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

Very cool, some nice machine work there. I await your next instalment.
Al.

 

Block Prep Work - Before Final Washing:
There is always a bunch of detail work that one should do on any high-quality rebuild - has nothing to do with Flatheads. I will run a tap through every single bolt hole in the block to clean them out, then I counter sink every hole and also run a large flat file across every surface (accept the deck) to remove any potential high-spots, burrs, etc.. If you think about it, these threads were originally done over 70 years ago - take the time to clean them and you'll have much better torque readings during assembly and nuts/bolts will actually be easily removed another 50 years from now. Everybody can do this stuff at home - all it takes are a few taps and some time.



Head Stud Clean Out Taps: You should never run a true 'cutting tap' through your 7/16 head stud holes - you need a special 'Block Cleaning Tap' - buy a high quality one from a place like 'Goodson'. (See the link below).

http://www.goodson.com/BCT-716-716-Head-Bolt-CleanerDeburring-Tool/

Camshaft Bearings: Always check your camshaft bearings to make sure they were correctly installed. On the two outer ones, there is a large oil hole and a small oil hole. I like to put the large oil hole toward the top of the block and the smaller hole toward the crank. I like to have every bit of bearing surface on the 'thrust side' of the cam (which is the bottom). Also, just make sure that the holes are in the right place - so oil can travel to your main bearings.


Full-Flow Oiling Modifications: I'm going to be using a specially modified 'full-flow system' oil pump. This pump does not pump the oil to the location that is normal for a flathead (into the housing and through the block). Instead, the pump is modified to take 100% of the oil flow out of the block (via a bulkhead fitting on the oil pan), run it through a full-flow filter and then bring 100% filtered oil back to the block. To do this, I'll be using one of the two/three oil ports on the back of the block. I do some modifications to increase flow . . . probably not necessary for a street engine, but this is really a race engine and I like as much oil flow as I can get. I drill the cross-port with a 7/16 drill bit - all the way to the 1/4" NPT oil-plug location at the back of the block (behind the oil-pump drive gear and plate). This location then takes the oil to the main oil galley tube that runs in the valley area. I then drill the block fitting with a 9/16 drill (by hand) and tap it with a 3/8 NPT tap. The reason is I want more flow than the standard 1/4" NPT port and fittings give. I'll cover the oil-pump and pan modification in a later posting.

Here you'll see where I'll be bringing the oil back into the block - enlarged to 3/8 NPT.



Well, all of this stuff took about 8 hours today . . . tomorrow the block will receive a final washing, then let the fun begin!

B&S

 

Great tips. Those intake ports look like a hall of mirrors; nicely finished!

 

Damn that block is gorgeous. I can't wait to see (and hopefully hear) the final product.

 

how much of a difference do you expect the port work to make?? looks like you've done a LOT of work to get this motor to flow... why only 2x2's?? what do you think of the factory crank at 4 1/8" vs the scat piece??

 

1) Port Work: This engine is really a full-on race type engine (other than only 284 cubes). I wanted to be able to flow as much as possible and experiment a bit - hence the large ports and the 1.72 intakes and the very large duration roller cam.

I'm sure the port work won't help me at lower RPMs, but my goal is to be able to spin the motor to 6,000 . . . the port work will probably start working at 3500, be in pretty strong by 4500 and really help above that. Let the dyno tell!

2) Two Carbs: The only reason is that I'm trying to stick to an 'external motif' that is very early - the Eddie Meyer heads are from 1939 and the manifold just after the war. I'm not aware of any 3 carb manifold (Edelbrock, Navarro, Sharp, etc) that fits my early motif. I'm sure it would make more HP with 3 carbs - at least at the very top end.

I am going to port the Eddie Meyer manifold for Holley 2110's - which flow quite a bit more than the Stromberg 48's (which I'm going to initially try). I used to run the 2110's on a blown flathead - they work quite well.

Dyno Data:

Fun part, once I get the new rear end built for the car (Columbia with high-strength 8620 steel internals), then I'm going to go to the chassis dyno. I'm going to compare to the current 59AB engine (well-used stocker), then the engine with 48's and then 2110's. Will be very interesting to see the torque/power curves for all three configurations.

