Projects FlatCab: 1932 Cabriolet, Hot 1941/42 Merc Flathead Build

I'll be here! Happy Easter!

 

Flathead Crankshaft: 1949-53 Merc, 4 1/8 stroke, Nitrided/Heat Treated:

As I've mentioned earlier, I've never Nitrided a flathead (cast) crankshaft - well, decided that since I really like this crank, why not try it and see what happens? Here is a basic description of Nitriding (a form of heat/metal treating):

Nitriding is the most prevalent method of heat treating used in aftermarket cranks, where ionized nitrogen is vacuum deposited onto the crank surface in an oven. By penetrating .010 to .012 inch into the metal surface and changing the microstructure of the steel, surface hardness is doubled from 30 to 60 on the Rockwell scale, and fatigue life is increased by 25 percent.

Read more: http://www.hotrod.com/how-to/engine/0710phr-crankshaft-tech/#ixzz3ZPzngQ2U

The crankwork was completed at Fowlers - and they sent it to Mile High Crankshafts in Colorado . . . took about a month to get it back. The process isn't cheap - about $250 or so. My goal is to have much tougher journal surfaces and an overall stronger crankshaft - to hopefully add to the overall longevity of this nice stroker crank . . . over time, I'll check the bearings and see if I like what I'm seeing. I've used nitriding on all my custom/billet cranks, why not try it on a Merc?

With a cast iron crankshaft, the nitriding process will create a sort of surface 'slag/scale' type material - especially in areas where the casting is rough. You must take the time to remove this, or some of it will flake/wear off and get into your oil and bearings. On areas of the crank that were previously ground smooth, there was very little scale . . . on areas like the side of the various counter-weights, quite a bit to remove.

Note: When the crank came back, Dennis (the crank guru) at Fowlers checked it to validate journal uniformity and crankshaft straightness - everything was spot on.

I double taped up all the journals and got out my trusty porting tools and spent about four hours getting the crank prepped. I'm just about ready to install it!

 

By cleaning the crank does that affect the balance any? Appears that a good amount was removed. I know, dumb question, just curious.

 

That is actually a good question. As it was really surface scale . . . and on all sides of the crank, I ended up doing all surfaces. There really wasn't much removed (I made sure of that) . . . all of the smooth surfaces on the counterweights were done before balancing was complete. I'm quite picky about balancing, but not really concerned in this case. Thanks for asking!

 

Thank you for your answer. That crank looks like a piece of art.

 

Crankshaft Installation and Seal Plate Rework:
In a previous post, I talked about bearing clearances, checking them, not having the rope-seal in when you do so, etc.. There is a LOT of prep work that goes into this BEFORE you put the crankshaft in for the final time!

1) Crankshaft Timing Gears - What Year?: As most of you probably know, there are TWO different crankshaft timing gears to be aware of - the 39-48 gear has the teeth angled such that the thrust of the camshaft timing gear is directed TOWARD the block, while the later 49-53 (when they changed the distributor location) has the teeth angled the opposite way -- forcing the camshaft timing gear away from the block.



This is very important in that if you happened to score a Merc crank, have it reground and just throw it into your 39-48 flathead, then the thrust will wear on the timing cover as the front-distributor mount cover was not really designed to be a full-time cam stop. So - make sure you use the 39-48 timing gears on an earlier motor. As a matter of fact, I like to use the earlier setup on even the later motors, but I make sure I setup the camshaft thrust clearances to be what I want. I'd rather have the cam on the front of the block, then pushing on the timing cover (buy hey, that is just me).

When you install the gear on the crankshaft, don't forget the key and also put some anti-seize on the snout (never a bad idea). I use a big pipe to drive the gear on - it should go one without an issue:



2) Rope Seals: There are TWO aluminum/pot-metal seal plates (one in the cap, one in the block) that hold the rope seals. The best rope seal to use is the Best Gasket's GraphTite rear seals - I highly recommend them!. They include a nice little kit and a set of instructions. They recommend the installation of a 1/16 roll-pin into the seal plate to keep the seal from potentially rotating with the crank. It is an easy installation - just drill a small hole and install the roll-pin with about an 1/8" protruding.



3) Test Fitting the Seal Plates - Important!: The rear main seal plates install in machined grooves in the block and the rear main cap. When I test fitted my block seal plate (before the gasket sealer or rope seal), I noticed that it was sticking up ABOVE the block surface a bit. It is CRITICAL that you check this - especially if you have had your block align bored/honed.

