: bbob - Correct Crank Scraper/Placement



dloch
03-22-04, 11:09 PM
Is this correct crank scraper placement? It almost looks like it should have been between the bolt heads and the oil manifold to me.

This is the bottom of that block that I have

BeelzeBob
03-23-04, 02:48 PM
Is this correct crank scraper placement? It almost looks like it should have been between the bolt heads and the oil manifold to me.

This is the bottom of that block that I have


I think you are correct. Where did you get that mismatched bunch of junk...LOL.

The clue is the oil distribution plate that is on the block. The one you have does NOT have the steel reinforcement washers cast into it that are absolutely REQUIRED for the main bolts to bear directly against it. On the other hand.....why are there all those stud headed main bolts....???? There should only be one if the engine was originally built with that oil distribution plate.....

An early oil distribution plate designed for use with the main bolts installed directly against it (like your picture shows) would have steel reinforcement "washers" csst into the plate instead of the oval, raised areas that the main bolts bear on. Those oval areas held the oval, two hole, load bearing "washers" in the early design engines. When the design was changed those areas just became aluminum to keep the same bolt length. In the later design, such as the distribution plate you have, the aluminum oval areas were covered by the steel oil scraper plate BEFORE the main bolts were installed. In this later design the steel oil scraper plate acts as the load bearing washer for the main bolts....so your setup there should have the oil scraper plate underneath the main bolts to prevent the oil distribution plate from cracking or recessing under the load of the mains bolts.

The early system put the main bolts directly against the cast-in steel washers in the oil distribution plate and the 10 stud headed main bolts were used. The stud headed mains were used to then mount the oil scraper tray using nuts. The older, original design oil scraper tray had only 10 mounting holes....not the 20 like yours does. Yours is designed to go under the main bolts and the "extra" ears sticking out pickup the outer main bolts to act as the load bearing area/washer for the main bolts on the outside.

It is no big deal, really, as the stud headed bolts just go along for the ride and the stud headed main bolts will function fine if installed thru the oil scraper plate. In fact, you still need one of them to mount the oil pickup.


Hopefully this rambling makes sense.....LOL

dloch
03-23-04, 04:03 PM
I think you are correct. Where did you get that mismatched bunch of junk...LOL.

The clue is the oil distribution plate that is on the block. The one you have does NOT have the steel reinforcement washers cast into it that are absolutely REQUIRED for the main bolts to bear directly against it. On the other hand.....why are there all those stud headed main bolts....???? There should only be one if the engine was originally built with that oil distribution plate.....

An early oil distribution plate designed for use with the main bolts installed directly against it (like your picture shows) would have steel reinforcement "washers" csst into the plate instead of the oval, raised areas that the main bolts bear on. Those oval areas held the oval, two hole, load bearing "washers" in the early design engines. When the design was changed those areas just became aluminum to keep the same bolt length. In the later design, such as the distribution plate you have, the aluminum oval areas were covered by the steel oil scraper plate BEFORE the main bolts were installed. In this later design the steel oil scraper plate acts as the load bearing washer for the main bolts....so your setup there should have the oil scraper plate underneath the main bolts to prevent the oil distribution plate from cracking or recessing under the load of the mains bolts.

The early system put the main bolts directly against the cast-in steel washers in the oil distribution plate and the 10 stud headed main bolts were used. The stud headed mains were used to then mount the oil scraper tray using nuts. The older, original design oil scraper tray had only 10 mounting holes....not the 20 like yours does. Yours is designed to go under the main bolts and the "extra" ears sticking out pickup the outer main bolts to act as the load bearing area/washer for the main bolts on the outside.

It is no big deal, really, as the stud headed bolts just go along for the ride and the stud headed main bolts will function fine if installed thru the oil scraper plate. In fact, you still need one of them to mount the oil pickup.


Hopefully this rambling makes sense.....LOLIt makes sense to me..... It didn't look right too me either. When I put it back together I will do it the right way this time.

What else was funny.... well not that funny I guess... was the bolt and washer that hold the intermediate timing gear back against the front of the block was loose... like I took it off with my fingers.

