4MG Rebuild

Hmmm, good point.

 

Probably ought to update this thread. Between waiting on things and having been busy on other work it has been awhile since I have done anything with with it.

Sent the block to Cat and they cut the liner bores and ordered shims accordingly, and I had them change out the cam bearings or bushings. They got the oil holes lined up incorrectly on the front bushing.
As you can see the hole that feeds the bushing is nearly in line with the feed hole from the block. Probably would have been ok, but they are supposed to be 90* off, so I pulled it and put in a new one.

I may regret this, but I ordered a complete IPD kit from KT (youtube channel KT3406E). KT is a good no-BS guy. He said right up that he hadn't done much with mechanicals, but was not having any problems with IPD fit or quality on C15s, and he was very helpful and responsive to questions It is their Durability kit that comes with steel pistons instead of aluminum. It has slightly lower compression (14.6) as I recall, and requires double oil squirters. He sold me some used oil squiters out of an E model that uses the same size bolts as the B. Also required for this adaptation is increased oil flow. Rather than buy a different oil pump I have learned that one can sipmply change the bracket that holds the oil relief spring to increase the pressure that it bypasses, so I ordered the different bracket and we will hope that it will suffice.

I have been a loyol Cat guy for a long time, but they no longer provide a complete kit for B models without ordering the individual parts, so I dedided to give IPD a try. The price was really reasonable I thought at around $3500.

Finally got back to it today:


Shim, new spacer plate, and checking line protrusion. First go-round we torqued all the bolts with brass washers to 40 ftlbs. and measured protrusion. Readings were between -.001 and .005. I was pissed because I hadn't taken the block in to get decked (trying to cut corners...I know, but it checed out really good with a straight edge) and thought that I would have to have that done. We screwed around rotating a couple of liners, and then read a bit out of the Cat book, which recommended torqueing all the bolts @ 10ft lbs., then 25, then 50, and finally 70. After doing that, all readings are now between .004 and .006. I am assuming 40 ft lbs wasn't quite enought to hold the spacer plate down, or crush the little rib on the shim evenly. Anyway, the readings are consistent now, although a little on the high side? So we removed the spacer plate and went to installing liners, which was much easier than I anticipated. We used Dawn dishwashing soap on the lower bore and o-rings, and engine oil on the top band that swells. I was able to push them in by hand with a little bit of umph. They would push back up just a touch, so we finished setting them using a piece of 2x2, and a prybar under one of the bolts that we used for checking protrusion.

As you all know, we are not mechanics and are fumbling our way through this process, but it has been fun and educational so far.

 

A friend is lending us one. It will be one that he has had for many years, but I don't know the type yet. Thanks for the heads up.

 

I've been thinking about this a bit and went out and opened a ring and a piston box and looked for directions. Other than break in procedure I didn't see anything. I guess the problem is that with the adjustable you can tighten on the rings too much, and with the type you showed it can only clamp until the sides meet?

 

Things are moving along.

 

The one we ended up borrowing was the adjustable ratcheting type. We were wary of problems, but found that if we overlapped the skirt a fair bit they went in pretty easy. Thanks again for the warning.