Disaster Strikes; What went wrong?

[Rich76_911s]

Originally Posted by Neil Harvey

Some advice that may clear your mind.


Go slow and look forwards not backwards.

Thanks Neil for your whole post. A lot of information to absorb there, and I can assure you I'll be referencing that one frequently.

[Rich76_911s]

Originally Posted by bpu699

So sort that happened to you...

Random thought...

The wear on the thrust bearing and ims suggests your case halves weren’t sling or set perfectly...

To be honest, I don’t think Porsche cases are machined perfectly.

When I took my virgin case apart, my ims bearing had wear on the mirror side flanges. So, from the factory, the ims bearing wasn’t sitting exactly right. The wear was significant. Yet, the thrust bearing flanges were just fine. Motor was fine ran well...

It looks like you had stuff inside your crank if the main bearings are shot...

The ims bearings sold now, in my humble opinion, are crap. The new ones I bought measured thinner than the ones I took out. Had to buy the Porsche item.

What brand were your main bearings? Glyco?

You also coated the bearings, as did I. The coating won’t absorb debris like the original ones do. It’s not designed to do that. So even small amounts of debris will scratch the bearing...

Thanks for your thoughts in regards to the case. It will have to be closely checked.

Yes, I think I had Glyco IMS bearings. (I thought this was something only boxster and 996 guys had to deal with) They were the only bearings not coated.

I'm only bummed I waited so long to just tear it down. Now it's just upward and onward.

[bpu699]

The new picks show tons of wear on your thrust bearings... that seems awfully odd?

Could the Teflon coating from the thrust bearings be the debris that went through the motor? The coating seems to soft to do that, but perhaps the experts can chime in...

Did your crank spin freely in the case when torqued down without the pistons in it? Did the ims shaft?

Can you take the plugs out of your crank and see if any debris is in there?

When we all work on these motors, we do our best, to the point of paranoia. I measured everything 10x, as I am still reassembling my motor. You do the best you can. Sometimes things just happen.

[boosted79]

Was the crank end float checked during assembly?

Also, was the case abrasive blasted?

[bpu699]

Originally Posted by boosted79

Was the crank end float checked during assembly?

Also, was the case abrasive blasted?

Curious, how would one adjust the end float? It’s set by the thrust bearing thickness...

You really don’t have much ability to slide the case halves as they are pinned...

[boosted79]

Assemble just the crank into the case with the new bearings with a little oil. Torque the thru bolts. Give each end of the crank a good wack with a rubber hammer. That makes sure the the thrust flanges are tight to the case and the thrust faces even. Then check the float. Make sure the #1 shells stay in their respective side after this. I have seen this bring a tight #1 into tolerance. If the float is too much to begin with then there are other problems.

If Porsche wanted 574 on the webs they would have done it at Stuttgart, just MHO. If you are worried about shuffling have the cases pinned or send them to cgarr.

[Mark Henry]

Originally Posted by bpu699

Could the Teflon coating from the thrust bearings be the debris that went through the motor? The coating seems to soft to do that, but perhaps the experts can chime in...

The coating is DFL not teflon, graphite is a main componente, even if it was poorly applied and came off it wouldn't do that damage as it's too soft.
One thing I don't like is it looks like the bearing backs and part lines were also coated which for me is a no-no. Also the coating must be lightly burnished with 800g scotch bright pad once baked as they do add a hair to the dimension.
BTW I do DFL coatings in house, during testing I found unburnished or coating applied too thick will lock up the crank on assembly, so proper processing is very important. Whether I'm using DFL or not, during engine assembly I'm always spinning the crank to be sure the assembly is rotating smoothly. I agree no sealant on the saddle part lines.

There was trash in the system somewhere, I can't see it coming from the scavenge side as the tank filter would catch that. It came from the tank/return hose or something was missed cleaning the case, cooler, some flashing came loose, etc.

[Catorce]

I actually make an oil filter console that is better than the 993 one. I have one on my own 930 motor. Check out the site in my signature,

However, pressure side oil filtration is NOT your problem here.

[Rich76_911s]

Originally Posted by bpu699

The new picks show tons of wear on your thrust bearings... that seems awfully odd?

