Well, been a while since I posted. Been doing a lot of surfing and reading up on things, finding specs sizes, etc. I finally got around to making up my mind on what I wanted and ordered parts the past month for the bottom end. So, I have my bottom end parts and have began the machining work for the past couple weeks now. Everything has gone fairly well, had a couple broken head bolts that didn't fair so well but I got those fixed up. Balancing the crank was a tedious process, took a good bit of heavy metal to bring it up to what I needed. All looking good as of now though. Main bores mic'd out with-in spec, ok one was a tad over but not enough to justify the work. Cylinders are still stock size, for now, and have a pretty good taper in them. Block was washed, baked, and shot peened. Chased all the threads by hand, heli-coiled two holes. Block is completely decked, took .010 off of each which should be zero deck. Tomorrow will be boring the block and honing if I'm lucky. Then after that, just need to check clearances for the rotating assembly and then do some porting. So, by the end of this week the bottom end and maching work will be completed. When all is said and done it'll be 304 cubic inches and around 11:1 compression. I plan on running a Schneider 270 .395 lift cam, unless someone convinces me otherwise. Gonna cap it off with Edelbrock heads and 4bbl intake, for now until I can round up some Strombergs. Looking at a 650 speed demon carb I think. Overall I know I'm gonna be flirting with the upper end of streetable, I think. So, that's where I'm at. Input and opinions are welcome. I'll put up what pictures I have now and there'll be more to come. Thanks, enjoy!
How can you measure deck height without having the piston in the hole at tdc.?You state deck at 0 before you bore ?? How's that happen? Tig
11:1? Do you know what the phrase " diminishing returns " means? That means with a flathead combustion chamber, they will increase in power relative to compression increases but only to a point. Not to pick on your post or your build, but when I see welded in tungsten or Mallory metal slugs, sorry, but that is very poor craftsmanship and machining. That is simply not the correct way to do that, but it is easier. But I must say Ive seen worse in my career, slugs welded in vertically. Just a hole drilled into the counterweight on the balancer, and the slug dropped in the hole and welded in place. Just one of the many reasons, I turned away other shops work. Good luck with your build. TR
I didn't read where you magged the block, after all it is a flattie. I'd hate to see you invest all of that time and money to find out its seriously cracked. Also, new crank, new rods and new pistons, I wouldn't just assume you have the deck height established. TR
Read your profile, good to see a young kid taking up with a flatmotor. I'll give a little unsolicited advice... I'd build your 2nd flathead engine first as a stock engine. Get that under your belt before you go for the big inches. If you think that you;ve got the engine all figured out then read a bunch more on it. Little things will throw you. ... Did you know that the cam is not in the center of the block?...which gives each bank a different valve angle......and so forth. If you do go with the big inch engine you had better get a girdle for the center main. Once together the heads must be clay checked for clearance. Good luck from an old man who's done that.......
Nice to see another flathead build -- best of luck to you and keep asking questions whenever you need help. Couple Things to Note: 1) With those cubes, I'd run a bigger cam - probably a Potvin 425 Eliminator grind - would work well with that motor. 2) You're going to need to do a fairly big port/relief job on that block. Do this before you deck it - as you'll probably put some 'lizard tracks' on the deck surface when your relieve it. I'd highly recommend a relief for this size engine -- it needs to breathe. There are quite a few posts on the subject - read, learn and ask questions . . . a LOT of them! 3) Compression: You need flow a lot more than a high compression number. The key to flathead performance (especially in big cube motors) is flow. This means a big relief, big transfer area and lower compression. Unless you're going to run pop-up style pistons, you're probably going to have to settle for somewhere closer to 9 to 1. You need to strike a balance between flow and compression. 4) Valves: With a large motor like this, you should consider some bigger intake valves - to go along with a big port job. I'd probably go to 1.7" on the street. 5) Porting: If you've never done a flathead before - you should have somebody who really knows porting help you out - or you're very likely to "hit water" and ruin the block. If you have a good block - you won't want this! If you have any questions, drop me a PM . . . or lookup some of the various posts on the subject - we have some real experts on this site!
Just curious about 2 items, first, it appears you have Ross pistons(?) and Scat/Eagle H-beam rods, what bobweight did you come up with??, and second, what made you choose the Scat shaft for the Flattie! I ask these because we've done numerous stroker builds and have never needed "Mallory" for correction. I have used only the Eagle shaft, most times the 4.250" piece, and have ended up removing 225 gms from the rear and 90 gms from the front. This was with a 1530 bobweight! In the conn rod area, the Scat rods are a "plus", having some 30 gms less due to .320" narrower beams and .110" narrower pin-end widths. They will support 300+ HP with ease! They also require much less "fitting" in the blocks at the lower bore sections due to the beam widths! Both brands use the CB610P Pontiac/Buick rod brgs! (Add) The only "Mallory" we've done was on a recent "stock" rebuild, with a 4-ring piston setup, and basically, we install the slugs the same way as yours. Pressed-in horizontally and welded in place! We only needed to add 20 gms on each end. This was with an "OEM", 4.000" stroke, Merc crank with a 1640 bobweight! (Add-2) I would also recommend doing the oil-filtering mod for the "95%" filtering setup. Easy mod and works really well. The stock M-19 Melling pump delivers 35# pressure at (hot) idle and 60# running, this is with .003" clearance on the mains and .002" on the rods. This was a recent dynoed build for us. Thanks, Gary in N.Y. P.S. Good luck on your build!
