Hello All,

As some of you know (I feel like a broken record here) I recently had a built short block from a reputable company (low compression 427). This has been my first build, ever. So, forgive the ignorance. With that being said, I wanted it to go successfully. I took every precaution, followed every instruction provided from the break-in manual provided to me by the builder.

The oil was changed around 8 times in the 9,700 miles on the shortblock. Each and every time, there was significant amounts of metal in the oil, all the way up to the last oil change, before I finally gave up on "hoping" for clean oil.... I decided to do something I never thought I'd have to do: Remove the engine, and completely disassemble the block to look and see what happened, and what "went wrong". I found nothing obvious at first... until I took a closer look.

Things to note:

1) Most of the bearings have the smallest/slightest scratches on them, nothing that would explain the amount of metal I've been seeing on every oil change.
2) The rod bolt connector ends can be moved slightly (they have a teeny bit of lateral play, but no "up and down" play
3) all the bearings (rod bearings and main bearings) seem mostly healthy, and not obvious signs of damage.
4) Cylinders look new.
5) I didn't remove the pistons heads to verify ring health. Engine is still in the garage

I need your help in identifying what's "normal" and what's abnormal...I guess...in a custom CNC shortblock. I've have employed the help of my camera, and my good friend. Pictures below:

My questions are:

1) Are the "hand dremeled" type of clearances normal to be seen in such custom blocks? The clearances are for the rod bolts. The picture with the rod bolt clearance is the best case scenario, the other clearances were even slimmer.
2) The picture showing the bad/scratched bearing - associated to the crank...is it just me, or does that seem like the crank is eating the bearing because of an "incomplete" grind on the crank?
3) Is it possible that over the course of 9,700 miles, these slim clearances have slowly been getting eaten away? Although to be fair... none of the ARP Rod Bolts show any kind of wear on them.


Thanks,
Andy











To my untrained eyes, these seems like a chop job. However, I need the board here to tell me if this is normally how these clearances are made for a sleeved block.

 

The notches are for added clearance due to the longer stroke of the crank. That would be normal practice. The fillet looks normal for a forged crank also. Not sure about the amount of wear on the bearings for the miles put on.

 

Are you talking about the "big end" of the rod having some axial play, but no radial play? If so, this is called "side clearance" and is normal and actually required.

Personally, I wouldn't be concerned that the rod bolt head clearance notches were ground in by hand by a dude with a die grinder. I've done it many times. It would definitely be "fancier" for that to be done by CNC, but unnecessary. And basically, the bolt heads either hit, or they don't. At high speed and high load, the components will bend/deflect/comply a little - but not much. I'd want at least 0.020", but even that much probably isn't actually required.

The shiny spot on the edge of the rod bearing does appear to be caused by the journal's fillet radius being too big. Just a guess here, but perhaps it'd been a while since the grinding wheel had been dressed, and it was a bit worn on that leading edge - resulting in a gentle ramp leading up to the fillet - resulting in a slightly oversized section of the rod journal. Do any of the others look like this? When they grind the crank, they usually use the same wheel for all the journals, so I'd expect to see this phenomenon across the board.

Do you have a micrometer? Would be good to mic the journal in the middle, as well as the ends to confirm/deny it is oversized where you see the bearing is shiny.

 

You should be able to slide the big end of the connecting rod along its journal, until the side of the rod butts right up against the flange of the crank. If you can't, there is interference between the fillet and the bearing. That's bad. When you push one rod up against one side, and the other rod up against the other side - there should be a gap between the rods. You can then use a feeler gauge to measure the gap. That gap usually needs to be in the 0.015" zone, give or take (on journal-guided engines, like yours). I'll also mention that it's important that with the rods butted against the crank, the side of the "small end" of the rod must NOT be touching the wristpin boss of the piston. (On a sidenote, this totally does not apply to some specialized race engines with "piston-guided" rods. On those, the small end is a precision fit inside the wristpin boss of the piston, while the big end "floats" on the crank, with clearance between the flanges of the crank AND between the rods)

Also, when you butt the rod up against the flange on the end of the crank, you should still be able to freely rotate the rod - it shouldn't get tight! Looking at the shine to the edge of your bearing, I suspect yours gets tight(er). This would be bad. Again, a micrometer would quantify this...

 

LaBLK, and Hodgdon E.

Thank you both for your feedback/help. Measuring that fillet will be a great idea, don't know why I didn't think about simply measuring the damn thing :-)

1) You are correct - the "play" on the rod connector ends have a slight axial "play" to them - I included a picture to make sure we are both talking about the same style of play


Is this considered axial play?