 

Looking forward to it.

 

6k RPM on a 4 1/8 stroker... yowsers!! you said the driveline was stock on the cabriolet in your other thread.... that mean it still has the 32 transmission in it as well?? I'm guessing that will be swapped out for a 39 trans??

what's your estimate for hp on this motor??

 

I can' t wait to hear that thing sing !

 

I've updated the other thread, the transmission will be changed to a 39 box with 25T Zephyrs, the rear end will be updated to a 33-34 Columbia, with 8620 steel internals and HotRod Works 28 spline late axles. The Columbia will be the weakest part - probably the 'sun gear' driver.

HP: With the two carbs, not exactly sure, but my guess is somewhere around 200 (give or take 25). When I dyno the 100 HP 59AB, hope to extrapolate that to the 284 Merc - will be fun!

RPM: I don't have a problem with the 6K RPM, used to spin my blown 59L to 6200 and it didn't have a steel center main. I think that proper clearances, the best parts, a good oiling system and dynamic balancing go a long way.

 

I'm kinda surprised to see the full flow oil mod on an engine you are trying to keep looking pre-war. Other than race engines I think the full flow oil filter modification is not desirable.

 

The good news is that I don't have too, but probably will. I may not initially start it with it - as I have lots of other stuff to figure out - but I have the option of putting it on.

What I plan to do is modify an old Fram oil filter setup to have an internal full-flow/modern filter . . . so that car looks like it is has just another old Fram. I think few would have a clue as to what I'd just done!

 

Bearings and Clearances - My Philosophy:
I've started the assembly process for the lower end. I'm a real stickler for bearings, clearances, oil, etc -- these are some of the most important aspects of a good build . . . yet many don't spend the time or do the work necessary to truly get it right and know that they did.

1) Clearances - Objectives:
The 49-53 Merc crankshaft for this engine was originally ground about 1 1/2 years ago - for another project. My goal for bearing clearances was .002 to 0025 on the rods (full-floaters) and .0025 on the first two mains and .0025 to .003 for the rear main. This is a street engine, with a wet-sump oiling system (49-53 oil pump) - so I need to make sure that the clearances are such that the pump can handle them. My philosophy and 'style' is to run flatheads a bit on the 'loose' side - as I've found that high-performance flatheads run better with a lot of oil going through them and you need bigger clearances to move more oil. Also, with 3 main bearings a stout flathead will undoubtedly experience 'crankshaft flex' - especially in the middle, so you need thicker oil and more clearance to account for that. If this was an all-out competition engine, I'd run .003 on the first two mains and .0035 to .004 on the rear and I'd have 110 lbs of oil pressure and a dry sump system.

2) Main Bearings: I had two sets of .020 bearings in my stash -- one for 39-48 and another for 49-53. The 59AB set were Federal-Mogul - a very nice looking set of bearings. I always hand dress the back-sides of the shells with fine Scotchbright and lacquer thinner. This is to insure that the surfaces are totally smooth and there are no burrs or other "junk" on them. I also check oil hole alignment with the block. Notice that I enlarged the front oil hole on the upper bearing shell - to better align with the block (did this by hand with a bearing scraper). I do the same thing on the full-floater rod bearings - keep in mind that the back-sides ARE bearing surfaces as well (remember 21A rods, full-floater bearings).



3) Checking Clearances: I make sure the bearing saddles are perfectly clean and then I install the shells and caps. I torqued to the middle of the spec - 85 lbs (spec is 80 - 90). I then checked clearances with a micrometer (I only have a 2 point barrel type inside mic). I measured the bearing bores and the crank. The crankshaft had exactly the same/consistent size on all 3 journals.



Hmmmmm - I don't like what I saw! The front was okay - at .00225 to .0025, but the middle seemed to be about .002 and the rear about .0015. That is not good. Keep in mind, that I do not have (as of yet) a 3-point dial bore gauge (Starrett, etc) - as they are over $750. AND - it is very difficult to accurately measure with a 2-point inside barrel mic - or telescoping mic. (hence the reason I'm going to have to buy a dial bore gauge soon!). The soft bearings want to 'grab/stick' to the mic and it is very easy to be 'off' a .001 in either direction - that isn't good enough for me.

