"Are girdles generally added for big rpm or HP or torque". What's your intentions? Circle track, 14-1, billet splayed caps, fuel=alcohol? Or maybe not so much? Total overkill! You don't need it. Yeah, it's a chev.
Are girdles generally added for big rpm or HP or torque
- Thread starter maca
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Girdles are a waste of money... spend that money elsewhere.
Wait until you waste money on one, then do a tear down and see cap walk... Seen it too many times.
Wait until you waste money on one, then do a tear down and see cap walk... Seen it too many times.
I have to ask, in the past, you have noticed cap walk in past engines?
In the current engine that makes use of the girdle, what kind of useage did it see and for how long?
Thanks Mike.
Ironmike
Well-Known Member
Had a 414 stroker that I ran a couple years, it made 515Hp, when I took it to the machinist he showed me the signs. Number 2 and 4. Pretty bad so he said. It ended up being a "shot" block in the end, so we didn't have to address the issue.
Current engine ran last year 2100 miles. It never leaves the garage without a couple passes. Pretty hard use. Had to tear it apart to ease my own mind, but the maincaps look new as well as the block mating surfaces. This is a 4 speed car with 430 gears and pretty sticky tires. No walk at all.
I don't consider wasting money on anything in my motor that MIGHT help. It can't hurt.
I think that's the simplest answer.
But, I wonder where that power level begins....
This thread reminds me of an older thread, it was titled something along the lines of “Is 600 hp the limit for a stock block?”
At what point is a girdle needed and under what circumstances? Mike has found a positive point for there use. Prior to this, if I was asked about it, I’d have to say for myself, the jury is out on the matter. And it is a good question. At what HP level should you add the griddle. Or what is high HP and Tq?
If you ask me what is big power, block size and strength aside, I would say 700 hp/tq. begins the territory for a NA engine. However, that opinion is just that and will vary by person to person, engine size to engine size.
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famous bob
mopar misfit
didn`t read all these posts, but some of u guys are missing the point. A girdle will strengthen a big block/r/b, probly more than any other block made , just because of its weak design. The girdles purpose is to stop the mainstuds from whipping around causing cap walk that breaks the block between the main and cam bores, in a ''higher'' h.p. hi RPM situation. More for engines that are run all the time in upper RPM . There are a lot of tricks to be used, all of them together should make a 440 , which is the worst , more dependable and last longer. In my case I use one because I don't want any future troubles, not that I run at higher rpm a whole lot.
Alum. main caps w/ studs , main studs by them selves , girdles , cryo treatment , block filling , line honing/boring , all will help a r/b .
A mega type block would solve a lot of this "if," u can afford one.
I`ve always had to buy parts a little at a time , never could afford to come up w/ a mega , or alum. aftermarket block all at once .
Some blocks will break in that area faster than others . I know a guy that even broke mega blocks between the main and cam bores " ,
dragcar-----------he eventually backed the linkage off to run consistant 9: 60`s, with alum. caps and studs .
I built a really hot 406sbc, that I had machined for 4 bolt mains , it still cap walked on every cap------
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Ironmike
Well-Known Member
Ya know Rumble, I think the jury is still out......
Maybe my caps would look good if I didn't have the girdle, I don't really absolutely KNOW if they work.
I know my macinist/dyno guy told me, at least in my case, with my block, it was money well spent. I consider him a Jedi Knight of engines. He seems to always end up right in the end. Maybe someone will do some real testing someday....
My personal feeling is you're going for 500 and above, the price of a girdle is nothing compared to what you're gonna spend. Why not throw it on there. Like I said before it can't hurt.
Maybe my caps would look good if I didn't have the girdle, I don't really absolutely KNOW if they work.
I know my macinist/dyno guy told me, at least in my case, with my block, it was money well spent. I consider him a Jedi Knight of engines. He seems to always end up right in the end. Maybe someone will do some real testing someday....
My personal feeling is you're going for 500 and above, the price of a girdle is nothing compared to what you're gonna spend. Why not throw it on there. Like I said before it can't hurt.
nm9stheham
Well-Known Member
IM, in relations to Rumble's question.... did your machinist explain what is causing the cap walk?
Same question to FB... Is there an explanation of what is making the caps/studs to whip around? Is this just crank flexing working through the bearings, or some resonance, or ???? This article for Ford mentions 'harmonics', which indicates resonant problems.
D.S.S. Racing - Main Support System And Pro-Tray Windage Control<meta name="description" content="D.S.S. Racing's Main Support System Dampens Harmful Harmonics That Cause Cap Walk And Can Crack Engine Blocks. The Main Support System Is Affordable And Easily Installed. D.S.S. Also Offers Increased HP With The Pro-Tray Windage Control.">
And yes, the girdles have the strength to control this direction of movement. This sounds like a good explanation. Many thanks!
Ironmike
Well-Known Member
I don't remember if he ever explained it I do remember very well that he said "wait a minute"....... walked away and came back and put a factory SBC 4 bolt cap on his desk, next to mine. Pretty dramatic difference.