I kind of agree with you about the mis-matched parts. Go back to the correct torque sequence post and look at the picture of the diagonal wall and the boss's that are there. I believe the boss is there, it's just not tapped for the knock sensor. Goto http://www.cadillacforums.com/forums/showpost.php?p=78151&postcount=11

I would sure like to know what the previous life of this motor was.... I know it's not an STS "9" motor I measured the intake lobe. The intake and exhaust are the same.

If I take the intake cams out of my current motor and put them in this one should I change the valve springs beforehand?

BeelzeBob
03-23-04, 11:24 PM
It makes sense to me..... It didn't look right too me either. When I put it back together I will do it the right way this time.

What else was funny.... well not that funny I guess... was the bolt and washer that hold the intermediate timing gear back against the front of the block was loose... like I took it off with my fingers.

I kind of agree with you about the mis-matched parts. Go back to the correct torque sequence post and look at the picture of the diagonal wall and the boss's that are there. I believe the boss is there, it's just not tapped for the knock sensor. Goto http://www.cadillacforums.com/forums/showpost.php?p=78151&postcount=11

I would sure like to know what the previous life of this motor was.... I know it's not an STS "9" motor I measured the intake lobe. The intake and exhaust are the same.

If I take the intake cams out of my current motor and put them in this one should I change the valve springs beforehand?


You should be able to drill and tap the boss for the knock sensor on that block. Use the same location as your 97 has when you pull the intake off to get the starter harness and such out.... It is one of the bosse on the side wall of the valley, though, not the one that is in the middle of the diagnonal wall.

The valve spring question depends on what the origin and year of the "extra" motor you have. The valve springs on the L37 engine were stiffer in the original Northstars back in 93. This was to allow the higher shift point that the 300 HP engines used. Interestingly the cam that goes into no follow the first is the exhaust cam....not the intake that is different between the two....as the exhaust cam is the more radical of the two interms of lift rate or acceleration of the valve. Anyway, the LD8 engine had slightly softer valve springs for less friction and better fuel economy. In 96 or 97 the valve springs were commonized to the stiffer L37 springs on all engines....the softer "LD8" springs were just canceled. So....the spare engine that you have may have the stiffer springs already...or maybe not. There was a wire diameter difference between the two so if you can measure the valve spring wire diameter on your 97 and compare you may not have to swap the springs. Changing the cams is pretty simple. Yes, just put the intake cams from your 97 engine into the spare engine and it will become an L37....the exhuasts do not need to be swapped as they are the same in both the L37 and LD8 from 93-99. There is some confusion always about this as the 2000 and later engines had both the intake and exhaust cams different between the L37 and LD8 engines...but the 93-99 only had the intakes different.

dloch
03-24-04, 10:03 AM
You should be able to drill and tap the boss for the knock sensor on that block. Use the same location as your 97 has when you pull the intake off to get the starter harness and such out.... It is one of the bosse on the side wall of the valley, though, not the one that is in the middle of the diagnonal wall.

The valve spring question depends on what the origin and year of the "extra" motor you have. The valve springs on the L37 engine were stiffer in the original Northstars back in 93. This was to allow the higher shift point that the 300 HP engines used. Interestingly the cam that goes into no follow the first is the exhaust cam....not the intake that is different between the two....as the exhaust cam is the more radical of the two interms of lift rate or acceleration of the valve. Anyway, the LD8 engine had slightly softer valve springs for less friction and better fuel economy. In 96 or 97 the valve springs were commonized to the stiffer L37 springs on all engines....the softer "LD8" springs were just canceled. So....the spare engine that you have may have the stiffer springs already...or maybe not. There was a wire diameter difference between the two so if you can measure the valve spring wire diameter on your 97 and compare you may not have to swap the springs. Changing the cams is pretty simple. Yes, just put the intake cams from your 97 engine into the spare engine and it will become an L37....the exhuasts do not need to be swapped as they are the same in both the L37 and LD8 from 93-99. There is some confusion always about this as the 2000 and later engines had both the intake and exhaust cams different between the L37 and LD8 engines...but the 93-99 only had the intakes different.
I ordered another knock sensor, I will get the tap size from it to drill and tap the boss valley like the engine in the 97. Is that boss an oil passage?

