Hi,

Long time since my last post. Previously I was trying to diagnose a misfire issue with my setup on the Fuel injection: http://slantsix.org/forum/viewtopic.php ... highlight=

Last thing I did in the thread was check my compression an it was consistently low on all cylinders, 90psi if I remember correctly. After looking back through all my information I realized that I neglected to use 198 length rods with my Weisco forged pistons...(Face palm). So I stewed for a about six months and then pulled the motor where it sat till this day.

I'm looking to replace the rods soon, next couple months. I've never torn a motor down before with the intention of putting it back together. My intention was to either buy the K1 pistons or the Molnar (not sure which is 'better') and then install them. I'm assuming I can use the same bearing caps etc. and just install the Rods?

I've also considered measuring the combustion chamber volumes while I'm their so I can determine actual compression ratio.

Thanks in advance.

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( Slant Six 73' Duster TBI )

The new rods come with caps. You cannot swap caps from one rod to another as they are finish machined after they are mated. This is why everything gets marked. The aftermarket rods use a floating pin which is different from stock rods with their pressed piston pins. You'll have to have the pins pressed out of your old rods very carefully to avoid damaging the pistons.

Also, retarded cam timing can close the valves very late and give low compression.

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Joshua

Okay. I was under the assumption that using the floating pin type was more of a function of the pistons and it may already be setup like that. Sounds like that may not be the case.

When it comes to the cam I suppose I should check that also when I take everything apart. I'll look into how to verify that. It is a clifford 268 cam by the way.

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( Slant Six 73' Duster TBI )

The piston pin is always free to rotate in the piston. With economy engines the piston pin is retained by a press fit in the rod. With full floating piston pins the pin will rotate in the piston and the rod. The pin then has to be retained by circlips or Spirolocks. There are other arrangements too. Studebaker locked the pin in the rid with a nut and bolt.

Absolutely do all the work to calculate the compression ratio, static and dynamic. Ypu may find that the Clifford cam is actually a little short on duration (too early intake closing) to run pump gas with optimal ignition timing.

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Joshua

Finally got around to removing the connectiong rods from the motor. I found that they are held in with retaining rings.

Rod with Pin coming out: https://photos.app.goo.gl/b7LlvBnqoxJ24Pti1

New rod installed: https://photos.app.goo.gl/yjHEYAc49BQaAAgu1

Motor pic: https://photos.app.goo.gl/JfqN39YyqiA6BQlg2

Top of pistons: https://photos.app.goo.gl/mg8KmtROa8OQ23Au2

I have a question about my rod bearings. Would it be acceptable to reuse these? https://photos.app.goo.gl/0m6qqjUekzaQnX5r1
I only drove the car for maybe 100 miles. I don't feel any rough spots on cylinder 1 bearings. There is some black spots, maybe that is oil? What I thought was that bearings become 'mated' to the journal and rod combination.
The cylinder 1 bearing is marked STD for standard size I suppose. https://photos.app.goo.gl/omFG3SkSbTE1ieyJ3

I'm still planning to check the head CC and I will also be checking my bearings clearances with a plastigauge.

While I'm here I figured I would check my ring gaps too. I would like to run boost eventually, around 10psi or so. If anyone has suggestions on that I would appreciate it. I'm seeing people may enlarge the gap by a few thousands to compensate for boost pressures.

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( Slant Six 73' Duster TBI )

The rod bearings should be fine to reuse.
However if you are planning on runing boost at some point in time..
Be sure to get the cc numbers on the head combustion chambers and the piston recession with those K1 rods and Wisco pistons, be sure to include the valve reliefs, I am betting that the static compression will be way too high, unless you run a thick copper head gasket.
Concerning the ring gaps, yes they need to be opened for boost, I would speak to a Tech at Wisco and get further info here.

Back on the rod bearings,
Would be best to keep the shells in sets, and back in the same crank pin position, but if not should be ok.

And after looking at the rod bearing photo,
There is more edge wiping on the top bearing, the loaded side, than I would expect to see after 100 miles,,
1) was the crank shaft inspected for journal size and are standard bearing the right ones?
2) what assembly lube did you use? Was there a good coating on the bearing and crank surface?
3) what was the rod bolt torque set to? Did you use a calibrated torque wrench? Did you use a lube on the rod bolts?
Pay attention to the torque on the K1 rods, it is different from the factory rods.

