I have my 59ab block thats been bored .030...well since i have that 4x2 intake I decided to go full bore with the motor so to speak...how big can i go what are the limitations on the block I was thinking of going with a SCAT rotating assembly and making it a 304ci...its got the 3-3/8"bore and 4-1/4" stroke...is it to big to work or can i use it...also camshaft for the set up here is the total run down for the engine...planning on Harrell heads, edelbrock 4x2 intake with 4 new strombergs, fenton headers, Harman Collins dual coil...just looking for help on building the internals
before you get carried away, find a shop that can sonic test the cyl wall thickness...3 3/8 is pushing the envelope. think cyl wall balloning, overheating probs etc. ive gotten water jacket with just 3 5/16 bore . also that long stroke can lead to to stupid high piston speeds, cyl wear and oil control problems. itll probably run like a raped ape, but dont expect to get 20k miles from it....
thanks good to know...this is the first big bore flathead im thinking about...im still a little worried about it...i do have a good flathead guy but he is more of a stock rebuilder...guess i need to make a trip down and talk to him
If you are going to go big-cube, then you'll definitely want to do some real porting work, probably relieving, larger valves, etc.. You'll end up with quite a bit of money/time invested in the block. Due to this, don't bore it out to the max - as you'll not be able to rebore it later on . . . which causes you to scrap the block with all the port/valve work. I'd consider 3 5/16 to be an ideal bore - with whatever stroke floats your boat. It is a good idea to have the block sonic tested --> with every bore tested and documented. You'll want to know if the block has any core shift. If it does, when they rebore it, they can move the holes a bit to compensate. If you have any other questions, let me know. Dale
Core shift has split many a flatheat cylinder wall......if its getting toward the thin side......you could sleeve that cylinder.....as B&S said.....stroke is where its happening.....as long as you have professional help choosing parts as not to disrupt the balancing..........your parts have got to be matched! And after all is said and done.....everything needs to be balanced if your Really gettin' on out there on the stroke. And you also have to keep your piston speed to a tolerable level or you could break some rods..........but a good engine builder can get ya on out there. With increased stroke......your maximum top RPM is lowered.....but power goes on up!!!!
Conventional wisdom is that MOST 59A and 8BA blocks can go to 3 3/8's BUT there has been lots of time for rust since the wisdom became conventional. And remember sonic tests one spot, and will not notice a divor right next to the spot. It is a crapshoot with odds getting worse with time, and people did sometimes lose a brand new block back when you could get them. Probably OK, possibly the last bore if it is OK. 5/16 is a safer and probably cooler bet, and in the future with some custom ordering you could rebuild it in small increments rather than jumping to 3/8 or 7/16.
Some guys have done this, but I'd prefer to not have an engine with 8 sleeves in it - especially at 3 3/8 inner bore. Boring into the water jackets and removing all that material for 3 3/8 sleeves makes the whole block a lot weaker. The original bore material helps strengthen the block and ties the deck down to the rest of the block . . . all the way to the bottom. The decks on flatheads are not all that strong to begin with, so one should really think about having large 3 3/8 sleeves - with no or little of the original bore left for internal support. This is even more true with a blown motor.
Yes - many did come from Ford with sleeves -- many were sleeved back to 3 1/16 and others to 3 3/16 (Fords were 3 1/16 for 221 cubes). Ford was not a wasteful guy - if a block had a problem in the machine centers with a bore, they'd typically sleeve ALL 8 cylinders, not just one. Also, there were many 'replacement blocks' that were sleeved to 3 1/16 - just so they matched the originals. Why they didn't just put 3 3/16 blocks instead - who knows. I've also heard that Ford sleeved many of these blocks so they could just replace the sleeve liners and easily rebuild the motors. I don't know if this was due to the war or if this was a general practice . . . or if it is a myth or the truth. There are so many flathead 'stories' -- there is no way to separate truths from myths! Strength Question: Keep in mind that in these engines, that there is still plenty of bore left to support the deck and tie things together . . . as they didn't need to bore past the original cast iron to sleeve back to those smaller bores (like you do when you sleeve to 3 3/8) - so the blocks are still strong. Also, in some cases the sleeves were pretty thin - not like most of the sleeves we use today. The story is much different when you bore past the bores to put eight 3 3/8 sleeves in.