I will take one of the valve springs off and measure the open and closed force to see if they are close to the L37 specs. If they aren't, do you know of anyone in the aftermarket sells springs for a Northstar? Comp, Crane...

BTW I seperated the case halves, the mains look like the day the factory put them in. I don't believe I'm going to crack open a rod at this point after what the mains looked like. The reason for the split was I wanted to re-seal the case halves. What sealant or gasket maker is the same as the GM Sealant? I also like the way the lower case half is drilled for oil drain back from the heads... clever... That certainly helps reduce any windage loss from oil hitting the crank.

BeelzeBob
03-24-04, 11:05 AM
I ordered another knock sensor, I will get the tap size from it to drill and tap the boss valley like the engine in the 97. Is that boss an oil passage?

I will take one of the valve springs off and measure the open and closed force to see if they are close to the L37 specs. If they aren't, do you know of anyone in the aftermarket sells springs for a Northstar? Comp, Crane...

BTW I seperated the case halves, the mains look like the day the factory put them in. I don't believe I'm going to crack open a rod at this point after what the mains looked like. The reason for the split was I wanted to re-seal the case halves. What sealant or gasket maker is the same as the GM Sealant? I also like the way the lower case half is drilled for oil drain back from the heads... clever... That certainly helps reduce any windage loss from oil hitting the crank.

No oil passage at all in that area. All the oiling is in the lower crankcase. The oil passages are all cast into the lower surface of the lower crankcase and formed by the oil distribution plate when it is installed. The main oil passages are the channels cast into the lower crankcase surface and the oil plate is the "4th" side of the passage. The mains are oiled by the passage formed around the OD of the main bolts and the ID of the main bolt clearance hole. So, the only oil passage in the upper part of the block is the drilled passage at the very front that feeds the head on each side...nothing at all in the valley of the block.

Check the knock sensor threads carefully. I believe the early knock sensors were a small pipe thread and the later ones for the valley were a metric machine screw thread....not sure...my memory is a bit fuzzy on that at the moment.

Never, ever take a Northstar rod bearing apart unless you plan on replacing the bearings. You cannot reuse a rod bearing shell no matter how good it looks. They are crushed considerably upon assembly and once heated/used they bearing is set to that crush and will not have enough crush for dissassembly and reuse. Nature of the beast to handle 7000 RPM.....


Check with CHRFAB. I'm sure that Alan Johnson is building enough mod engines with hot rod springs that he can spare a set of production L37 springs...!!! Those are perfectly fine for your use in a production car. They are good for about 7200 with no problems with the production L37 cams so they will work fine. No problem with a used set. Just check them for load to make sure you have a complete set of the correct springs. The springs are an excellent quality, chrome silicon wire spring that don't fatigue or loose load with use with the production cams...they are probably "better" springs than any hot rod spring...just they are a little less design load than the racing springs to keep the cam lobes from wearing prematurely in normal high mileage use.

Use the red Loctite "gasket eliminator" to seal the lower crankcase in addition to the normal "spagetti" silicone seal that is laid in the groove on each side. To ensure a leak proof lower crankcase, slide the rear main seal into place onto the crank and into the installation land in the installed position BEFORE assembling the LCC to the block. Put a dab of RTV at the junction of the spagetti seal to the rear main seal to make sure that there is no gap in that area. Then install the LCC with the rear main seal in place. Much easier and no need to press it into place. This is a rare, bbobynski "do it like I say, not like the service manual" procedure....LOL

There was a tremendous amount of development work done on the oiling system to keep the drain back oil off the crank and eliminate windage loss and aeration of the oil... If you follow the oil drain back path from the heads to the pan the oil drain backs are a completely segregated path that returns the oil via the drain backs to the bottom of the pan below the oil level in the sump. The system is designed to accomodate a continuous 1G accelertion in any direction with the sump 2 quarts low and the engine at 6000 RPM. We ran the engine on a tilt stand at 6000 RPM for 60 seconds per run with the engine tipped 45 degrees sideways (both ways) and nose up and nose down to simulate a continuous 1G acceleration...like a 60 second continuous 1G corner....