See what I'm talking about:



You see, when a block is align bored, material is either removed from the rear main cap mounting surface or the block mounting surface. Once this happens, then the seal plate will be too tall . . . it needs to be machined to match the correct depth! This is a very easy thing to not check and then your rear main cap will not correctly sit flush with the block. This is a very bad situation to have - and one that most people won't catch as most of us don't even take the seal plates to the machine shop when we have operations done.

I used a depth mic to figure out what I needed to remove on the seal plate - put it in my mill and machined it as such.



4) Installation the Seal Plates, Seals, etc: I use a very slight bit of high-temp silicone gasket sealer on the mating surfaces of both seal plates. This is to prevent oil from seeping past them. When I disassembled this Merc engine, it had two very thin paper gaskets underneath the seal plates - with a red gasket sealer on them (first time I've seen that). Just spread a small amount on both plates - prior to installation.



Use a wooden block and a rubber hammer to ensure they sit all the way down in their mounting grooves. Just follow the Best Gasket's instructions on the rear seals - they will be extra long, so you'll cut them about .015 above the seal plate with the supplied box-cutter knife. Use a BIG socket or other round form to make sure the seals are all the way down in their grooves - before you cut them off!



I put a small amount of silicone sealer on the ends of the seal plates (where the two meet) - to help prevent any oil from seeping by these mating surfaces.

5) Crankshaft Installation: This is just normal routine stuff. I use Redline assembly lube (that red/pink stuff you see in some of the pictures). I also fill the bearing shell grooves with it. I figure when the engine first starts, it is a good idea to have a lot of this stuff around!.

Word of advice: If you have main studs in the block - REMOVE them before you try to lift the crankshaft in! It is really easy when you're lifting this 60+ lb chunk of iron to hit the main journals on the edges of the studs. If you can't easily remove them, then 'cap' the ends with some thick duct tape to protect your nice new crankshaft!

6) Seating the Rear Main Thrust: When you get the crank in the saddles, have the caps on and have them partially tightened (before you do your final torque), I use a big wooden block and a 2 lb hammer on the front of the snout to drive the crankshaft back and ensure the rear thrust bearings are firmly against the block/caps. I give it a couple decent whacks before I finish tightening/torquing down the main caps.

7) Crankshaft Rotation - Check it!: Now that you have the rear main seals in, the crankshaft will be a lot tighter as far as hand turning it goes. Even though I checked all clearances and had previously installed the crankshaft to check everything out, I still make sure that the crank can be turned by grabbing the counter weights, that it doesn't bind up in any particular rotation, etc..



Ready to install #1 pistons and start checking cam/valve timing . . .
Okay, enough for now . . .

B&S

 

Dale, it appears your front main studs might be too long to clear the oil pan.

Fantastic documentation of your build. Will you be doing the same on all your builds??

Flat32

 

Hey Ray - thanks for checking in. I'm trying to create/write as much documentation as possible - might help the next guy. I tend to over-document, so I'm sure I'll be doing this on most things I conjure up - glad you appreciate it.

You're probably right - haven't tried the pan as of yet! If they are too long, I'll either cut them down, or have ARP send me some shorter ones. Much appreciate you giving me a 'heads up'! Hope to see you soon my friend.

B&S

 

Hi Dale:
Your thread on building a flathead right is the best. Great detail and clarity. Thanks for taking the time putting it in on the HAMB. Let us know when the book is available!! TEB

 

Thank you for taking the time to read it . . . I know that I babble on at length at times. I have enough pictures and real material to write a book, maybe I should do that to pass on to the next poor bastards building these goofy motors that we love!

 

As i have said before Dale, You need to get this published in a Book

/K

 

Camshaft Timing Setup - Degree Wheels, Dead Stop, etc:
Anybody who knows me, probably has figured out that I've always been into/fascinated with camshafts and all the various styles, grinds, performance claims, etc.. I have all sorts of flathead cams - many that I've never ran. The whole reason I'm running this roller cam in this build is because I've had it 30 years (since I made the core and had Isky grind it) - and I just want to hear/see it run. Starting when I was about 20 or so, I started manually graphing camshafts (even Harley KRs) - so I could visually 'see' them, overlay the different plots/curves and compare them. Ed Isky used to tell me to "don't show that stuff to people" - guess he was worried that some dang secret would get out.

I have camshaft software that uses either manually entered lobe information or specialized camshaft analysis jig data to plot the profiles/curves of the lobes (Performance Trends Cam Analyzer) . I manually record all camshaft events with the cam in the block - every 5 degrees of crankshaft rotation and then enter all this stuff into my software and analyze the results. I will get into that on a following post . . .

