The Final Hours - Last of the Long Block:Man, I must be an eternal optimist - it is always a much bigger job and takes so much more time than I think. Guess that is why I talk myself into these projects in general!
The following is from Wednesday evening - night before Buddy arrived. I needed to complete the assembly of the heads . . . which all of you flathead guys knows is a real PITA. This is doubly true on a custom engine, where you built 'clam shell' heads, have never had studs in it before, etc.. You really don't know what you're in for.
1) Assembly Tip:
Preaching to the Choir: When you have a custom engine (girdle, special mains, special crank, etc.) - it is a good idea to mark the girdle and block with your torque specs. If this engine has a life beyond me messing with it (one can only hope!), wanted the "next guy" to know what to do.
I stamped the girdle and the block with the torque settings for the mains, rods and the pan rails. We use about a .005 crush on the main caps (from the steel girdle). The stock specs call for about 150 lbs on the mains, but both Jeff and I didn't want to go that far . . . worried about cracking the block or pulling the webs out of it - so 130 it is.
2) Heads - Blue Gooooo: The FlatCad has custom 2-piece clam shell heads. Not only do we have to worry about sealing the deck surface, we have to worry about sealing the surfaces between the head pieces. As we have solid copper head gaskets (from FlatOut) - with a rubberized coating on them and stainless O-rings in the heads (mandatory with solid copper gaskets), we wanted some extra sealing insurance. (Who knows if even this will seal!).
a) Rubber O-Rings: When Chris designed the heads, he put in some square grooves around the perimeter and the plug holes - then I put in the same bulk O-ring material that is frequently used on high-pressure blower manifolds. Hopefully these O-rings, plus the hylomar will do the trick.
b) Hylomar: This is a special non-setting polyurethane concoction that is used in the aircraft industry and many others for specialized sealing/gasket situations. It is expensive and messy - costs about $55 for a brush on can (about 250 ml) and is available in a spray on can as well. We're using both:
- Spray on was used to coat both sides of the head gaskets. You spray one fairly thin coat and give it a few minutes to flash out the solvents (it never dries though).
- Brush on was used between the head pieces and also on the bottom of the blower manifold.
3) Head Studs: @#%@#$$@#$! These are one of those things that you know you need for blown applications, but you dread using them all the same. I had
temporary insanity - coated the coarse (block-side) threads with a special teflon thread sealer, put anti-seize on all the surface, put ALL of them in for one side in the block . . . and then with stupidity and optimism, tried to put the heads on!
You guessed it - not a chance in the world of putting a head on this way. (I know better, but I guess I'm too stupid to remember what ALWAYS happens with flatheads - you just can't do it this way!).
So, then I took about 3/4 of the studs out - put the head gasket back on, put the head pieces on and THEN put the rest of the studs in . . . one by one. I used anti-seize on all stud surfaces other than the coarse threads - don't forget to do this or you may never get the heads back off!
Also, we use hardened ARP 'hat washers' - that shoulder the stud and go down into the head. These really help align the stud and ensure a good torque reading. Also, they stop deformation/galling of the head itself. The head design had machined pockets to accept this style of washer.
Okay - this method works . . . here is one head on. Notice the thin line of blue Hylomar coming out - this is actually a good sign that we have good clamping forces and hopefully a good seal. This crap never hardens and about the only solvent that will cut it is MEK (not nice stuff - be careful!
).
Torque: Stock iron heads are 70 lbs -- I didn't want to go that high. I'd like to talk to some of the LSR boys and see how much they are using. (I used to go to 55 on my blown flathead Fords - but with limited boost).
I was conservative for now --> 50 lbs on the stock location studs and 35 on the 7 new ones that we added. I did NOT want to torque the new studs too much as the deck is thin (no stud bosses), and it would be easy to crack the deck and ruin the block. Again - nobody has experience with FlatCads, this is all semi-educated guess work at best. :rolleyes:
My guess is that we'll increase the torque once the engine is warmed on the dyno - as head gasket issues and water sealing are typically some of the biggest issues to overcome on LSR flatheads.
:confused:
Any experience on LSR torque on blown flatheads??? - please send me your thoughts! Address: dhays@tdci.com
Next: The following post will show more pictures . . .
Topic: XXO/BVGC '38 Chevy Coupe Build (Read 1032005 times)