Bent Valves ?!??

[gypsysdad]

first a little history. the motors been completly rebuilt from top to bottom. which makes this even harder. the other day i went out to fire it up and the timing belt jumped off and i got a lot of racket and i stopped turning it over immediately. well i just run a compression check on it and heres what i got. #1=0,#2=145,#3=0,#4=150. so with those findings i believe that it would be some bent valves. i have a spare head that i can get the valves out of so thats no problem but i wanted to make sure before i paid to have the thing fixed again. i just put a new head gasket on a few weeks ago so it shouldn't be that. just a little feedback to make sure.
thanks

 

[Irrational]

How far did the T belt jump. If you herd crunching and are getting 0 compression you bent the valves.

 

[gypsysdad]

yeah i heard some crunching. but isn't it weird that #1 and #3 has no compression. 1 runs with 4 and 2 with 3. anybody that has a good head let me know cause i have parts to swap. complete 6-bolt block,4-bolt rear, and bunches more

 

[johnk]

When you get the head off you can spin the cam and you'll see how the valves open. They work in a specific order one cylinder at a time open both of it's valves it's something like 4-1-3-2. It's not what you might be thinking 1-4 are open at the same time then 2-3 open.

When you get the valves done you should just take it to a machine shop. I tried lapping the valves like some people here suggested as the cheap fix. It's not worth it the money I saved is going to be spent redoing the job sooner rather than later. The seal is not as good. Pitts are still visible in the seats and such.

 

[gypsysdad]

what are you talking about lapping the vavles and how long will it last ? please explain

 

[johnk]

it's a procedure where you take your valve and put some lapping compound on the edge of it and spin it on the seat of the head. It's you get what you pay for results. While you save a lot of money your results are a less than perfect seal. You have to strip down the whole head in order to do it any way so if you don't have a valve compressor you can't start the job in the first place. It's best left to the pros with the machines to resurgace everything and the gauges to make sure it's within tolarences.

 

[huafist]

Now that I've had a little time to think about it (I live like 4 miles from gypsysdad, looked at it yesterday), I think the reason it bent 1 & 3 is because the crank made another rotation after the belt slipped. If valves were open on 1 & 3 (intake on one and exhaust on the other), then as the crank rotated it would've bent those two.
Let me know when you get the head off - did you call the shop I recommended?

 

[gypsysdad]

yeah i called that shop and the guy that answered the phone was kinda dumb but he give me a hell of a price. he said about $20. if that's accurate then hell yeah. i come to the same conclusion about the compression #'s as well. i guess i'm going to pull it off tomorrow and see if i can find a spring compressor to get the spare valves out of that other head and take them down. or i can put that other head on. .

 

[huafist]

Unfortunately I don't have a valve spring compressor. But yeah, you can put that other head on and see what happens