Billet caps necessary when using girdle?

[UncleDave]

Planning on stroking the 4.1 block, and using a girdle. Is adding billet mains necessary, unnecessary, or a good idea 'just because'?

 

[750H.P.V6]

Planning on stroking the 4.1 block, and using a girdle. Is adding billet mains necessary, unnecessary, or a good idea 'just because'?

Billet caps aren't necessary if using a girdle. The girdle by design preloads the caps and distributes the load over the bottom of the engine by tying the pan rail and caps together.

Neal

 

[Nick Micale]

What if you turned that question around?

"Billet caps necessary when using girdle?" or instead,

"Girdle necessary when using steel caps?"

I have heard 3 different opinions from "Buick experts".

1. Girdle only

2. Steel caps only

3. Both

4. Pour hard block up to the water ports [My opinion!]

None of these items remedy a very weak point in a production block - the thin main webs.

Have seen broken block with both.

Have heard of broken caps with a girdle.

Have seen damage with caps.

My personal opinion, in the 10's first choice of parts would be a forged crank. Faster than that, go with a better block!

 

[UncleDave]

"Billet caps necessary when using girdle?" or instead,

"Girdle necessary when using steel caps?"

I have heard 3 different opinions from "Buick experts".

1. Girdle only

2. Steel caps only

3. Both

4. Pour hard block up to the water ports [My opinion!]

None of these items remedy a very weak point in a production block - the thin main webs.

Have seen broken block with both.

Have heard of broken caps with a girdle.

Have seen damage with caps.

My personal opinion, in the 10's first choice of parts would be a forged crank. Faster than that, go with a better block!

Forged crank is a given as far as I'm concerned. I was going to add a separate question regarding hard block, so Nick, do you recommend doing this along with the girdle or billet mains, or would it be sufficient by itself?

Thx

 

[750H.P.V6]

One think I was going to mention, If you are planning to go the stock block route I would stick with the 3.8 "109" block rather than a 4.1. Although you can't get the same displacement from the 3.8 (252" vs 274") the 3.8 block casting is stronger especially in the are of the deck and the lifter valley.

Neal

 

[dr_frankenstein]

One think I was going to mention, If you are planning to go the stock block route I would stick with the 3.8 "109" block rather than a 4.1. Although you can't get the same displacement from the 3.8 (252" vs 274") the 3.8 block casting is stronger especially in the are of the deck and the lifter valley.

Neal

+1

I dont see the girdle or the mains really being pushed to the point of needed them. the deck most certainly fail before either of the other 2. or atleast distort enough to make head sealing damn near impossible.

a good forged crank will take that motor to its limit. save the money for better tuning goodies IMHO.

A.j.