engine girdle

87TIGN

Death by boost
Joined
Aug 21, 2006
So what exactly is an engine girdle and do you suggest one on a stock rebuild?
Thanks
-Andrew
 
A block girdle ties the main caps to the pan rails to keep the caps from flexing and the crank from walking. it basically ties the bottom end together in high-hp applications. unless you're looking at going in the mid to low 10's range, i'd say just go with the 2 billet center mains, that'll be plenty.
 
So order some billet center mains and leave th eouters huh? Ok thanks for your help!

P.S. what is crank walk?
 
As you probably know, there are very tight tolerances that MUST be kept inside the block. What happens is when there is so much pressure in the cylinder, it will try to push the piston out the bottom of the motor (this is how a motor works). The crank will actually started bending out of shape, pushing on the caps. When this happens the crank will "walk" back and forth on the main bearings. Heat builds up, bearing sieze up, and the crank breaks. Then you have a mess! As stated before all you will need are the center caps because this is where the crank flexes. Now if you are like me, I always want to go faster. Think about what your goals are and leave room for upgrading down the road. Personally I would go with the girdle since the motor is out. Then if you want to bolt on some good heads, bigger cam and a bigger turbo a few years from now, you will have the bottom end squared away. Good luck!
 
For a stock rebuild you probably don't need either. If you plan to run alot of boost (now of in the future) it is probably worth it to do now. Bear in mind, the caps are cheaper initially but will require a line bore which will cost $300 to $500 depending on how many passes are required. The girdle only requires a line hone which is around $150. But with a girdle there are other machining costs and a bit of setup time. Plan on spending $500 to $700 to do either.
 
ANY Buick getting close to 400 HP should have, at least, steel caps and ARP Main Studs. Any Buick going into the 500+ HP range should have a Girdle. We have seen, first hand, engines that were at the 500 hp level with steel caps and experienced crank flex and cap walk. You can see the markings on the main saddles. We've seen this problem vanish once we started installing engine girdles back in '97. As a rule of thumb, we install our engine girdle (made in USA) on any engine making 500 HP or more.

Hope this helps you.
 
What is a line bore and a line hone? As far as the caps and girdle they boht do the same thing right? So i dont need to be both i just need to decide on which one to do?
 
You align bore, and hone, the mains to be sure they are straight. Any time you change the load configuation you change the shape. Even if it's only a thou of an inch.
The caps and girdle do NOT do the same thing. With caps, which are stronger caps, you are still holding the main bearing and crank in location with only two bolts or studs. You can/will get stretch in the bolts/studs. The girdle utilizes all the hardware of the bottom end to hold bearings and crank in place. ** During testing of our ESP Girdle, back in '97, we bent connecting rods on Dyno runs that failed. When we checked the the crank and main bearings, they were fine. As mentioned earlier, what you purchase depends on your HP goal(s).

Hope this helps you.
 
I know this thread has been down for awhile, but what is a better idea? Stock main caps with arp studs and a girdle. Or billet main caps and arp studs. Like esp products said, the crank can still walk with billet caps because there are two bolts on each cap. What do you guys think?
 
Great post. I too am looking and hoping this summer to do a rebuild. I’ve got a few quotes of $6-9k to build the engine. Some with stock crank, rods, and then capped and some with griddle, steel crank, and rods. The people I spoke with did not mention to use the stock crank once griddled. They said it’s just an accident waiting to happen. Most likely assuming that if you are willing to griddle the block you are planning on making big power. I only want to do this once and realistically if I could run low 11’s on an everyday driver I would be happy. I do not want to spend $ that is not needed. However, I do not want to go cheap myself out either. Nor do this again anytime soon.
 
The stock crank and rods in these motors are pretty damn stout so if you arnt gonna be making 600+ hp I was told these will be ok. Also I was told no need for a girdle unless you are making about 500+ hp. On a pretty stock buildup there is no need for this stuff I have found out. On a stock buildup or close to stock you should be fine with stock main caps and some ARP studs. HTH
-Andrew
 
Yeah I think the stock stuff will be just fine for me then, I will deffinetly get arp studs maybe billet mains. Im planning on buying a NA 109 block with a rolled fillet crank and 2 dot rods, with 8445 heads, then building it up from there. But I can get a NA 3.8 in the junk yard for 150, and I was thinking about buying a rotating assembly from full throtle speed, http://www.fullthrottlespeed.com/customkititems~CartId~%7BDEEVEREST9C97D3-ACF5-4E1E-918B-1E7450F08E95%7D~kc~001STROKERKIT~eq~.htm
and building it up from there. Im starting from scratch with no engine. Im not planning on building a 500hp 10sec ride, its going to go in my s10, and if anything ill take it to a road track. So do you think the 1500$ rotating assembly is over board for my plans? I got a GN turbo and intercooler going in. Any help?
 
I dont know if the internals on the N/A Regals are the same as the Forced Induction Regals but as far as buying a rotating assembly that is up to you and what you have to spend. If you have the deep pockets than why not but on a limited budget if the internals on the N/A are the same I would keep those if you are planning on less than 500 hp. But that is my opinon do what you can afford. Good luck and let us know if you have any more questions!!
-Andrew
 
You align bore, and hone, the mains to be sure they are straight. Any time you change the load configuation you change the shape. Even if it's only a thou of an inch.
The caps and girdle do NOT do the same thing. With caps, which are stronger caps, you are still holding the main bearing and crank in location with only two bolts or studs. You can/will get stretch in the bolts/studs. The girdle utilizes all the hardware of the bottom end to hold bearings and crank in place. ** During testing of our ESP Girdle, back in '97, we bent connecting rods on Dyno runs that failed. When we checked the the crank and main bearings, they were fine. As mentioned earlier, what you purchase depends on your HP goal(s).

Hope this helps you.

Would a forged steel crank & steel main caps work ok together (without girdle) , i mean by the crank being better than stock will the crank cause the connecting rods to bend or flex even its all a forged rotating assembly or do you still prefer the girdle over the caps. what causes the connecting rods to bend? trying to address that problem also while your in the bottom end.
 
I am interested to hear how people are doing with steel caps and a forged crank. Would it be safe to take this to the 10 sec. zone? My stock crank w/steel caps walked and took out the main bearings last month. Hp is in the 550-600 zone.
Mike
86 GN
 
The Steel crank is always a good upgrade. Same with the rods. If you only go with caps, the possibility of walk is still there. You have a steel crank that is now flexing and MAYBE it won't crack (as soon), but you can still wipe the bearings which will in-turn take out/damage the crank. The caps and a girdle are like apples and oranges. Yes, they are both fruit, but the are different. The rods are bent by a couple of things; detonation for one, 20 years of use, and the increased stress of increased HP. We still run stock rods on our ESP Twin Turbo car, but if I built the engine today it would have new rods for sure. I think the stock crank is pretty good with a girdle in place.

Hope this helps you.
 
Trying to follow this...
400+ get billet caps & studs
500+ get a girdle

Thats was clearly said, but does that mean at 500+ hp when getting the girdle, is it assumed you already have caps? Or, is the caps not required when going for 500+ and a gridle is all you need?

Thanks to anyone clearing that up for me.
 
Im not sure on this but cant you buy a girdle for the price of billet main caps, and a girdle will be able to handle more power so wouldnt it be the way to go?
 
Maybe you need to get caps after 400+ hp to keep the crank in the block, and a girdle after 500+hp to keep the crank from walking.

I always thought the girdle did both, I was hoping to see someone post something definite. If the girdle is all you need at 500+ hp, you may as just well get it at 400+ hp then...being they will cost approx the same either way.

Can anyone confirm?
 
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