I pulled the timing cover today to find the drivers side bottom timing chain tension guide bolt broken. This is the second time it has broken. The first time, I put a balance shaft elimination kit in it. I got a replacement bolt from Napa. Does this bolt need to be graded or am I doing something wrong when I put the tension guide on?
The motor jumped timing, I pulled the head and all four pistons have indentations from were the intake valves were hitting them. The head gasket and fuel pump were leaking oil. I haven't had the head tested yet, though I don't see any cracks. I read FastEddy's head replacement writeup so I am go when the head is ready to be put back on. After reading the posts on heads, I will probably put a Clearwater or caravan head on.
My other question is, do I need the catalytic converter? My old one is plugged. Anything else I need to do while I have the motor out. I am going to put a new clutch in it also.

Thanks, Nate

I would be scared of that head even if it's still sealed up, and I don't know how it could be if the vavles hit (and bent). And hammered the guide bores and the rockers. I would buy an AMC or Clearwater head with hydraulic valves and no jet valves. I would also get a dye type crack tester and test the tops of the pistons. Rod(s) may be bent, too.

Now to the chain. Did you replace the chain and sprockets? New guides? New rubber tensioner block? New lower small chain guide on the oil pump drive? I think the guide bolts are small to start out with, but I think the guide must be getting hammered even with the small bolts to make them break. I don't remember the head marks, but I think they were the black 10mmhex bolts, right? About a 6mm x1.25 thread?

I put new chains and rubber guides in, I used a Napa elimination kit and it had everything in it. The bolts are small, 10mm, I didn't see anything that looked like it was hitting. I am leaning toward a new head because I don't know if it has ever been overheated. The Monty was given to me with a loud clanking sound, thats when I found the timing chain worn the first time and the guide broken. The guide bolt was broken also. I put the balance elimination kit in and had been driving it for about 7k miles. I will get some pics of the pistons tomorrow and see if I can get them posted.

AFAIK, the 2.6 carb motor is not an interference motor. I'm sure the 2.6T is not. Unless the pistons are not stock. Sorry, been a while since my head was in 2.6 mode.

With that many miles, could the guide bolt have worked loose, letting the guide rattle and fatigue break the bolt? Might loctite that bugger back in there.

Here are some pics, all 4 pistons have the same impression in them from the intake valves.







Nate

These pics look just like my friends 2.6 that we pulled out last month. His guides were in the bottom of the pan.The bolts that held them on were smooth. There was also an extra plunger from the oil pump in the pan. Also had rounded rod bolts where the parts worked thier way to the bottom of the pan.

It died of an oil leak...

I may stand corrected on carby 2.6 non-interference...

# 2 cylinder wall has a deep scratch in it. I am wanting to do a turbo upgrade if I can find a doner, but am worried about the 5 speed holding up so I will probably just rebuild this block. Anybody in East Texas have a doner? <img src="/forums/images/graemlins/smile.gif" alt="" />

Chances are the timing skipped when that bolt head dropped, possibly into the lower chain gear. If the tensioner plunger wasn't keeping proper pressure on the chain it could have been slapping the bottom of that chain guide which caused the bolt to break. Where is your lower oil pump chain guide? The oil pump chain looks aweful loose and if that was skipping teeth periodically, could explain why the plunger didn't keep proper tension. Just a thought.

The kit didn't come with a lower oil pump chain guide, I guess I better get one if I rebuild this motor. I haven't had any luck finding a starion or conquest yet so I will probably rebuild what I have, new head, a different carb, and anything else that looks bad.