Note: I do not use PlastiGauge! If you have nothing else, it can be used - but I'm not a big fan. I've seen too many people convince themselves that what they were seeing was okay (when it wasn't) . . . it is a crude test at best.

So, I took the block and crank down to Fowlers to have them mic it and see what they see. Their long-reach dial-bore gauge costs well North of $1000. They let the crank/block sit overnight to stabilize the temperature (was in my truck in the cold). When they measured this morning - they saw what I 'thought' I saw. The front was about .0025, the middle was .002 and the rear was .0015. What the heck was going on?

So - they did the correct thing and re-checked all the machine work:

a) Pulled the bearings back out and checked the new align bore/hone - was perfect.
b) Checked the crankshaft again - was perfectly straight and on the money on all three journals.
c) That leaves the bearings . . . those nice-new FM bearings that I liked so much! Argggghh! Obviously this set is not consistent front to rear. This is not an uncommon thing - performance engine builders deal with this all the time.

4) How to 'Fix' It: I could have them 'tune' the crankshaft to match the bearings. Which means putting it back in the grinder and taking off .0005 on the center and .001 to .0015 on the rear. We both think this is a bad idea as what happens if I need to put a new set of bearings in later on . . . probably won't be the same. So, I decided to call up Speedway. Their flathead bearings are made by 'King Engine Bearings' out of Israel. I've used King bearings in a lot of other engines - happy to try them in my flatheads.

I ordered TWO sets - so I can mix-match bearing shells if necessary to HOPEFULLY get a consistent set of bearing clearances. They won't be here for a couple days - so the lower-end is on hold for now.

Okay - enough about main bearings today . . .

 

First Crank Installation - Checking Clearances
1) Bearing Clearance Issues - Resolution: I ordered two sets of King Engine bearings, they arrived today. So I went down to Fowlers and we started the 'bearing swap a go go game' - measuring them with mics, trying to come up with the best combination. We don't have the luxury of ordering +.001 bearings like we can with modern engines, so we just try a few sets.

Here is what I ended up with:

1. Front: King Bearings: .0025 Clearance
2. Middle: Federal Mogul Bearing: .002 to .00225 Clearance (very concentric - same on the 45 degree angles)
3. Rear: King Bearings: .003

So, I'm happy with the clearances . . . about as close as you're going to get.
​

2) Crank Installation - No Rear Main Seals: I always put the crankshaft in without a rear main seal the first time. This gives me the ability to check how well it rotates, check thrust clearances, etc..

1. I hand polished the bearings - to remove the little marks caused by the dial bore gauge. There isn't much you can do to prevent them - will always happen when you measure them in the block. I use a little bit of extremely fine polish (used for final paint clear coat hand rubbing) - and use a cotton cloth to polish all the bearing surfaces - works out really well.
2. 
   
3. Rear Main: I chamfer the edge of the rear main bearings (at the parting line) from the oil groove to the rear thrust surface. I do this with a jewelers file. The purpose is to direct a bit of oil to the thrust surface of the crank. I have a heavy clutch going in the car and when you have the clutch engaged, all the lbs of force are being shoved into the rear thrust surface of the crank. Having a bit of oil keeps the thrust from getting hot . . . which can burn it and also the heat will expand the diameter of the rear main journal . . . so a bit of oil is a good thing.
4. 
   
5. Taping Off the Studs: Notice that I put a bit of duct tape over all the studs - this is to protect the crank when I lay it in the saddles. I've seen too many nice new crankshafts 'nicked' on the main journals because somebody hit up against the sharp threads of the studs. Cover them to protect the crank!
6. 
   
7. Bearing Assembly Lube: Everybody has their own favorite brand - I've been using Redline for many years on all my racing engines and have had very good luck with it.
8. 
   
