timing belt or something more serious??? please help

2drcam · Jan 5th, 2004, 09:37 PM

i own a 93' nissan pathfinder se 4x4 3.0 vg30e

ok. i was driving down the highway today and as i was getting on the ramp i heard a buzzing noise(like the sound of 4wd not fully engaged) and engine went dead. tried cranking over a few times but nothing. i'm thinking it is the timing belt but i want to know if anyone has ever experienced this kind of problem before i go ripping half my engine apart for nothing. could it be this or something more serious like the tranny or something. any help would be greatly appreciated.

thanks

nissannut · Jan 5th, 2004, 10:44 PM

You can check the blet by removing the top plastic cover.

How many miles? Have you ver changed belt, needs changing ever 100k.

2drcam · Jan 6th, 2004, 08:42 AM

Quote:

Originally Posted by nissannut

You can check the blet by removing the top plastic cover.

How many miles? Have you ver changed belt, needs changing ever 100k.

i bought it with 135,000 miles on it. he claimed to have changed it, now it has 143,000. i did not change the t-belt. i know it's a huge job 10.0 hrs shop time. so i don't want to start tearing away until i'm convinced it's the belt. thanks

96R50 · Jan 6th, 2004, 10:09 AM

Quote:

Originally Posted by 2drcam

so i don't want to start tearing away until i'm convinced it's the belt.

I am not sure if your engine is an interference engine, but if it is I would highly recommend taking a peak at the timing belt before you crank the engine if indeed you think that it may be the timing belt. If you don’t check the belt and you do have an interference engine you’ll be looking at a lot more than a $30 belt, a $200 water pump and 10 hours of shop time.

nissannut · Jan 6th, 2004, 02:59 PM

Its not to hard to check the belt condition. I would assume it was never changed.

I bought a maxima with 145k miles. I changed the belt as soon as I bought it. It cost about $50 (belt and tensioner) with Factory parts. The belt was soooo loose... its amazing it never broke..

2drcam · Jan 11th, 2004, 06:23 PM

ok....i have removed the old belt and btw it was shot. it had soooo much play and it was missing several teeth. i followed the instructions and put the new one on and set the timing marks. after i put it all together and started it the engine was squeeling and it had a REALLY rough idle. so i advanced the timing on the distributor as far as it would go and that helped alot. is there some sort of spec on the tensioner pully for the belt or is it until it is tight?

my question is could there potentially have any internal damage to cause this?

is there a way or some kind of test to diagnose valve or piston damage like a compression test.

last, next weekend i'm ripping it all apart again so i can make sure the timing is EXACT, what do you guys suggest i do while i have this puppy ripped apart
again.

thanks for all your help

nissannut · Jan 11th, 2004, 07:11 PM

Did you line up the cam sprockets with the marks on the head AND belt. You should not have to adjust the Distributor timing when replacing a belt.

Did you use some kind of manual? Haynes FSM etc?? They tell you how to set tensioner.

Did the new belt have 3 lines on it?

2drcam · Jan 11th, 2004, 10:12 PM

Quote:

Originally Posted by nissannut

Did you line up the cam sprockets with the marks on the head AND belt. You should not have to adjust the Distributor timing when replacing a belt.

Did you use some kind of manual? Haynes FSM etc?? They tell you how to set tensioner.

Did the new belt have 3 lines on it?

I set all the marks up according to several resources including Alldata.

the tensioner setting i saw was very vauge but it stated to use a feeler gauge to get the correct setting but it was a very inaccurate measurement.

yes the belt had 3 lines on it and i matched up perfectly with the cams and the crankshaft marks. Alldata stated from cam to cam was 40 teeth and from L.H. cam to crankshaft was 43. i followed this very accuratly and triple checked and so did my friend.

also, the car kind of idle's like a big block with a very loby cam in it (if this makes any sense at all) but it's the only thing i can compare it to. but if i lay on the gas it runs perfect. so i'm confused. if it were internal damage would i be able to drive the car and have this idle? let me know what you think.

thanks nissannut

nissannut · Jan 11th, 2004, 10:38 PM

I have heard it is possible for the valves to hit the pistons. When the cams come unsynched with crank. I think you bent a valve. Hopefully the damage happened when you cranked it over, and it was a slow hit. And only in the head.

I would do a compression test on each cylinder and find out which one(s) are low. Then remove that head(s) and have valves fixed/replaced.

Good luck...

2drcam · Jan 13th, 2004, 08:32 AM

you really think it could be a valve? i mean other than that rough idle the truch has power 1500 - 4000 rpm range with no hesitation. do you think i could be off 1 tooth on the timing to cause this.

because if i was off 1 tooth that could throw the timing off. if i have power and no hesitation thru those ranges i makes me wonder.

i have no clanking coming out of the motor.
will a compression test detect a bad valve?? well anyway i'm going to tackle this job this weekend again so i'll get more info for you guys.

thanks

96R50 · Jan 13th, 2004, 10:02 AM

A compression test should indicate your timing belt alignment. If you’re off a tooth all of the cylinders will read low. Someone correct me if my thinking is wrong. If you’re idle is rough check your intake for leaks and clean your throttle body with some throttle body cleaner.

2drcam · Jan 13th, 2004, 10:06 AM

what psi is the stock compression for the cylinders.

because i did a compression check to the # 1 cylinder (for test purpose) and it was 125 - 130 psi.

thanks

96R50 · Jan 13th, 2004, 03:16 PM

I'm not sure about the 3.0, but 178 psi is normal for the 3.3. 128 psi is listed as the minimum for the 3.3.

jordan11 · Jan 13th, 2004, 11:57 PM

I have a 300zx with the vg30e in it and the FSM says for it in non turbo variety that the standard compression should be 173 psi and minimum of 128 psi. But if you are using a cheap screw in pressure gauge I have heard they can be somewhat in accurate. In the FSM it says if the compression in one or more cylinders is low, pour a small amount of engine oil into the cylinders through the spark plug holes and restest compression. If it helps the compression then your rings are worn out, if it doesn't then your valves are the problem. It also says that if 2 adjacent cylinders are low, and adding doesn't help, then there is leakage past the gasketed surface. I hope this helps.

**morepower2** · Jan 14th, 2004, 02:23 AM

Quote:

Originally Posted by 2drcam

ok....i have removed the old belt and btw it was shot. it had soooo much play and it was missing several teeth. i followed the instructions and put the new one on and set the timing marks. after i put it all together and started it the engine was squeeling and it had a REALLY rough idle. so i advanced the timing on the distributor as far as it would go and that helped alot. is there some sort of spec on the tensioner pully for the belt or is it until it is tight?

my question is could there potentially have any internal damage to cause this?

is there a way or some kind of test to diagnose valve or piston damage like a compression test.

last, next weekend i'm ripping it all apart again so i can make sure the timing is EXACT, what do you guys suggest i do while i have this puppy ripped apart
again.

thanks for all your help

Your tensioner pulley may have seized, I usualy change these when I do the belt.

Mike