UPDATE! Engine Cylinder wall question - V6

I don't know which section this should be in, but here goes:

I'm tearing my 'new-to-me' used Dauntless 225 down for an inspection before trying to run it. I have the heads and oil pan off and so far it looks mostly decent. There are no ring ridges to speak of and appears to be bored .040 over.

Here's the 'mostly'. the PS (right?) bank had water on top the pistons on the rear two cylinders:


Can I use emery cloth or a cylinder hone to 'buff this out', or is this going to be surgery at the local machine shop?



Edited by LesBerg - 27 Oct. 2017 at 6:29pm

So here's an update with the rust sanded out. I ended up using 1000 and 1500 grit paper.

Cylinder 4


Cylinder 6


I'm most concerned with #4. I can feel the pitting.  If this was body work, you wouldn't even need a sandable primer to hide it. It looks like there's a hell of a ring ridge, but there isn't. I almost can't feel it.

Can I run it like this and maybe smoke a bit? Would hone dress it out?

I'm not looking for this thing to run forever, I just need it to last until I can pick up a freshly built motor. Then I'll swap them and have this one built as a back-up.

Time to go back out and check the bearings. It's not fun when it's 97 degrees.

Because your future plans include replacement; 

Unka, I'd take you up on it if I was closer, too!

Only the one cylinder has pitting I can feel. A LOT of the info I'm finding online says:

A). Run it.
B). put it back together and compression test it. Run it if compression is acceptable.
C). Pitting where the rings sit as the piston reaches TDC is BAD. Fix it.

I'm going to try B. Only one cylinder has pitting that can be felt, and it's not very deep.

There are a couple of reasons I don't want to build a motor right now. Because of where we live vs. where my wife works, we need at least two running vehicles at all times. 

Our VW Golf, one of the currently 'running' needs suspension work. I smacked a curb-shaped asphalt dam about 4" tall that WDOT put across a back road to the north side of Spokane this spring. The warning sign the put 50 away from it on a blind 45mph corner was "CAUTION - LOOSE GRAVEL". I need the jeep running so I can tear into the damage and see what can be done.

Another is that finding ANY reliable machine shop or mechanic in the area is nearly impossible. I know only two shops where I would take anything I own. One only does transmissions, the other is European imports only.

Once I get the Dart sold I'll pick up a Dauntless offered by a member here that was rebuilt and stored. Knowing the members here, I would trust a motor you guys cobbled together from scrap to run better than anything built locally.

Oldtime, I'm going to check the bearings tomorrow and look for surprises. I will probably pull the pistons as well, as there's gunk trapped in the gap around the top of the pistons. I figure to clean them up, oil them, and stuff them right back in. Then I'll check out the timing chain, clean up the lifters, and clean the crap out of the block.

I tackle the heads after that and get them cleaned up too.

Willy M, same here but never with rust. Even if it smokes a bit and loses power on that cylinder, it will be better than the cracked motor.



Edited by LesBerg - 27 July 2017 at 4:38am

Put it together as is and get it running.

If you run it as is, let us know how it works out.  Unless there's something else going on that we're unaware of, you won't have a problem other than some possible increased oil usage.  And that should be minimal.  

I'd be inclined to clean it up and run it if it's just a stop gap... fwiw, I've never honed a cylinder without replacing rings. 

checking bearings right now. So far they look good.

biggest issue is how to remove the carbon from between the piston and cyl wall without pulling the pistons. New rings aren't in the cards right now, and I'm very curious to see first hand how well it runs.

I have been using the thinnest brass feeler gauge I have to clean the carbon from the gab between the cylinder walls and the piston, and it barely fits, even with the piston a bit down the bore.

I just don't want any crap in there that can damage the walls any more than they already are.

I'll get some bearing pictures up in a bit.

I found some good advice for removing the crud between the piston and cylinder*. Now it's all cleaned up.  Rods bearings look good to me (an amateur). The main I pulled isn't as nice as the rods, but it looks serviceable. 

The crank is a 10/10 unit. Casting number says it's a 75-76 Buick 231 unit.
Block checks out as a 67-74 225, date stamped as 1967
Heads are 67-74 225, dated 1967

The even fire motor castings say it's an 80-81 Turbo Riviera. I'll dig into it later.

I still need to run the intake casting numbers for both motors.

I'll get more pics posted as soon as my phone syncs with my computer...


*I found an article by an aircraft mechanic who detailed how to do it. With the piston part way down the bore, pour a bit of motor oil on top the piston and get it into the gap. Spin the motor one revolution and gunk will be left in an oil film on the top 3rd of the cylinder wall. Wipe with a clean rag and repeat until you see no more.

time to go clean the lifters, then start de-funking the block itself.


Edited by LesBerg - 27 July 2017 at 7:21pm