9. Torque the Mains: Went to the high-end of the spec = 90 ft lbs.
10. 
    
11. Crank Rotation: At this point you should be able to grab the front of the crankshaft and easily spin it around - with no force required and it should feel like it is rotating in butter. If for some reason it isn't like this, then there is a problem and you'll need to find out what it is and NOT continue to assemble the engine.
12. Check the Rear Main Thrust Clearance: I used my dial indicator and found it to be .006, perfect. I move the crankshaft back and forth with a large screw driver.
13. 

3) Installation of Two Rods and Pistons: To Validate Compression Height: I put two pistons on two rods, without rings or pin keepers. I then installed the rods, bearings and pistons for both front cylinders (one on each side). Then I used my dial indicator to measure the piston pop-up height on each side.


If you read earlier in this thread, I talked about calculations for compression height (used to order my custom pistons) as well as the fact that I 'trued up' the deck heights on each side. I had Fowler deck the driver's side .010 and the passenger's side .018. This was so that I have exactly the same compression/quench height on both sides.

• The as-measured compression height difference from side to side was only .001! I was hoping to get to .005 or so - this makes me a happy camper!
• The top of the piston domes are .204 and .205 above the deck. This combined with a .051 (compressed) head gasket and a chamber that will be sunk .0065 (reworking the chambers on the CNC for the Eddie Meyer heads) - ending up with .040 quench over the piston. If it was a 100% race motor, I'd run it down to .035, but with carbon build-up on the street, wanted to get to .040
• Math:
  • Piston crowns: .204 to .205 above the deck surface
  • Head Chambers: Same radius as piston, .1935 deep
  • Head Gaskets: Cometic - .051 thick
  • .1935 + .051 = .2445 total height above deck surface
  • Quench: .2445 - .204 = .0405

Guess between myself, Ross pistons, the crank grinder and Fowler, we all did our jobs.

4) Rod Side Clearance: I'm a big believer in pushing a lot of oil through the bearings. You can put larger bearing clearances in the rod bearings, but unless you have enough side clearance (between the rods), the oil can't get out. I like to run about .020 side clearance on my flatheads.

• I used a feeler gauge to check between the first two rods - the value was .019 - close enough. I will check ALL rod combinations upon assembly. If I need more clearance, then I'll use my surface grinder to narrow the rods.

Okay - time to take the crankshaft back out and send it off to be nitrided - this is a chemical process to toughen up the bearing surfaces. I've never done this on a flathead crankshaft before - figure that I have a lot invested in this lower end, might as well see how well nitriding works out. It will probably cost me roughly $250 (including shipping) to get it done. A bit pricey - but I already have $800 of work in the crankshaft.

Stay tuned . . .​

 

Roller Cam - Endplay and Lifter Clearance:
I pulled the crankshaft back out today and bagged it - will be sent out for nitriding on Monday. Now I need to work on the top-end a bit.

The camshaft is a custom designed roller cam that I made the core for 35 years ago and then I conned Isky into grinding it for me (has a SBC roller profile on it - which may be too slow). It has been sitting all these years, so I decided to throw it in this engine and see if it happens to run. I have no clue as to what I'm in for . . . and in case it is a big pig (as it has a ton of duration), I'll put in a Potvin 425 instead.

Lift = .415
Duration = Advertised = 314, 272 @ .050

Anyway, when I made the core I was going to be running cut-down Harley KR lifters - they have a lifter body that is around .750 diameter (can't remember off hand). Anyway, due to this I made the lobes pretty wide. Well, come 35 years later and I'm going to run Crower roller lifters that are regular flathead diameter. So, when I put the cam in . . . sure as hell, some of the lifters were hitting the adjacent cam lobes. Now that sucks big time - as I have to narrow the cam lobes. Hmmmm . . . the cam is heat treated, how am I going to do this ????

I decided to use my tool-post grinder today and see if I could do it. I bought five .275 width wheels (knowing that I'd be wearing the corners off them in a hurry). Anyway, after about 5 hours - got it done. I had to narrow about 8 lobes and the middle and back journals . . . came out nice, but sure made the cleanup of my lathe a lot of fun (tool-post grinders are really not good for your lathe!).



