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Author Topic: Engine locked up on dyno  (Read 34762 times)
dangerous
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« Reply #30 on: March 07, 2016, 21:08:12 pm »

That loose rod bearing is what happens when they get hot.
Provided the rods measure up OK, a new bearing will have the 'nip' required.

Have them crack tested and resized, if they measure poorly.

Any decent machinist can straighten a crankshaft BEFORE, it is reground,
so it should be an easy fix if it has crack tested OK, but is bent.

You would be surprised how little oil volume a bearing needs,
but if the sump has run dry, or the pump sucked air(like a bathtub draining)
due to sustained rpm, it will kill bearings instantly.

But yes, a nice detail would be the oil holes not overlapping!

Make sure your sump capacity and oil level are enough!

Another point about engine lock up is,
you should know the actual measurements of ALL the assembled bearing clearances,
not just the end float.

Some times the crank journals may have to be ground, to get the exact clearance required
due the tolerance stack up, of both case (and rods for that matter), and also the bearings used.
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dragvw2180
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« Reply #31 on: March 07, 2016, 21:52:21 pm »

JMHO ,  It is easy to speculate on the causes and at this point it really does not matter. You would be surprised how many times I have seen engines be built where they took for granted that because they had a standard crank, case and rods that their bearing clearances would be good to go with standard bearings . Too low of oil pressure for the rpm's turned, wrong viscosity or not enough capacity so the engine runs out of oil. My suggestion would be to find a machinist locally who you can pay to measure the case, crank, and rods , repair or replace everything that got damaged . I would have him check the bearing clearances for the viscosity of the oil you intend to run and then reassemble the engine yourself . I like a 4 quart sump and I run more oil pressure than others , I'd rather give up a few HP and have my bearings look like new when I pull them out at the end of a race season. Mike McCarthy
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baz
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« Reply #32 on: March 07, 2016, 22:24:54 pm »

I originally planned to build the motor myself but chickened out as I got a bit overwhelmed by it all and decided to get a pro builder to take care of it. I expected the builder to take care of every detail and I was happy to pay for attention to detail, I even told him this the day I dropped all the parts to him. He wasn't my first choice but someone who was recommended to me. I reckon my first choice would have done all the blueprinting I was expecting so I should have stuck to that plan.

Perhaps I should take heed of the advice above and assemble it myself this time, what I'll have to pay someone else to build it would buy me the tools I'd need. I'll sleep on it and see how I feel about it tomorrow.

Thanks everybody for your help and advice
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spanners
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« Reply #33 on: March 07, 2016, 22:37:07 pm »

DIY is OK to a point, untill it comes to trouble shooting when an experienced eye can't be beat, now the shits hit the fan, it all needs careful scrutiny, There needs to be crush on the big end bearing shells, Andy also noticed, they should just be very slightly proud of the shoulder, so somethings way off in your pic, the shells in both halfs are below the rod shoulders and look as if they would just fall out, as new they should almost 'snap' into place, I've seen it on well hammered race motors were they were literally hammered thinner, and loose in the assembled con rod eye but showed no copper, you say oil pressure was constant, it may have indicated thus at the gauge, but I suspect volume and pressure to that no2 has hammered it, some bearing types these days seem to skip the copper layer and there seems no sign of it in the pics, cost cutting?? Nothing can be taken at face value anymore, even snide bearings could be a possibility, I'm concerned also the backs of the bearings look high mileage? Maybe it's just photo quality poor with resizing or summat.  Undecided
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judgie
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« Reply #34 on: March 09, 2016, 18:35:54 pm »

well thought i would post as i'm the one now being trusted to rebuild this. was gutting to watch it lock up on the dyno.
had a lot of oil pressure which surprised me even if it is all new , was showing 80+psi @2500rpm warm with a 20/50 mineral oil, the oil holes in the bearings not lining up would account for the high pressure but we all know pressure and flow are very different.
tried some new ks bearings in the rods and they snap into place like you would expect. need to check the part numbers on the bearings we removed to find out what they are.
crank is off with the machine shop to be checked and ground. I have also asked him to check the journal width and fillet radius.
then its give it all a dam good clean as there is a lot of bearing materiel floating about.
end float was 007" so about where i would expect
i think the bearings are silverline ones but going to try and source some steel backed ones for the rebuild.
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baz
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« Reply #35 on: March 09, 2016, 19:12:56 pm »

I was gonna call you today mate to see if anything was happening, saved me the trouble now having read that Smiley

Thought those silverlines were steel backed?

