My Z has about 130,000 miles on it. It needs a tune-up pretty badly. While I'm at the Optispark, should I go ahead and replace the timing chain? Maybe even the oil pump?

Opinions, please. Thanks!

 

I did and while I was at it, changed the cam! (mine had much lower miles on it thought,and high mileage cam changes can spin bearing sometimes.)

 

Changing the cam crossed my mind. lol

But that's the first that I've heard that changing the cam might cause a spun cam bearing. Is that something that's peculiar to the LT1?

 

Oh, BTW, is the LT4 timing chain a bolt in?

 

If you spun any bearing, more than likely it would be a rod bearing. I changed my first cam at 113,000 then went bigger at about 120,000 and that motor is still doing fine at 132,000. It is currently awaiting to go in a friends car. If your going to change the timing chain, might as well swap the cam out for some more power, just make sure you keep everything clean on the install.

 

The LT4 chain will not fit the LT1 timing sprockets. You have to get the entire LT4 timing set and change the sprockets as well. If you are staying stock or only doing a mild cam/mods, a stock replacement LT1 timing chain should do just fine and be a lot cheaper than doing an LT4 set.

 

Thanks for the info all.

I figured on changing out the whole timing set and not just the chain. I just didn't know if it was "bolt in".

I don't want to get too crazy with this car. I want to hop it up a little, but not too much. It's my daily driver. It also has to pass emissions. I was thinking about an LT4 or Hot cam, but I have more investigating to do before I take the plunge. I would also have to change out the valvesprings if I went that way. Still undecided.

Basically I want to take it to the track every once in a great while (just to say I did), but not go "too far" with it. I want reliability. I take good care of my cars, but I don't want to spend all of my free time on it.

Also, will the oil pan drop out without lifting the engine, etc.? I believe that I have to loosen the front of the pan to get the timing cover loose; right? I thought that I might go ahead and replace the oil pump. Opinions?

 

Let me ask you this question. What do you want out of the car? You said, you just want to hop it up alittle, a tune up, daily driver, and still pass emissions. Then I would suggest bolt ons..ie. cold air intake, headers,exhaust,underdrive pulleys. Change your optispark if it's that old. Do a gear change, a high stall converter (if auto).
Yes, to fully drop the oil pan, engine must be lifted. To remove timing cover, you must loosen oilpan bolts.
Are you having problems with your oil pressure?
(oil pump) The saying " If it aint broke, don't fix it"
As for your timing chain, is it broke? When you're ready to really do some major modifications on the car, like heads,cam then it will be the right time to change everything(including timing chain,waterpump) since it will be taken apart anyway. Hope this help you a little, good luck man.

 

The LT1 chain and gears are MUCH better than given credit for. I am aware of more LT4 ED timing sets breaking than stock LT1 sets and obviously there are FAR more LT1 sets in use. I run a stock timing set.

 

^I run a stock timing set too. Original gears with close to 110k miles, just got a new GM chain when I changed cams.

 

There have been occurrences on some higher mileage camswaps for LT1. Some say that it could be due to the cam driven water pump, but it is really not a solid set in stone deal. Do a search on it on cz28.com and see what you pull up.

I am not saying your going to spin a bearing if you put a cam in, but it happens sometimes .

 

When I rebuild my engine I went with an electric water pump which allowed me to use the standard style timing chain. The total cost was actually about $10 cheaper than if I had bought an LT1 style timing set! I don't have part #'s with me but I can PM them to you if you want. Just another option!

 

Thanks again all for the info.

The oil pressure is good, as far as the stock gauge says anyway. I've only read a little about the oil pumps. But I did read where the oil pump drive should be replaced if given the opportunity.

The timing chain is just as old as the car, but not broke. I guess I'm still stuck in old school thinking. I've fooled with enough of the Gen I SBs to have seen plenty of timing gears with nylon teeth chipped off and broken (and, yeah, I know the LT1 doesn't have nylon teeth). But I've also seen plenty of stretched timing chains. THAT, I can only imagine, is still a possibility with the LT1s. That's the only reason that I was contemplating changing out the timing chain.

The car is an auto. The tranny has supposedly been rebuilt to "cop specs" (the rebuilder does the tranny builds for the Putnam County, TN Sheriff's Dept. and some other police depts.) It shifts pretty hard. But I know that is probably only due to the Hypertech programming (Tunercat/LT1edit to come).

I bought another whole rearend from another '94 Z. It has the 3.42s. I'm just waiting for delivery. A higher stall convertor will have to wait until at least next Spring.

The car has the Moroso CAI and Borla catback already. I'm still trying to decide on which long tube headers (leaning toward AS&M). It NEEDS a good tune-up. I believe that I'm going to go with a new MSD cap and rotor and 8.5mm wires. I'll do the changeover to the '95 type vented cap and do the vent tube mod.

This isn't my first "hot rod" by a longshot. But it is my first computerized one. I just know that there's a LOT of work in doing a tune-up, etc., and I want to only do it one time (at least for a good long while), and I want to do whatever else I can/have to while I'm there.

Thanks all for the info. If you have any other comments I'd appreciate them. Jeff