I think that the engine you have probably has all those stud headed mains because there were a large quantity of the studheaded bolts in the plant when that changeover occurred (to the later style of engine that only used 1 stud headed bolt) so there were engines built with the stud headed bolts in the center position even though the stud head was not required.... I still can't explain why that block wouldn't have the knock sensor tapped though because if it were a 96 or later block then it would have the knock sensor in the valley....?????

dloch
03-24-04, 12:51 PM
[QUOTE=bbobynski]No oil passage at all in that area. All the oiling is in the lower crankcase. The oil passages are all cast into the lower surface of the lower crankcase and formed by the oil distribution plate when it is installed. The main oil passages are the channels cast into the lower crankcase surface and the oil plate is the "4th" side of the passage. The mains are oiled by the passage formed around the OD of the main bolts and the ID of the main bolt clearance hole. So, the only oil passage in the upper part of the block is the drilled passage at the very front that feeds the head on each side...nothing at all in the valley of the block.

Check with CHRFAB. I'm sure that Alan Johnson is building enough mod engines with hot rod springs that he can spare a set of production L37 springs...!!! Those are perfectly fine for your use in a production car. They are good for about 7200 with no problems with the production L37 cams so they will work fine. No problem with a used set. Just check them for load to make sure you have a complete set of the correct springs. The springs are an excellent quality, chrome silicon wire spring that don't fatigue or loose load with use with the production cams...they are probably "better" springs than any hot rod spring...just they are a little less design load than the racing springs to keep the cam lobes from wearing prematurely in normal high mileage use.

I'll give them a call after I check the ones I have.

Use the red Loctite "gasket eliminator" to seal the lower crankcase in addition to the normal "spagetti" silicone seal that is laid in the groove on each side. To ensure a leak proof lower crankcase, slide the rear main seal into place onto the crank and into the installation land in the installed position BEFORE assembling the LCC to the block. Put a dab of RTV at the junction of the spagetti seal to the rear main seal to make sure that there is no gap in that area. Then install the LCC with the rear main seal in place. Much easier and no need to press it into place. This is a rare, bbobynski "do it like I say, not like the service manual" procedure....LOL

QUOTE]

I though those bosses could have been an oil passage of some sort. But after looking at the oil manifold and the oil passages around the main bolts it should have dawned on me........... Are those bosses then from the forming of the block process?

I was going to ask you if I could install the rear main seal before assembling the LCC. It seemed to me that it would be much easier than pressing it in, altough I was concerned that it might alter the torque of the rear main bearing some what. Although having said that the concept of the intial torque is to get the slop out before twist the additional.... what 65 degrees?

Now another question, would it be acceptable to use a very thin layer of the red Loctite "gasket eliminator" to the oil manifold where it meets with the LLC on the pressure quadrate side of the manifold? That area looks like it could be potential leak area that could be thought of as a case half leak.
I bought most all of my gaskets and seals with the exception of the oil manifold, which was about $70+ if memory serves me correct.

The way the question and answers keep going back and forth this may turn out to be a long thread...... although I sure a number of other people can benefit from this information if they ever pull one of these motors apart.

FYI with the mis assembly of the order of the baffle/scraper and the bolts #4 main bolts weren't as tight as the others, it was tight but not as snap loose tight as the others. There was no appreciable witness marks of the crank spinning on the lower bearing shell.

BeelzeBob
03-24-04, 02:37 PM
Yes , you can use a thin skim of the loctite "gasket eliminator" on the oil distribution plate surface.


There are several bosses on the block that are "contingencies"....LOL when you design and make a die large enough to cast a block you always put in some 'extra" bosses and such in places where you think you might need them. Sometimes bosses are added as fills and chills to control the shrink of the metal cooling in the die and control porosity in the metal. Those can be cut off, machined away or just left depending on where they are. The bosses in the valley were purposefully put there for future use.

dloch
03-24-04, 02:57 PM
Yes , you can use a thin skim of the loctite "gasket eliminator" on the oil distribution plate surface.