It has already been suggested to me in a pm that the rod bearings may be chevy size, I'm a little confused about this as I'd have thought if they were too small for the journal then the rods would have seemed very tight on assembly? 
« Last Edit: March 09, 2016, 19:15:35 pm by baz » Logged

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Jim Ratto
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« Reply #36 on: March 09, 2016, 21:51:11 pm »

well thought i would post as i'm the one now being trusted to rebuild this. was gutting to watch it lock up on the dyno.
had a lot of oil pressure which surprised me even if it is all new , was showing 80+psi @2500rpm warm with a 20/50 mineral oil, the oil holes in the bearings not lining up would account for the high pressure but we all know pressure and flow are very different.
tried some new ks bearings in the rods and they snap into place like you would expect. need to check the part numbers on the bearings we removed to find out what they are.
crank is off with the machine shop to be checked and ground. I have also asked him to check the journal width and fillet radius.
then its give it all a dam good clean as there is a lot of bearing materiel floating about.
end float was 007" so about where i would expect
i think the bearings are silverline ones but going to try and source some steel backed ones for the rebuild.


If you need NOS steel backed mains, depending on crank size and case size, you might call Terry at Griffin Motorwerke. 510-524-7447
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baz
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« Reply #37 on: March 09, 2016, 22:23:20 pm »

well thought i would post as i'm the one now being trusted to rebuild this. was gutting to watch it lock up on the dyno.
had a lot of oil pressure which surprised me even if it is all new , was showing 80+psi @2500rpm warm with a 20/50 mineral oil, the oil holes in the bearings not lining up would account for the high pressure but we all know pressure and flow are very different.
tried some new ks bearings in the rods and they snap into place like you would expect. need to check the part numbers on the bearings we removed to find out what they are.
crank is off with the machine shop to be checked and ground. I have also asked him to check the journal width and fillet radius.
then its give it all a dam good clean as there is a lot of bearing materiel floating about.
end float was 007" so about where i would expect
i think the bearings are silverline ones but going to try and source some steel backed ones for the rebuild.


If you need NOS steel backed mains, depending on crank size and case size, you might call Terry at Griffin Motorwerke. 510-524-7447

Thanks.
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Bruce
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« Reply #38 on: March 10, 2016, 03:50:04 am »

was showing 80+psi @2500rpm warm
Baz, put your mechanical aptitude cap on and think about what this is telling you.
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baz
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« Reply #39 on: March 10, 2016, 06:57:35 am »

Hmmm I'd probably tap the gauge a couple of times with my finger tips to see if it changed, if that didn't fix it then scratch my head for a bit whilst wearing a puzzled expression on my face. Oil too thick?  Blockage somewhere in the case?

That's pretty much the extent of my mechanical aptitude Wink
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judgie
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« Reply #40 on: March 10, 2016, 09:15:42 am »

re; the oil pressure. Have just finished a rally car build with a hot 1600 in it which has similar oil pressure but has had a few mods done to increase the low rpm pressure which will also increase high rpm pressure. As i did not build this engine I did not know if any internal mods had been done to the oil system.
now the engine is apart we can see why the oil pressure was so high.
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baz
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« Reply #41 on: March 10, 2016, 19:35:03 pm »

The guy who built it when questioned on the bearing feed to oil gallery overlap said "thats normal and never had a problem before" 
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Bruce
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« Reply #42 on: March 10, 2016, 21:54:58 pm »

Oil too thick?  Blockage somewhere in the case?
Both.
The blockage is the entrance to the bearings.  When the entrance is tight, it causes the oil to pile up at the entrance resulting in high oil pressure.  IOW, oil is not getting into the bearings.  That is what the high oil pressure reading is telling you.
A lot of guys say the engine has good oil pressure when the reading is high.  I say the opposite.  High pressure is bad.
If you switch to lower viscosity oil, it will be better able to enter the bearings.  Causing less back pressure and more flow through the bearings.
That is why low oil pressure is GOOD!
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baz
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« Reply #43 on: March 10, 2016, 22:31:12 pm »

Makes sense to me, we'll try a lighter oil next time and judgie is gonna make sure I get best possible flow path to the bearings too.

Thanks
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spanners
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« Reply #44 on: March 10, 2016, 22:47:31 pm »

.  I say the opposite.  High pressure is bad.
If you switch to lower viscosity oil, it will be better able to enter the bearings.  Causing less back pressure and more flow through the bearings.
That is why low oil pressure is GOOD!

