92 buildup and questions

[ak diesel driver]

ideally yes you do a full machine job for the part fill the T bros are planning it's probably not as important

 

[turbonator]

The only girdle worth making or buying is one that ties the main caps into the rail of the block, PERIOD.

All others are a band-aid and some might actually be worse than leaving it stock.

Don't waste money on making or buying one. Ask any reputable machinist and he'll tell you the same thing.

All your doing with a girdle that is mounted to the caps themselves is moving them in unison, which could do more damage.

IT MUST BE TIED TO THE BLOCK, the block won't shift or move.

Look at the p400 motor for proof of a sound design.

Home made crap is just that, crap.

Please don't take my word for it ASK A HIGH PERFORMANCE ORIENTATED MACHINE SHOP.

DSG IS CRAP, show that to a machine shop and they'll laugh at you.

Save your money for mods that work. Sorry for the rant I hate to see people waste money on junk.

great rant.... maybe instead of just negative input you could add something useful here... maybe you should build a p-400 girdle and show us how it is done..... there is always someone who trashes what everyone else is doing but shows no accomplishments of his own.... do you even have a diesel? it is not in your signature, and with 70some posts one would think that you could at least list your truck and its mods for everyone to see? and oh yeah, performance guys have been using girdles in small blocks since the 1960's..... hmmmm they must all be wrong according too you....

 

[turbonator]

OK I see, that makes sense. Hmm, I am going to have to really weigh my options here.. so many choices!

Isn't it true that you need to have machining done past just a regular cylinder hone when you using block filler?

I wish DSG would sell a 5 pin girdle or sell their studs in a kit! Hmm maybe I could contact them.... thanks turbonator, you are making me think

we just have to wait and see... 6.2turbo did his new motor with a tall-fill and did just a hone in the cylinders.... he says the motor runs nice and smooth...

 

[turbonator]

one more thing, the p-400 is not even available to the public yet used... how do we know if the cracking problems are totally eliminated? lets see a few used ones on the market first and say they are so great after they have been inspected....

 

[ak diesel driver]

I would think the critical areas that would be affected would be the main crank bore and cam bore. neither of which would be noticeable except in a tear down inspection or worst case metal in the oil. One of the things to keep in perspective here is that most of the people who go to all the trouble to do this are racers and every last bit of friction cost them time and HP. engine might last just fine for everyday driving

 

[6.2 turbo]

I had a home made girdle on the 6.2, and the main bearings spun,but have no proof it was the reason.

 

[robzombie4551]

great rant.... maybe instead of just negative input you could add something useful here... maybe you should build a p-400 girdle and show us how it is done..... there is always someone who trashes what everyone else is doing but shows no accomplishments of his own.... do you even have a diesel? it is not in your signature, and with 70some posts one would think that you could at least list your truck and its mods for everyone to see? and oh yeah, performance guys have been using girdles in small blocks since the 1960's..... hmmmm they must all be wrong according too you....

No need to get your panties in bunch. This forum is great in that you can post the facts and your opinions.

I have posted the facts about girdles, they are only truly considered a girdle if they tie the mains to the block.

I'm not trying to insult you or piss you off, but the fact is tying the mains to one another does little to nothing for support. The block will not move due to torsional rigidity,the same can't be said about the mains.

As far as owning a diesel, I do. And before you attack me why not prove that what I say is full of crap. I also have been in the high performance engine building arena for over twenty years. I admit that I have been into diesels for about a year now, and still learning. But as far as a girdle goes I know the facts, GAS OR DIESEL.


If I must, I will list the reasons and the facts about block girdles, I just thought that any level headed person would do the home work themselves or post the reason why a half girdle {half assed} would be better than a full girdle {full protection}and as I've said in that post, SHOW THAT CRAP TO A PERFORMANCE ORIENTATED MACHINIST, and they'lll tell you it's crap and a waste of money, or laugh at you if they're not afraid of hurting your feelings and watch you walk out the door feeling like a fool.