There are several bosses on the block that are "contingencies"....LOL when you design and make a die large enough to cast a block you always put in some 'extra" bosses and such in places where you think you might need them. Sometimes bosses are added as fills and chills to control the shrink of the metal cooling in the die and control porosity in the metal. Those can be cut off, machined away or just left depending on where they are. The bosses in the valley were purposefully put there for future use.
By the looks of it I would say it's a Die Cast process, lost core. So if that is the case and you are shooting that much material at one time you would certainly want to shoot it from as many angles as you can. Are they done in house or from an outside vendor? The machines would have to be extremely large (tonnage) to shoot that big of a part.

BeelzeBob
03-24-04, 03:10 PM
By the looks of it I would say it's a Die Cast process, lost core. So if that is the case and you are shooting that much material at one time you would certainly want to shoot it from as many angles as you can. Are they done in house or from an outside vendor? The machines would have to be extremely large (tonnage) to shoot that big of a part.


Die casting and lost core casting are two different processes.....not related other than you end up with a casting in the end....LOL

The block is done with a die cast process. If you look at it carefully there are no "hidden" passages or anything. Every feature of the Northstar block is drafted for clearance for the die pull. There are several parts to the large die that forms it but it is all pulled and on slides for the various surfaces. The cylinder liners are loaded into the die on mandrels that form the cylinders and are cast in place.

"Shooting" the molten aluminum into the die is a very very critical part of the process. Metal temp, pressure, rate, etc. are all monitored and carefully controlled. That part of the process can make or break the process. The blocks are diecast inside of GM at Bedford Foundry. The lower crank cases have been supplied by several different suppliers over the years. Basically, they are a die cast part, also, with an iteration of that , called Squeeze Casting, used by one company.

Lost core casting is a process where a core is coated with a refractory coating and buried in a vat of aerated sand. The sand is settled and metal is poured into the mold. The core, that is still there, is vaporized and "lost". Nothing like diecasting. Saturn engines, the inline 6 Vortec engine and the EcoTec 4 cylinder all use the lost core process for casting. The "cores" are actually styrofoam for those engines...if you look closely at the aluminum casting the surface of the metal looks like tiny pebbles...like the surface of a foam coffee cup. The styrofoam is formed in the shape of the part and then the molten metal vaporizes the styrofoam, taking it's exact shape. That process enables many hidden and blind passages and reduces maching costs dramatically since features can be cast in rather than machined in later. The lost foam castings are very very accurate dimensionally, so there is little material to machine off.

Why weren't Northstars cast using lost core..??? Lost core casting was in it's infancy for production engine volumes when the Northstar was designed. Basically it wasn't considered mature enough to use to design the engine around. An engine is designed around the process that is going to be used to make it (so as to make full advantage of the process) so changing it now would not be fruitfull.

dloch
03-24-04, 03:33 PM
I am somewhat familar with die casting in that most machines run hydraulically, which is what I generally do for a living, among other things. I have worked on some casting processes, one of which was the venture between Cosworth and Ford which is now the Romeo engine. That machine could run V4's, V6's, V8's and/or cylinder heads from the same machine and furnace. Did the intial hydraulic system system design for the rotary index/rollover machine. I believe GM is having some of those same type machines being built for Grey Iron Foundry right now, don't know for what engine or the nature of the process though.

Lawrence
04-03-04, 03:53 AM
I think you are correct. Where did you get that mismatched bunch of junk...LOL.

The clue is the oil distribution plate that is on the block. The one you have does NOT have the steel reinforcement washers cast into it that are absolutely REQUIRED for the main bolts to bear directly against it. On the other hand.....why are there all those stud headed main bolts....???? There should only be one if the engine was originally built with that oil distribution plate.....

An early oil distribution plate designed for use with the main bolts installed directly against it (like your picture shows) would have steel reinforcement "washers" csst into the plate instead of the oval, raised areas that the main bolts bear on. Those oval areas held the oval, two hole, load bearing "washers" in the early design engines. When the design was changed those areas just became aluminum to keep the same bolt length. In the later design, such as the distribution plate you have, the aluminum oval areas were covered by the steel oil scraper plate BEFORE the main bolts were installed. In this later design the steel oil scraper plate acts as the load bearing washer for the main bolts....so your setup there should have the oil scraper plate underneath the main bolts to prevent the oil distribution plate from cracking or recessing under the load of the mains bolts.

