Engine Rebuild Vs. New turbo

AngM018 · 10-26-2007, 02:14 PM

I heard a rumor that it is a bad idea to run a new/good turbo when breaking in a freshly rebuilt engine. The reason being, metal shavings go through the oil supply and could destroy the seals etc.

Anyone have any experience with this? Will I be ok to run my new turbo (k27HFS), or would it be best to salvage my old K26 until the break it is completed (turbo is in ruff shape)

Thanks for any advice you can give!

DonE · 10-26-2007, 03:32 PM

You heard wrong - typical rumor. If the engine were built correctly, there shouldn't even be dust left over from the rebuild. Put it all together and go have fun.

JimCulp · 10-26-2007, 03:42 PM

It's possible for slag from the header welds to come loose and go through the turbo- that's the reason for not running a new turbo on a fresh engine. Just be sure to clean the inside of the headers (if new) really well and you should be fine. I was going to run my old K26 on my rebuilt engine, but it turned out to be a PITA to mount everything for the K26, so we just cleaned everything really well and used the HFS straight out- so far so good.

sand_man · 10-26-2007, 04:14 PM

...been waiting for this one to show up, John! As I mentioned to you before, I only mentioned it to cover all the bases. I remember when A 930Rocket first took a spin around the block in his fresh rebuild, complete with HFS turbo and he roasted that damn thing in short order, FOD style! I remember from few replies that he got on Rennlist that it wasn't the worst idea to intsall a "less important" turbo for break-in!

sand_man · 04:25 PM

Here is the thread...and I mention it to you only because I know you are running different headers (see Kevin's response some where on page 2 or 3)
http://forums.rennlist.com/rennforums/showthread.php?t=309639

AngM018 · 10-26-2007, 04:56 PM

I bought the headers used, so any slag should hopefully be worked out of them by now. I am just worried about anything going through the oil line. I think I might just have to cross my fingers and see what happens, b/c it would be a PITA to get the turbo off the old headers, then swap it out with the HFS which is already installed.

DonE · 10-27-2007, 04:25 PM

I have to say, this is an odd discussion. John, you are worried about crap in the oil system that could make its way to the turbo, and destroy the seals. What about the same crap getting into the main and rod bearings? The cam journals or cam itself? Wouldn't you be more concerned about damaging the entire engine?

Now we are talking about crap in the exhaust circuit going through the turbo. For your info, I've had a piston melt and go through the turbo - no damage, only specks of aluminum but that was removed with Easy Off oven cleaner. This isn't to say FOD can't damage the turbo, so I would make sure the circuit is clean when you put it together.

ayglass · 10-27-2007, 04:30 PM

I suggest you make sure that oil exiting the turbo is filtered before returning to the oil system. I just replaced some cams because of what I believe to be coke from the turbo bearings. It's not a break-in issue so much as a turbo oiling design issue. Poop in your oil from any source is a *bad* thing.

A930Rocket · 10-27-2007, 05:29 PM

That turbo had 22 miles on it with no boost. It was FOD from a new set of headers. I would use an old turbo to break in the engine just to be on the safe side. There was nothing to salvage but the center section.

NathanUK · NathanUK's Garage

I have my old 3LDZ on my new GHL headers. I will fit the K27HFS at a later date.

DonE · 10-28-2007, 06:07 PM

Quote:

Originally Posted by A930Rocket

That turbo had 22 miles on it with no boost. It was FOD from a new set of headers. I would use an old turbo to break in the engine just to be on the safe side. There was nothing to salvage but the center section.

If you don't mind, what brand of headers did this come from?

Craig 930 RS · 10-30-2007, 07:12 PM

New engine, new turbo, why not? On the other hand, what is there to lose by using an old turbo...
Kevin had no warnings against this in my case.

Newly repaired headers, me no weld cleanup, stupid owner, look what happened to here to my turbo:

pdqcarrera · pdqcarrera's Garage

This is why I'm having an inline filter installed before turbo.
Cheers!

sand_man · 10-31-2007, 10:55 AM

Quote:

Originally Posted by pdqcarrera

This is why I'm having an inline filter installed before turbo.
Cheers!

I'm actually planning to install a filter AFTER the turbo, but before the scavenge return line hits large oil tank.

Lots of talk here:
Clogged Spray Bar autopsy

AngM018 · 10-31-2007, 11:09 AM

Since my headers already have some miles on them, I am just going to leave the new turbo on there. Right now my rebuild is held up once again, b/c of the oil line going to the t-stat. Luckily I picked one up from a fellow pelican and will be here tomorow. crossing fingers for the start up this weekend...

A930Rocket · 10-31-2007, 06:22 PM

GHL. In their defense though, I had my ignition timing off and it was retarded. The headers were starting to glow, something probably got hot and fell off inside. Because I was just cruising, I didn't think about it until later and re-set the timing when all was back together.

Hard to believe I can rebuild the engine and screw up the ignition timing...

Quote:

Originally Posted by DonE

If you don't mind, what brand of headers did this come from?

les_garten · 01-02-2008, 03:19 PM

Quote:

Originally Posted by A930Rocket

GHL. In their defense though, I had my ignition timing off and it was retarded. The headers were starting to glow, something probably got hot and fell off inside. Because I was just cruising, I didn't think about it until later and re-set the timing when all was back together.

Hard to believe I can rebuild the engine and screw up the ignition timing...

I'll submit this respectfully here. If you read Wayne Dempsey's book, he explains that the first few Oil dumps will look like you are panning for gold if you look at the oil carefully. He's right. It goes on for a few hundred miles. I'm sure lots of it is off the rings. There are lots a metal fragments for the first 4 or 5 oil changes if you do it like Wayne suggests. Whether this targets the turbo for attack more than anything else is I'm sure where this discussion stemmed from.

Moral to the story, look at your first 4 oil dumps and you'll be a little queasy.

Les

NathanUK · NathanUK's Garage

The wheels of the turbo can only be damaged by foreign objects in the air ways (unless the bearings get wiped out).

pdqcarrera mention a filter, I take it he meant a air filter/screen?

les_garten · 01-03-2008, 01:02 PM

Quote:

Originally Posted by NathanUK

The wheels of the turbo can only be damaged by foreign objects in the air ways (unless the bearings get wiped out).

pdqcarrera mention a filter, I take it he meant a air filter/screen?

Hi Nathan,
I think they are talking about engine break in frags in the oil. Stuff coming into the airstream will cause issues on a new engine or old engine, ehhh? He's talking about putting in an inline oil filter i believe in the Turbo feed line.

Les

NathanUK · NathanUK's Garage

The oil going to the turbo will come from the engine which should be fresh oil from the oil tank.

All the oil is filtered before going back into the tank from the engine. The exception is the oil from the turbo. It seems on all but the very early cars the oil from the turbo is not filtered when it comes out of the turbo and then gets pumped back into the tank.

Both the oil tank & the engine should have been cleaned during the rebuild.

I don't see any harm in fitting oil filters before and after the turbo providing they are cleaned on a very regular basis.