Could the Teflon coating from the thrust bearings be the debris that went through the motor? The coating seems to soft to do that, but perhaps the experts can chime in...

Did your crank spin freely in the case when torqued down without the pistons in it? Did the ims shaft?

Can you take the plugs out of your crank and see if any debris is in there?

When we all work on these motors, we do our best, to the point of paranoia. I measured everything 10x, as I am still reassembling my motor. You do the best you can. Sometimes things just happen.

The wear on the thrust bearing seems crazy for 500 miles. The teflon coating (or whatever it is) wears off and is almost like a paste. I don't think it would have damaged the internals, but will defer to those that know more than I do.

Yes - crank rotated perfectly fine at all points, even on disassembly.

Yeah I did a lot of measuring, though it may not seem like it now. Since my measurement techinque isn't up to professional standards I usually measured and noted all measurements 5-6x, drop the highest and lowest and average what remained. Don't want you guys thinking I just slapped this thing together in some mad dash.

I did rely on the machine shop for the bore dimensions because I didn't have a bore gauge. <- this may have to change.

Here's and example of my measurement notes on the crankshaft:


And I'm a checklist manifesto type so I basically did waynes book in word as a checklist and checked everything off as I went.

[Rich76_911s]

Originally Posted by boosted79

Was the crank end float checked during assembly?

Also, was the case abrasive blasted?

No the case was not media blasted at all. According to the notes from the machinist it was first pressure wased, then All oil galley plugs were removed and all oil passages were cleaned with high pressure hot water and detergent rinsed and blown out with air. make and install new oil galley plugs with loctite - pressure check all oil squirters"

They did assemble the case and measure the main bearing bores. They noted that some were big by .0005 inch (1/2 thousandth) other bores are Very Good most are .002 - .003 big.

They did machine the cylinder mating surface .004 inches due to some damage done by the #6 cylinder's broken headstud.

Also just for reference they did measure the crankshaft from the flywheel and these are the measurements of main bearings:
#1 - 2.3611
#2 - 2.3611
#3 - 2.3611
#4 - 2.3611
#5 - 2.3612
#6 - 2.3612
#7 - 2.3611

Rods were measured as follows:
#1 - 2.1644
#2 - 2.1644
#3 - 2.1644
#4 - 2.1644
#5 - 2.1644
#6 - 2.1642

[Rich76_911s]

Originally Posted by Catorce

I actually make an oil filter console that is better than the 993 one. I have one on my own 930 motor. Check out the site in my signature,

However, pressure side oil filtration is NOT your problem here.

That is a thing of beauty, thank you!

[Rich76_911s]

Originally Posted by Mark Henry

The coating is DFL not teflon, graphite is a main componente, even if it was poorly applied and came off it wouldn't do that damage as it's too soft.
One thing I don't like is it looks like the bearing backs and part lines were also coated which for me is a no-no. Also the coating must be lightly burnished with 800g scotch bright pad once baked as they do add a hair to the dimension.
BTW I do DFL coatings in house, during testing I found unburnished or coating applied too thick will lock up the crank on assembly, so proper processing is very important. Whether I'm using DFL or not, during engine assembly I'm always spinning the crank to be sure the assembly is rotating smoothly. I agree no sealant on the saddle part lines.

There was trash in the system somewhere, I can't see it coming from the scavenge side as the tank filter would catch that. It came from the tank/return hose or something was missed cleaning the case, cooler, some flashing came loose, etc.

Right on thanks for the data on the DFL coating. I went and checked and the backs of my bearings weren't coated, part lines were. But I did not use 800g scotch pad on them before installation.

[bpu699]

Originally Posted by boosted79

Assemble just the crank into the case with the new bearings with a little oil. Torque the thru bolts. Give each end of the crank a good wack with a rubber hammer. That makes sure the the thrust flanges are tight to the case and the thrust faces even. Then check the float. Make sure the #1 shells stay in their respective side after this. I have seen this bring a tight #1 into tolerance. If the float is too much to begin with then there are other problems.

