Hello again, decided to make this its own thead after getting fed the advice that I should. I have an 8ba (actually an 8rt) flathead that I'm currently rebuilding. Originally I had planned on just giving it a bit of a freshen up, like just new gaskets, that sorta thing. Its kinda snowballed like everything seems to though. I had pulled the pistons out of it and noticed the rod bearings were quite worn and decided that it at least needs those bearings. The main bearings seem pretty nice however. I noticed the pistons were not in the engine in the order that was stamped on the caps and that the caps don't seem to match the rods. I've also noticed this weird ugly wear that 2 rods seem to have. One question I have is has anyone seen anything like this before? I'm never built a flathead, or any engine for that matter so this is a bit beyond my knowledge. As for the block I've been looking over it carefully for cracks like I'm assuming any of you would on any flathead. I've only found this one tiny one that really I don't think I'm worried about at all Its barely visible, but its the line coming off the bottom right of the head bolt hole there. However in that photo I'm sure you're gonna notice the groove to the left of the top of the bolt hole, and that's leading me into a second question. Its got a bunch of weird notches in the deck on the passenger side, like someone took a cold chisel to it or something similar.. not quite sure I understand why someone would do something like that. I'm going down the rabbit hole of "well I guess this things getting decked" but my only worry is that these grooves are pretty deep. How deep can I really deck this block before I have to worry about clearance issues, I'll just be running the factory 8rt heads on it that might just get skimmed, if that, and nothing too big for a cam. I'm sure I'm going to have more questions as I go along building this, or going back through my photos of other things I've pulled out of this engine. Thanks in advance for any help, I really appreciate it.
8BA rods are plentiful and cheap. Find a set that hasn't been mismatched and have them resized and rebushed. Then you can put your new bearings in those. The small crack heading to the cylinder seems to stop at the edge of a sleeve. Is that right? I'm guessing that cylinder cracked and was sleeved long ago. Probably will live longer than we will. The weird staking marks look like they were somebody's weird attempt at locking the valve seats into place. I can't think what else they would have been done for?
I have seen marks similar to that,,,,it is usually done by accident . If someone is trying to remove a stuck valve assembly with a bar of other tool to pry with . You can easily mark the deck in that fashion,,,,,the decks are fairly soft in that regard . I’m looking at an enlarged pic of your crack,,,,,,I can’t see a crack . I think your bolt holes are fine . As for decking the block,,,,,,I don’t think you need it . The cylinders were sealing good around the fire ring,,,,,no leaking looks like around the gasket . Do you plan on having it bored ? If not, ,,I wouldn’t go to the trouble to deck it . You can take a piece of square tubing,,,,,,2x2,,,,or 2x3,,,,,,wrap a piece of sand paper around it and go to town . You can make those decks pretty slick with just a few minutes work . Try it,,,,you’ll be surprised how good they will look . Tommy
Best you get yourself a better set of rods and then have them rebuilt The crack you mention as long as it goes from water hole to bolt hole there's nothing to worry about. If the areas on the deck that have you concerned simply sand the decks like Tommy above wrote. You can use some JB weld epoxy to fill any deep areas and simply sand the areas flat if your still concerned. Ronnieroadster
Looking again at your crack pic . That might be a crack ,,,,but I’m not certain,,,,it doesn’t seem to go all the way to the bolt hole . It really seems like a scratch mark or something on the deck . This engine has been apart before,,,,,so maybe someone got overzealous in trying to clean the old gasket surface. If not,,,,,,,I’m with Alchemy,,,,if it is a crack,,,,it will probably outlive all of us . I marked a pic with a red line,,,,,it doesn’t seem to go to the edge all the way . Replace some rods ,,,bearings,,,rings ,,gaskets,,,,,good to go . Oh yeah,,,,,add a good valve job too . Also,,,,,,listen to Ronnie and the others,,,,,some of the smartest guys here on Flatheads! Tommy
Thanks guys, that's what I was hoping to hear with it. What you marked with red is what I believed to be a crack, I'm not 100% certain it is. Once I get the engine fully disassembled I'll go over the decks with something to make sure they're clean. I've pulled all the valves out today and started working at the guides, which is proving to be difficult. I have them soaking in some PB blaster hopefully I'll have better luck tomorrow, then all I have left to do is pull the cam out. Learing as I go.
You might already know this but whatever you do, do not clean out the threads for the head bolts / studs with a standard tap. If you do you will have trouble getting the threads to seal. There are a number of previous posts on this.
I would not worry about the marks on the deck. Here’s why, Mercedes Benz diesels have a bad problem with pitting on the deck of the block, their fix(factory approved) is to take a titanium epoxy putty and fill in all of the damage, then file and sand it smooth. I’ve repaired several blocks this way and all are in heavy truck service and still running fine with no problems.
Alright gents, I have the block basically down to a bare block. I have a question for the New England locals, what machine shops do you guys use for flatheads, I'd like to take it to one that actually knows these motors and not just one that tells me "yeah we'll do that" Also is there any advantage to an aluminum cam gear? I was looking on h&h and they're like $50, just wondering what the real point to an aluminum one is.
Don't know how far you are from Uxbridge but Joe at Joe's Antique Auto would be a good person to ask for a good machine shop. Joe knows old Fords AND he is one heck of a nice guy. (508) 278-3980 https://www.joesantiqueauto.com/
The aluminum cam gear is because the replacement fiber gears are pretty crappy . New aluminum gears are really good . Tommy
Looking closely at the one it appears the highlighted red crack ends at a previous sleeve yellow. As is noted and should be OK. But have you looked good at this one? Is it a crack?
As far as i can tell looking at the block it doesn't appear to have been sleeved, that mark i i believe is from the headgasket. And that second one I'm fairly confident isn't a crack as i cannot seem to even find that mark on it now that I've wiped the deck off again.
One more thing (famous last words) there's a swap meet coming up on the 17th, I'm gonna see if i can score anything good. If i were to try and get my hands on a merc crank, are the rods different for an 8ba crank? Or do they make up for the stroke difference with the piston?
Yes you can use the 8BA rods with the merc 4" crank, and yes you are correct it is the pistons that make the swap work with the merc crank. And I know that to be true as I have real word experience with this swap.
You should stop wasting your time on the internet and take the block to a reputable shop and have it magnafluxed and pressure tested. If that checks OK, have both decks surfaced the same amount just to clean. The finish on them now along with all of the "dink" marks will cause head gasket problems. Those rods are junk. Look for a rebuildable set that have not been in a lack of oil failure. An excellent source of flathead rebuild info is the public library, and it is free.
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