jeepguy1948
Well-known member
Re: “B” Grind Cam
Anybody have an idea what a .100 overbore to add compression on top of a 5.5 head?
Anybody have an idea what a .100 overbore to add compression on top of a 5.5 head?
“B” Grind Cam
- Thread starter jeepguy1948
- Start date
Re: “B” Grind Cam
With the two extra bearings, the 5-bearing cams had shorter journals. The change is covered in the Ford Service Bulletins and Ford made some for use in the 3-bearing blocks by turning down the 2nd and 3rd journals so as to ease installation.
I have wondered if the use of the shorter journals camshafts had much effect on wear of the bearings in the 3-bearing blocks. Ford seems to have thought it OK to use them as such. I have one of the converted 5 to 3 journal camshafts that has little or no wear but I've never used it. A fellow that has run one in his car told me that his seat of pants perception is that the 5-bearing cams seemed a bit more peppy albeit with a slightly rougher idle.
With the two extra bearings, the 5-bearing cams had shorter journals. The change is covered in the Ford Service Bulletins and Ford made some for use in the 3-bearing blocks by turning down the 2nd and 3rd journals so as to ease installation.
I have wondered if the use of the shorter journals camshafts had much effect on wear of the bearings in the 3-bearing blocks. Ford seems to have thought it OK to use them as such. I have one of the converted 5 to 3 journal camshafts that has little or no wear but I've never used it. A fellow that has run one in his car told me that his seat of pants perception is that the 5-bearing cams seemed a bit more peppy albeit with a slightly rougher idle.
jeepguy1948
Well-known member
Re: “B” Grind Cam
I forgot, I also had to take 0.017 of the head to clean it up. So I have a 5.5 head, a .100 overbore, and a head with .017 milled off.
I forgot, I also had to take 0.017 of the head to clean it up. So I have a 5.5 head, a .100 overbore, and a head with .017 milled off.
alexiskai
Well-known member
Re: “B” Grind Cam
I would be suspicious of these anecdotal reports. There's no evidence that the design of the cam lobes changed. Most likely your friend was comparing a new part to a worn part and reporting the difference.
Jim Brierley says, "Ford made 3 versions of the 5 bearing cam, the first had all 5 bearings ground to the same size, this is the one Donovan uses. As the 5 bearing blocks were used up, the next version had all 5 ground, but the 2 intermediate ones were smaller, in the 3rd version those bearings were just rough-turned on a lathe."
If you're building a banger engine, the 5-bearing cams are said to support stiffer valve springs.
I would be suspicious of these anecdotal reports. There's no evidence that the design of the cam lobes changed. Most likely your friend was comparing a new part to a worn part and reporting the difference.
Jim Brierley says, "Ford made 3 versions of the 5 bearing cam, the first had all 5 bearings ground to the same size, this is the one Donovan uses. As the 5 bearing blocks were used up, the next version had all 5 ground, but the 2 intermediate ones were smaller, in the 3rd version those bearings were just rough-turned on a lathe."
If you're building a banger engine, the 5-bearing cams are said to support stiffer valve springs.
updraught
Well-known member
Re: “B” Grind Cam
Hi Jim,
I thought that article might lurer you out ...
Interesting to compare to the Stipe cams and Burtz.
https://web.archive.org/web/20150222092226/http://www.fordgarage.com/pages/stipecamshaftspecs.htm
https://burtzblock.com/products/camshaft
Hi Jim,
I thought that article might lurer you out ...
Interesting to compare to the Stipe cams and Burtz.
https://web.archive.org/web/20150222092226/http://www.fordgarage.com/pages/stipecamshaftspecs.htm
https://burtzblock.com/products/camshaft
Re: “B” Grind Cam
It appears that Jim Brierley was referring to the Model B cam having 3 different versions. I have never seen a Ford print that supports this for camshafts installed in Model-B engines during the 1932-34 period. However, I have seen camshafts with little wear in engines that were made during the post Model-B period, particularly in the lift ranges described by Jim Brierley, so he and I have seen the same thing. These were always in engines built for industrial applications. As to the 5-bearing camshafts being able "to support stiffer valve springs", I wonder if this was due to a change from a forging to a casting for the 3-bearing cams. Ford was noted for finding less costly means of production.
It appears that Jim Brierley was referring to the Model B cam having 3 different versions. I have never seen a Ford print that supports this for camshafts installed in Model-B engines during the 1932-34 period. However, I have seen camshafts with little wear in engines that were made during the post Model-B period, particularly in the lift ranges described by Jim Brierley, so he and I have seen the same thing. These were always in engines built for industrial applications. As to the 5-bearing camshafts being able "to support stiffer valve springs", I wonder if this was due to a change from a forging to a casting for the 3-bearing cams. Ford was noted for finding less costly means of production.
Jim Brierley
Well-known member
Re: “B” Grind Cam
That is right. There were three 5 journal cams produced. The first one had all 5 journals finish-ground to the same diameter, the second one was finished but to a smaller diameter, the third was just rough turned, and smaller to make engine assembly easier and quicker. All were of the same lobe design.
That is right. There were three 5 journal cams produced. The first one had all 5 journals finish-ground to the same diameter, the second one was finished but to a smaller diameter, the third was just rough turned, and smaller to make engine assembly easier and quicker. All were of the same lobe design.