On the dyno last week, the Caddy flathead made 570 HP. While we were very pleased, we're far from convinced that we have done enough to make the engine survive. Plus, I'm are looking for a lot more HP! So, what can I do the strengthen the bottom end of this 3 mained beast? It has a Crower billet crank and rods, billet mains, and a 1.25" thick steel girdle. The girdle is installed with .005 crush on the caps, with ARP studs. I'm considering dowels, cross bolts, and a girdle that has the mains milled right on to it. I need some advice/direction from serious HP engine builders, experienced racers, etc., on the course to go. Any ideas?
Unless Im mis understanding the pic.......Use proper length Main studs so that the shoulder is to the block.....in other words ....no threads exposed block side Studs will flex at the threads..... Dowels are good ..but I dont know if you have room......a doweled stud area maybe A way to side bolt the caps through the block sides mid cap is nice if possible.... Tying the bottom together and keeping it from moving around is whats going to keep from breaking itself..... Are the caps walking around now? The pan rail girdle is good.....a one pc w/the caps is always better..might be over kill at that power level Billet crank will be a lot stiffer than a stock style...this is good Also keep the rotating weight as light as possable as well as the bobweight pieces Tony
I did something similar with our 57 Olds.....1200 hp right now 7.0's 197mph My girdle is deeper as our caps are not flush with the pan rail Tony
Tony, thanks for the info. We've tried to keep this thing solid, but we were only thinking of 500Hp. Now that the goals have changed, so the build will have to also! I'm concerned that with more HP, the mains will try and walk. As you know, I need to dind a way to keep this solid, so I don't grenade the block.
38Flattie If it were me, I'd go back and ask John Beck (Pro Machine). If anyone could help with at least some suggestions, he'd be the guy. He was able to make a multi-thousand horse nitro fueler run for 5 minutes, and live. Jim
Have you considered making and using of the additional "side main bolts" like a Hemi, Big Ford, new chevy LS series and Tony the "goatroper" is doing? For all but especially on that lonley center cap!
John Beck haven't hered that name in awhile i worked across the street from his shop in anaheim cal,he is one of the best in the bissnes
Jim, I'm picking his brain, along with everyone else's! Yes, except I called them cross bolts in the original post. Actually, in my first meeting with Fowler, we discussed this. Somewhere along the line, this was overlooked.
Future problems are not going to be with the main caps. It is going to be the main bearing webbing, which nothing can be done about. IMO, this is where this block is going to fail. The stiffer you make the caps and pan rails, the more abuse the webs are going to take.
I agree, that one of the two fail points I'm concerned about is the webbing. The other is the cylinders, due to pressure. I disagree, however, that nothing can be done about it. There is always an answer and solution-it just won't be an easy one! 5 mains would help, I was just hoping to avoid that cost and time consuming option!
TR If the mains were built to meet the webs than cross bolting would seriously stiffent the lower end including the block. Something along the lines of the braces that Mondello made for the lifter valley for an olds mobile. Just a thought, a stud girdle helps but being able the cross bolt the mains ties it together real well. It will require building new mains for sure.
Ask Ron Main, his FlatFire made 653 HP. Im sure anything Landy did to his could have crossover possibitlities for the Caddy engine.
Different cl*** then your Caddy, better set your sites on Ferguson's GMC. More power to you if you can bump wallets with them guys. Landy is who built Mains flathead
Here is the BLOCK POSTING link in case others are curious, http://www.muller.net/sonny/crx/engine/posted.html
Very good tip Tman I have not seen this before, but again I'm just a freshman Buddy, I understand your concern, but as said above, The main webbing will be the weakest points. I have thought about slanted bolts in the center, but we found out that we probably weakes it by drilling even more. I don't know if this is the case with the Flatcad but? Also this: A known LSR record holder with a Ford Flathead, making 600+ hp, spunn out rewing the pore Flathead 8800 rpm. producing 32 psi of boost. 3 mains with a solid girdle, keeps it together and no major damage! Br Kjell ............................... Taildragger&fenderless
The webbing will be a concern, but not one that I feel we can't overcome. We'll try and tie everything together, from every direction. Still looking for the magic answer, if anyone has ideas!
Not sure what kind of arm is in that beast but I'd pay an equal amount of attention to limiting crankshaft flex. A good forging with extra large main journals and journal radii will help the bottom end live. Maybe add a crank snout support to limit crank flex. You may have built enough strength into that bottom end already. Remember...the big show top fuel cars run with aluminum main caps but their cranks are really stout. Best o' luck!
Thanks! Been there-done most of that! It has a Crower billet crank. Stock main bearings were 2.49", and we went to 2.75" Chevy BBC mains, billet main caps, with a BBC crank snout.
Buddy, how much clearnce do you have on each side of the center webbing? betveen it and the piston/rod? If you have space, how about making a solid plate on each side, going all the way down the valley contecting it both in the block and girdle? K ................................ Taildragger&fenderless
With maybe a plate that you could bolt to the other side and sandwich the center web,might have to drill through and sleave the bolt holes.
can you machine the faces of the sloping areas next to the centre main flat, and make the centre cap the same angle,so its like a big triangle and then machine a 'keyway' down the centre of the angled surface,so it locks in as you slide it in? this then would take any vibration forces off the longish studs, and allow them to just work as a clamping force, with location taken up by the keyway along the angles surfaces. Im no big HP engine builder, but just applying lateral thinking . this may, or may not be viable.
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