8BA Piston Removal...Success!!!

[cadillac512]

Originally Posted by Fortunateson

Cadillac512 and Tubman,

Thanks for the comments. I re-did the math to get a preliminary wear of between .0025-.0045 in the bores. Still need official measurements especially taper. But if I'm at the wear indicated a re-ring would be fine? Not trying to build or drive crazy but it will get what it needs. Price isn't the issue but what does it need....

I just finished a 260" Merc (4" stroke/.030" over bores) for my '41 Merc. The block had been bored in the past and was worn .003"-.004" at the tops of the cylinders but pistons were fine. I reamed the ridge at the bore tops and honed lightly to break the glaze. Put it back together with a set of Hastings cast rings,leaving the bottom oil ring off the 4 ring pistons. I have 1500 miles on it in the last couple months and it runs great and uses no oil. No piston noise either.

I completely disassembled the engine and cleaned it ( hot tanked and crack checked )same as if it were getting a full-on rebuild. All new bearings and clearances checked.

If yours checks out I'd sure do the same if it were me. Be sure to check the top ring lands for wear!



Terry

[Bored&Stroked]

I don't know - looks like there was quite a bit of rust in various areas of the bores. If true and if there is pitting, then why throw it back together without boring it? Heck, pistons are not that much money for stock style rebuilds and you're going to buy rings anyway. You can probably get a set of pistons and rings for $200 - $300. I'd just do it right and know that it is right . . . but hey, it is your engine, not mine! LOL

[Fortunateson]

Borrowed a pickle fork from a club member and went after the valves. First half hour I tried to pull those retainer clips. They weren't budging so... instead of following the official procedure I went about it a little backwards. First I released the keepers, then that conical disc, pulled out the valve, pulled the spring sideways to "spring" (LOL) it loose, and then gently tapped th evolve guide down to release it. Only two moderately stubborn. Bagged and tagged. For my next trick... cam and lifter removal. Pics later.

[cadillac512]

When I take the valves out of a old flathead, I pry each valve open and stick a 5/16" nut between the valve and seat to hold it open. When they're all open I pull the cam out with the engine upside down so the lifters are away from the cam. Then pop the nuts out, remove the keepers and the springs will fall out the bottom through the guide holes. Then the guides are easy to tap down and out.

That's my weird method, LOL!


Terry

[tubman]

Terry,

That sounds like a real good idea, The only downside I can see is that you may bend some valves, but if you're going to replace them anyway, who cares.

[Mart]

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That's a good idea above. I might try that on the next one I do.

[Fortunateson]

Well I got the lifters and cam out. The cam was a little hesitant but finally yielded. I would have thought it would have pulled right out? Anyway, on Thursday I'll be taking the block and its various bits to an old time engine rebuilder for assessment...

[Fortunateson]

Just checked the crank and it has the well know Merc dimple!!!

[Fortunateson]

B6AD29C5-622D-48C0-AF7F-53C7314E82D9.jpg

C95D3DEA-D431-46B6-B34E-57BBBE7428D1.jpg

61DAEC50-160B-407F-BC9B-85D86AEB64E0.jpg

81B23025-51CE-4CDA-9D56-CC6D19761441.jpgHere are some pics after I removed the valves, guides, lifters, and crank. An any tell if that is a stock cam? I figure if they had swapped in a Merc crank perhaps the changed the cam as well.

Well a couple of pics didn't load so I'll try again...

[Ol' Ron]

Yes, that is agood idea, I'll have to try that. Learn sumpin every day.

[Fortunateson]

Haven't done an update for awhile.

The engine shop discovered two or three teeny cracks from bolt holes to coolant circulation holes, the kind with their own part number. They will probably get pinned at any rate. One crack goes into a cylinder so one sleeve needed. Two weird cracks by the upper centre bolt hole to circulation hole. Engine shop looked and found that this area isn't a big deal as that it initially looked like it would easily pull a chunk of the deck out if over torqued. In reality it is anchored into th rest of the block. Kind of like and island in a river, it ain't going anywhere.
Engine came apart like it was built last week.

