Gorilla Girdle
- Thread starter durallymax
- Start date
We started making our own early last year.
Ours are .500 thick, trying to give a little more clearance between the pan and the chassis without giving up the needed structure of the girdle. In a truck where we have room I make them .750.
I hadn't seen a Gorrilla girdle in person. I had a customer bring one by today for us to install in his engine. I took one look and told him not to bother. In my opinion they are way too thin to have any effect.
I don't mean to be harsh on someone else's product, I was just so suprised to see how thin they are.
Ours are .500 thick, trying to give a little more clearance between the pan and the chassis without giving up the needed structure of the girdle. In a truck where we have room I make them .750.
I hadn't seen a Gorrilla girdle in person. I had a customer bring one by today for us to install in his engine. I took one look and told him not to bother. In my opinion they are way too thin to have any effect.
I don't mean to be harsh on someone else's product, I was just so suprised to see how thin they are.
guy , trying to learn here, so i hope this isnt taken by people on here the wrong way but, why would you ever need this in a block designed with the caps seated below the pan rail? i can see where a girdle would help in a old sbc or bbc where the caps are above the rail and have a tendancy to move around some in high horsepower motors. with these blocks it seems that the block would be sort of a girdle and billet main caps would be the upgrade suited for it . like i said i could be way off on this , but just trying to understand it better
guy , trying to learn here, so i hope this isnt taken by people on here the wrong way but, why would you ever need this in a block designed with the caps seated below the pan rail? i can see where a girdle would help in a old sbc or bbc where the caps are above the rail and have a tendancy to move around some in high horsepower motors. with these blocks it seems that the block would be sort of a girdle and billet main caps would be the upgrade suited for it . like i said i could be way off on this , but just trying to understand it better
....because the caps can still walk when the engine is pushed hard, even at ~550rwhp/3500rpm levels. Saw evidence of it on my engine when I tore it down. That being said, I did not install a girdle when I rebuilt.
Question: When you install one of these girdles (no matter the make), dont you have to line-hone the mains first? Seems you should, what with using studs instead of OEM bolts.
Last edited:
Billet main caps? Oh hell no....Im a stock rebuild. I like taking crazy risks.
yeah , then your motor would not be an example i would want to test, lol , of course the caps will move on a stock bottom end that is pushed beyond its limits. I'm saying on a block with stock mains and a girdle , your really not doing anything it seems
So what force is the girdle supposed to be resisting??? It's surely not to resist twist if the gorilla is designed for resistance because it's way too thin to stop a twisting action. Like a sheet of paper can't resist you grabbing opposing corners & twisting them opposite directions.
So then that leads me to believe the girdles must be to stop lateral movements parallel to the mains? That is side-to-side or front-to-back. IF that's the case, and the loading on the girdle is pretty much axial, it wouldn't take a very robust piece to resist such a force I wouldn't think.
Am I waaay off on my thinking? What type of force is the girdle trying to resist?
So then that leads me to believe the girdles must be to stop lateral movements parallel to the mains? That is side-to-side or front-to-back. IF that's the case, and the loading on the girdle is pretty much axial, it wouldn't take a very robust piece to resist such a force I wouldn't think.
Am I waaay off on my thinking? What type of force is the girdle trying to resist?
Another thing... I keep hearing "cap walk". What is that? I think it means the caps are moving around on the main bearings, right?
What I'm wondering is like the other guy, how can this happen with the supported caps the way they are in the block? Is it really the caps moving relative to the main bearings/crank? Seems to me the caps are actually pretty well held in place but perhaps it's actually the block flexing in the "webs" that support the caps and that flex is what moves the caps around causing what folks are calling "cap walk"?
So if that's the case, then the two common angles of fixing this would be stronger caps or some kind of brace for the webs that'll add support to them & keep them in place, a la girdle.
Of those two, in my mind, it seems the girdle would be much superior to stiffer caps by tying all of the caps & webs together by a common brace. Whereas the caps just give extra resistance to the flex in each web of the block that it's in and not make one strong, connected unit, no?
Anyone have an opinion on my thoughts? Am out in left field totally lost or understanding somewhat what's going on?
What I'm wondering is like the other guy, how can this happen with the supported caps the way they are in the block? Is it really the caps moving relative to the main bearings/crank? Seems to me the caps are actually pretty well held in place but perhaps it's actually the block flexing in the "webs" that support the caps and that flex is what moves the caps around causing what folks are calling "cap walk"?
So if that's the case, then the two common angles of fixing this would be stronger caps or some kind of brace for the webs that'll add support to them & keep them in place, a la girdle.
Of those two, in my mind, it seems the girdle would be much superior to stiffer caps by tying all of the caps & webs together by a common brace. Whereas the caps just give extra resistance to the flex in each web of the block that it's in and not make one strong, connected unit, no?
Anyone have an opinion on my thoughts? Am out in left field totally lost or understanding somewhat what's going on?
What is the recommended fill for the length for drive time. Is it true that a filled block is a one pass and cool motor? Half fill them then??
IMHO......The block is flexing. Fill it and don't look back
I'm doing both..... See what I can break next
My block is half filled and I didn't notice a difference in coolant temp. Most I've towed is 6000lbs. I also run Mcrats thermostats so it runs around 160-185
Main girdles are to prevent cap walk mostly, which is also what billet mains are meant to do... The girdle ties all the mains to each other, by sandwiching them into the block. If one moves, it has to try to move the other 4 fore and aft. The thickness or material can never add much strength to a twisting motion. 3/8" thick like Randy's or 3/4" thick like Fleece's and SoCal's, neither is thick enough to reduce much twisting... The strongest and best way to do it would be to use a milled Bedplate, where all the mains and girdle are one piece with the girdle part being 2" plus thick. Then it would help with twisting more.
I want someone to build me a 3" thick girdle and long studs, and longer oil pan bolts or studs that are the same material. And I would make a aluminum oil pan. I would look cool if nothing else...
The girdle provides structure to the bottom of the block by tying all the main caps to each other and to the pan rail of the block. This helps with the cap walk scenario, adds structure to the block and to a certain extent reinforces the main caps which tend to distort under high cylinder pressure. The factory main caps tend to fold in on themselves, in a sense tightening up their “U” shape, which is the reason for the billet main caps, the billet caps also provide structure to the block.
Both the girdle and the billet main caps are addressing the block/main cap distortion issues which we see in high horsepower Dmaxes. Some of this is due to cylinder pressure and some of it is due to harmonics occurring in the crankshaft. Internally balancing the crank seems to help with these harmonics along with the cap walk and premature main bearing wear as well.
As an FYI, the Gorrilla Girdle is 1/8" thick at the pan rails and 1/4" thick at the main cap. It then has some straps that bolt across the center 3 main caps. The good thing is it only moves the pan down 1/8". I'm just not sure how effective it is.
Guy
Both the girdle and the billet main caps are addressing the block/main cap distortion issues which we see in high horsepower Dmaxes. Some of this is due to cylinder pressure and some of it is due to harmonics occurring in the crankshaft. Internally balancing the crank seems to help with these harmonics along with the cap walk and premature main bearing wear as well.
As an FYI, the Gorrilla Girdle is 1/8" thick at the pan rails and 1/4" thick at the main cap. It then has some straps that bolt across the center 3 main caps. The good thing is it only moves the pan down 1/8". I'm just not sure how effective it is.
Guy
Funny that many were so opposed to girdling the bottom end of a duramax now all are so for it to the extent of even designing there own...
No Cap walk here No Girdle here. Good setup up short block goes along ways.
No Cap walk here No Girdle here. Good setup up short block goes along ways.