I have done the 304ci modifications on my last french flathead. Full ported and gasket matched, Literio l100 cam, isky springs, 1.6 valves. navaro heads and intake. Aluminium flywheel. Joe Hunt Lookalike Magneto. Crazy engine, it is true that it is comming hot fast, but never hit more than 190° it is a screamer! real power, real pleasure, but as many people can tell you, this engine will not stay alive 20 000miles.... But what a pleasure to drive it! http://www.youtube.com/watch?v=aMeRWBB4psc I won't do that in the next flathead, I'm thinkin about 296ci low compression and blower.
I don't recommend 3 3/8 because it gets really close on the gasket. Also if you sleeve to 3 3/8 there very little original deck surface and my pull the deck surface up. Stick to 3 5/16. For every 3 3/8 engine running great there are 20 that did not work.
Hey Mike: Thanks for chiming in . . . it is always good for folks to hear the practical side of 'flathead lore'! I'm in 100% agreement, that is why 3 5/16 is my bore of choice.
Ford didn't sell engines with repair sleeves...if they needed that, they would have been repaired by melting! Sleeved original blocks had very thin sheetmetal sleeves, about .040 thick with a thicker register at top, meant to allow rebuild by just resleeving with a simple puller/pusher tool. 3 1/16 and 3 3/16 blocks were different castings with different diameters at outside of cylinder castings. 3 5/16 is pretty safe on all fronts mentioned above, I think, with maybe a 3 3/16 limit on engines born as 221's. many engines do fine at 3/8 and even 7/16, but you are taking a considerable risk even after sonic. I also think 4 1/4 is too much stroke for rod length, giving piston rock and early ring and wear problems. Not for street engines.
I had an engine 3 3/8+.030X4 1/8 301cubic inch. Cracked the block in several places. Remember you have to fill and empty those big cylinders through the same roundabout passages as a smaller engine.
You are obviously thinking of building what we used to call a mild street motor. With the 59a block I would definetly have it sonic tested NO MATTER WHAT bore you choose to go to. At most places you have this done, you can specify what spacing increments the test is done at. Pay extra and have it done as close as they will do it. Chances are you will be ok at 3/8. Remember bigger is better..ALSO remember, at 3/8 you will have enough for at least 2 more bore jobs...They seldom need more than .020 to clean...No problem with 1/2 inch stroke...SCAT cranks are WAY heavy on the throw sides so you can take as much off there as you have time to do..Saves money later on at the balancer shop. You do not want any heavy metal used in the balance job. As far as an engine like this not lasting more than 20K miles, I say horse hockey. Properly built, they will last at least 75K miles. The last engine I built was 323 ci. Who knows how many miles it has on it by now. The one I'm working on now is 345 ci. but it is a race engine. 4 carbs is kewl....Works good...H&C ign is kewl. I can help you with a cam.
No way!! They have to run 30 lap main events..20 laps on the half mile tracks. First bore is 3 3/8 +.030.
Guys used to build 3/8s by 3/8s motor all the time. That was when flatheads were fast. Unless this is a race car running in a flathead class, it's not going to be considered fast by many people. If I was building a nice street motor I would go with a 3 5/16 X 4. I might step up for the scat crank. Havn't looked at them. But I would rather have a stock Merc crank if I was doing this.
Hi Dale , really great to accidentally find you on HAMB after all these years . Just picked up an 8RT complete core and will do initial teardown in the next couple weeks . Got it from our old friend Alan on Gramercy . How far can I go on c.i. without hollering ," No don't do that !" ? I'm living down the street from where Mr Shaw lived so I can afford a presentable reliable and powerful flattie .
Hey Flathead Freddie - great to hear from you, but can you give me your full name . . . so I have a clue as to where in my past our paths crossed (sounds like in Torrance - in our pre-college years!). If you mentioned Mr. Shaw, then it has to be Highschool - now that is going back a ways! I haven't been on the HAMB much in the last few years - have been too busy in too many other things - cars, design work, software development, etc. So, what are you building the flathead for? As noted up above, I'd probably go with a 3 5/16 bore for a street engine - most can be bored that big and still have material left for future bores. There are multiple options for crankshafts for the street - from original Mercury cranks, to SCAT, to EAGLE, etc.. It really comes down to the complete combination that you want to put together (and the application) - as all the components need to be "sized" to fit the build. And of course, then there is the "budget" aspect . . . the bigger they get, the more needs to be done to use the cubic inches . . . so the more they cost. LOL Drop me a PM and we can take this offline . . . be great to catchup a bit . . . after what . . . maybe 45 years or so! LOL
I ask because there is info says the 8RT is beefier casting than a 8BA . I've not weighed the motor at this time .