Started taking apart my C1BA which I think is a '51-53 block. I really just want the original Johnson lifters to use and they will get surfacing. However, this second engine had been rebuilt with very few miles on the clock. Bearings look quite good as do the cylinder walls. However.... five of the valves and one piston are so frozen it's like they were part of the block casting. I can't get the valves to lift up after removing the keepers and I even tried oxy/ace on hem to heat them up to see if the rust bond would give. The piston will be sacrificed. The engine shop is going to tank the second block for a short time as the cam bearings will contaminate their tank solution. I'm hoping that the valves will free up in order to get them out and finally the last five of those lifters. I may have to cut the valve spring and valve stem if they don't free up. I want to remove the last five guides. That however leaves me with a problem of getting the shortened valves out... wedge them out after I got the lifters? The shop says the second block might need two sleeves and the valve seats look kind of horrid so new seats perhaps. I'm going to keep this block but the first block is the one that's going to be rebuilt.

Advice appreciated!

[flatheadmurre]

Holesaw with a thin plastic sleeve on outside...holesaw should have the diameter just above the inner diameter of ring grooves. Drill down past uppper 3 rings...then pistons usually go out.
For valves...plasma cutter...cut stems and and springs...push lifters up...take cam out.
Plasma cut valveheads around stem...put a pipe on outersize just under guide...drive guides down into valley.
May seem like a bruteforce aproach but it works...
Pounding on a real stuck piston and you may damage cylinderwalls...crack them.

[Fortunateson]

Yeah I thought about the holesaw trick but I really appreciated the plastic sleeve idea! I don't have a plasma cutter so I was thinking cut off wheel for the valve stem and perhaps holesaw for the top of the valve.

[flatheadmurre]

For valvestems the big boltcutter works better then trying to shoehorn down an anglegrinder...

[Aarongriffey]

Good trick Mart. I must try that.
I bought an 8ba 11 years ago with the heads off, in a big wooden box, uncovered, in a three sided shed.
I got one piston out but cant get any more rod caps off. I’ve been soaking them with acetone/ATF but never been able to turn the crank to get at more caps.
I recently bought a boxed set of used rods so now I can torch off the rods that are holding me up. But first I must try the Magic Mart Trick.
As for bore or not to bore.............If you bore it to the next size there will never come a time in a few years from now when you will wish you had not done it, whereas if you just ring it.......

[Fortunateson]

I like the bolt cutter idea.

[Fortunateson]

Originally Posted by Aarongriffey

Good trick Mart. I must try that.
I bought an 8ba 11 years ago with the heads off, in a big wooden box, uncovered, in a three sided shed.
I got one piston out but cant get any more rod caps off. I’ve been soaking them with acetone/ATF but never been able to turn the crank to get at more caps.
I recently bought a boxed set of used rods so now I can torch off the rods that are holding me up. But first I must try the Magic Mart Trick.
As for bore or not to bore.............If you bore it to the next size there will never come a time in a few years from now when you will wish you had not done it, whereas if you just ring it.......

I am going to have my 8BA block bored to the next suitable size, perhaps only .0300 over.

My second block was a bit of a bugger but loosening the main journals allowed a wee bit of movement and I was able to free them except that one last piston.

What is the "magic Mart Trick"?

[tubman]

Any 8BA that won't support at least an 1/8" overbore ain't worth havin'.

[Fortunateson]

We'll see about the final bore dimensions...

I think I've come up with a better way to remove whatever is left of the stuck valves after I cut them in order to get the lifters. If they are still stuck I'm going to weld a redirod/allthread coupler to a piece of steel plate and then insert a bolt. Just a handy dandy jack screw should solve the problem.

[flatheadmurre]

If the valves are really stuck...they won´t move even with the biggest sledge in the shop...you need to drive the guide down a bit to get the horsehoeclip out...or bruteforce pull the clip out...then drive the guide up.