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Doo Ron Ron and the Duke of Earl are friends of mine.....
https://www.youtube.com/watch?v=uX8Nj8ABEI8

Using those bearings again isn’t a good idea. Never use an old set of bearings in a new rod,plus they have contamination from foreign matter in them and the edges are exbibiting high levels or wear. Don’t cheap out , you’ve spent big on new rods, bearings are relatively cheap.

And I don't know if you are planning bigger valves or not, but many of us have had to enlarge the valve reliefs. The edge of the valves would catch the edge of the reliefs. I know all of my Intakes needed it on my new motor. Just a FYI.

Rick

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

I also have concerns about the rod bearings. There should not be wear at the edges of the bearings. The wear should be even across the bearing. On one bearing half I see a black spot with a shiny border. That's foreign material embedded in the bearing causing a high spot. There was obviously some debris in the lubrication system. I feel strongly that the crankshaft should be measured carefully across the crank pins. The journals need to be measured on each side and in the middle. They also need to be measured for roundness. Typically the rod journals wear oval and so measurements need to be taken at right angles to be sure roundness is within limits. I would appreciate a picture of the rod journal.

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Joshua

Hey DadTruck (Funny name )
For 1,2, and 3 I couldn't tell you because I had this motor rebuilt quite a few years ago. I really didn't do my due diligence at the time I was full time in school and was just looking to pay a 'pro' to help me out.
I was planning to torque the K1 bolts to their spec via the torque + angle method for yield preload.
Do you have any suggestions on assembly lube?
Hi Rick. Are you saying people have needed to enlarge the valve reliefs on the pistons with stock valve size or enlarged?
Hi Josh. I was afraid that could be the case. I'll have to get my hands on micrometers to check this better. Here is cylinder 1 rod journal : https://photos.app.goo.gl/CWIUp9J8LP0xQug72

This is cylinder 2 bearings: https://photos.app.goo.gl/bhU6lCPnvTEPtToI3
Cylinder 2 rod journal: https://photos.app.goo.gl/ZT9ej6rCjkjcIhLH2

Thanks for the information guys.

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( Slant Six 73' Duster TBI )

I use Lubriplate 105 on the cranks main and rod bearings and journals and other internal moving parts. It is an oil soluble grease that can also be packed into the oil pump gear cavity to assist with oil pump priming.
I use Moroso Moly Paste as the cam lube on the mating can-lifter surfaces.
I use an inexpensive 10w30 motor oil and filter and add a bottle of break in additive like Comp Cams 159.
I like to run the 20 minute 2000 rpm cam break in, then 2 or 3 moderate rpm cold engine oil to warm/hot engine oil cycles then change out the break in oil and filter.

Your #2 rod bearing does not look good either. Checking the crank journals for size and roundness is the right next step.

Do you remember the oil pressure at idle with a fully warmed up engine that you were seeing?

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Doo Ron Ron and the Duke of Earl are friends of mine.....
https://www.youtube.com/watch?v=uX8Nj8ABEI8

Only if you are running larger than stock valves. And if this is going to be a performance build most people use larger valves and spend some time making the head flow better. Since the pistons are out, now would be the time to do that if the future called for larger valves.

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

Check the valve reliefs clearance no matter what valves you're using while you have it apart................

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

If the bearings were not standard size my hypothesis would be that the crank grinder didn't dress the grinding wheel and the journal ended up smaller in the middle. But that's what it looks like, the journals appear to be smaller diameter in the middle of the pin. The finish on the journals doesn't look good either. Did your "Pro" polish the crank maybe?

Here's the good news. It will never be easier to fix this than right now. The bad news is I would be doing a full tear down so that everything can be cleaned and the crank sent out for a regrind.

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Joshua

V-ing of the journal is symptomatic of someone over polishing the journal and using too much pressure with the polisher. This causes the belt to form a V because it has no support behind it to keep it flat, and makes the journal smaller in the middle and fatter on the edges. But yes, much easier to correct now since you are also replacing the rods.

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There's no such thing as too much cam....only not enough engine!