There's a reason the p400 uses a full girdle and not a half girdle, For ultimate durability you need a full girdle. Do we need it,probably not for a DD, extreme towing/performance yea it would be nice. And as for not being available to the public yet, they can be had for the paltry price of 12 grand.

If a half girdle makes you feel safe that's cool with me, but if it throws a main will you tell everyone so they don't waste their time or money, or will you let your pride hide the truth.

Don't shoot the messenger unless you can refute the truth.

 

[vdb11]

Hey sorry subclatter I missed your first post...

Like I said, I am open to all ideas. I have heard both sides of the story from many different guys. Many say a DSG girdle or a girdle like turbonators works great. As I have mentioned, I think they just need to be done exactly right. I have also heard from many that said girdles can do more damage than good. Like 6.2 turbo mentioned, his motor spun a bearing, but he has no proof it was the girdle...

This is why I was on the fence about the girdle in the first place. It seems to me though that a well made girdle addresses our problem better than block filler since it more directly affects the main strength, which is what ultimately causes crank failure (that and a bad balancer). However I am not opposed to filler either. As I have talked to 6.2 turbo, like you said turbonator, he is skipping the girdle on his next motor and using some non shrink grout as a filler. I am looking forward to seeing how that goes.

I think this is good discussion, so keep it going

turbonator, I contacted DSG and asked them a few questions so hopefully they will get back to me soon, I noticed in their picture they include ARP assembly lubricant. Do you think the studs in their kit are ARP studs???

subclatter, I can see where you are coming from. My truck is going to be a DD, but I do want it to be very strong as I will be playing with large amounts of fuel, and maybe higher boost. Do you have any pictures of this type of girdle?? Also, what would you do to strengthen the bottom end of the motor? I want to reach 300 hp at the wheels, and maybe experiment with more after that, so that is where I need the strength to be. Fill me in on your idea to keep my mains from loosening and moving to a point that keeps my crank and block safe at 330-350 hp. Thanks guys!

 

[robzombie4551]

The TA Performance block girdle is a must with any higher horsepower or high RPM Buick 400-430-455. The conservative casting of the factory Buick big block has main webs that are approximately 3/8” thick which is adequate for stock and mildly built big blocks, but is far from what it should be with serious HP and RPM. Buick engineers used a combination of a conservative casting with a large main journal crank to distribute the loads found during a stock application. However, severe main cap oscillation takes place when power levels go beyond the 600 HP mark, when RPM levels are above 6000 and/ or with the use of heavy aftermarket steel crankshafts.

The TA girdle is made from 1” thick high tensile strength ductile iron which is stronger than the iron used in the block itself. The girdle requires installation by a machine shop and when installed the girdle is an integral part of the block. The main caps must be cut and machined to fit within the saddle of the girdle. The girdle ties into the pan rail to complete this structural upgrade. This is the only way to prepare your foundation for the potential horsepower that these big blocks have. (Use of any type of girdled oil pan, no matter what type of material used will only give you a false sense of security). Ask anyone using a TA block girdle that has had a rod bolt break or Nitrous mishap, and they will tell you that the block stayed together. All that was needed was to refurbish the engine and they were back to business. Why spend so much money to race prep a block then have it gone in seconds due to a mishap.

The design of the TA girdle will help prevent blocks from distorting, cranks from breaking and main webs from cracking, all while allowing the use of a stock or deep sump oil pan. Each block girdle is machined to clear the starter, and crank counterweights and comes with complete instructions, main studs, other required hardware and necessary spacers for a complete package. Weighs 25 lbs.

This is what is used on my buick 455. If you read the ad, and confirmed by more than one machinist that deals with hi-perf engines, this type of girdle is the only one to use.

All professional girdles are made with the same material as the block, aluminum block [aluminum girdle] cast iron block [cast iron girdle], and tie the main caps to the the block.

Due to the material[cast iron] MUST BE SAME AS BLOCK DUE TO SAME EXPANSION RATE AS BLOCK AND MAIN CAPS, steel will actually distort the caps due to different expansion rates. [So even if you made one out of steel that tied into the block, you would be worse off than with none at all.

the ones by dsg will not only expand at a different rate, they will walk all the caps back and forth, instead of just the one with the thrust bearing on it which usually takes the most abuse.

