Help needed, newly rebuilt engine, now have lots of blow by.

[Brad S.]

Finally got this engine all put back together as of the end of May, seemed like everything was ok, (outside of needing a new IP) now I'm getting mega blow by. (almost the same from before the rebuild)

After I was back on the road, did the normal,"drive it hard to break in routine" what some here have said a rebuild motor should have.
I just changed oil for the 3rd time since start up.
Have about 2000-2500 miles on motor.
Switched the CDR valve, but with the amount of pressure coming from crankcase, don't think the CDR is to blame.
Over this last weekend,drained the oil, pulled all the GP's and pumped in about 2 qts, divided out between all cylinders, of diesel fuel. Every morning and evening turning the engine by hand, forward and backwards.
Most of the fuel ended up in the drain pan after the fact, I measured it out from the drain pan.
Monday night with Gp's all out spun the engine with starter, to make sure it was clear.
This took place from Friday night-fill up to Monday night -restart.---no difference on blow by

When I first got it all together and driving had very little if no BB.
I've narrowed it down to a few things I think it could be.
About a month ago some friends of ours said they use a deep fat fryer and have some oil to get rid of, I said no problem I could use that.
First possible cause??
This probably was no more then a gallon. So I filtered it, took about half of that and run it with a tankful of regular diesel.(Don't think this would be enough to cause stuck rings on a cylinder....but maybe??)
Second possible cause??
The other 2 quarts I put in a batch of wmo that I run through my CF, filters and into my heated tank, have only burned about 10 gallons of that wmo tankful.(Another possible problem area...???)
If I have some stuck rings, is a auto RX time, or some other item to clean things up??
If my rings have not seated, is there a way to get them to seat???
My next step is doing a compression check on the engine to find some problem areas..
So let me know what you think, questions, comments or general direction I can go. Thanks

 

[riotwarrior]

My first and only question is the engine REBUILT or OVERHAULED??

My understanding is rebuilt entails squared bores and new pistons and rings aka bored over to true any taper etc.

Overhauled is frezh rings old piztons and checked bores?

Second queztion

What rings did you use and did uou match the grit of hone and cross hatch pattern to the ring type?

Report back

 

[icanfixall]

Very good questions Al.. Add this note. There is no way possible to have broken in the rings to the bore in just a small amount of miles you have put on this engine. The least you are going to see works is about 5000 miles. Now no amount of city driving will break in the rings to cylinders... EVER. If anything driving in traffic carefully like an egg is under your throttle peddle will build up varnish on the rings and cylinders. Then your looking at very possibly 15,000 miles to break in the rings. You need to keep the rings hot enough to burn off any oil buildup. Adding a ton of weight to the bed works well for this. Another great idea is to be in first gear and speed up. Then let off and feel the engine slow down. This heats up the rings and burns off the varnish. This takes many hours to do. So speed up and back off constantly to work both sides of the rings on the cylinders. Lugging the engine will only heat it up and then you create other issues. Find a long grade and run up and down it hauling a load in the bed or towing something. Even a bed full of dirt works great and its usually free conpared to towing something.

 

[Brad S.]

Machine shop did the boring etc.
Mahle pistons with their chrome moly rings.
I would doubt very highly the machine shop did things wrong.
This shop and the guys that run it have been around long time 30+ years.
For instance, one time I stopped they were working on a crankshaft from a old & rare tractor.(don't remember what kind) Four cylinders, it was 6-8 ft long, from PA, truck shipped to them in Tea SD, or Sioux Falls SD. J & L Premier Automotive.

So Gary would constant driving like what your recommending, help seat the rings, and using a "flush" of some kind when changing oil speed up the seating process???

Part of the problem, my daily "commute" is mostly high way driving, with one town in the middle of 30 miles of driving.
Also, would downshifting and letting the engine rev up help this???

Thanks Al & Gary

 

[cpdenton]

Isn't there a gauge you can put on an engine to test the actual amount of blow-by?

I really need to test my truck too.
Mine appears horrible at idle, but backs off a lot when revved up.


And if there is, what is the factory spec on it?

