Budget friendly oversized pistons?

[Chippy]

Howdy folks,

 

 

Removed the head tonight, and much to my dismay I discovered some corrosion and moderate pitting on cylinder 2. Curious are there any budget friendly options for pistons if I have this block bored? I've read about a guy using toyota 20R pistons, but he was turbo.

 

Car is a 72 '02. 

 

Any pointers appreciated!

 

[NickVyse]

there's a thread about these somewhere.

 

Quality perforamce Clutch Flywheel Engine Parts at affordable prices – QSCUSA

WWW.QSCUSA.COM

---

Quality clutch flywheel exhaust header cylinders pistons for Porsche 911 356 Acura Integra Honda civic accord Volkswagen type 1 type 4 Nissan Mitsubishi Subaru

 

[pehlivanov_tii]

I have had very bad experience with QSC, don't waste your time. Their sizes are not correct. I ordered 90 mm pistons, they came around 89.75 and the piston rings were not correct, i couldn't find proper 89.75 rings anywhere. Moreover all the pistons were not the exact same size and they had around 0.5-10 mm differences each. Yes, i ordered years ago, probably their first batches, but i wouldn't bet much that they fixed this.

 

But, there is a very very good solution here:

Motor9

SHOPWARE.BMW-OLDTIMERTEILE.DE

 

 

I bought these and they have perfect fitment, correct size, correct rings and they look just like OEM, but for way better price. They have E12 and 121 type - 89.25 and 89.50 mm.

[NickVyse]

1 hour ago, pehlivanov_tii said:

I have had very bad experience with QSC, don't waste your time. Their sizes are not correct. I ordered 90 mm pistons, they came around 89.75 and the piston rings were not correct, i couldn't find proper 89.75 rings anywhere. Moreover all the pistons were not the exact same size and they had around 0.5-10 mm differences each. Yes, i ordered years ago, probably their first batches, but i wouldn't bet much that they fixed this.

 

But, there is a very very good solution here:

 

Motor9

SHOPWARE.BMW-OLDTIMERTEILE.DE

 

 

I bought these and they have perfect fitment, correct size, correct rings and they look just like OEM, but for way better price. They have E12 and 121 type - 89.25 and 89.50 mm.

 

wow, they're cheap - and Stefan is one of the good guys

 

[Chippy]

Got a better look at it this morning. 

[jimk]

By the looks of the cylinder walls, it's sleeving time.  Boring may not clear the pits that run deep in castings.  You might get lucky.

[kbmb02]

35 minutes ago, Chippy said:

Got a better look at it this morning. 

 

 

With pitting like that, suggest you bring block to machinist and have them rough-bore the rusted cylinder(s) to target size (*to the size of the pistons you’re considering) - if the pitting doesn’t clean up, have them stop and then consider your options (particularly if this is a budget-minded build). -KB 

[TobyB]

Dah, that'll buff out.

 

But you'll be a bit down on compression in that bore.

 

Having run across similar joy in different engines, give it a gentle

hone to remove the corrosion that's standing above the wall surface,

and then take it apart.  

If you really don't want to spend money on it, throw some Deves rings in,

and see if it re- seats.  Again, you'll never get 100% power out of that bore-

but it'll run pretty well IF the rings can seat.

 

What we can't tell over the internet is how deep the pitting is.  If it's as bad as

Jim sees, yeah, you might need to go to S14 pistons...  

...but given the odd way it's traveled, it may not be much, and then an aggressive

ring package will mitigate most of the leakage.

 

t

in cheapskate mode.

[tech71]

First thing I recommend is to begin by adjusting your cost  expectations... upwards.

It's going to cost more (to properly repair)  than your current expectations are tuned to accept.

Second, get the block out and determine if it can be salvaged.

Third, cast your scrounge net wider, as in overseas. 

This guy in Egypt  has NOS Mahle M10 2L flattops in several sizes and will negotiate.

What cylinder head do you have? From the looks of things its going to need work.

 

https://www.ebay.com/sch/i.html?_dkr=1&iconV2Request=true&_blrs=recall_filtering&_ssn=egyptn_0&store_cat=0&store_name=nosclassiccarparts&_oac=1&_nkw=bmw

 

Edited February 7, 2023 by tech71

[Chippy]

We've got the 121 head with flat tops. Got the block mostly apart this everning. Gotta figure out dipstick and oil tube.

 

Does anyone know - are the NOS Mahle 90mm truly 90mm?

 

Thanks for the input and links fellas! 

Edited February 8, 2023 by Chippy

[tech71]

1 hour ago, Chippy said:

Does anyone know - are the NOS Mahle 90mm truly 90mm?

89.96mm, pretty close