Anyway, I always 'degree' a camshaft and not only determine the timing specs (sometimes they are WAY off, and I won't use the cam) - but to also set it's position (advanced, straight up, retarded), etc.. If you don't do these things - how are you supposed to have any clue as to how your cam's timing events are actually setup and if it was ground correctly? I'm not one to just throw it in and pray . . .

I needed to make a new degree wheel setup to plot the roller cam, compare it against some others (in the same block), etc..

I took a late crankshaft hub (with the flange on it), made a degree wheel adapter and it works just great:



Once I had it mounted, I setup TDC and validated it with both a dial indicator as well as a dead stop. It is super easy to make a dead stop - all you need is a big washer (round the back side edges a bit - so you don't mark the piston crown) - and a 7/16 NC bolt. To check TDC with a dead stop, here is what you do:



1) Mount the dead stop . . . duh!
2) Mount the degree wheel . . . duh!
3) Slowly rotate the crankshaft in the normal/clockwise position until #1 cylinder comes up and the piston gently touches the dead stop (it can't go past it). Record the reading on your degree wheel.
4) Rotate the crankshaft in the opposite direction - until you once again gently kiss the dead stop with the same #1 piston. Record the reading on your degree wheel.
5) TDC will be exactly the MIDDLE location between these two dead-stop points.
6) Remove the dead-stop.
7) Rotate your crankshaft and degree wheel to the 'middle point' and setup your TDC pointer to match this location for 0 degrees / TDC
7) Now place your magnetic dial indicator mount on the block and validate that the piston is at the top of it's travel and that the degree wheel and pointer are at TDC.

Stay tuned - have some fun camshaft stuff to share in the next post . . . with plot curves and other such fun!

B&S

 

Beautiful. Yes, for sure a book. So much fantastic information. Thank you sir.

 

I'd buy a book. I plan to copy all the engine building steps out of this thread and save them as a pdf, in case you don't write that book. Thanks for sharing all the details.

 

Pistons, Chambers and Coatings: I've used ceramic thermal barrier piston coatings on other projects - namely the FlatCad Bonneville engine . . . with good results. Now I'm not going to sit here and make all sorts of claims as "to coat or to not coat" . . . these debates have been going on for years and I'm not going to attempt to take a major position - as I don't really have enough of my own facts to support it.

What I do know is that lots of folks swear by coatings and a whole hell of a lot of NASCAR, NHRA, LSR and other racing folks use them . . . so why not try them on the street? I've read a lot of articles by a lot of high-end engine builders - this technology sure seems viable in my eyes.

If you send your pistons out to be coated, you'll probably pay $35 - $50+ per piston to get it done . . . not cheap. I decided to look into it a bit more and determined that if you have the proper equipment and learn the details, there is no reason that guys like you and I can't do it ourselves. So - I decided that since this engine is one big fricking experiment -- lets do a variety of coatings as well.

I'm going to do the pistons, head chambers and the valve tops. The following post will focus on the pistons only and the 'prep phase'.

Here is a basic article on the subject . . .

http://www.hotrod.com/how-to/engine/hrdp-0612-engine-coatings/

To me, it is not all about a few horsepower gain, but other 'potential' benefits --> keeping heat in the chamber, friction reduction, protection against oiling issues, etc..

So, given that I like to do things myself - I decided to purchase CeraKote products . . . as I've heard good things about them, their application engineers were happy to talk to me, etc..

I'm using two coatings: A ceramic thermal barrier coating for piston tops, valves, combustion chambers, etc - and a friction reducing coating for piston skirts, lifters and other such things.

1) Piston/Thermal Coating: http://www.cerakotehightemp.com/finishes/V-136Q/piston-coat-oven-cure/
2) Ceramic Dry-Film Friction Reduction Coating: http://www.cerakotehightemp.com/finishes/C-110HQ/micro-slick-dry-film-ceramic-coating/

Today I masked off my pistons, put them in the blast cabinet and used the correct aluminum oxide material in 100 grit to prep them for the coatings. Once I blasted them, then I used ScotchBrite to polish all the blasted surfaces a bit - as they do get a bit rough. I masked off the ring lands and protected the pin-bores with wine corks.



Once blasted, then I baked them in the oven for 30 minutes at 300 degrees - just to ensure that no oil or other crap is on them (even though they are new). You need to be extremely careful to NOT touch the surfaces with your bare skin/fingers - you'll need some latex gloves for the handling.



Tomorrow I'll put the thermal barrier coating on them and cure them (I bought the oven cure version), then the skirt coatings.

Check back tomorrow for more details . . .

 

I wanna see that 9 cyl flattie

 

Hopefully I'll ALWAYS have that 9th piston to show off . . . .

 

Curious, with blasting, is there any concern of taking more material off one location than another, making the piston out of round by a few thou?