This ^^^^^^^^^. Too much pressure is bad, but what is too little?  The race engine norm of 10psi per 1000 rpm is fine to a point, but over 80psi is costing power and getting near bearing wash territory, a high mileage race motor may well perform at its best with a hot maximum of 35/40 psi at 7000 rpm, my Wasser runs 60/70psi at 7000 hot on millers 20/60, too high, I'm dropping grade this season to a 10/40, I'll be aiming to run it at 50psi hot, volume over pressure any day.
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Best regards, spanners.
dragvw2180
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« Reply #45 on: March 11, 2016, 00:03:00 am »

Here is a general bearing clearance vs oil viscosity chart , hope it helps , Mike

Here are some recommended rod bearing oil clearances for various oil viscosities:

.0015 to .0018 for 5W-20 or 20W

.002 to .0024 for 5W-30 or 30W

.0025 to .0029 for 10W-40 or 40W

.0030 to .004 for 20W-50 or 50W

.0041 to .005 for 10W-60 or 60W

For main bearings:

.0015 to .002 for 5W-20 or 20W

.002 to .0025 for 5W-30 or 30W

.0026 to .003 for 10W-40 or 40W

.0031 to .0041 for 20W-50 or 50W

.0042 to .0052 for 10W-60 or 60W
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1946vw
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« Reply #46 on: March 11, 2016, 18:25:49 pm »

Clearance changes with journal size.
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baz
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« Reply #47 on: March 12, 2016, 11:17:59 am »

Can anyone help identify a rod bearing from this part number?
0111 COC 13452 STD
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judgie
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« Reply #48 on: March 12, 2016, 11:20:25 am »

0111coc 1345z std
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baz
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« Reply #49 on: March 12, 2016, 11:23:02 am »

0111coc 1345z std

Must have your glasses on this morning Rob?   Tongue.

Cheers
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hotstreetvw
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« Reply #50 on: March 12, 2016, 15:02:05 pm »

I've been reading through this thread and I just had to get out of the bed and compare a Chevy bearing to a VW journal.

There is no "snaps into place" with this combination.


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baz
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« Reply #51 on: March 12, 2016, 15:23:57 pm »

It's unbelievable that someone could fit that thing and think it looks ok. I reckon my bearings must be vw and have just been damaged through oil starvation.

Do you know what brand those bearings are?  Any part number on the back?

I've been searching everywhere for info on the number posted above and cannot find anything. I think they are silverline brand, can't be 100% though as its over a year since i bought them.
« Last Edit: March 12, 2016, 15:29:17 pm by baz » Logged

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hotstreetvw
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« Reply #52 on: March 12, 2016, 15:30:31 pm »

They are Clevite bearings, CB-610P (STD) on the underside of the bearing.

I couldn't find the part number you posted either.  Did you buy the bearings?  Your engine builder provide?
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hotstreetvw
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« Reply #53 on: March 12, 2016, 15:31:51 pm »

I agree, they don't even remotely lock in place.  It would be a giant PITA to keep all that shit together to install the rods.
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baz
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« Reply #54 on: March 12, 2016, 15:38:49 pm »

I'm pretty sure I bought them, but like I said it's been over a year and I can't be 100% sure.

There is something Rob mentioned when we were stripping the engine, he mentioned it looked like the bearings had picked up mid way and not at the split where he said they normally do. It's possible they were stretched on install to better fit the rods, hence being tight at 90 degrees to the split.

Hopefully the numbers will say for sure either way
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hotstreetvw
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« Reply #55 on: March 12, 2016, 15:45:46 pm »

I think its very unlikely these are not "VW" bearings.  It should be slightly larger than the rod cap like others have mention, then "crush" when the rod is bolted together.

I would lay the bearing on its side and trace it onto a piece of paper and then measure the width.  Does the arc length match that of a stock bearing?  If it doesn't, the width better have increased, other wise where did all that material go?  into the oil...maybe, but unlikely.
« Last Edit: March 12, 2016, 15:50:41 pm by hotstreetvw » Logged
baz
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« Reply #56 on: March 12, 2016, 15:53:13 pm »

I left all the parts with Rob,  I'll ask him to send me the scrap bearings and measure them like you say.

There was a lot of bearing material in the oil.

Cheers
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spanners
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« Reply #57 on: March 12, 2016, 18:21:22 pm »

 They look like Porsche 53mm shells in both dia' and width. Still fails the common sence test.. Perhaps the Porsche name would fix the cock up automatically.
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richie
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« Reply #58 on: March 12, 2016, 22:17:49 pm »

Part number I got off VW journal Silverline is 0111COC2414B STD without my glasses on Wink so not sure what those are

cheers Richie
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baz
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« Reply #59 on: March 12, 2016, 22:43:45 pm »

Thanks Ritchie.

I can concentrate soley on silverline part number searches now as the numbers are so close that mine have to be silverline.

So is it likely that these are not vw journal if the numbers don't match? 
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