2) Nope - none of the other Crank Fillet's/associated bearings have that kind of marking on them against the edge.

Thanks,
Andy

 

Yep, we're talking about the same thing. Some folks would call it "end play" or "sideplay".

 

Pull a rod bearing. What brand is it? It should give you a part number on the bearing.

 

Was this engine allegedly balanced? I don't see any evidence of material removal on the rods or pistons in your pics...

 

Metal removal on rods? You seem to be from a different generation that hasnt worked on an ls engine or used newer rods before.

 

How are you guys balancing (weight matching) rods over there at the WS6Store?

 

Interesting.....

The short block was ordered as a complete short block, with what I presume would be a balanced rotating assembly (I can't imagine they'd not balance it if they sell it as a complete package). For such a big name/company, I just can't imagine they'd *not* balance it.... thoughts?

I hate to throw names out there, because I like to do my research first. But I feel obligated to mention it, since it might help get to the conclusion here about balance.

This short block was built/assembled by Texas Speed and Performance. I assumed it would be a balanced shortblock.

When I take it to the machine shop, should that be something I mention? To check the balance on the rotating assembly/crank?

Thanks everyone for the invaluable input,
Andy

 

Most places dont have to weight match a rod for a rotating assy of you use them brand new out of the box. You CAN try to weight match to the gram but then youre doing that to the piston also.
In most of the quality rods ive seen 8 rods in the box will differ by maybe 3 to 4 grams. If youre trying to match those then you have to have a very accurate scale and then you have to weigh the big end vs small end and start grinding away on whichever end is out of range.
Pistons can and sometimes are off by as much.

Since we cant balance a rotating assy in house, if i have to assemble short or long, which we rarely do in house, then i will pull out my postal paraphernalia scale and weight match pistons to rods with bearings and pins to get within 1 to 2g of each other. Requires no material removal on the rods or pistons or bearings etc.

On lesser quality rods ive seen them have to be ground down but that would be no name chinese stuff or speedmaster or a few other ebay parts. I haven't seen any from scat, eagle, callies, manley or K1 and definitely none from the more expensive setups.

Will I on something that sees over 7k? Id check em to make sure, but like i said since we cant balance in house that part is left up to the machine shop.

The main issue i was pointing out is he has said quite a few things in quite a few threads that dont pan out to what todays engine parts and systems are like. In the sbc era youd have to grind rods etc brand new out lf the box. With todays machinery and processes, thats hardly ever necessary.

 

I will do this hopefully when I have the chance this Saturday.

Thank you!!

 

I was not aware that matching the all up weight, big-end weight, small-end weight and piston weight had generally fallen out of vogue. I guess the machine shop I use is old fashioned.

We also always did it on the 5.0L LS2 Daytona prototype and LS7 Dakar Rally engines we built with Carillos.

Anyway, my bad.

 

No "bad" at all - your insight and knowledge has been extremely helpful. The more people chime in, especially people more knowledgeable than myself, the better I can approach the machine shop with concerns, etc.

I have full intention of measuring that fillet as well as pulling a bearing and getting a number off of it.

Thanks for your insight (to everyone who has chimed in)

 

What does the metal in the oil look like?

Have you cut open a filter to inspect that for larger chunks?

 

I'll see if I can find a picture.
The metal in the oil was a glittery mix of copper and silver, with some being magnetic. Also, the larger pieces that have come through were a blend of those two colors together...

I've cut open almost every filter I used - all of them had some chunks. I got tired of cutting them, and I got a magnetic oil plug just to catch most of it for me. Picture below of what the magnetic oil plug caught in just 50 miles of driving:




Thanks,
Andy

 

I have this done on every engine I build. New rods, used rods, whatever. Maybe I’m old fashioned. I am oldish. I’m passionate about perfection because I came up being taught to be passionate about perfection. The rotating assembly for my 434, I bought as a brand new balanced assembly. It was close, but I don’t want close. $250 later, it was balanced by my shop.

 

To truly find where the metal is coming from you are going to have to completely disassemble it.
Could be coming from most anywhere.

Ron

 

TechWs6:

CB663HN - Looks like it's a clevite bearing

HodgExtreme:

2.09" vs 2.115" - That little lip is definitely raised and needs to be fixed...

Long story short: TSP didn't do a great job on the crank... This engine needed better attention to detail before it was assembled.

I sent an email to TSP to see how they handle my situation. Obviously, this isn't a break in procedure or tuning issue, this is clearly a manufacturing issue.


Thanks,
Andy