Ford Racing X302 piston seizure
05-27-2017, 04:59 PM
#1
Thread Starter
Join Date: May 2017
Location: Bavaria, Germany
Posts: 9
Ford Racing X302 piston seizure
Hi,
My name is Andy and I have a 67 Mustang Coupe. It is powered by a Ford Racing X302 crate engine which recently run into a piston seizure. I noticed that the pistons are from Mahle with part number SBF600040FPF. They have an oversize of 0.040“.
My machine shop told me one cylinder needs to be bored to the next oversize, the damage cannot be fixed by just honing. With the part number from the piston I can't find any parts for sale so I am struggling to find out if Mahle offers this piston with .060“. Does anybody know if that part number is a Ford specific one and on the market they are sold with a different one. And are they available in .060?
Regards
Andy
My name is Andy and I have a 67 Mustang Coupe. It is powered by a Ford Racing X302 crate engine which recently run into a piston seizure. I noticed that the pistons are from Mahle with part number SBF600040FPF. They have an oversize of 0.040“.
My machine shop told me one cylinder needs to be bored to the next oversize, the damage cannot be fixed by just honing. With the part number from the piston I can't find any parts for sale so I am struggling to find out if Mahle offers this piston with .060“. Does anybody know if that part number is a Ford specific one and on the market they are sold with a different one. And are they available in .060?
Regards
Andy
05-27-2017, 05:44 PM
#2
6th Gear Member
Join Date: Aug 2007
Location: Elk Grove, CA
Posts: 5,896
Honestly, I'd recommend looking at sourcing a new block. 0.040" is the largest overbore most people recommend with SBFs due to cooling issues as the cylinder wall thickness decreases.
I understand 5.0 blocks may not be in ready supply in Bavaria, but if you roll the dice and try to punch yours out to .060, you may end up with a motor that constantly overheats.
I understand 5.0 blocks may not be in ready supply in Bavaria, but if you roll the dice and try to punch yours out to .060, you may end up with a motor that constantly overheats.
05-28-2017, 01:15 PM
#3
Thread Starter
Join Date: May 2017
Location: Bavaria, Germany
Posts: 9
The block is a F1SE one, the last one Ford produced with the thickest cylinder walls. I feel ok by going to 0.060, but a second choice would be a cylinder sleeve if no further oversize is offered by Mahle. So the initial question remains, does anybody know where this piston can be bought? My local dealers who sell Mahle stuff were not able to find them by the number I found on the piston. And the web search lists only eBay offers already sold. I have the feeling that they are labeled with a Ford specific ID and the ones for sale on Summit or anywhere else might be the same but with a different ID. But I need a verification. Mahle itself revises me to local distributors but as said they can't find the piston with that ID. <br />
05-28-2017, 02:42 PM
#4
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Join Date: Aug 2007
Location: Elk Grove, CA
Posts: 5,896
If you're set on punching it out, why are you stuck on the same Mahle part #? Go pick up a set of something that you can get in .060" over that will give you the compression ratio you want, and this becomes a non-issue.
(you do realize you need to overbore all of the cylinders to match, right?)
(you do realize you need to overbore all of the cylinders to match, right?)
05-28-2017, 04:29 PM
#6
Thread Starter
Join Date: May 2017
Location: Bavaria, Germany
Posts: 9
The block is a F1SE one, the last one Ford produced with the thickest cylinder walls. I feel ok by going to 0.060, but a second choice would be a cylinder sleeve if no further oversize is offered by Mahle. So the initial question remains, does anybody know where this piston can be bought? My local dealers who sell Mahle stuff were not able to find them by the number I found on the piston. And the web search lists only eBay offers already sold. I have the feeling that they are labeled with a Ford specific ID and the ones for sale on Summit or anywhere else might be the same but with a different ID. But I need a verification. Mahle itself revises me to local distributors but as said they can't find the piston with that ID. <br />
If you're set on punching it out, why are you stuck on the same Mahle part #? Go pick up a set of something that you can get in .060" over that will give you the compression ratio you want, and this becomes a non-issue.
(you do realize you need to overbore all of the cylinders to match, right?)
(you do realize you need to overbore all of the cylinders to match, right?)
Like @Summit
SBF600030I26 -> .030
SBF600040I26 -> .040
So there might be some SBF600060FPF out there I have not found yet.
And no, I don't need to overbore all cylinder if I make the weight equal the 0.040 ones. Not the best solution but something I can afford.
05-28-2017, 04:50 PM
#7
Thread Starter
Join Date: May 2017
Location: Bavaria, Germany
Posts: 9
05-29-2017, 09:34 AM
#8
Thread Starter
Join Date: May 2017
Location: Bavaria, Germany
Posts: 9
I actually found .060 Mahle pistons (http://www.cnc-motorsports.com/mahle...-ford-302.html), however not clear how the Ford Performance part number matches to the ones available on the market. As I have not found the Ford ones available for sale....
the ones installed SBF600040FPF = Mahle SBF600040F06
Ford Performance .060" = Mahle SBF600060F06
the ones installed SBF600040FPF = Mahle SBF600040F06
Ford Performance .060" = Mahle SBF600060F06
06-01-2017, 02:15 AM
#9
6th Gear Member
Join Date: Apr 2007
Location: California
Posts: 10,468
Mahle makes a **** ton of pistons, and they're probably the best on the market. They make pistons for a lot of factory sports cars, as well as F1. The PN you have could be some Ford specific # for something Mahle makes for the For engines that Ford had sourced for them.
A few things though....
You don't want to go .060 over on a factory 5.0 block, don't care how good the block is. The real issue is the factory blocks have all sorts of core shift and cylinder alignment issues, so regardless of overheating issues (even at .040 over) I'd be WAY more worried about wall integrity and getting a crack in a cylinder wall or pinhole leaks.