 

[franklin2]

Did you assembly it yourself? After rebuilding 5 or 6 engines I found out from my last machine shop guy I used I was making a big mistake. I was honing the cylinders, wiping them clean with a rag, oiling the pistons and putting it together. On this last engine I went to a different guy and I told him it seemed each time I did a engine it took a month or so of driving it before it would quit smoking and "break in". He asked me was I cleaning the cylinders before I assembled them and of course I said yes. He then asked when I was turning the engine as I was assembling it was I getting a swooshing noise when I turned it. I said yes, he then quickly said I was not getting the bores clean enough.

He told me to take soap and water(which I never did) and clean them, and then clean them again and then again. And then take a piece of tissue paper and wipe the cylinders, if the tissue paper had any black on it, clean them again. He said I could also use tissue paper and transmission fluid, and keep wiping and wiping till the tissue was clean on all cylinders.

This last engine he cleaned them for me, and then I checked them and they were super clean. This engine did not have any sort of break-in problems, no smoking or oil use. Learned a valuable lesson from a old timer.

 

[riotwarrior]

Need I say this again???


BETTER THAN SURGICALLY CLEAN FOLKS......CANT SAY IT ENOUGH....BETTER THAN SURGICALLY CLEAN

JM2CW BWTFDIK

 

[chris142]

All you can do now is to load it up with a trailer and go up hill

 

[stealth13777]

If you put it together yourself, are you absolutely, 100% certain the rings are facing the right direction? They have a specific direction that is hard to see but can cause big issues (compression rings though; the oil rings pretty much only go the way they go). Just an idea. Worse to not know what's wrong in my mind, even if that scenario would suck.

Weigh it down and do some hard 2nd gear pulls and coast downs. Let the oil stay in it longer now that the initial dirt is out, imo changing it all the time isn't going to help much. Really run it for awhile (3-4k or more) and reevaluate. I'd want to fix it right away too, but really hard to say if you actually have an issue.


Sent from my iPhone using Tapatalk

 

[IDIoit]

I would doubt very highly the machine shop did things wrong.
This shop and the guys that run it have been around long time 30+ years.

remember, to error is human.
which we all are.

question everything, and then inspect.
when someone has been doing something for so long, its VERY easy to make a simple mistake.

hope you get this taken care of.

 

[BDCarrillo]

Did they have your new pistons on hand? Are the rings the correct oversize? (You can fit regular rings on a 30 over piston!)

Did you measure piston ring end gap?

The oil control ring SHOULD have stopped the diesel from running down into your oil pan... And those ones don't really "break in" like the compression ring. That's what makes me think the ring set may have been the wrong size...

OR the bores are too large. Piston ring end gap should have revealed that

 

[typ4]

First, lets assume its assembled correctly.
Second, you are changing the oil too much.
Stop putting things in it till you find the problem.
You have to load these up, hard work and heat is your friend. You dont have stuck rings. And as Gary said 5k is a minimum to get a seal unless you do special things on rebuild. Not going into that here.
I put a camper on my truck and went from Oregon to Wisconsin 2 days after fire up. It has little blowby and uses no oil in 5k, no special tricks as I have learned much since that one.

 

[Brad S.]

So is it common for these engines not have any blow by right after start up, then after a 500-1000 miles put on then blow by starts happening??

The oil change frequency was something I took from here (OB) about getting rid of machining leftovers....???

 

[sjwelds]

So is it common for these engines not have any blow by right after start up, then after a 500-1000 miles put on then blow by starts happening??

My question exactly...Now if it'd been having lots of blow-by all along, I could see how maybe it isn't broke in yet, but to go from none, to lots .. ?????

 

[riotwarrior]

So is it common for these engines not have any blow by right after start up, then after a 500-1000 miles put on then blow by starts happening??

The oil change frequency was something I took from here (OB) about getting rid of machining leftovers....???

I am a huge fan of of the following oil/filter change for remanned engines.

20 min break in oil change
500 mile oil change

1500 mile oil change
regular oil change

It was what I was taught and with good reasoning to which here I wont discuss.

Load it good however do not let idle much. Some variation in RPM as well do not set it and forget it....

Vary the RPM and intensity of driving but get heat into that engine.