I think our caps are just too flimsy with only a 2 bolt connection. Once you start increasing stroke and upping the torque they just can't hold still. Just my theory. I think the 340 blocks might be even more prone to it. Again, just my own theory.
The 340 shouldn’t be any more prone than another engine except that it does produce more power and torque just in cylinder size. All else being equal.
Ironmike
Well-Known Member
What about the actual size of the 340 journals?
Crank main journals are 2.50 for everything except the 360 which is 2.81. All rods are 2.125.
MOPAROFFICIAL
Oogliboogli
Exactly. more material around the main, so saying a 340 would be more prone is just plain oversight...
MOPAROFFICIAL
Oogliboogli
A good balance is worth a ton.
As is a good machinist and assembling of said rotating assembly.
Each main must be checked. Some things get by at the shop, swedgeing/staking can be needed to get it where I like it. I had to do some of that on my own stuff a time or two. Things to keep that in mind.
As is a good machinist and assembling of said rotating assembly.
Each main must be checked. Some things get by at the shop, swedgeing/staking can be needed to get it where I like it. I had to do some of that on my own stuff a time or two. Things to keep that in mind.
Ironmike
Well-Known Member
Oh man! I don't know why I was thinking the 340 was BIGGER. I had it backward. So in my mind, I guess the 360 might be more prone to cap walk.
My guy thinks like MO above. He absolutely insisted on balancing my Scat "balanced" rotating assembly. I guess all good machinists think alike.
It is worth the cost to check. How well balanced the kits are I don’t know. Perhaps passable for no vibration is what there doing. Which is different than a race assembly which should be down as close as humanly possible. An assembly can be 3,4 or more grams out of wack and you won’t feel it. OE balance jobs can be worse. If he can get it a better balance, then by all means, do it.
Is the 360 more prone because the journal is larger? I don’t know. Is the cap smaller, thinner?
I’d have to check.
And yea, no worries. Don’t feel bad. When I read your question, I was like, “OH yea it’s.. oh ****, it’s ummmm, it is... crud! Where’s my book damm it!”
Yea, I had failed the pop quiz and looked it up.
It happens!
Is the 360 more prone because the journal is larger? I don’t know. Is the cap smaller, thinner?
I’d have to check.
And yea, no worries. Don’t feel bad. When I read your question, I was like, “OH yea it’s.. oh ****, it’s ummmm, it is... crud! Where’s my book damm it!”
Yea, I had failed the pop quiz and looked it up.
It happens!
MOPAROFFICIAL
Oogliboogli
2 grams is a lot. Imo
But are we talking throw side or counter..
Remember the rpm multiplies it.
But are we talking throw side or counter..
Remember the rpm multiplies it.
I agree. However I have heard first hand how bad the factory balance can be and I have been in the very car that had the very engine that didn’t vibrate in he car ran. It was a smooth ride. The cars owner must have had a discussion with the builder on this topic and the engine builder proved to him how bad it was but spinning the OE rotating assembly.
The builder claimed the worst he ever had was 7 grams. Which otherwise, I would have never believed in.
If the assembly can be finished to a 100th a grams poop, then go for it.
The builder claimed the worst he ever had was 7 grams. Which otherwise, I would have never believed in.
If the assembly can be finished to a 100th a grams poop, then go for it.
mjs69gts
Well-Known Member
i have one installed in my 416 im happy so far
Krooser
Building Chinese Free Engines since 1959...
The shop that originally built my SB 383 said the Mopar's seldom have block issues if you stud the mains. I asked about Mopar girdles at the shop that built my kid's SBC... he said he never sees crank or block issues with SB Mopars...
My engine is a mild 575 hp deal that will run just north of 7,000 rpms on a 1/2 mile dift track.
My engine is a mild 575 hp deal that will run just north of 7,000 rpms on a 1/2 mile dift track.
gzig5
Well-Known Member
What does a "mild" 575 hp small block combo look like?
I was wondering the same thing. I've been involved in dirt racing my whole life and the last time I even heard of a production block Chrysler running was in the 80's. And yes, I never saw a LA block break. I attribute that to the fact that something valvetrain related always parked them first. And the ones I saw were in the lower stock and sportsman divisions (about 400hp back then).
A few guys ran W2/R/X engines in the 358 modified division in the 80's. They ran well, but the guys running them never did so for long. Too expensive, and problems getting parts. In later years some guys ran the R/A/W/5/7/9ect ect. Those engines were very competitive, cost a fortune, very difficult to get parts for, and were not even remotely Mopar.
How are they “Not even remotely MoPar” if there running MoPar R/A blocks and a W series head?
A Mopar part number, yes...even remotely related to a small block Chrysler, no. Chevy deck height, Chevy oiling, Chevy valvetrain angles and locations, off the shelf Chevy rotating assembly, accepts Chevy front accessories, Chevy trans bolt pattern, heads are a modified copy of the Chevy SB2 and RO7. So yup, 95% Chevy, 5% custom, and 0% Mopar. Not one single piece of these engines is compatible with a Chrysler small block. They did have cool Mopar valve covers though.
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