Then I put the cam in the block and put a gasket and timing cover on to check end-play. This is a VERY important step in the build process - especially if you have some sort of billet/custom cam. On 1932 - 1948 flatheads, the thrust is controlled by the cam gear running against the back of the timing cover . . . on 1949 - 1953 flatheads, the extended snout of the camshaft rubs on the later timing cover to set thrust. Also, on 32 - 48 engines, the timing gears thrust the cam toward the block - while on 1949 - 1953 engines, the cam is thrust toward the timing cover. I can see no real reason why you can't run the early timing/crank gear sets on ALL flatheads - but you do need to ensure your end-play is within spec.

I like to have the end-play somewhere between about .006 to .010 . . . you can probably get away with a bit more, but this is my goal. I put a dial indicator on the front of the cam - it was at .007, works for me. If I needed to "tune it", there are a variety of ways . . . thinner/thicker timing cover gaskets, machining the thrust surface on the cam or cover, etc..



Tomorrow - time to start the fun process of getting the valve, guide, spring packages setup correctly. They always take work!

B&S

 

Damn Dale and I thought I was anal man !! LOVE this thread/build - keep the tech coming brother.

Might have to get you to put together a short for me lol

 

Awesome details Dale! Thanks for taking the time to document it.

 

OCD...pretty sure they have pills for this

 

They are called greenbacks

 

Dale, i always read what You've written with great interest. Thanks for taking time to do such a documentation.

 

Dale:

Love the detail. Man, I can't wait to hear this engine run.

Best of luck with the assembly and initial firing!

Tim

 

Hey everybody, thanks for the kind words and encouragement - helps keep the fuel in a builders engine! Also, the main reason I write this stuff is to share it with others, so knowing that folks see some value in it - makes it all worth the time/effort.

Yah never know . . . I've taken on a few projects in my time!

Hey Larry . . . those aren't those little blue pills are they?

Oh - those pills! There really isn't a huge amount of money in this engine, but there is a huge amount of time!

Next installment should be either tomorrow or Wednesday - been damn busy on valve stuff!

B&S

 

They are called greenbacks

Everything requires "greenbacks" the difference here is Dale is doing the work and enlightening all who care on correct ways to do it, like most of us there are some things you cannot do yourself and have to ship it out to do. We all don't have balancing equipment or other things required to make a complete job. Some of do what we can with what we have and let it go. Dale inspires all of us to go the extra mile. That's what makes the Flat Cad team so successful thanks for the inspiration Dale and keep it up..............Flatheads Forever

 

Thanks Carl - too nice of you. In the end, I was/am fortunate to have the opportunities to build this type of stuff, to have had some great flathead engineers/mentors in my life and to have access to the equipment, technology and be able to learn what I have in the last 40 years. I don't take that for granted or as 'owed' to me.

I figure it is my job to pass on what I do, what I believe I know (and I'm not perfect by any means) . . . to help guys build the best engine they can, with whatever 'greenbacks' and time they have to spend. We all compromise in certain areas - that is life, but there are some thing where those compromises can really hurt the result.

Keep em' flat and get em' running boys . . . stay tuned, more to come . . .

B&S

 

Thanks again for documenting all of this. When you are done with the engine I plan to save this entire thread for a reference on flathead Ford work.

 

Dale, why don't you get that move done so we can build the banger for the lakester!?!?!?!

 

Setting Up Valves, Guides, Spring Height and Retainers:
The valves in this engine are standard Chevy SBC length - which are about .100 longer than stock flathead. Lots of flathead guys use these valves for two reasons: They're readily available (and cheap if you buy cheap valves - which I don't) and the extra length works well with high lift cams . . . as the cam core base-circle is much smaller and the longer valve takes up some of that space.

If you don't run longer valves - AND you're running adjustable lifters, then you have to screw the adjusters WAY out - which reduces the amount on interference fit on the threads. The net result is that you're adjustable lifters keep 'self adjusting' . . . and your lash keeps changing. The longer valves keep the adjustable top part down into the lifter body - which helps keep them 'locked in'.

