05-18-2020, 04:05 PM | #1 |
Senior Member
Join Date: May 2010
Location: Alabama
Posts: 3,268
|
Rod Clearance
Installing a Scat 4 1/4”” stroke crankshaft and H beam rods in a 59A block. What’s the minimum clearance I can get away with between the rod and the bottom of the bore. ? I can get a .070 feeler gauge between the rod and block.
|
05-18-2020, 07:08 PM | #2 |
Senior Member
Join Date: Jul 2015
Location: SouthWest Michigan
Posts: 363
|
Re: Rod Clearance
My personal opinion is i would be grinding a spot in the block to the rod will clear and get more clearance
Wish I could tell u how much to take out but more id better than not enough Sent from my iPhone using Tapatalk |
Sponsored Links (Register now to hide all advertisements) |
|
05-18-2020, 07:11 PM | #3 |
Senior Member
Join Date: Dec 2010
Location: East Coast in CT
Posts: 1,538
|
Re: Rod Clearance
Usually on a stroke that big some lower bore relief is needed. I use a plastic Ty-rap to check clearances the ones I have measure a bit more than the .070 When I can get the Ty-rap in between the rod and bore I stop grinding I like to see at least .100
Ronnieroadster
__________________
I use the F word a lot no not that word these words Flathead , Focus and Finish. "Life Member of the Bonneville 200 MPH Club using a Ford Flathead block" Owner , Builder, Driver of the First Ford Flathead bodied roadster to run 200 MPH Record July 13, 2018 LTA timing association 200.921 in one and a half miles burning gasoline. First ever gas burning Ford flathead powered roadster to run 200 MPH at Bonneville Salt Flats setting the record August 7th 2021 at 205.744 MPH |
05-18-2020, 07:25 PM | #4 | |
Senior Member
Join Date: May 2010
Location: Alabama
Posts: 3,268
|
Re: Rod Clearance
Quote:
|
|
05-18-2020, 08:24 PM | #5 |
Senior Member
Join Date: Sep 2011
Location: Christchurch New Zealand
Posts: 1,614
|
Re: Rod Clearance
Just been reading on such items seem to recall a figure of 0.110 quoted for this clearance.
Phil NZ |
05-18-2020, 09:07 PM | #6 |
Senior Member
Join Date: May 2010
Location: Alabama
Posts: 3,268
|
Re: Rod Clearance
|
05-18-2020, 09:22 PM | #7 |
Senior Member
Join Date: May 2010
Location: East Shore of LAKE HOUSTON
Posts: 11,118
|
Re: Rod Clearance
Ronnie's 0.100" surely seems to work for him, and I've seen HIS tach buzzing near 8 grand-ish! DD
|
05-18-2020, 09:30 PM | #8 |
Senior Member
Join Date: May 2010
Location: Alabama
Posts: 3,268
|
Re: Rod Clearance
|
05-18-2020, 09:48 PM | #9 | |
Senior Member
Join Date: Dec 2010
Location: East Coast in CT
Posts: 1,538
|
Re: Rod Clearance
Quote:
Its worth the effort I can say from experience rod clearance is extremely important. Just go easy on the cylinders towards the oil pan rail side of the bore that area is not extremely thick. The area towards the inside /center of the block is a bit thicker at the bottom of the bore from what I have learned. Ronieroadster
__________________
I use the F word a lot no not that word these words Flathead , Focus and Finish. "Life Member of the Bonneville 200 MPH Club using a Ford Flathead block" Owner , Builder, Driver of the First Ford Flathead bodied roadster to run 200 MPH Record July 13, 2018 LTA timing association 200.921 in one and a half miles burning gasoline. First ever gas burning Ford flathead powered roadster to run 200 MPH at Bonneville Salt Flats setting the record August 7th 2021 at 205.744 MPH |
|
05-18-2020, 10:12 PM | #10 | |
Senior Member
Join Date: May 2010
Location: Alabama
Posts: 3,268
|
Re: Rod Clearance
Quote:
|
|
05-18-2020, 11:40 PM | #11 |
Senior Member
Join Date: May 2010
Location: Long Island, NY
Posts: 1,052
|
Re: Rod Clearance
Assuming you have a 3.312" bore size you will be fine with .050" for a "streeter", it's all you really need!
We've sent dozens out with .050" clearance and absolutely no grinding using the 3.312" bore x 4.250" stroke! It's not an issue unless you "spin" a rod brg! The only time we've found it necessary to grind in any add'l clearance is when you have the 4.250" stroke and the bores are smaller than the 3.312", e.g., for an .080" o/b you'd be grinding some! Thanks, Gary in N.Y. P.S. Due to the limited amount of room in this area it is the main reason we use the Scat rods, they will clear, the Eagle H-beam rods with a 1.100" beam width will NOT go with the 4.250" stroke in the program!
__________________
http://www.stromberg-bulletin.com/me...berg-equipped/ Last edited by GOSFAST; 05-18-2020 at 11:42 PM. Reason: C |
05-19-2020, 01:49 AM | #12 |
Senior Member
Join Date: May 2010
Location: Qld, Australia
Posts: 4,224
|
Re: Rod Clearance
Gary, what if you used the 21a rods,
Lawrie |
05-19-2020, 04:53 AM | #13 | |
Senior Member
Join Date: May 2010
Location: Alabama
Posts: 3,268
|
Re: Rod Clearance
Quote:
|
|
05-19-2020, 08:15 AM | #14 |
Senior Member
Join Date: May 2010
Location: Long Island, NY
Posts: 1,052
|
Re: Rod Clearance
Hi Lawrie, I would surmise due to the difference in the beam widths on the Scat (.790") and the OEM type rods (.710") you'd have more room with the OEM's?
The Scat rods are reasonably "straight" along the beams from top to bottom while the OEM's are tapered some. The area of contact at the bottom of the bores is about where the sizes are written on the beams? Thanks, Gary in N.Y. P.S. Here's a shot of both rods comparing the actual beam widths, you can see there would some slightly add'l room with the OEM's.
__________________
http://www.stromberg-bulletin.com/me...berg-equipped/ |
05-19-2020, 05:31 PM | #15 |
Senior Member
Join Date: May 2010
Location: Qld, Australia
Posts: 4,224
|
Re: Rod Clearance
OK , the originals would be better though if using the floaters ?.
Lawrie |
|
|
Sponsored Links (Register now to hide all advertisements) |
|