It's Engine Re-building Season at SLHS

[ashyers]

I'll just call Carrillo, JE and get down to business.

Once the lottery check arrives !

[Elwood]

Elwood,
I'm curious where you removed weight for the balancing. Any photos where you removed weight from a piston and rod? The rods have me nervous because there seem to be no balance pads of any type.

As far as rings, I'll keep you posted. I wish an old friend of mine was still around, he'd likely find 'em.

Andy

Andy, I removed material on the pistons at the bottom end of the thicker "buttress" which extends vertically down the inside of the skirt from the piston pin hole.

You're right, these rods have no balance pads. Obviously Dodge wasn't worried about engine balancing when they designed these things back in 1933, and they never saw fit to change the forging to add pads over all of those years. I guess they figured that the Floating Power concept was sufficient to cancel out any engine harmonics before it got to the passengers.

I started by accumulating a good sized collection of rods, both the original 954408 and the later 1554530 style. The 1554530 can be used as either even or odd rods, since they're drilled on both sides for the squirt hole, but the 954408 ones have the squirt hole on only one side. There are differences in the small end, too, as some have a slot across the top to get oil into the bushing, some have a hole, and some have no provision at all! I was successful in getting a set that all had top end lube holes, but I don't think it would be too difficult to drill one if needed. This chart might help those searching for rods: http://www.danamotorssac.com/kec/catalo ... g_2012.htm


1554530 on the left, 954408 on the right.


1554530 with no small end lube hole on the left, 954408 with lube slot on the right.

After cleaning and inspection (I picked up a Sunnen TN-111 to have on hand so that I could measure these things for twist and bend without having to run back and forth to the engine shop, and also because I like to verify outside work), I did a magnaflux test for cracks. And be sure if you're buying rods that someone hasn't mixed the rods and the big end caps. Also, watch for rods with too thin of a wall between the bearing bore and the bolt holes. I suspect this is either an original manufacturing defect, or the result of re-sizing during remanufacturing.


Note how the hole for the cap bolts has broken into the area of the bearing shell insert. The bolt was actually pressing against and distorting the bearing shell.

Finally, note that Dodge changed the rod design at some point (I don't recall if the change was consistent from the 954408 to the 1554530) to eliminate the counterbore for the split lock washers on the rod bolts. They went to a self-locking nut instead. Don't install self-locking nuts without lock washers on rods designed for lock washers. I was unable to find an exact match for the OE lock washers from fastener suppliers, but there are still some of the NOS lock washers out there if you search long enough.

Then I weighed all of the rods - total weight, small end, and big end - and spent some time mixing and matching within the rod groups (954408 and 1554530) until I found six 954408 rods that seemed the closest in weight, i.e. I would have to remove the least amount from the heaviest rod.


Weighing the big end. Total variance over all of the rods I weighed was 65.5 grams, or something around 8.5% of the lightest rod.

Since I'm also polishing these rods, at this point I'm cheating a bit, since I can be a little more aggressive or not with the ridge removal and smoothing depending on how much weight needs to be taken off and where. It's a work in progress at the moment, so I'll take some photos when I'm done. But one area I'm not removing material is on the big end cap; I'm fairly certain that those two ribs are for strength, and not balance pads. I haven't yet decided how close in weight that I'm going to force these rods. It will be a trade-off between how much material I'm removing and how much weight variance remains. I don't expect to get down to race engine balance, but then again we aren't spinning these engines at 7,000 rpm, either.


Before polishing.


Test polish in process. This rod was already scrap, so I was experimenting to see how and where I could remove weight.

When I'm done polishing and weight matching, I'll have them shot peened.

[ashyers]

Elwood,
Thanks for such a detailed and thoughtful reply! I think we have the "new" rods in the spare motor. We have not pulled them out yet, but the round area on the bottom of the cap looks familiar. We're still removing the valvetrain, but may get to the bottom end tomorrow. One thing about teaching in an Auto Shop that's been there since the early '50's, we have all the flathead tools !!!

I wonder if Dodge balanced the rods/pistons/pins/rings using total weight alone for bob weight purposes and ignored the end to end weights due to the low RPM's. That may explain the lack of balance pads. I think that factory Ford rods are similar.

It would be fun to use some lightweight pistons and Ti pins to get the mass down so the rod stresses dropped enabling a few more RPM and a bit of durability with factory rods. I figure if I go down that road I'm just headed down a rat hole. More RPM will just fry my T-case more rapidly...

I'll have to post some photos tomorrow of some of the bits we've removed. It's fun working with the flathead with the kids, we're all learning together!

Tomorrow the M37 is headed down the street to visit the 3rd grade for a bit. One of my former students is teaching now and we thought it would be fun to do a bit of show and tell. The funny part is my students caught wind of this little adventure and they all want to go! I told them to be careful what they wish for, I may trade 'em in for the 3rd graders! Should be good fun. We've packed up a bunch of step stools, an engine cutaway (1930's Chevy 6), and a Horizontal shaft Briggs to play with. Maybe I can get some of the bunch jazzed about big mechanical toys .

Andy

[Elwood]

Travis,
just me,
Interesting comments on the pistons. NOS is certainly less $ if I can find the correct overbore.