I salute you on taking on the flathead. That being said... Take a trip over to roadrunnerengineering.com and buy the book http://www.amazon.com/Blown-Flathead-Build-Supercharged-Ford/dp/1880047810 which is no longer listed at his website but is loaded with all the information you will need to get the right parts together for dyno proven performance in both blown and naturally aspirated engines. This includes a mountain of flow bench data and dyno proven packages. Stop spending money on parts until you read that book cover to cover and spend a few days looking at his website. There are other recipes out there, but Joe has spent an incredible amount of money and time to get dyno proven recipes to the public. You won't go wrong if you follow his advice. My favorite piece of advice from him is with regard to boost and compression, stating that you are better off with higher boost and lower compression pistons than the other way around and then proving it. Good luck!
Ok, forgot a few things. Yes, I magnafluxed the block. Had two cracks each deck from water to bolt, the ones between the outsude two cylinders. Everything else checked ok. Yes I know mallory doesn't get welded in. It's pressed in. These are but there was one that was a light press that we didn't trust so we went ahead and welded them for insurance. Yes I know you can't tig cast. Lol and I certainly know not to put mallory in the bottom of the counterweight! Luckily this operates in the dark and if it sees daylight its for bad reasons! The deck height I figured off of specs that I found. Yes I won't know for sure until its assembled, but purely by the math it should be. I know should is a bad word. The decks are still the same angle, I didn't try to "true 90". Lol and yes i am regretting the Scat choice. Of course I somehow missed the eagle crank and found it after I already had the part. Scat metal is really soft and its like they kept the stock counterweight but added the stroke so it came up light. My bobweight was 1580. I have arias pistons, I didn't order a rotating assembly just parts. I'm liking the questions and pointers, thanks a lot!
You can't tig cast?? Let us know why not.How about the lifter adjustment what do you plan on there.What spec's did you find on the deck height to determine the cut on the block. Tig
Sorry, tig, I misspoke. You obviously can, but from my understanding just not the best. I remember using powdered iron and spray welding provided better bonding. I think you know what I'm talking about, is that correct or not? That's how I understood it at least and what I was more thinking of.
One more area of concern with these Flatheads is the cam to cam bearing clearances. For all the years we've been doing these units, it's one of the least checked items during the preassembly checking period! Over here we measure the block holes first then the actual cam/brg clearance. These number are recorded on all the job sheets for the customer! Many of the blocks have cam tunnel holes that are on the high side and then some. Recently we've begun a program to have the new cam brgs "Teflon" coated for 2 reasons. First, you can "close" the clearance down slightly, and second, you get much better wear from the "Teflon". The holes can be closed up by as much as .0005"/.00075" with the coating. Worn cam brgs on these Flatheads can be a worse source of internal leakage for oil pressure problems than worn mains/rods! Thanks, Gary in N.Y. P.S. On many SB's and BB's we get to see the "Teflon" condition when these builds come back for freshen-up, some every year. The cam brgs look the same as the the day they were installed, no wear whatsoever, with the "Teflon" intact!
I have been thinking about coating pistons both top and skirts, Ceramic top and that "teflon" on the sides. I never thought about that but it does bring a good point to do it.
Tig welding and spray repair are 2 different processes Welding melts the base material and causes the bond with filler rod.. spray is usually for surface repair and build up.Tigging cast with correct filler is done every day. What were the specs you looked up in reference to your deck height?
I used specs off of a program called prosis, not sure how popular it is, but we use it for specs on any engine building here at school. Really good database and from what I can tell, accurate. All specs I could measure readily were correct. I also cruised around the web and checked sites and seemed to come up with the same answer. The spec for the block deck height was 10.446-10.447 I believe, don't have the paper in front of me. So to find the height of the rotating/moving parts it starts with half the stroke, 2.125; rod length, 7; and piston compression height which is 1.311. So that all adds up to 10.436 height, so it should have been a ten thousandths cut to get the piston flush with the deck. That's how the math worked out and hopefully holds true.
"Crap shoot" you need to put together a rod and piston brg assy and stuff it in all four corners of the block to establish what you have. Then make some calculations from that.You have a 50/50 chance of being correct.Waiting till you bore and do the above mentioned proven method you will be 100% correct no more money just a procedure. you will still have to measure anyway to confirm your findings.What did you save?Definitely not time and accuracy! Tig Tig
Yeah, exactly. Proves nice in the math, but I won't know until I do that. Either way I should still be ok.
Thanks. Well, I didn't get as much as I hoped done today but it'll be finished boring tommorow. I only got one bank done cause we did some practice runs on another block to figure out the new Rottler. Just wanna take my time to not screw up. Here's how it went and what it looked like.
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