Please HELP!

hey guys, i have a 1.6 98 nissan sentra 4 door. The timing chain skipped and bassically took a whole buncha stuff with it. im about 1000 into it so far. Then i go to get it on sunday and it wouldnt stay on. The mechanic had to mess with the timing to get it to start in the first place then it ran for a while, he took it on a ride it sputtered and died. He ran a compression test before all of the work and they all blew 130. after his joy ride, the 3 blew 150's and the second one blew a 125. I then convienced them to hook up one of those hand held .. i dont know what their called but they read the error codes. The 2nd plug was missfireing. and the cam shaft position sensor was bad. The only problem i have is this guy keeps telling me its gone. but if it started and ran i have a hard time giving it up. Because it did run, do you know what im saying. Do you think this part can be makeing that second cyl. missfire, cuz its not timing right? or is my motor gone and i shoul buy a scooter?

If he had to mess with the timing , it sounds like it may be off , maybe a tooth or 2. Depends on how he messed with it. If he turned it all the way and such. If it's an honorable repair shop, they should recheck there work at no charge to you if you just payed 1k to have the work done

If he had to mess with the timing , it sounds like it may be off , maybe a tooth or 2. Depends on how he messed with it. If he turned it all the way and such. If it's an honorable repair shop, they should recheck there work at no charge to you if you just payed 1k to have the work done

its a mechanic that works for my dad. so he would fix it for free. but he re did all the timeing and double checked it. it ran for a bit then went out.

id replace the cam sensor and check your compression after your timing issue is figured out, if youre only getting 150 youve got a warped head or something, it should be up around 180-190

if i have a warped head does that mean im screwed? and 150 is low? i was told for my motor that a 130 is normal on a cold start

you can have it decked for not too much if you pull it

Low compression can be caused by a number of things, if that one cylinder is the only one that is low and the rest are fine your timing is probably ok. You may have slightly bent a valve so that it is not quite seating all the way, it could be a weak spring that is not holding a valve closed all the way.

Piston rings might be an issue but I kind of doubt it, could also be a very small bad spot in the head gasket. Another possibility is that when the pistons and valves slammed into each other you bent a push rod or collapsed a lifter (if you engine has these) but I kind of doubt either happened or your valve would have gone through the head destroying the head on the way through.

If you have one spark plug misfiring check the wiring and install a new plug, if it is still misfiring either the spark plug wire and/or the ignition coil is bad.

haha a sentra with a pushrod? lol
nah it sounds like bent valves to me. get the head pulled, take it to a machine shop. should be no more than 300 or so to get the head fixed up. it may need a valve job, some valves replaced. if they say it needs to be decked, get the block decked also, and get a thicker head gasket. if you only plane one surface, the other surface may be warped and you will blow head gaskets left and right.