This is my favorite thread on the HAMB

 

Thanks! No - as all you're really doing (especially on a new set of pistons) is lightly blasting and preparing the surface such that the coatings have something to 'bite into' . . . such that they stick/last. On the FlatCad Bonneville engine, we've used two different coatings providers. The coatings on our pistons held up well - especially after we had them re-coated by 'Diamond'.

The original chamber coatings were not a heat-cured variant and we were not impressed with them at all. As I'll be prepping and coating the chambers on the old Eddie Meyer heads, will be very interesting to see how well it holds up over time.

One of the potential side benefits of the micro-slick anti-friction coatings is that they can help out in a situation where there is a short/temporary oil supply issue - they might save a piston skirt - or a bearing/journal. Same with ceramic coatings on piston domes - might save a piston in a too-lean situation. This is not as big of an issue here (NA street motor), but with a heavy amount of boost in a racing situation (especially like Bonneville - long run times), the coating might just save one from a melted piston and a resulting catastrophic failure.

That is the fun of all this experimentation - we'll have real world results in the future!

 

Man, this is a great thread!

 

Those pistons are finer than the silverware at the

 

To finish. Those pistons are finer than the silverware at the Ritz!! TEB

 

dale, does the coating affect the diameter, therefore the piston/cylinder clearance? the reason i ask is, my machinist was disappointed when i showed him my pistons that were coated by Swain tech. he wanted to measure the pistons BEFORE they were coated.
tom

 

For dry film lubricant types of skirt coatings, most piston manufacturers say don't worry about the coating, bore/hone the block to the uncoated piston dimensions - as the coating will be very thin (.5 to 1.0 mil or so). With that said, there are some coating processes (Diamond has one) that are multiple stages --> including hard anodizing and a thin-film lubricant. In these cases, the pistons need an extra .002 or so of clearance . . . as the 2-step coating process will take up the .002. Obviously the machine shop would need to know this - to get the piston to bore clearances correct (if they had the raw/naked piston in their hands).

The skirts of these custom Ross pistons measured 3.3075 before blasting/coating - for a 3 5/16 bore. I'll measure them after the coating process just for shits and giggles. The CeraKote C-110 micro-slick coating goes on very thin - it really kind of binds into the pores of the sand blast 'craters' and very lightly coats the outside. When I spoke to the application engineer, he said they actually add 'tint' to the coat as it would normally be clear. The tinting/pigment makes it possible for the applicator to see that they've create a thin and consistent coating. As this is the first time I've used it . . . we'll see shortly (pistons are currently in the over curing the ceramic heat coating on the domes).

 

Pistons for Dinner Anyone . . . Hope You Like Well Done - Is the Only Way We Serve Em: Today was coating day.

1) Domes - Ceramic Thermal Barrier Coating (TBC): I masked and sprayed to tops of them with a ceramic thermal barrier, used a small HVLP touch-up gun, with the fan turned down to narrow.



This gun worked really well. I let them dry for about 20 minutes and then put them in the oven at 175 degrees for about 30 minutes - to 'gas out' any remaining solvents. Then I turned the over up to 300 degrees and let them cure for another hour.

Took them out - mighty tasty looking!



2) Skirts - Anti-Friction Coating: The MicroSlick coating that I'm using is an air dry product - so I could not put it on the same time as the TBC dome coatings. I masked the ring lands and domes off, put corks in the pin holes and then sprayed two light coats of the skirt lubricant on every piston. This material goes on very thin - so you really want a small gun to lightly apply the material (still wet sprayed), but not too much to run it.



This coating is air-cured - so it drys to a 'handling' stage in about 24 hours, then you 'burnish' it with a very fine steel wool by hand. Then it needs to cure for a total of 5 days before assembly. If you're shipping the pistons - you can do it after the 24 hour period. I've ordered another type of friction coating that is over-cured, this will save me the 'wait time' when I do my valve stems, rod and cam bearings and other such stuff.

Here yah go - four more days of waiting . . . . tic-toc, tic-toc, tic-toc . . .

 

Man .... you are so money. I love this.

 

Thanks for your interest in my goofy shit!

 

Just to clarify dale you are cooking that in the house right lmao Looking good my friend

 

Damn right! I only have one oven . . . works for all sorts of stuff . . . pistons included. Notice the nice 'cookware' that I used . . . it is all groovy stuff - serves up just right with a nice bottle of wine!

 

I know right hell my kitchen looks like a speed shop right now with a 4-71 blower a eelco fuel tank and a hilborn injector sitting on the kitchen table but hey not only is it a safe place to keep it but it stays way cleaner than the shop lol