Water Pump install and rumbling

[TurboAxe]

Alright, I will try and make a long story short. I took my 95 gst to a local shop to have the water pump replaced and spent mega bucks and waiting time to get it back. When I get it back the car is out of time. The mechanic put the cams back to the factory mark instead of his original marks. It was idling like I had a performance cam in a v8, however when it was driving down the road it rode just a smooth as could be. Anyway I take it back to the shop and get it put back in time like it is supposed to be and when I get it back the motor now has a rumble to it. It drives fine, but it sounds like I have an Apex Dunk on the car, except for my car has a stock exhaust. Also, I look at the timing belt and there is some slack in it. So, once again back to the shop. The mechanic then tells me that the timing belt is supposed to have a little slack in it. Is this true?
Also, he came up with several scenarios as to why my car is vibrating and rumbling so loud. He agreed to go back and look at his work to make sure everything was okay and is supposed to call me to come look at it when he has it apart.
Does anyone know what could be causing this rumble and is there something I need to look for when he gets it apart? Oh yeah, just about everything was replaced in the timing belt area. (Water pump, belt, tensioner, tensioner pulley, timing belt covers, harmonic balancer) Just about everything except the balance shaft belt, but it was replaced about 4 months ago when I had a timing belt replacement prior to the water pump failure!

Sorry for the long post
Any help would greatly be appreciated!!!!!!!!!

 

[jjbrasil]

The balance shaft info was takin from Vfaq...so it is accurate
yes thier is gonna be a little bit of slack of the belt but to much is not good, also does it rumble or vibrate the higher u take the rpm's? I did a water pump one time and it turned out that my balance shaft belts were out of phase....this basically means that the oil pump sprocket needs to be flipped 180 degrees,
- Remove the balance shaft plug on the rear side of the cylinder block and insert a Phillips screwdriver {shank diameter 8 mm (.32 in.)} through the hole. The balance shaft is in the correct position if the screwdriver can be inserted at least 60 mm (2.4 in.). If the inserted depth is less than this only 20-25 mm (.8-1.0 in.), the oil pump sprocket must be rotated one full turn and timing marks realigned. Recheck the balance shaft position using the screwdriver to ensure that it can be inserted 60 mm (2.4 in.) or more. Keep the screwdriver inserted until timing belt installation is complete (Figure 13).

-NOTE that there is an easier way to do this. Simply rotate the mark on the oil pump sprocket until it is pointing straight up, and let it go. If the sprocket rotates towards (counterclockwise) the timing mark on the engine, the oil pump sprocket is aligned correctly. If it rotates away (clockwise) from the mark, spin the sprocket a full turn and test again, and it should properly rotate towards the mark now. Now line the mark on the sprocket back up with the mark on the engine. This avoids having to remove the rear access bolt entirely.

-Caution: MAKE SURE THE BALANCE SHAFT IS PROPERLY POSITIONED. It is possible for the oil pump sprocket timing marks to be properly aligned, and have the balance shaft out of phase. This could result in a SEVERE engine vibration
sorry for the long reply

 

[TurboAxe]

Thanks,
Now I just have to try and get this info to the mechanic. I am capable of doing the work, but the way I see it is, it was running fine (with the exception of the water pump) when I took it in and I feel like they should be responsible for fixing it!!!!!!

Thanks again

 

[jjbrasil]

Thanks,
when I took it in and I feel like they should be responsible for fixing it!!!!!!

yea exactly...take it back and make them fix it....thier a shop they should be able to do the job right...if they cant do it right they shouldnt have even been doing it in the first place...u paid money to fix it..not for them to do a half arse job..

 

[TurboAxe]

Well here's the deal

The mechanic says he checked everything and everything is fine and that he didn't feel a rumble. Of course, he doesn't know how the car drove before, so he has nothing to compare it to. I just told him as long as his work is okay, I'll let it be. It's warrantied for a year anyway. I'm just not going to go back to that particular shop anymore. I took two weeks for him to go back an look at it. Anyway if I get it back and its still vibrating, and I do find the problem, I'll post the solution!