If Porsche wanted 574 on the webs they would have done it at Stuttgart, just MHO. If you are worried about shuffling have the cases pinned or send them to cgarr.

You hit it with a mallet AFTER torqueing down??? Would the bearings even move any at that time???

Hmmmm.... I didn't check end float, but everything spun freely

Any benefit to still wacking it to align it? case is together awaiting cam regrind...

[bpu699]

Originally Posted by Mark Henry

The coating is DFL not teflon, graphite is a main componente, even if it was poorly applied and came off it wouldn't do that damage as it's too soft.
One thing I don't like is it looks like the bearing backs and part lines were also coated which for me is a no-no. Also the coating must be lightly burnished with 800g scotch bright pad once baked as they do add a hair to the dimension.
BTW I do DFL coatings in house, during testing I found unburnished or coating applied too thick will lock up the crank on assembly, so proper processing is very important. Whether I'm using DFL or not, during engine assembly I'm always spinning the crank to be sure the assembly is rotating smoothly. I agree no sealant on the saddle part lines.

There was trash in the system somewhere, I can't see it coming from the scavenge side as the tank filter would catch that. It came from the tank/return hose or something was missed cleaning the case, cooler, some flashing came loose, etc.

I wonder if we are thinking of the same coating? Will need to find my old threads. There were lots of posts about sending your bearings to places that do dragsters/race cars/etc, as it tightened up clearance and was very "slippery" to avoid bearing damage if the oil film was transiently too thin. This was meant as a long term coating, not something that wears off immediately.

I agree, it isn't hard at all...

I know the coating places advertise its like Teflon... Cant remember where I sent it too, but it was highly recommended by the engine builders on this forum...

I think we are talking about the same thing...

They coated the front of the bearing AND the parting line, but not the back...

[bpu699]

Originally Posted by Mark Henry

The coating is DFL not teflon, graphite is a main componente, even if it was poorly applied and came off it wouldn't do that damage as it's too soft.
One thing I don't like is it looks like the bearing backs and part lines were also coated which for me is a no-no. Also the coating must be lightly burnished with 800g scotch bright pad once baked as they do add a hair to the dimension.
BTW I do DFL coatings in house, during testing I found unburnished or coating applied too thick will lock up the crank on assembly, so proper processing is very important. Whether I'm using DFL or not, during engine assembly I'm always spinning the crank to be sure the assembly is rotating smoothly. I agree no sealant on the saddle part lines.

There was trash in the system somewhere, I can't see it coming from the scavenge side as the tank filter would catch that. It came from the tank/return hose or something was missed cleaning the case, cooler, some flashing came loose, etc.

I wonder if we are thinking of the same coating? Will need to find my old threads. There were lots of posts about sending your bearings to places that do dragsters/race cars/etc, as it tightened up clearance and was very "slippery" to avoid bearing damage if the oil film was transiently too thin. This was meant as a long term coating, not something that wears off immediately.

I agree, it isn't hard at all...

I know the coating places advertise its like Teflon... Cant remember where I sent it too, but it was highly recommended by the engine builders on this forum...

I think we are talking about the same thing...

They coated the front of the bearing AND the parting line, but not the back...

[boosted79]

Yes, after it is torqued. This makes sure the thrust flanges are even at the mating line of the shells by deforming the flange that is not even with the other flange. The crank will still turn if the float is less than spec but it will not have the proper clearance to allow oil between the crank and the #1 thrust surfaces. Minimum float is 2.8 thou.

[bpu699]

Originally Posted by boosted79

Yes, after it is torqued. This makes sure the thrust flanges are even at the mating line of the shells by deforming the flange that is not even with the other flange. The crank will still turn if the float is less than spec but it will not have the proper clearance to allow oil between the crank and the #1 thrust surfaces. Minimum float is 2.8 thou.

Thanks... guess I can still do that. Will do!

DO you do the same to the IMS shaft bearing?

[nocarrier]

I didn't notice any mention of pulling the plug and flushing the intermediate shaft.

[nocarrier]

This is how much gunk came out of one.

[Bigtoe32067]

I have nothing constructive to add other than offer my condolences and my wishes that you get it resolved without too much more pain and struggle.
Tony