Yes, I have also purchased a set of the narrow K1 rods.
From talking with Tom at K1, I got the last set... he is starting another batch.
DD

Good to know they are selling these. I still need to get my narrow K1's to the shop to get a bearing clearance on my crank and then that short block is ready to go together.

Lou

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Home of Slant6-powered fun machines since 1988

The oil pan came-off last night and I feel that the thinking above is what killed this engine.

#1 rod bearing had obviously over-heated to the point where the slender, 12 point rod cap nuts failed, then all h#!! broke loose inside the engine.

So what does this have to do with con rod side clearance and spurt holes... reduced oil flow over the bearing surface at higher RPMs.

My notes show that the rod bearing oil clearances were all set at .0014 - .0016 I know this for sure because I actullay sent the crank back to the shop and opened these clearances up to that number.
Con rods # 1 & #6 were both tight on side clearance... both of those rods had .002 to .003 of side play.
Guess what, con rod bearing #6 was also overheated and ready to fail, #1 just happened first.
Side clearance on 2 thru 5 were in the .004 to 007 range.
I still need to open-up those rods and look at the bearings but if my thinking is correct, I will see more bearing "distress" on the bearings in the location(s) that have less side clearance.

So my current thinking is that the factory spurt hole and recomended .007 to .014 of con rod to crank journal side play, allows a pathway for an "engineered" amount of oil flow. Reduce the amount of oil volume at the bearing and the bearing overheats and fails.
DD

Wow, what a bummer. This sounds like a lubricant cooling failure rather than oil starvation. Interesting mode of failure, but it still stinks.

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Joshua

I would aim to the high side for side clearance . Also i would like more bearing clearance too. At least .002"
Does the engine have full groove mains? (or a grooved crank. )

Don

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Don

The lower main bearing inserts were "partially grooved", I would say there is 240 degrees of pressurized oil feed.

I worry more about the oil flow into the crank bearings on all Aluminum SL6 engines seeing that the oil flows into the main bolt bosses and has to flow up and around the main bolt shank, before entering the bearings.
(I have to think that the Chrysler engineers got the flow path's volume "right")

Anyway... I pulled the Buster engine and took the pan off... what a mess.
You know you have trouble when you see this:



And this...



Long story short, this block is now junk.



If it was just a "big hole in the side" I could weld that closed but somehow... a big chunk was also knocked-out of the bottom of cylinder #2.

If you look closely at this photo, you will see a long crack, running up the front side of the engine... the whole left front corner of this block is ready to fall-off.
DD

*moment of silence*

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Drat.

I hope to try this w/ the K1 rods at some point. I found a machine shop that doesn't blink when I ask about custom machining as would be needed here. My first cast crank motor is about to come out of that shop, so we'll see how that runs first.

Lou

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Home of Slant6-powered fun machines since 1988

Too bad ... really a pitty ... one aluminum block long gone, and Doc didn't even had the chance to enjoy it a little ...

R.I.P. Buster ....

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Martin Zappettini
1974 Dodge Polara RT 318cu.
1965 Valiant III Coronado Slant Six 6-Pack (soon!!)

if you not breaking parts ...you arent trying hard enough


keep on roddin'

did it let go without warning?

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11.02 @ 120.56
http://www.youtube.com/watch?v=EAxRmoDgsdY
Chassis dyno
http://www.youtube.com/watch?v=wd6hFGzLJMc

This failure happened fast.
I saw the engine temp gauge move from a steady 185 up to 200 degrees so I slowed the car from 70 MPH to 55 and pulled to the right lane. Then I thought I heard something... and boom, the engine blows-up.
DD

sorry to here what happened.you know what you were doing is traditional hotrodding at it's best.building hot rods is all about taking a idea run with it and seeing how it all turns out

Thanks for the support and feedback...

I need to "regroup" on the Light Rotating Assembly (LRA) concept and do another one... one that will stay together long enough to get some real performance data.

If I salvage the good parts from Buster, get a couple of replacement pistons and rework the crank, I can have another "go" at the LRA idea. Next time around, I think I will do the build in a cast iron block.
DD

so doug what `s the weak point ? did the rod bolt or cap fail or was it the bearing form lack of oiling.