Checking Guides: I bought this set of guides from 'Red's Headers' - first time I've used them. They appear to be good quality stuff - and I like the fact that they have the correct versions for intake and exhaust. Having the solid exhaust guides are important as they help transfer the heat from the valve - having the solid ones aids in this process. I put one of my valve seat pilots in the lathe and lock the headstock. Then I put a dial indicator of the OD of the guide and check all of them to make sure they are correctly machined, are concentric, etc.. I saw a max run-out of about .001 to .0015 . . . okay by me.



1) Retainers: I take some Comp Cams steel retainers (part number is '743-16' mentioned earlier) and I turn them down in the lathe to 1.00 diameter. They have the perfect spring centering shoulder and take standard valve locks. I also do a 30 degree cut on the bottom to reduce weight and ensure that we're not close to the lifter bore tops. These retainers are very high quality and super strong - as I'm running a lot more spring pressure than standard flatheads, I don't skimp here (or anyplace else it seems!)



2) Isky 185G Springs and Installed Height: I almost always use the Isky 185G single spring. It is more spring than you'll need for typical 3/4 street motors and mild cams, but if you're running bigger cams, have a high-rpm motor, have a roller cam (like I do) or a blower, you need a lot more spring pressure than the common LZ (Lincoln Zephyr) springs will give you (which is about 50 - 60 lbs on the seat). Here are the basic numbers at installed heights:

a) 2.000 Installed Height: 85 lbs on the seat (perfect for most 'big' cams and naturally aspirated engines)
b) 1.950 Installed Height: 100 lbs on the seat (at .410 lift, about 225 lbs)
c) 1.900 Installed Height: 110 lbs on the seat

Given that I'm running a roller cam with fairly heavy Crower roller lifters (about 120 grams each), then I'll be running the 1.950 installed height. Also, I want to be able to spin the motor to 6,000 RPM - I don't want to float the valves.

3) Checking Installed Height - Making Shims: When I put the assembly with a lightweight checking spring into the block, I get an out-of-the-box installed height of about 2.180.



Obviously this is WAY too big - I need to get down to 1.950. I need .230 of spacer to get down to 1.950. What you don't want to do is stack up a bunch of .060 spacers - you need to make your own custom spacers to fit the guide - and I rework the guide as well to get rid of the spring centering 'lip' on the spring surface. It takes a while to make all the spacers - as I set the height for each individual valve . . . occasionally using a .015 steel spacer on top. I make sure my spacers have a little centering ridge so the spring correctly centers on them (like the guide originally had).



I then put the guide and the spacer assembly back in each location and recheck the spring height:



4) Here is a New Assembly - Exhaust (Intake is the same, just a 1.72 valve instead of a 1.6):

All this work is quite tedious - but I prefer to have everything exactly as I want it. I have about 12 hours into making the shims and setting up all the installed heights for the 16 valves. Yes, that is a lot . . . which is why I don't pay engine builders to do this stuff for me.



More guide work to follow - need to cut them back so they don't overhang into the ports as they do now . . .

B&S

 

dale, thanx for documenting the details of your machining/assembly work, i`m sure a lot of guys will be using it as a reference. what are your thoughts on using bronze liners, or am i getting ahead of you?
tom

 

Valve Spring Shims: Part numbers and pricing . . .
I don't know about you guys, but when I looked up the prices of valve spring spacers on Speedway and other places - for the Isky 185G springs, couldn't believe they wanted $88 for the 16 spacers . . . Hell, they cost almost as much as the damn springs! I thought to myself . . . "BS" . . . so I went out and found the part numbers to order them myself from Goodson:

Goodson A-101, .060 thick, box of 100 = $19.99
Goodson B-101, .030 thick, box of 100 = $19.99
Goodson C-101, .015 thick, box of 100 = $19.99

www.goodson.com

So I just bought 300 spring shims for less that 16 of them from Speedway! Also, you'll need an assortment - one size does not fit all.

 

I've got a couple other things I need to take care of in the next few weeks - while I wait for the crank to come back - so check back about mid-April! Happy Easter Gang!