Stroker block boring - Done! (pic)
07-17-2004, 12:01 PM
#31
Rennlist Member
Hi Andy
Sunnen makes an excellent bore guage for checking piston holes, and yes it is about $2k. A standard bore snap micrometer won't work well enough. You need 3 points of contact for a good measurement.
Adam, make sure to use some very gentle car wash soap and wash the hell out of every head bolt hole with a bottle brush and the same with every other bolt hole on the engine. If you have any crappy water pump holes, timesert or helicoil them now instead of later. Clean the oil gallery etc and run a stone over both halves to clean up any burrs.
Hey Marc, you said that you have a tool that measues to half a hundred thousandth of an inch? What is it, where did you buy it, and how is it mounted? I know of many race teams and know that there tolerances are held to around 0.0001 inches. I also visited Ford and GM in Detroit checking out there race and engine design specification, engineering and manufacturing facilities and they were about 0.0005 inches on bores for. I am sure there CART and IRL projects that Chevy was involved with has advanced, but I really have to hear more about this tool. Piston manufacturers can only hold 0.0001 inches so to go to 50 times more precision seems highly irregular.
Let me know.
Good luck!
Sunnen makes an excellent bore guage for checking piston holes, and yes it is about $2k. A standard bore snap micrometer won't work well enough. You need 3 points of contact for a good measurement.
Adam, make sure to use some very gentle car wash soap and wash the hell out of every head bolt hole with a bottle brush and the same with every other bolt hole on the engine. If you have any crappy water pump holes, timesert or helicoil them now instead of later. Clean the oil gallery etc and run a stone over both halves to clean up any burrs.
Hey Marc, you said that you have a tool that measues to half a hundred thousandth of an inch? What is it, where did you buy it, and how is it mounted? I know of many race teams and know that there tolerances are held to around 0.0001 inches. I also visited Ford and GM in Detroit checking out there race and engine design specification, engineering and manufacturing facilities and they were about 0.0005 inches on bores for. I am sure there CART and IRL projects that Chevy was involved with has advanced, but I really have to hear more about this tool. Piston manufacturers can only hold 0.0001 inches so to go to 50 times more precision seems highly irregular.
Let me know.
Good luck!
07-17-2004, 02:27 PM
#32
Rennlist Member
Thread Starter
Erik from Denmark wrote:
Hi Erik,
Sorry for the miscommunication.
Yes the pistons are Porsche/Mahle, but they are 968/944S2 pistons. Not stock for the 928. Does that clarify?
I think you misunderstood my question 1. and 2
I try again:
1. I think you have 100 mmØ as start and now you are going up to f.ex. 104 mmØ?
2. If you went up to 104 mmØ you cannot get original Porsche/Mahle pistons
Regards from Erik in Denmark
I try again:
1. I think you have 100 mmØ as start and now you are going up to f.ex. 104 mmØ?
2. If you went up to 104 mmØ you cannot get original Porsche/Mahle pistons
Regards from Erik in Denmark
Hi Erik,
Sorry for the miscommunication.
Yes the pistons are Porsche/Mahle, but they are 968/944S2 pistons. Not stock for the 928. Does that clarify?
07-22-2004, 01:30 AM
#33
Rennlist Member
Marc, tell me more about this tool!
Hi Andy
Sunnen makes an excellent bore guage for checking piston holes, and yes it is about $2k. A standard bore snap micrometer won't work well enough. You need 3 points of contact for a good measurement.
Adam, make sure to use some very gentle car wash soap and wash the hell out of every head bolt hole with a bottle brush and the same with every other bolt hole on the engine. If you have any crappy water pump holes, timesert or helicoil them now instead of later. Clean the oil gallery etc and run a stone over both halves to clean up any burrs.
Marc please read this:
Hey Marc, you said that you have a tool that measues to half a hundred thousandth of an inch? What is it? Where did you buy it? How is it mounted? I know of many race teams and know that their tolerances are held to around 0.0001 inches. I also visited Ford and GM in Detroit checking out there race and engine design specification, engineering and manufacturing facilities and they were about 0.0005 inches on bores for. I am sure there CART and IRL projects that Chevy was involved with have advanced, but I really have to hear more about this tool. Piston manufacturers can only hold 0.0001 inches so to go to 50 times more precision seems highly irregular.
Let me know.
Good luck!