If DSG's or turbonators were made of cast iron it might help a little as it would transfer the back and forth motion of one cap over all of them and buy you some time.

Also,MUST TIE INTO THE BLOCK, to keep the rigidity, front to back as well as side to side. The homemade steel ones WILL NOT WORK, for these specific reasons period.

Basically the 6.5 has the same weaknesses as the buick motor. I would post pics but don't know how to here.

I know turbonator might disagree, but don't take my word for it ask a knowledgeable machinist and you will get the same answers I gave you.

As far as what I would do? The P400 is the only option unless they are willing to sell you the girdle only, or have one cast yourself.

Those are the only options that I know of. A P400 engine complete can be had for around 10 grand or so.

 

[vdb11]

Haha well a P400 is unfortunately WAY out of my budget, thats more than I have in the whole truck, almost twice as much! Also, who sells the P400?? I have heard about the motor but I can't remember who sells it. Maybe I could get in contact with them about the girdle.

However, I can see how a well made steel girdle like turbonator's could help as well, since it transfers the stress from one to all which essentially strengthens the weakest one, yet I guess kind of weakens the stronger. However, the real world testing they have done with theirs is certainly a testament to its strength, and I am impressed with what their 6.5 can handle.

Those of you that have mentioned tying the caps to the block, where does the girdle tie into the block?? Could you make like "individual" girdles that tie each end of each cap onto the block??

Thanks guys!

 

[robzombie4551]

http://www.jegs.com/i/Ford-Racing/397/M-6340-B351/10002/-1?parentProductId=763475

Here is a pic of a real girdle. Sorry I don't know how to post a pic.

Notice how the main caps are tied to the oil pan rail of the block. Totally boxed so there is no movement in any direction.

Consult an engine builder before you buy or make one, he will tell you the detrimental effect of not using the same metalurgy, unless you want to experiment with the DSG junk.

I'm trying to be as kind as possible by telling you not to put anything less than a full girdle in there made of cast iron.

Splayed main caps would be better than those homemade/aftermarket junk steel girdles out there.

Steel ones like the DSG's are junk, how many times do I have to say different metals have different expansion rates, and could actually cause the caps to push and pull. Although small in movement it could wear the edges of the bearings or cause a spun bearing if they move to much and pinch them.

Imagine the steel girdle expanding more, and faster than the cast iron caps. Cast iron absorbs more heat than steel does. Now imagine what will happen after many heat cycles of pushing and pulling the caps due to different expansion rates.

Those girdles are a band-aid at best and catastophic at worst. If that was all you needed why build girdles like the one in the link I put above.

It's ultimately your engine and your decision, whatever you choose I hope it stays together for you and you get many trouble free miles out of it. GOOD LUCK.

 

[vdb11]

I was actually wondering if the girdle could be tied into where the oil pan bolts up. Now that girdle you linked, it appears to be flat where the main caps are, wouldn't a 6.5 girdle need to go up and over each cap??

I understand that different metals expand/contract differently, which is one of the reasons I was on the fence about doing a girdle in the first place. The one in your link is aluminum, so that means the ford 351 has an aluminum block??

Hmm so it almost seems not doing anything is better. But how much can the factory mains and bolts take?? Although I would like to have a machine shop make a girdle from cast iron, that seems like it would be very expensive, but I will look into it.

What about main studs and some block filler?

 

[buddy]

The P400 has more of what you might describe as a skirt rather than a girdle, since the one on the P400 is like 3" tall visible under the block. This skirt ties all the main caps together, to the block all around and all the way to the timing cover, so the oil pan is a flat mount. the skirt could simply be the main caps too, so main caps and skirt is all one piece.