Old Flathead Wives Tales! And there are plenty of them to go around. The only way to know anything is to take it apart, clean all the rust/crap out of the water jackets and then sonic test the heck out of every bore - in about 12 places each. Then you'll now what you have to work with. Keep in mind, that even if you think you have material left - there can still be rust pockets that get into a cylinder (which can be sleeved). I like to keep cylinder wall thickness (after boring) to a minimum of .150 on the street.
Ok a PM when I figure how . Easy for you Ha! I stuck with the wrench so perhaps you can tell me how to start a PM . This is Anthony with the light grey primered 34 truck . Sold it for a college stint and Freddie is the 8RT planning on 32 Tudor from County Line but still shopping no hurry yes perfection or nothing . So how do we navigate a PM or is it necessary I think alot of members will get a kick out of this . Never been to a high school reunion but then again Flatheads Are Definitely Forever
Go to the top of the page/site and you'll see an envelope icon - there you can start a private conversation. I went to one reunion . . . looked in the door of the ballroom and thought to myself "Hell, can't be this room - that is full of a bunch of old goats . . . wonder where our room is???". This was over 20 years ago - and it was the RIGHT room! LOL
Hi Dale Hope your day is ok and we'll for you . Conversations I am limited probably due to me having to build a profile . The black box pops up but mine only says " Show All " on the bottom line . No Icon to start conversation . Question for you please can you summarize Core Shift . Is it torque stress or from seizing or churning damage in water jackets . Freddies not apart yet but will start teardown Thursday . The two head bolts Alan used for the sling look great but inside the water pump and thermostat throats feels pretty bumpy so seems Freddie ran with straight water for along time . After teardown it's off to Harry at Vellios . If I have a seized bolt I have a NoMar brass hammer a can of powerful non greasy penetrant and if at worse an acetylene brazier outfit just to expand things a little . Haven't pulled a plug yet so let you know more Thursday . Is there any way to coat the water jackets in the block ? I'm open to the idea of hiring Plasma Technology for any thermal efficiency and longevity processes they may have . Time fo zzzz now got an A and a cougar at a client's to build up in the morning . You stay well smart and happy now . Anthony,
Hi Dale , looks like teardown got moved to Saturday . Client cars first . I am real thankful for all who advise me on Freddie's rebuild . Screaming Metal spoke of power over RPMs . I'm building a highway star so long hills and alot less overheating sssoooo yes Merc 4" stock rods 3 5/16 pop-ups with nice accumulator pad ( thinking of cutting grooves in that area ) and that should allow for open relief area . If one breathes so does the other . I like the original Offy with Quadra Jet ( I've other secrets too ) so long as compression can hit 8.5 - 9 with pop-ups compensating for the relief . Heads Offy or shave the 8Rt's and relief them for 1.6 valves on adjusters and run a cam from maybe .380 would be swell . It's going in a fiberglass bodied Tudor so weight control is good . Like to back it with a DG 4+3 or an automatic from an older 300ZX Thunderbird OD or get lucky with a Lincoln OD who knows that's paste work for later . Time frame is now till completed at least a grand every month for now . Will let you know Saturday what's inside . Exciting stuff . Have a restful evening Thank you Anthony
Just a note and maybe a bit of advice. I tried adapting a Quadrajet to a flathead about 3 years ago; I use a Sharp 4 BBL manifold I had laying around and a couple of adapters (Quadrajet to Holley; Holley to Square Bore) and everything bolted together easily. I could NOT get it to run decent. The general consensus here was that stacking that many adapters and trying to change the airflow that much was a non-starter. I still have all the parts, and may jump into it again, but I'm not as excited about it as I once was. Also, I am not willing to do any modifications to the Sharp manifold in an attempt to make it work. https://www.jalopyjournal.com/forum/threads/quadrajet-on-a-flathead.1110317/
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