Sunnen makes an excellent bore guage for checking piston holes, and yes it is about $2k. A standard bore snap micrometer won't work well enough. You need 3 points of contact for a good measurement.
Adam, make sure to use some very gentle car wash soap and wash the hell out of every head bolt hole with a bottle brush and the same with every other bolt hole on the engine. If you have any crappy water pump holes, timesert or helicoil them now instead of later. Clean the oil gallery etc and run a stone over both halves to clean up any burrs.
Marc please read this:
Hey Marc, you said that you have a tool that measues to half a hundred thousandth of an inch? What is it? Where did you buy it? How is it mounted? I know of many race teams and know that their tolerances are held to around 0.0001 inches. I also visited Ford and GM in Detroit checking out there race and engine design specification, engineering and manufacturing facilities and they were about 0.0005 inches on bores for. I am sure there CART and IRL projects that Chevy was involved with have advanced, but I really have to hear more about this tool. Piston manufacturers can only hold 0.0001 inches so to go to 50 times more precision seems highly irregular.
Let me know.
Good luck!
07-22-2004, 02:01 PM
#34
Burning Brakes
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fst951,
You can actually get a (relatively) affordable "3-leg" for checking holes - I'm trying to remember who I got it from (obviously it ain't Browne & $harpe) want to say Mitu, but I'll have to look again.
Yeah, Marc's res number is REALLY low. I haven't seen anything that accurate outside a research lab. I wonder what it is too.
Last time I checked, Probe was claiming they could hold 50 millionths on their pistons - but I don't know anybody using their stuff - it's geared domestic.
Greg
You can actually get a (relatively) affordable "3-leg" for checking holes - I'm trying to remember who I got it from (obviously it ain't Browne & $harpe) want to say Mitu, but I'll have to look again.
Yeah, Marc's res number is REALLY low. I haven't seen anything that accurate outside a research lab. I wonder what it is too.
Last time I checked, Probe was claiming they could hold 50 millionths on their pistons - but I don't know anybody using their stuff - it's geared domestic.
Greg
07-22-2004, 02:22 PM
#35
Rennlist Member
Mitutoyo makes fine stuff, but it ain't .000005 fine stuff!!! I am not familiar with the mitutoyo units for bore. All I have is the Mitutoyo snap guages to give a rough approximation. I use a Sunnen unit to actually check the bores. The Sunnen unit can actually be found for about $700 on ebay in like new condition. I dropped one once and it still works fine. Really well made for the rigors of a machine shop or careless workers.
As far as 50 millionths, it is still 10X less acurate than the previously mentioned specs for bore checking.
As far as 50 millionths, it is still 10X less acurate than the previously mentioned specs for bore checking.
07-22-2004, 02:46 PM
#36
Rennlist Member
It is manufacturered by mitutoyo, and can read down to .000050, "split a ten thou" you cant hold it and measure....nor can you hold a stock piston and take your time measuring. It really is a pain in the a$$ and you need to really want to measure to that level to go through the process. If I can figure out how to take a pic and have some free time, I will post it.
Boring and measuring are two temperature critical procedures, and take a lot of time to do it right.....
Marc
DEVEK
Boring and measuring are two temperature critical procedures, and take a lot of time to do it right.....
Marc
DEVEK
07-22-2004, 07:11 PM
#37
Rennlist Member
I agree with what you posted. I am just responding to this quote:
"I would measure the bores and the pistons. Maybe it is just that I like to measure to extreme tols...our tools can get to .000005, or maybe I just want to know the effects of the tols on engine performance. Maybe it makes a difference....well, we know it does!"
The measurement stated here is ten fold better than what you show now. I do believe that they mitutoyo can measure half a ten thousandth. I just don't believe that the jig used would likely be reproducable enough to try to analzye that accuracy. Temp is critical, I agree. So is dirt in the air when you try to get to those levels.
Thanks for the clarification
"I would measure the bores and the pistons. Maybe it is just that I like to measure to extreme tols...our tools can get to .000005, or maybe I just want to know the effects of the tols on engine performance. Maybe it makes a difference....well, we know it does!"
The measurement stated here is ten fold better than what you show now. I do believe that they mitutoyo can measure half a ten thousandth. I just don't believe that the jig used would likely be reproducable enough to try to analzye that accuracy. Temp is critical, I agree. So is dirt in the air when you try to get to those levels.
Thanks for the clarification
