I swapped my 882 heads for vortec 062 castings. I bought these vortec heads used and did nothing to them but put them on. I also changed the cam to comp 270h along with lifters and timing chain. I went to start the motor and it acted like it didnt have any spark. So I verified it does indeed have spark. then I double checked it was in time. It is in time.

Next I do a compression test, my tester goes up to 30 then drops back to 0. Then with both valves closed I pumped compressed air into the cylinder. It won't hold air and the compressed air is going out the tail pipe. I back off the rockers to make sure the weren't overtightened and no change.

I pumped compressed air into every cylinder and the same thing happened. also before I bolted the heads on I looked at the valves and they didnt look cracked, burned, or broken.

What can be causing this? I have never come across this before. Thanks

camshaft is out of time.
did you line up the dots?

david

its in time. I took the rockers completely off so the valves will not open and compressed air still goes out the tail pipe which makes me think the exhaust valves are bent. But what are the chances of all 8 exhaust valves being bent?

its in time. I took the rockers completely off so the valves will not open and compressed air still goes out the tail pipe which makes me think the exhaust valves are bent. But what are the chances of all 8 exhaust valves being bent?

did you check clearance with the new cam? could be the valves hit the pistons when you turned it over. that would explain them all being bent.

Sounds like you have the valves too tight.

Dave

Sounds like you have the valves too tight.

Dave

How can they be too tight when I removed the rockers and compressed air still goes out the tail pipes?

maybe you had them too tight at the beginning, when you cranked it over it bent all the valves.

How did you go about adjusting the valves to begin with?

How can they be too tight when I removed the rockers and compressed air still goes out the tail pipes?

=
Assuming the heads were ok when you got them,,
It sounds like you installed the cam retarded a bunch & all the ex valves hit the pistons as soon as you turned the engine over
What timing set?

Multi-keyway timing set ?

But what are the chances of all 8 exhaust valves being bent?

Pretty good if they kissed the pistons in the previous owners engine. It's also possible that there was rust on the valve stems that caused them to bind in the open position. Either way, it's time to pull the heads.

Tom

Jeremy,
I would almost bet dinner that you have the timing chain wrong and it bent valves. Is it a new chain set ? Is it a three keyway type ? Did your bottom sprocket look like this when installed:

http://www.chevelles.com/showroom/data/500/crankgear.jpg

How can they be too tight when I removed the rockers and compressed air still goes out the tail pipes?
Sorry bout that didn't read that post, just the top one.

Its a new cloyes double roller timing set and it does have three key holes like in the picture. I put it in the squared off hole.

It cranked over real easy like I didn't have spark plugs in it from the beginning so....

I suppose the previous owner could have bent the valves in his engine and then ripped me off :confused:


Jeremy,
I would almost bet dinner that you have the timing chain wrong and it bent valves. Is it a new chain set ? Is it a three keyway type ? Did your bottom sprocket look like this when installed:

http://www.chevelles.com/showroom/data/500/crankgear.jpg

Its a new cloyes timing set and it does have three key holes like in the picture. I put it in the squared off hole.

I suppose the previous owner could have bent the valves in his engine and then ripped me off :confused:

Which mark did you line up to the top towards the cam gear, the round one?

It's been a few months since I put the timing set on so now I'm second guessing where I did put the key way on and Im pretty sure I set it dot to dot.

Which mark did you line up to the top towards the cam gear, the round one?

It's been a few months since I put the timing set on but Im pretty sure I set it dot to dot.

That is your problem
If you use the square key you must use the square mark or you end up off by a bunch
Look at the pic closely, the crank key should be at about 2 o'clock when your marks are lined up no matter which one you use
The round is straight up or put's the cam as it was ground assuming everyting is correct.
The triangle is 4 advanced & square is 4 retarded using the correct accompanying marks

I just went out and rechecked. cylinders 1,3,5, and 7 all have compressed air go out the tail pipe, I rechecked 2, 4, 6, and 8 and those cylinders have good compression. My friend who was helping me misinformed me about what was happening. So if some valves are bent shouldn't all of them been bent?

If people would just look at the key in the crank and the dowel in the cam they wouldn't have problems with those multi-keyed sets. Crank key pointing dead middle of left bank deck, cam dowel at 3 or 9 o'clock. Any visible deviation in the dowel from 3 or 9 = wrong, and in my case had better put my glasses on even if it pisses me off.

If people would just look at the key in the crank and the dowel in the cam they wouldn't have problems with those multi-keyed sets. .

If they would read the instructions on the back of the package, they would do even better :D

I personally have probably seen or heard of about 20 of these things being installed incorrectly :(

I have put many of these on in the past, it's been a few months since I put this one on. It is possible I had a brain fart and put in on wrong. I guess I need to go out and tear it back apart and check

I have put many of these on in the past, it's been a few months since I put this one on. It is possible I had a brain fart and put in on wrong. I guess I need to go out and tear it back apart and check
=
You do not have to tear it apart to check
Put your timing mark at zero
Either #1 or 6 will be on overlap the other will be on the base circle
If either cylinder has one of the valves open more than the other (lifter or pushrod up) it is wrong

What Mike said. you can see this with only the #1 and #6 pushrods installed if you're sharp eyed. With the timing mark at TDC none of the 4 pushrods should be sticking up more than the others.

How did you go about adjusting the valves to begin with?

What Mike said. you can see this with only the #1 and #6 pushrods installed if you're sharp eyed. With the timing mark at TDC none of the 4 pushrods should be sticking up more than the others.

How did you go about adjusting the valves to begin with?

I adjusted the valves per a write up on this site. I took it apart and I put the crank gear on the square key and then lined it up dot to dot so I did make a mistake. I have never done his before. Live and learn :D

well I put the timing chain on correct this time, reapplied my assembly lube to the cam. Reset my valve lash, dropped the distributor in and it fired right up with a tap of the key so I went ahead and broke in the cam

After break in the idle was just right and boy does that comp 270h sound good, has a nice little lope but not bad enough to where it sounds like it's going to die out on me.

Tomorrow I will recheck the compression to make sure everything is ok

Glad to hear that was the problem and not that you had a bunch of bent valves.
Congrats on the fire-up!:hurray:

well I put the timing chain on correct this time, reapplied my assembly lube to the cam. Reset my valve lash, dropped the distributor in and it fired right up with a tap of the key so I went ahead and broke in the cam

After break in the idle was just right and boy does that comp 270h sound good, has a nice little lope but not bad enough to where it sounds like it's going to die out on me.

Tomorrow I will recheck the compression to make sure everything is ok

Good deal, it sounds like you may have been very lucky :thumbsup:

that's what I was thinking, it must be miracle he didn't bend any valves. Amrk it up to clean living....

yes I know I'm lucky I didn't bend any valves. I better go sacrafice a hyundai to the malibu gods for watching over me...