A sleeve would probably be a better option to reuse the existing piston PN, that way you have no balance issues. Mahle pistons tend to all be within a few grams of each other, so you should be able to get away with not having to rebalance the assembly.
The real issue though, is you need to find out why it seized in the first place. Were they full floating pistons? If THOSE things seized, you have some kind of major issue. Even the non full floating (standard configuration) pistons from Mahle shouldn't seize...or any decent piston for that matter.
The wrist pin is oiled from splash coming off the rod journals on the crank that flings up onto the cylinder walls, then is scraped off by the oil control ring which directs oil onto the wrist pins. So if you get a seizure, you're either not getting oil down in there (indicating an oil control ring issue, or a splash oiling problem), you have a pin fitment problem (unlikely with Mahles), a heat problem causing distortion (engine overheating, detonation, pistons are too tight etc), or the cylinders might already be too overbored and distorting around and pinching the pistons under load (having the same effect as a piston that's too tight, except it occurs intermittently).
A few things though....
You don't want to go .060 over on a factory 5.0 block, don't care how good the block is. The real issue is the factory blocks have all sorts of core shift and cylinder alignment issues, so regardless of overheating issues (even at .040 over) I'd be WAY more worried about wall integrity and getting a crack in a cylinder wall or pinhole leaks.
A sleeve would probably be a better option to reuse the existing piston PN, that way you have no balance issues. Mahle pistons tend to all be within a few grams of each other, so you should be able to get away with not having to rebalance the assembly.
The real issue though, is you need to find out why it seized in the first place. Were they full floating pistons? If THOSE things seized, you have some kind of major issue. Even the non full floating (standard configuration) pistons from Mahle shouldn't seize...or any decent piston for that matter.
The wrist pin is oiled from splash coming off the rod journals on the crank that flings up onto the cylinder walls, then is scraped off by the oil control ring which directs oil onto the wrist pins. So if you get a seizure, you're either not getting oil down in there (indicating an oil control ring issue, or a splash oiling problem), you have a pin fitment problem (unlikely with Mahles), a heat problem causing distortion (engine overheating, detonation, pistons are too tight etc), or the cylinders might already be too overbored and distorting around and pinching the pistons under load (having the same effect as a piston that's too tight, except it occurs intermittently).
06-01-2017, 06:33 AM
#10
Thread Starter
Join Date: May 2017
Location: Bavaria, Germany
Posts: 9
Mahle makes a **** ton of pistons, and they're probably the best on the market. They make pistons for a lot of factory sports cars, as well as F1. The PN you have could be some Ford specific # for something Mahle makes for the For engines that Ford had sourced for them.
A few things though....
You don't want to go .060 over on a factory 5.0 block, don't care how good the block is. The real issue is the factory blocks have all sorts of core shift and cylinder alignment issues, so regardless of overheating issues (even at .040 over) I'd be WAY more worried about wall integrity and getting a crack in a cylinder wall or pinhole leaks.
A sleeve would probably be a better option to reuse the existing piston PN, that way you have no balance issues. Mahle pistons tend to all be within a few grams of each other, so you should be able to get away with not having to rebalance the assembly.
The real issue though, is you need to find out why it seized in the first place. Were they full floating pistons? If THOSE things seized, you have some kind of major issue. Even the non full floating (standard configuration) pistons from Mahle shouldn't seize...or any decent piston for that matter.
The wrist pin is oiled from splash coming off the rod journals on the crank that flings up onto the cylinder walls, then is scraped off by the oil control ring which directs oil onto the wrist pins. So if you get a seizure, you're either not getting oil down in there (indicating an oil control ring issue, or a splash oiling problem), you have a pin fitment problem (unlikely with Mahles), a heat problem causing distortion (engine overheating, detonation, pistons are too tight etc), or the cylinders might already be too overbored and distorting around and pinching the pistons under load (having the same effect as a piston that's too tight, except it occurs intermittently).
A few things though....
You don't want to go .060 over on a factory 5.0 block, don't care how good the block is. The real issue is the factory blocks have all sorts of core shift and cylinder alignment issues, so regardless of overheating issues (even at .040 over) I'd be WAY more worried about wall integrity and getting a crack in a cylinder wall or pinhole leaks.
A sleeve would probably be a better option to reuse the existing piston PN, that way you have no balance issues. Mahle pistons tend to all be within a few grams of each other, so you should be able to get away with not having to rebalance the assembly.
The real issue though, is you need to find out why it seized in the first place. Were they full floating pistons? If THOSE things seized, you have some kind of major issue. Even the non full floating (standard configuration) pistons from Mahle shouldn't seize...or any decent piston for that matter.
The wrist pin is oiled from splash coming off the rod journals on the crank that flings up onto the cylinder walls, then is scraped off by the oil control ring which directs oil onto the wrist pins. So if you get a seizure, you're either not getting oil down in there (indicating an oil control ring issue, or a splash oiling problem), you have a pin fitment problem (unlikely with Mahles), a heat problem causing distortion (engine overheating, detonation, pistons are too tight etc), or the cylinders might already be too overbored and distorting around and pinching the pistons under load (having the same effect as a piston that's too tight, except it occurs intermittently).
I made some images from the damage.
https://drive.google.com/drive/folde...i0yX2VkMEJVVWc
Just to avoid I describe the problem wrong (sorry, English is not my native language): The piston got pinched by the cylinder - the pins are OK as far I could see.
The seizure happened while driving under load on the Autobahn around 105-110mls. It was the first time I pushed the car - the engine is only 2y old and has around 2000 milage. I drove that speed for about 3mls distance and noticed a vibration in intervals. I thought it is a accumulation of tire and maybe drive shaft imbalance.
Oil pressure and water temp were fine at that moment as far as I can remember.