I think there is merit in the 5 stud girdle, even though everyone will readily agree tying it to the block would be better. Putting in a metal with different expansion rates may not be all that bad in this scenario when youre adding any girdle to increase rigidity in the first place. Any girdle will resist movement in a direction something wanted to go, which is the point, to prevent forces from creating a greater twisting torque that causes cracking. Stress by definition is something that occurs on a deformable body and we are trying to reduce the deformation. Deformation of the main cap can place a shear stress on the bolt, but if movement of the top of the main cap is limited, then the torque on the the bolt will be reduced, as well as the stress the bolt can inflict on the main webbing.

Now, I am sure machinists have seen hundreds of these things on high performance motors and they have been educated in metals and materials for the most part, to understand how to cut and manipulate them. They are experts through application and experience. It is also possible that they know the only ones that never come back to them are the better girdles that are tied to the block, because they are better, but they likely dont know exactly what caused failure in others. It may not be the same failure mode in all engines, especially when comapring compression ratios, connecting rod lengths, stroke, V-angles, RPMs, thermal loads, block design, etc...

The webs are already cracking, so to figure out what may be helpful we would have to define the failure mode. What force is causing the cracking. If it is due to a force the crank is applying to the main caps, causing deformation of the main caps themselves, then making the main caps alone more rigid will help the deformation which is independent of the block. If the cracking is due to stresses applied to the block, and the block twisting in some way then making the main caps more rigid would make the problem potentially worse. Now tying the main caps together will distibute localized forces across more area to reduce maximum stress on the bolts and webs. Tying that to the block would distribute the force over greater area and counteract additional types of forces.

If you have some fab skills, then you could take the 5 bolt cap girldle and make a couple tabs the opposite way to oil pan bolts. then modify the pan just where those tabs are, and seal it with silicone instead of a flat gasket.

 

[vdb11]

You bring up an excellent point buddy, I wondered this myself. Like you mentioned, the answer to what force causes cracked main webs and in what direction would tell us what method would work best. If the crank is is causing stress to the mains or if the block itself is causing stress to the mains are two very different things. Also whether the force is a twisting force or a linear force is also important.

What makes sense TO ME (although it could be 100% wrong) is that the crankshaft wants to move around, leading me to believe main bearings are very important to the whole thing. Is there any point in the rotation of the motor causes unequal forces on the crankshaft? If the forces on the crankshaft are unequal at some point then there would be some type of acceleration net force, which is counteracted by the main caps and the block (webs) depending on the direction of this net force. This consistent unequal force would then push against the webs or main caps. If against the webs, they could crack because they were not cast thick enough or heavy enough to handle that extra force. If it is against the caps, this would put alot of stress on the bolts holding the cap on, or the cap itself, whichever is weaker. This could pull on the bolts, possibly stretch them or cause cracks in the block from pulling on the threads over time, and as they loosen, the crank moves more and more until it breaks.

In this way, I see the extra force as linear that when against the caps pushes in any direction, but all of which yield some force pushing the bolts and mains outward (straight up with motor upside down). This would mean that girdle that ties all the mains together would distribute this upward force from one cap to all, which would work well if some caps experience more stress than others. However, that could potentially be worse because you are subjecting all caps to that force and over time could pull all of them loose and spin a bearing and break the crank because you are loosening all of them.

This leads me to believe studs (or something that will not stretch) are absolutely necessary the hold the mains down to resist that upwards force (but would it cause extra stress on the threads in the block then). What about "individual" girdles into the block that almost act as a second main cap that secure the first main cap down, like adding an extra bolt/stud to spread that stress. However, the problem I see with that is if you did individual for each cap you would only tie into one or two oil pan bolt holes, which I would expect are weaker than the original main cap holes themselves and you really wouldn't be adding much strength....

The advantage I see with doing individual is that you don't have to worry about twisting/stress across the whole block as much as you do with tying all together. However, I really have no idea so that is just my thought, what do you guys think?

Oh and one last thing, if I wanted to use cast, I may be really dumb here but doesn't cast iron break, not bend?? So theoretically you could not make a cast girdle unless you actually cast it???

