The Ford Barn

TStiles · 12-17-2012, 02:22 PM

I'm in the midst of a conversation with a guy regarding cylinder bore on an 8BA rebuild using stock crank, cam, etc. The plan is to go .020 over original (the block has never been bored).

He states that it would be advisable to bore an extra 1 thousandth because the clearance might save the day for pistons in the case of an overheat situation.

Wisdom of the Barners would be appreciated on this.

Thanks,
Tim

V12Bill · 12-17-2012, 02:25 PM

Boil the block to clean out sand and rust and other crud. Use rebuilt water pumps, clean out the radiator so you don't overheat in the first place.

trainguy · 12-17-2012, 02:28 PM

The xrtra thou will not make much difference one way or the other.But can't hurt.Phil

Ken/Alabama · 12-17-2012, 02:51 PM

I would follow the piston manufacture instuctions on the proper clearance.

Karl Wolf · 12-17-2012, 04:36 PM

Yup, Ken, me too... Read manufacturers instructions, they'll have info that will work for their product...
Karl

s nichols · 12-17-2012, 06:24 PM

Sponsored Links (Register now to hide all advertisements)

id go .060 or get avalible off shelf piston- boring is done smaller than size then honed to final size according to piston measerments- you must have pistons before proper boring to instructions

Frank Miller · 12-17-2012, 06:36 PM

I thought my block would clean up at 20and ordered pistons. There was an eyebrow at top of bore and had to go 40. Like the guys said whatever is recommended. If there is anyone near you that does thermal cleaning then that is the way to go.
https://www.youtube.com/watch?v=MSp09dhYSio

Ol' Ron · 12-17-2012, 07:39 PM

I go .125 over and use Egge 3 ring pistons. Nothing runs like a 258.

Kahuna · 12-17-2012, 08:00 PM

What Ron said

ole39 · 12-18-2012, 10:47 AM

thats what mine is.

s nichols · 12-19-2012, 06:08 PM

Frank is right-measerment of bores should shoud be done first - to see what they are - they might not clean up at .020

Ronnie · 12-19-2012, 07:45 PM

Quote:

Originally Posted by trainguy

The xrtra thou will not make much difference one way or the other.But can't hurt.Phil

That extra thow will open up the ring end gap by .00314"

R

Frank Miller · 12-19-2012, 10:45 PM

Ring gap will not make a significant difference. We discussed that last month. I personally would not want the piston any looser in the bore than it has to be. I have read about people over heating but I have not seen many post about siezing the motor due to it. I am sure by 10k or so you will have worn another thou in the bore and you will be where you want to be.

Ol' Ron · 12-19-2012, 11:15 PM

That's why I use Egge pistond and fit them tight. Besides a bigger engine, with more compression is more fun to drive.

t-head · 12-20-2012, 09:07 AM

I have been boring blocks here in the shop for years as mentioned earlier clean up is chancy at .020.

Instead of using cast pistons, call some one like Arias and get some of their low expansion alloy forged pistons. From our experience with many sets in both tour cars and vintage racing cars they are the only way to go and really don't cost much more. Their quality of is unbelievable.

I just took a set out of a racing engine that had seen over 3000 miles of hard use on the road and the track and they look like they are brand new. They don't even have any scuff marks on them.

They would work perfect in a flathead that might turn into an occasional tea kettle as the will not expand as much as cast pistons.

TStiles · 12-20-2012, 09:58 AM

Thanks, all. Your thoughts on this are very much appreciated. Tim

Ol' Ron · 12-20-2012, 06:35 PM

$525 a set, not much more than Egge?? and what clearance do you start with? These are exelent racing pistons, but a little over kill for a grocery getter.

Jason M. · 12-22-2012, 01:15 AM

I just purchased cast .020 pistons from Patricks. I was informed that at that relatively small overbore higher end pistons where not available.

