b230ft 9mm piston/rod to 13mm possible?

I wanted to know if a 13mm piston/rod combo off a '90+ b230ft would bolt directly up to the bottom end of a pre '89 b230ft block? Are there any differences in the dimensions? Or any differences in the compression ratios? Or would one have to swap the whole engine/bottom end thanks.

You can just swap the rods if you want. For the price of a set of H beams why not just go the hole hog?

I was planning on just ripping out a set from a junk yard, I'm trying to do all of this as cheap as possible. Plus I don't have the tools for a complete swap. Any info on the compression ratio?

Pretty sure compression won't be affected at all.

I too have a question on this subject. Do you just reuse your rod bearings that came with your engine (i.e., you're *only* swapping in the rods)? Should you plastigauge each rod when installed?

The pistons are matched to the block bore size with a letter.

just swap the rods to the old pistons, make sure to number em.

.17c/hr much?

No cheap 13mm rod engines around?

Can be swapped though.

This sounds expensive

IWantedAnAE86 said:

Plus I don't have the tools for a complete swap.

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If you have the tools to pull pistons and rods you have enough tools to just swap the long block or short block if trying to be extra cheap.

But, personally I can't understand why anyone would go through that effort and not just throw in H-beams with new bearings and rings. To each their own I suppose.

Yeah. Seems crazy to pull it completely apart and not do bearings and rings at least...

Plus.........my local PnP lists a rod and piston for $20, $80 for the set. A short block isn't much more expensive, will save time and was professionally built.

.

another stealthy 240240 bump...

CAPT_BLOTTO said:

The pistons are matched to the block bore size with a letter.

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Bear in mind that is important at time of manufacturing the stuff...

A block is machined, bore is dial-bore gauged and the worker sees 96.001mm so he reaches over and satmps in a A, checks the next hole--stamps another A, next hole Oh wait 96.002..Stamps a B..last hole an A (or grade 1/2/3/4...I have seen on Cadillac blocks grades A thru M)

(and same time somebody check mainline bore and splashes a little red or bluse paint indicating the size of the bore for the main bearings.)

Then somebody looks in the rack of piston sets and sees Oh how nifty 3 grade A and one grade B and drops them in the corresponding holes.. The piston grades can me a couple of 1/10,000

After anybody has driven the motor for couple thousand miles that is meaningless....

Ever notice we don't but pistons by the 1/10,000 th? or main bearings with .0001 bigger OD?

Don't overwhelm this guy...keep it simple..like this:

Yes change rods and noting else changes, then you'll have just scary weak rods

rather than fawkin nuts they-have-to-be-kidding little soda-straws.

And yeah going to the wrecking yard and grovelling under an engine and pulling the head and wasting tons of time is a much better use of time and money than just buying a set for $20+postage.

The 13mm rods aren't THAT scary small. They'll be perfectly fine one a stock setup with 15psi.

culberro said:

The 13mm rods aren't THAT scary small. They'll be perfectly fine one a stock setup with 15psi.

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You evidently don't mind a lot more DNFs on things you work on than I do..


They are ridiculous. They are one extreme and the old B21/23 rods are they other: so heavy that the weight alone cause problems..

I know you know everything, Robert, which is an amazing feat considering your extremely tender age and necessarily limited experience..are you even 30 yet??
...and I know you have virtually impregnible faith in your un-erring correctness.

But, how in the world have you come to be so confident?

Have you ever considered using any qualifying phrases, the ones that drive mediocre English teachers insane?
Qualifiers like "It seems" or "evidently", "I believe....", or just for you "In my limited experience" ?


You might try...

I'm glad you acknowledge my intelligence!

My post is based on my experience running 15psi on an 180k mile engine for 3 years, including numerous track days. it's also based on the b230 in the rally car that had similar miles and was constantly spun to 8k rpm on a stock bottom end.
What's your experience with b230FTs and b230s with 13mm rods?

culberro said:

I'm glad you acknowledge my intelligence!

My post is based on my experience running 15psi on an 180k mile engine for 3 years, including numerous track days. it's also based on the b230 in the rally car that had similar miles and was constantly spun to 8k rpm on a stock bottom end.
What's your experience with b230FTs and b230s with 13mm rods?

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Seeing lots of picces of rods sticking out of the sides of the blocks..

And comparison with other motors..There are other engines that get beat on..You look at them then look at a 13mm rod..
Like a lot of things its a simple matter of "compare and contrast", a great way of learning instead of just believing...

That and talking to engine builders who build serious things...

fake news

Even the 9mm rods aren't too bad, I had almost 320k on mine when the car was rear ended and I've seen some with more than that. The 13mm rods are downright bulletproof at reasonable power levels, they only break when someone either runs it out of oil or boosts the hell out of it. In terms of stock engines, the Volvo redblocks are very stout. Not many other engines out there are legendary for routinely going >300K miles with only basic maintenance. It's a Volvo, not a Ferrari, as much as I love them, an old Volvo is what it is. It was never intended as a high performance racer, instead it's just a good rugged car jam packed full of usefulness and safety. The turbos have enough pep to be fun while still retaining utility but it's never going to compete with a real sports car for all out performance.

If you want big power though everything changes. Big power = big money. By far the cheapest way to get 300+ horsepower is to drop in a smallblock V8. If you want to get that kind of power out of a Volvo motor it's going to cost you. Rod swap is possible but trust me when I say that a motor swap is much easier. You absolutely cannot change the rods without pulling the motor, the crossmember is in the way and prevents removing the oil pan. Once you swap the rods, you've got a tired old motor with stronger rods, if you're going to do the complete disassembly required for that job you may as well rebuild the whole thing. If you don't have the budget, tools and skills to do a motor swap then you don't have the budget, tools or skills to get the kind of power you want. It's that simple. If you want 300hp on a budget, buy an old Mustang, Camaro, etc, something with a 302 or 350 V8, there are TONS of aftermarket parts for those and you can probably get the whole car for what it will cost you to build the motor alone for a classic Volvo.