opens and fully closes and then set the exhaust valve. I do this in the firing order all the way around.

I would agree with CheZ sounds like your dist was put in backwards or as he stated 180 out

ok. well I will get the heads machined for the new studs and put it back together and make sure the dist. is in properly this time.

Gerard.... if you don't check out & reset your cam timing you will be taking this motor apart again ..for the same reason.... the CAM timing is out an I'm not talking about 180 degrees ... my best guess over the computer sceen is you used the WRONG keyway... or just plain didn't line up the dots correctly..

Ok, I will pull the engine and check the cam!

you don't have to pull motor to remove timing cover !! use a puller on balancer then just loosen the oil pan bolts removing the front 3 or 4 bolts & loosening the rest then prop the front of pan down a little with a screwdriver BUT be carfull about messing up gasket your going to reuse the pan gasket ..go to parts store & get timing gasket set & you'll see what to trim when resembling .. you really are new to this ( don't worry about it we all were once !! ) :)

Well I just got my heads back and while I am adjusting the valves I feel a resistance when some of the exhaust valves go down but It will go past it, it doesn't lock up. Normal or not?

I think if the dots are lined up in the 12 and 6 o'clock setting and you have it in the 0 degree key way your cam should be lined up. I think degreeing a cam in is a real good thing to do but I have not had no problems not doing it. In the future I will do it because I want to know if the cam is made wrong. I think you might have binding problem in the rocker arm and pushrod area.

Are your rocker arms the slotted type or roller? If you have the small slotted rocker arms you will have problems with adjustment of lifters.

Valve springs need to be checked for height at full lift for coil bind.

If your running the 1.6 ratio rockers, your pushrods could be binding against the cylinder head holes where the pushrod goes through.

I usually adjust my valves this way.

Start at cylinder # 1 and turn the motor wait for full lift on the intake valve and then adjust the exhuast valve then turn until the exhaust valve is all the way open and then I adjust the #1 intake valve. This seems like the long way of doing it but I never have adjustment problems.

I think I figured it out!!!! While I did have the crank sprocket on the correct keyway and I had the circles lined up, it was incorrect. On the edelbrock timing set you need to line the rectangle up the circle on the cam sprocket to be at TDC. I'll put it all back together and see if she starts!

68kmeno feel free to come down here and beat me in the head!

couple of questions ....... did you get valves checked when at machine shop for strightness ?? hitting pistons & Pulling up head studs bends them most of the time !!! same story on push rods they bend too... as for your cam timing being out .....WOW I never would have thought ... ;) last but not to be forgotten how about those rocker arms ... long slot ?? or stock ?? if you're trying to get by with the stock ones you better check clearance on both sides of slot full lift & base circle for hitting stud..

no bent valves or rods. Machine shop said he didn't have to ratchet the studs out because they were so loose. Maybe that saved me. No bent valves or rods. Now a new problem when I was putting the balancer back on the balancer bolt seems to have striped. I thing the thread in the crank are striped. are the helicoil or am i back up that creek?