Steel Caps or Girdle (Which is Stronger)

[blackgn1]

Which is Stronger? If you where installing a $1000 forged crank which one would you choose to hold it in place? Have we ever established which one was the stronger? Lots of guys building or rebuilding engines. Which bottom end the best?

 

[gs462]

Girdle is always best, but its ALOT more money than just the caps.

 

[daves87gn]

I did both center two caps and girdle

 

[it_ss]

I did both center two caps and girdle

both seems to be safest

 

[hemi8]

Just the caps, with a forged crank it will not flex in the middle and that is what causes all the trouble. If you use a stock crank for high HP then a girdle by all means. This is what I learned a few years ago talking with Dan at DLS and Bill Coleman of Coleman Brothers.
Mike

 

[Cme2fly]

Which is Stronger? If you where installing a $1000 forged crank which one would you choose to hold it in place? Have we ever established which one was the stronger? Lots of guys building or rebuilding engines. Which bottom end the best?

A girdle will add strength to the block and eliminate cap walk. Caps will require a main alignment hone/bore. Usually, a girdle will be slightly more $ to set up then a set of main caps. Using steel caps in conjunction with a girdle is a giant waste of $ IMO. Most big HP 109s have girdles installed. I have used them both and the girdle gets my vote.

 

[Chris Hogeland]

Girdle with stock caps will stay longer then the Block will.

 

[blackgn1]

Girdle is winning.:biggrin: I wonder why DLS doesn't use them?? He told me caps as well.

 

[ttaowner]

bison uses a girdle and doesnt do the caps so this would also be the road i would take building one of these engines

 

[bison]

Properly installed caps or properly installed girdle are much stronger than the stock block as Chris already stated. Using a stock crank will cause problems if running high hp over time

 

[TurboTnZ06]

Why choose between either or? I have all billet caps AND a girdle

 

[UncleDave]

I was told by a couple shops they would recommend going to a stage block before using a girdle. Not sure why that is, but they view the girdle as a band-aid, and the stock block as a gamble at best beyond a certain HP level. Maybe some shops just have strong opinions, or little or no experience with girdles and would rather not deal with them. The fact is, of all the shops I've spoken to, not one will guarantee that the extra cash spent on caps, girdle, or better block is going to help an engine live under the abuse of racing. So, budget-minded, I went with 4 steel caps on my mild street build, and it's just fine. If I wanted to race I wouldn't use stock anything, I'd go Stage II and set up a separate bank account. But that's just me.

 

[bison]

I was told by a couple shops they would recommend going to a stage block before using a girdle. Not sure why that is, but they view the girdle as a band-aid, and the stock block as a gamble at best beyond a certain HP level. Maybe some shops just have strong opinions, or little or no experience with girdles and would rather not deal with them. The fact is, of all the shops I've spoken to, not one will guarantee that the extra cash spent on caps, girdle, or better block is going to help an engine live under the abuse of racing. So, budget-minded, I went with 4 steel caps on my mild street build, and it's just fine. If I wanted to race I wouldn't use stock anything, I'd go Stage II and set up a separate bank account. But that's just me.

A 4.1 stage block would be the best option. I'd still run steel caps and some kind of engine plate if planning on building a high power engine though. Opinions are just opinions. Stock blocks with caps or girdle have both been up to around 900hp but why gamble on a junk $300 block when you are about to have $15k invested in your engine. Drop the extra and get the proper block for the job.

 

[bison]

A girdle will add strength to the block and eliminate cap walk. Caps will require a main alignment hone/bore. Usually, a girdle will be slightly more $ to set up then a set of main caps. Using steel caps in conjunction with a girdle is a giant waste of $ IMO. Most big HP 109s have girdles installed. I have used them both and the girdle gets my vote.

A girdle will not eliminate cap walk. If you're getting cap walk you have detonation. A girdle will not prevent the block from failing as it would without it. I've cracked 3 blocks so far. One of them was girdled. Two had a stock bottom ends. The common factor on all of them is that they all had a stock crank flexing away side loading the mains and block. I've ran a lot more power than any of those had through other engines but had no issues cracking blocks. Is the stock crank a problem with high power? I know what lll be running for 600hp or more. I'd rather run a forged crank and stock caps with an engine retention device than a stock crank and anything else in a stock block if i had to choose. I've never broke a stock crank either. Just because it's not breaking doesn't mean it's the correct thing to be using for big power.

 

[Pronto]

So is the consensus to run low tens more than once, a forged crank and either steel caps or girdle are needed. I know tune is paramont when you get to that realm but with a "safe" tune and everything running the way it should what would the life expecptancy be for a forged bottom end with caps or girdle? Once season of racing or several seasons of street driving with a few track runs? Just curious.

 

[bison]

So is the consensus to run low tens more than once, a forged crank and either steel caps or girdle are needed. I know tune is paramont when you get to that realm but with a "safe" tune and everything running the way it should what would the life expecptancy be for a forged bottom end with caps or girdle? Once season of racing or several seasons of street driving with a few track runs? Just curious.

You could run high nines 40 times or you could run sub 10.50 once with a stock bottom end and break it. Life expectancy will more often than not depend on the tuner. Even with nothing wrong it could chit the bed without warning.

 

[Nick Micale]

There is one un-disputible fact in the thread - a stock crank will flex a LOT more than the cast stock crank, and it gets worse as RPM, HP and use [fatigue] increases.

A casting has a wider range of strength and reliability than does a forged piece which is more consistent and stronger.

The question of "which is stronger, caps or girdle" reminds me of the "chicken/egg" question, either answer is correct!

Actually girdles or caps do not break, it is like bison said, the block will break, or crank flex will take out main bearings.

To answer the original post with the forged crank, I would do, and have done a few times, a production block with caps and hard block, no girdle.

No matter what mods you go do to a production block, at the 650-700 HP level and above, it will give up, maybe sooner with a few passes or later...?

 

[Pronto]

Would that be rear wheel or crank hp?

 

[Mike Licht]

as others have said the reason caps move and break is because of detonation and crank flex. I took a girdle off a block with stock crank and caps and one cap came out in two pieces so for me caps are a must. a forged crank and good properly installed caps are the best choice for most guys with the addidtion of a girdle when they get into the middle 9's
Mike

 

[GARY HARVEY]

I'm with Uncle Dave on getting a S2, which will end the problem.. to a point.
But, if the issue stays with a stock block, steel caps are the way to fly.
A girdle will have no impact on controlling crank walk.