 

[turbonator]

why do these engines use steel bolts to hold down the cast main caps if the metals are not compatible? IMO our 5 pin girdle has worked for us so far ( i dont think that there is anyone that is pulling and carrying as much weight as us on any of these forums with a 6.5l) like i said in a previous post we will be taking this motor out of the truck and pulling the pan, so WE will see for OUR selves what the result of this girdle is.... and whether it is good and bad, we will share our results with everyone.... i think that is the purpose of this "6.5 performance" forum is R&D and sharing the results..... i think that it is time for someone with better machining skills and more experiance to try to make a "real" main girdle and test it and share the results... i know CIL6 was talking about a billet girdle, but from what i understand it would be quite cost prohibitive, and we have not seen anymore than plans on paper from most of Wills ideas.....

 

[turbonator]

Haha well a P400 is unfortunately WAY out of my budget, thats more than I have in the whole truck, almost twice as much! Also, who sells the P400?? I have heard about the motor but I can't remember who sells it. Maybe I could get in contact with them about the girdle.

However, I can see how a well made steel girdle like turbonator's could help as well, since it transfers the stress from one to all which essentially strengthens the weakest one, yet I guess kind of weakens the stronger. However, the real world testing they have done with theirs is certainly a testament to its strength, and I am impressed with what their 6.5 can handle.

Those of you that have mentioned tying the caps to the block, where does the girdle tie into the block?? Could you make like "individual" girdles that tie each end of each cap onto the block??

Thanks guys!

splayed mains is kind of along those lines, however i dont really see a benifit of removing more material and saying that it is stronger, as they machine the block farther out towards the pan flange and machine another hole in the main web....

 

[buddy]

I was kind of pondering that some of the forces that cause the cracks are from torque in the direction towards the back of the engine. The crank turns and any rotating mass will generate a torque in the axis of rotation, straight back in this case. And the crank throw rides up against the main webs, potentially pushing back on them. This backwards force on the main caps could pass stress to the webs through the bolts. However, the 5 stud girdle would counteract this torque to keep the main caps firmly in place so they cannot transfer stress through the bolts.

The splayed mains I can see as helping, because the main caps have no lateral (side to side) support. When the piston is at TDC and about to push down on the crank its at a 45 degree angle to the main caps. and then a normal force on the bolts. A splayed main bolt would place the intial force at TDC axial to the bolt (the axis in which the bolt has the most stength) and a much less normal (shear) force on the bolt as the crank is almost near BDC.

I cannot prove either of these theories, but I could see how either could be proven helpful.

Now, the splayed mains in some ways reduces the utility of the full girdle tied to the pan bolts. Because the full girdle would provide that lateral stability, much more of it though. Ideally, the block would have been cast with the oil pan surface like and inch or two higher than the main webs, so the main caps rest against the block for that lateral support, removing any shear forces on the bolt that can transfer stress to the webs.

 

[turbonator]

IMO, i think that it is a dead-end to pursue any thought of using a P-400 girdle for several reasons, the most prominent one being that buying a p-400 motor just to have the girdle for an old motor..LOL.. from what i can see from many different pics, the p-400 girdle cannot be bolted to the pan rail? without major machining.... also i dont believe that they sell the girdle seperately.....the best used blocks that can be had right now are the 5996.2l/6.5l and the red blocks( the optimizers are becoming available) it would be an expensive endeavor, thats for sure.... and i am not convinced that the p-400 girdle could be swapped from one motor to the other without a trip to the machine-shop for some costley machining...

following what buddy said,( some cool ideas) a spacer/girdle could be cut from billet to mount to the pan-deck, and some longer main caps machined, that fit into slots in the spacer which would solidify things even more..... but would require a custom pan to allow for the 1.5-2" of drop on the pan deck... something like this... but it would be nice to win the lotto, or own stock in a cnc/ high tech machine shop...LOL edit: looking closer at it, it seems that the back cap with the oil pump is left free-floating....

 

[3500GMC]

I like how they are still using the OEM damper in the pic.... What?

That is the ideal setup however if it were CAST IRON...(maybe it is?) But way better than nothing. Or angle iron.

The rear cap should be a part of the assembly too IMO.

That is the general idea of a P400.

Add a steel crank and never look back.

 

[turbonator]

heres a pic of p-400 girdle...