Walt Dupont--Me. · 12-22-2012, 09:50 AM

Very seldom anybody goes .020 we always figure .030 is the first oversize. Walt

JWL · 12-22-2012, 09:59 AM

I would do mucho measuring and checking before determining a .020 bore increase would be acceptable for clean-up of worn bores. While I do not agree with the "automatic" +.125 concept I do believe in being "safe" with an overbore size decision. I think .020 is risky.

Ol' Ron · 12-22-2012, 10:56 AM

I always figger that the amount of overbore is dependent on your age. Below 50, .030". 50-60, .060". Above 60, .125". My next engine will be .187" Over.

flatjack9 · 12-22-2012, 02:13 PM

I like the way you think. Got some that are .187 + .030. Guess I'll have to wait a few years to put them in an engine.

12-17-2012, 02:22 PM	#1
TStiles Senior Member Join Date: Sep 2012 Location: Kitsap Peninsula, Western WA Posts: 276	"Boring" Question I'm in the midst of a conversation with a guy regarding cylinder bore on an 8BA rebuild using stock crank, cam, etc. The plan is to go .020 over original (the block has never been bored). He states that it would be advisable to bore an extra 1 thousandth because the clearance might save the day for pistons in the case of an overheat situation. Wisdom of the Barners would be appreciated on this. Thanks, Tim

12-17-2012, 02:25 PM	#2
V12Bill Senior Member Join Date: May 2010 Location: Mt. Holly,NJ Posts: 1,822	Re: "Boring" Question Boil the block to clean out sand and rust and other crud. Use rebuilt water pumps, clean out the radiator so you don't overheat in the first place.

12-17-2012, 02:28 PM	#3
trainguy Senior Member Join Date: May 2010 Location: Lehighton Pa Posts: 1,085	Re: "Boring" Question The xrtra thou will not make much difference one way or the other.But can't hurt.Phil

12-17-2012, 02:51 PM	#4
Ken/Alabama Senior Member Join Date: May 2010 Location: Alabama Posts: 3,260	Re: "Boring" Question I would follow the piston manufacture instuctions on the proper clearance.

12-17-2012, 04:36 PM	#5
Karl Wolf Senior Member Join Date: May 2010 Location: Mill Valley,Ca. Posts: 1,509	Re: "Boring" Question Yup, Ken, me too... Read manufacturers instructions, they'll have info that will work for their product... Karl

12-17-2012, 06:24 PM	#6
s nichols Member Join Date: Jun 2010 Location: Des Moines, IA Posts: 69	Re: "Boring" Question Sponsored Links (Register now to hide all advertisements) id go .060 or get avalible off shelf piston- boring is done smaller than size then honed to final size according to piston measerments- you must have pistons before proper boring to instructions

12-17-2012, 06:36 PM	#7
Frank Miller Senior Member Join Date: May 2010 Location: Auburn, MA Posts: 2,106	Re: "Boring" Question I thought my block would clean up at 20and ordered pistons. There was an eyebrow at top of bore and had to go 40. Like the guys said whatever is recommended. If there is anyone near you that does thermal cleaning then that is the way to go. https://www.youtube.com/watch?v=MSp09dhYSio __________________ “The technique of infamy is to start two lies at once and get people arguing heatedly over which is true.” ~ Ezra Pound

12-17-2012, 07:39 PM	#8
Ol' Ron Senior Member Join Date: May 2010 Location: Chester Vt Posts: 8,860	Re: "Boring" Question I go .125 over and use Egge 3 ring pistons. Nothing runs like a 258.

12-17-2012, 08:00 PM	#9
Kahuna Senior Member Join Date: May 2010 Location: NorCal Posts: 2,617	Re: "Boring" Question What Ron said

12-18-2012, 10:47 AM	#10
ole39 Senior Member Join Date: May 2010 Location: west central ill Posts: 170	Re: "Boring" Question thats what mine is.

