Timing Belt on my 88 Nissan 300ZX

After being scammed twice by not-so-great mechanics, I was told by a myriad of people to have my timing belt replaced. A trip to my father’s mechanic confirmed the suspicion. Initially the other mechanics I started out with thought it was my catalytic converter, then my muffler, which I had replaced. But my car still lacked acceleration and I’m sure I’d be run over if I tried to take it on the interstate. If I drive normally, I can hit 45 mph before my engine starts to lag. If I’m in overdrive I can hit 75 mph and maintain 55 mph for an extended length of time. I took the car in today and for $700 I can have the timing belt replaced. Does this sound accurate and has anyone had similar problems before?

. From what you describe, it you may have a timing belt problem. They can slip and mess up the engine timing. The cost is within believable.

. According to the information I have you have an interference engine. That means if it breaks, it can do a large amount of expensive damage to the inside of your engine. Generally the owner’s manual list a replacement schedule for that belt. You have not told us if you have ever replaced the belt. If you don’t know I would avoid driving it until the belt is replaced. If a belt slips, it usually means it is about to go and BANG with no more warning than you already have.

. So unless you know the belt as been recently replaced, I would not be driving it to the grocery until it is replaced. Along with the belt, on most cars it is a good idea to replace the water pump and tensioner at the same time. It will save you money in the long run.

Keep us informed and good luck

If I read this right the theory is the timing belt has “slipped” but not enough to cause damage or stop the car from running? I don’t buy it one bit.

Get a manifold vacuum test this should identify a out of valve time engine.

I have seen plenty of timing belts break,but slip,show me.

Timing Belt??? I don’t think so.

Car is running normally until 45??? This sounds like a fuel starvation problem to me.

In order for the timing belt to be a problem in drivability it must have slipped a tooth or two. And if it did you’d see the problem the minute you start the vehicle (if you CAN start the vehicle). If you haven’t had the timing belt changed it’s well past due, so please get it done. This is a interference engine. If the belt breaks it could destroy your engine. But I seriously doubt replacing it is going to solve the problem.

I’m thinking that MikeinNH could be on the right track. Your car may have more than one fuel pump if there is a carburetor. It does sound like a lack of fuel. Of course it could be a timing belt issue and there is one way to find out. The mechanic will know as soon as he gets the cover off.

It’s no great difficulty for a real mechanic to put these various theories to the test. Unfortunately, it doesn’t sound like you have found one.
For example, to find out if the engine is in time (the crankshaft and the camshaft are at the places they should be, when they should be there), #1 spark plug is removed, a straw is stuck into the hole, until it touches the top of the piston, the engine is turned, by hand, until the straw stops rising. Now, the crankshaft position indicator (“timing mark”) should align with the zero degrees mark. This will be TDC (top dead center). If it’s more than, say, 10 degrees off, the engine is out of time. This is not to be confused with ignition timing … which can be electronically varied.