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I’m using 5/8” bolt head , not 11/16” , head bolts on my 239ci 8BA . Just wondering if I should be using flat washers because of the smaller bolt head size. Any thoughts ?
Tim
I’m using 5/8” bolt head , not 11/16” , head bolts on my 239ci 8BA . Just wondering if I should be using flat washers because of the smaller bolt head size. Any thoughts ?
Tim
Good question. What is the grade of your 5/8" headed head bolts? Any washers for that purpose should be grade 8 and SAE sized, not a sloppy nominally sized washer.
Just curious.....how is this possible? if it was originally an 11/16 bolt how are you managing to get a 5/8 to thread in and hold?
But, i see no reason why you couldn't or shouldn't have a washer on there providing it was like Bob mentioned and was the right sized washer for the bolt.
Just curious.....how is this possible? if it was originally an 11/16 bolt how are you managing to get a 5/8 to thread in and hold?
But, i see no reason why you couldn't or shouldn't have a washer on there providing it was like Bob mentioned and was the right sized washer for the bolt.
Bobby
7/16" bolts (all grades) have a 5/8" hex head. The "heavy hex" (oversize hex) come in some larger sizes 1/2" and up. 7/16" nuts are also 5/8" for all grades, with the exception of "heavy hex" nuts which are 11/16" hex. The 11/16" hex 7/16" head bolts are a special grade, approximately between grades 6 and 7.
I might add that machine threaded bolts are better than roll-threaded bolts.
Another problem will be that the blocks and the OEM head bolts are a tighter-than-standard thread class, to prevent leakage. Hardware store bolts will not have as deep of thread engagement.
As far as washers, you'll probably need them to prevent water leaks. Grade 5 should be fine but should be SAE washers as noted. Rolled threads are fine.
VanPelts offer a 7/16 “ head bolt with either a 5/8 “ hex head or 11/16” hex head . My thought was it may be better to have a washer with the smaller 5/8” head . Maybe I’m just over thinking things .
Im using grade 8 bolts
thanks for all your input , I appreciate it .
Tim
If you use washers make sure you use a thread lube on both sides of the washer. You'll need to do this in order to get a good torque reading. Also rolled threads will give you a better torque reading than machined threads. The thread surface is smoother on a rolled thread than a machined thread thus giving a more accurate torque reading. I learned all of this being an engineer in the nuclear energy business where accurate torque readings are essential. I second Mixer Man's recommendation on the thread sealant to prevent leaks. It will also lube the threads when torquing, i.e. until it hardens.
Tim, if you still have the original head bolts, compare their lengths to the new ones. The decks on flat V8's are notoriously thin, so you want the same amount of thread in the block. Washers might reduce that too much.
I'd also torque to 55 ft-lbs, not the manual's 65-70.
The Nuclear power industry used the Electric Power Research Institute to do research on the technical needs and to produce uniformity in practices and procedures in the industry. My knowledge about bolted joints comes from their research papers. That research showed that to get uniformity in the torque application to the bolted joint, that rolled threads produced the the most consistent results. Or that is what my over 40 year old engineer memory tells me.
The Nuclear power industry used the Electric Power Research Institute to do research on the technical needs and to produce uniformity in practices and procedures in the industry. My knowledge about bolted joints comes from their research papers. That research showed that to get uniformity in the torque application to the bolted joint, that rolled threads produced the the most consistent results. Or that is what my over 40 year old engineer memory tells me.
My engineering memory is older than yours, and undoubtedly more faded , but then again this isn't about nukes or rocket science, it's about a 60-odd year old Ford engine. But I can tell you this fwiw, - a 90,000 HP Sulzer 12RTA96 diesel engine has no rolled threads in it anywhere.
My engineering memory is older than yours, and undoubtedly more faded , but then again this isn't about nukes or rocket science, it's about a 60-odd year old Ford engine. But I can tell you this fwiw, - a 90,000 HP Sulzer 12RTA96 diesel engine has no rolled threads in it anywhere.
That is what I love about engineering, everybody's experience is different and those differences still produce excellent results. If your engineering memory is older than 73, then you are older than me and great for you.
I only refer to nuclear power because that is my experience and it can be applied to other things. We all still want to make the 70 year old flathead run without leaks, You makes your choices based on what you think will make the old girl run.
One thing I have learned from this forum, is that it will give you a fountain of good information all intended to help you out in some way.
Thanks for your well considered and kindly information and opinion.
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, but then again this isn't about nukes or rocket science, it's about a 60-odd year old Ford engine. But I can tell you this fwiw, - a 90,000 HP Sulzer 12RTA96 diesel engine has no rolled threads in it anywhere.