12-19-2012, 06:08 PM	#11
s nichols Member Join Date: Jun 2010 Location: Des Moines, IA Posts: 69	Re: "Boring" Question Frank is right-measerment of bores should shoud be done first - to see what they are - they might not clean up at .020

12-19-2012, 10:45 PM	#13
Frank Miller Senior Member Join Date: May 2010 Location: Auburn, MA Posts: 2,106	Re: "Boring" Question Ring gap will not make a significant difference. We discussed that last month. I personally would not want the piston any looser in the bore than it has to be. I have read about people over heating but I have not seen many post about siezing the motor due to it. I am sure by 10k or so you will have worn another thou in the bore and you will be where you want to be. __________________ “The technique of infamy is to start two lies at once and get people arguing heatedly over which is true.” ~ Ezra Pound

12-19-2012, 11:15 PM	#14
Ol' Ron Senior Member Join Date: May 2010 Location: Chester Vt Posts: 8,860	Re: "Boring" Question That's why I use Egge pistond and fit them tight. Besides a bigger engine, with more compression is more fun to drive.

12-20-2012, 09:07 AM	#15
t-head Senior Member Join Date: Jun 2010 Location: In my machine shop. Posts: 1,047	Re: "Boring" Question I have been boring blocks here in the shop for years as mentioned earlier clean up is chancy at .020. Instead of using cast pistons, call some one like Arias and get some of their low expansion alloy forged pistons. From our experience with many sets in both tour cars and vintage racing cars they are the only way to go and really don't cost much more. Their quality of is unbelievable. I just took a set out of a racing engine that had seen over 3000 miles of hard use on the road and the track and they look like they are brand new. They don't even have any scuff marks on them. They would work perfect in a flathead that might turn into an occasional tea kettle as the will not expand as much as cast pistons.

12-20-2012, 09:58 AM	#16
TStiles Senior Member Join Date: Sep 2012 Location: Kitsap Peninsula, Western WA Posts: 276	Re: "Boring" Question Thanks, all. Your thoughts on this are very much appreciated. Tim

12-20-2012, 06:35 PM	#17
Ol' Ron Senior Member Join Date: May 2010 Location: Chester Vt Posts: 8,860	Re: "Boring" Question $525 a set, not much more than Egge?? and what clearance do you start with? These are exelent racing pistons, but a little over kill for a grocery getter.

12-22-2012, 01:15 AM	#18
Jason M. Senior Member Join Date: May 2010 Location: Lower Mainland B.C. Canada Posts: 136	Re: "Boring" Question I just purchased cast .020 pistons from Patricks. I was informed that at that relatively small overbore higher end pistons where not available.

12-22-2012, 09:50 AM	#19
Walt Dupont--Me. Senior Member Join Date: May 2010 Location: Gardiner Me. Posts: 4,200	Re: "Boring" Question Very seldom anybody goes .020 we always figure .030 is the first oversize. Walt

12-22-2012, 09:59 AM	#20
JWL Member Emeritus Join Date: May 2010 Location: Fitzgerald, Georgia Posts: 2,204	Re: "Boring" Question I would do mucho measuring and checking before determining a .020 bore increase would be acceptable for clean-up of worn bores. While I do not agree with the "automatic" +.125 concept I do believe in being "safe" with an overbore size decision. I think .020 is risky.

12-22-2012, 10:56 AM	#21
Ol' Ron Senior Member Join Date: May 2010 Location: Chester Vt Posts: 8,860	Re: "Boring" Question I always figger that the amount of overbore is dependent on your age. Below 50, .030". 50-60, .060". Above 60, .125". My next engine will be .187" Over.

12-22-2012, 02:13 PM	#22
flatjack9 Senior Member Join Date: May 2010 Location: Oshkosh, Wi Posts: 4,527	Re: "Boring" Question I like the way you think. Got some that are .187 + .030. Guess I'll have to wait a few years to put them in an engine.