Took off front cover in search of noise

[6SENSE]

Okay guys, finally got the front cover off and unfortuneately didnt see anything wrong. Chain and tensioner look new. The chain is tight and all the nylon teeth are perfect on the top gear. Top gear bolts are nice and snug too. I didnt see anything wrong with the cam sensor either. I really thought I was going to find something.

What sound do bad cam bearings make? Can they be changed with the engine in the car? I do remember a spot on the 1st cam bearing when I installed the cam that looked suspicious.

Or.......... guess I need to just pull the motor and redo the bottom end, huh? If thats the case, it brings me to another dillema. Do I stick with this hotair engine or rebuild the '87 engine I have on a engine stand. Its from a T that I bought from the auction as a parts car awhile back. The car had caught on fire. That would mean no more "dont need a intercooler, like being the underdog". I was planning on using that engine for another car (maybe a old vette, or if I got ahold of a '87GN body) and still have the hotair.

Watcha think? If I do take out the engine, I dont need to do anything to the heads. How should I approach the rest of the engine? Try to reuse everything (if they check out), and just clean the block, replace bearings and freeze plugs?

Thanks, Justin.

 

[irockwithdirt]

I can't remember but what is/was your oil pressure like? I'm new to TR's but with my experience with engines, along with what I have read about the turbo 3.8's oiling, the first sign of bad cam bearings should be significant loss of oil pressure. Have you dropped the pan, checked the play on the rods........felt the thrust on the crank to look for something obvious? Sounds more like something in the valvetrain to me

 

[6SENSE]

I can't remember but what is/was your oil pressure like? I'm new to TR's but with my experience with engines, along with what I have read about the turbo 3.8's oiling, the first sign of bad cam bearings should be significant loss of oil pressure.

Thats what Ive been thinking, and why Ive been looking elsewhere for the problem. My oil pressure has never gone down. Cold it idles with around 40psi, and hot 20-25psi. PLENTY of pressure. Compression is good. No metal in the pan (Ive got one of those magnetic drain plugs and it has not had any significant accumulation of metal particles at all; looks the same as when I usually changed the oil in the past).Everything, including power is good, other than the knocking sound and the false KR from it.

I just got a email back from Red. Even after my findings with the cover off he still thinks its the chain. He says "....the tensioner does nothing but hold the slack while the cars not running. Rotate the motor and watch the timing chain and see if the slack dont go from one side to the other". This was his opinion, and I tend to value his opinion. Sooo..... I guess I will order a Rollmaster double roller and see if it solves the problem. Worse comes to worse, I will already have the good Rollmaster chain for the motor even if I do need to take it out.

 

[irockwithdirt]

Once again I don't know these motors but.........thought of removing the plugs...........pulling the valvecovers.........then rotating the enging by hand a bit at a time and looking for any abnormal play in rockers (ie. bent pushrod, collapsed lifter, flat lobe)?

 

[6SENSE]

Originally posted by irockwithdirt
Once again I don't know these motors but.........thought of removing the plugs...........pulling the valvecovers.........then rotating the enging by hand a bit at a time and looking for any abnormal play in rockers (ie. bent pushrod, collapsed lifter, flat lobe)?

First off thanks for your interest .
I didnt take out the plugs, but I did have the valve covers off. I took out all the pushrods. They were all new and still look that way, not bent. I even tried swapping out rocker arm shafts on the side where I originally thought the sound was coming from (passenger). I ran the engine with the valve covers off and the sound was still there but I could not say that it was definately coming from the upper valvetrain area. I think the sound just resonates to there. I used a stethescope and could hear the noise around the valve covers, but also at the front cover (a little louder). I you want check out my (I think its two) other thread(s) from recently. They should still be on this page of threads, and list all the specifics. Hopefully I will get this figured out soon and if anyone else goes through it, this info will save them time. Thanks.

 

[racemybuick]

Drop the pan

I think it is time to drop that pan! Take a look at the crank, and look for signs of abnormal rotation, maybe scratching or something. Do you have a compression tester? If so, go through each cylinder and see if there is one weak n in the set...At least you may know where to have a closer look. Good luck, keep us posted, and definately keep that motor, put the 87 in a sleeper, like an old Caprice or some unsuspecting "grandpa" car...lol...Put a little shock on the local high-schoolers and their honda's!

John