The early system put the main bolts directly against the cast-in steel washers in the oil distribution plate and the 10 stud headed main bolts were used. The stud headed mains were used to then mount the oil scraper tray using nuts. The older, original design oil scraper tray had only 10 mounting holes....not the 20 like yours does. Yours is designed to go under the main bolts and the "extra" ears sticking out pickup the outer main bolts to act as the load bearing area/washer for the main bolts on the outside.

It is no big deal, really, as the stud headed bolts just go along for the ride and the stud headed main bolts will function fine if installed thru the oil scraper plate. In fact, you still need one of them to mount the oil pickup.


Hopefully this rambling makes sense.....LOL

bbobynski.......... now I am really confused. I just received a new oil manifold today, PN 12581822 w/ a suffix of G2 added to the casting. If you remember, my 94 STS had a service engine installed in 97. I had posted pics of the oil manifold earlier. My assembly looks just like dlochs, above, except it was installed correctly, manifold>windage tray>hex head main bolts one stud head. You told me earlier it was the new design. But the new part I received today is very different. The manifold is flat at the main bolts openings, not the oval raised areas around the two main bolts holes like the original. Flat as a pancake.

Do I understand correctly, above post, that both the old and newer design were raised in this area, the only difference being invisible internal cast steel washers? If so what is this new (flat) one that I have, yet a third design? There are also a couple of the oil passages that have been moved and one eliminated.

When I called the parts counter with my VIN # he said (not knowing of the service engine) there was a "redesigned oil manifold" that required the use of a "redesigned pickup tube and baffle". When I found out I already had what I thought was the "redesigned" parts, I ordered only the manifold, to reuse the pickup and baffle. But now I've got this "flat" manifold. So what to do now? Will my existing pickup tube and baffle work? Will the main bolt length be correct for the deeper penetration, without shimming?

I'll get some pics of the two manifolds posted tommorow, with the light.

BTW the cast in PN of the original manifold is 3441106-3 (as cast). This first pic here is the same one I posted in that earlier post.

Lawrence
04-03-04, 02:07 PM
Here is a pic of the oil passages, new plate on top.

Lawrence
04-03-04, 02:14 PM
And here are the two manifolds, new one has no bosses at main bolt holes.

Lawrence
04-03-04, 02:28 PM
After pulling the parts for pics I found whats happpening.

Apparently there is now a 3rd design.

The original (w/bosses and already the re-designed part) is approx. .255 thick and .285 at the bosses.

The new part is a uniform and flat .280 across the board.

No problems for the main bolt length, just a bit less reach for the others.

I am assuming the oil passages are OK, but curious as to the reason it was modified.

My only question now is if I am OK to use my original (re-designed 97 vintage) pickup tube and baffle with the new manifold.

Thank you, Thank you

Lawrence
04-03-04, 02:40 PM
BTW, Dennis if you catch this. I would replace your oil manifold. It is tough to tell with the condition of my original, but the new one appears to have a better seal. More profile. And the oiling issue change, whatever that may be.

dloch
04-05-04, 10:39 AM
My bottom end is together right now. The seal on the one I have appeared to be alright. I did apply a skim coat of sealant to the outside edge of the manifold during assembly though.


BTW, Dennis if you catch this. I would replace your oil manifold. It is tough to tell with the condition of my original, but the new one appears to have a better seal. More profile. And the oiling issue change, whatever that may be.

Lawrence
04-05-04, 03:35 PM
I am assuming the oil passages are OK, but curious as to the reason it was modified.



Here is the new manifold installed. Just doesn't look right. Is this OK?

BeelzeBob
04-07-04, 03:49 PM
Looks fine to me..... The oil distribution plate was modified several years ago and was superceded into service with the revised seal location and thicker crosssection. The new supplier of the plate found it easier to meet the flatness spec with the continuous thicker crosssection. I wasn't even aware that they were superceded into service yet.....you just couldn't leave the lower end alone, eh..???? LOL