Timing chain skip and damage?

[dpok69]

If the timing belt skip say a couple of teeth (car never restarted), what type of damage can be expected? This has hapopened to me and my mechanic says i need to rebulid my engine.

The timing cover came of and alot of the nylon is missing fom the gear. He says he must clean out the engine of the nylon and remove the oil pan (to get to screen?).

Also he said my pushrods and valves must also be damaged with that type of skip and says i need a engine rebuilt. He qouted me for $4000 at first then went down to 3500(with use of some used parts).

That is too much for me so i am having the car towed back to me with the timing cover off and loose parts. I plan on doing most of the work with the help of this forum on my own this summer. The farthest i ever gone into the engine was doing the intake manifold gasket.

I need some serious advice on what steps to take to repair my daily driver. Is this something that can be done with the engine in the car. This forum has never let me down, so help me if you can. Thanx

 

[Pronto]

The push rods are easy enough to check. Roll them on a pane of glass and see it they are bent.

 

[Red Regal T]

Your mechanic is really in a hurry to get into your pockets. You may have no damage. Just drop the pan and clean it out. Check for bent push rods........ if there are none, replace your timing chain and put it back together.

You really can't get too stuck with all the folks here on the board to help you.

 

[rb68rr]

Excuse my ignorance, but how do the push rods get bent in this scenerio?

 

[BoostKillsStres]

If I'm not mistaken the 3.8 is an interference engine meaning if the cam stops turning or jumps far enough then the pistons run into the open valves and then either bend valves or pushrods or both.

Since yours did jump and lots of teeth are missing please be aware to check your rod and main bearings for damage as mine didn't jump but about 14 teeth of 40 I believe were missing and when they're gone the chain tears into the aluminum part of the cam sprocket and when the oil pump bypass is in effect when the engine is cold all those alum bits get run thru the bearings as the filter can't catch it..BTDT put new rods and mains in on my back.

Just something to check while you have the engine out and pan off.

HTH my .02

 

[sumnerw]

If the timing chain slips or jumps, then the relationship of the cam and crank changes. This can cause the pistons and valves to interfere with one another and something has to give. Bent valves and pushrods are typical results.

My timing chain jumped on me once. Fortunately it was while cranking the engine and not while running. No damage. Just had to replace the chain and gears. Did manage to crack my timing cover putting it back on over the dowel pin so I got really good at R&Ring the cover!

Good luck,
Buzz White in Houston, TX (sumnerw@flash.net)

 

[MSDGN]

Besides checking the pushrods I would also do a leakdown test to see if any of the valves got bent...

 

[S10xGN]

Like John said... check it first before paying for unecessary parts. I've personally checked my own engine and have seen valve interference ONLY past 0.480" lift. Most factory-type cams are under 0.420".

 

[seeyabye]

So far I have replaced around 10 timing chains on Buick 3.8s that have jumped time. (only one was a Turbo) I have never had one bend any valves. Just be sure to clean out the nylon teeth out of the oil pan. Don't take your car back to this guy, he seems to eager to jump off the deep end. If you can do an intake manifold, you can do a timing chain. Good luck!

 

[dpok69]

Thanx alot for all your advice. Just got my car back today. With the timing cover and all parts in the trunk. The engine doesn't look so intimidating now with those parts off.

I took a brief look at the oil pan. It looks as if it can be pulled without removing the engine. But i need to double check that. I guess the pushrods can be easily removed with the valve covers off and not touching the heads. (I want to maintain the stock factory head gasket clamping force if possible and avoid doing things that may be over my head).

Hey Red Regal T i will be ordering your gasket kit when i am ready. My mechanic qouted all the gaskets for $235. Its so cold here in NYC i cant work on the car, wish i was in florida too.

I figured he was charging me a little too much. I tried to trust him, since he works on alot of turbo regals. I only bring the car there when i think i cant handle the job myself since the car was a daily driver.

I guess i have to do evreything myself and get educated. Thank god for this forum and to all of you who participate.

 

[xtremexnyc]

Hey dpok whats up. Sorry to hear what happened to your timing chain. I hope it is not as bad as you think. It is freezing here in NYC. I also want to handle some projects but I can't. If you need some help this summer I'll try to help you on my free time. Anyway PM me the mechanic you are talking about. Take care and good luck.

 

[Red Regal T]

Look.......there's probably nothing wrong with your motor. Just need to do the timing chain and clean out the pan. The pan comes out, no problem, while in the car. When you get started, just ask questions here on the board or do a search on any specific job. You'll find loads of information to help you. Good luck!

 

[dpok69]

I plan on getting another ride now and keeping the GN as a project for now. I will post back when i start to do the repairs for help. Thanx alot evryone

Hello xtreme, i sent you a PM.