I've been trying to remember where I sourced my collection of oversized OEM pistons. I know that some of them came from Dennis Sherman at Power Wagon Parts out in Massachusetts: http://powerwagonparts.com/. His website shows that he still has some 0.020 and 0.040 o/s pistons available, although the prices seem to have gone up. At one time, he had pallets of NOS o/s pistons, and was pricing them to move, so maybe he sold off most of his excess. He doesn't list them on his site, but I'm sure that I bought the OEM 0.020 and 0.040 o/s ring sets from him, too. Everything was still in the original packaging and lathered in cosmoline

If you want to go new pistons, Silv-O-Lite still shows them in their catalog (std. through 0.080 o/s), and the matching Hastings rings sets are available in either cast iron or chrome, but no listing for moly. VPW shows both the o/s pistons and the rings, but they don't identify who their manufacturer is, or what type of rings they are.

[52PLOWERWAGON]

here is what ill say about the cam

it gave me very good acceleration
it made the flathead very responsive
if I had good spark and more compression It would have been excellent
I could not burn the fuel it was letting into my engine ,making it run very poorly

I would recommend it for what you are doing with the truck

you know how the flat head hesitates slightly when you shift lugging down for a second until it starts to come back up in rpm
the dots represent time between shifts
this is the best I can describe it ;
stock cam , 1st..........2nd.........................3rd..........................................4th

aftermarket cam 1st..2nd....3rd.....4th

you do not need to run the engine past 3200 rpm

somewhere between 2800-3200 is the sweet spot

this is just my personal experience

[ashyers]

Here's some data for all you number crunching types out there

218 Cylinder head combustion chamber volume: ~86cc, there's a bit of tolerance
Felpro head gasket volume: 19cc (.070 thk.)
Piston to Deck height: .035"
Piston rock: .008"
Valve lift: .367"

The compression ratio, even with the 218 cylinder head is LOW!!! For comparison M37 heads are around 100cc's. I'm debating how much to chop off the deck. I'd like to "0" deck the block, but I'm not sure how it would effect the valve seats and the flow. Either way I'll be mowing off a bit of the head to get the compression ratio up to around 8:1. I was originally thinking of 8.25-8.5, but I don't have a feel for how thick these things are and I'm worried about removing too much material and weakening the block/head.

[Elwood]

Here's some data for all you number crunching types out there

218 Cylinder head combustion chamber volume: ~86cc, there's a bit of tolerance
Felpro head gasket volume: 19cc (.070 thk.)
Piston to Deck height: .035"
Piston rock: .008"
Valve lift: .367"

The compression ratio, even with the 218 cylinder head is LOW!!! For comparison M37 heads are around 100cc's. I'm debating how much to chop off the deck. I'd like to "0" deck the block, but I'm not sure how it would effect the valve seats and the flow. Either way I'll be mowing off a bit of the head to get the compression ratio up to around 8:1. I was originally thinking of 8.25-8.5, but I don't have a feel for how thick these things are and I'm worried about removing too much material and weakening the block/head.

Andy, have you seen this head milling chart that RMS posted on 23-Nov-2012? http://www.g741.org/PHPBB/viewtopic.php?f=3&t=5180

[ashyers]

Elwood,
I've seen the chart and it may be a good guideline, but from what I've seen of heads I'd be very cautious taking it at face value.

I suspect we'll be doing a bit of cut and measure. Hopefully not too many times! I may try arriving at a value for the cut with a bit creativity, the students seem to like burettes, ATF, and clay! I'd post a photo, but it would be scary . Where's that darn digitizer...

We need to get going faster on this end so I can get things to the machine shop and start ordering parts.

Andy

[just me]

Are you still looking for that carb bracket? David Moore just posted one on the Facebook Dodge M37/M43 group.

[ashyers]

Here's some more #'s:
Swept Volume: 629cc
Volume between piston & deck: 5cc
Volume of valves: -2cc
Volume of head gasket: 19cc
Volume of current 218 head's chamber (casting #1326304-11): ~86cc

If you're bored and run the #'s it should work out to 6.8:1 CR. This with the small chamber 218 head!
A new M37 chamber my buddy Mark "The Texas Tornado" measured was ~101cc.
To get to 8:1 CR I'll need to get the 218 chamber (1326304-11) down to 68cc. Tomorrow we'll look at how much material would need to be milled from the head to get there.

Edit: It looks like it will take around .120" to get the chamber volume to 68cc. If I go .100" with the current bits this leaves .045" between the valves and the head.

I'm thinking I may have to deck the block and I may look into angle milling the head.

If anyone knows some of the limits of these blocks and heads as far as "too thin" please post! I don't the $ for too much "R&D" .

Andy

ps. just me, thanks for asking, I was able to get a bracket from Storm.

[RMS]

my understanding is that its not about how much meat there is but how shrouded the valve gets. a 3 angle grind will help open it back up but you don't want the valve to touch the head and the more space above and behind the better it will flow.....

make sure you use the vales your going to run when measuring ....
I have seen domed, dished and flat top valves..couple cc give or take

[ashyers]

Does anyone have the compression distance for a NOS piston? I'd like to compare it to some of the new stuff.

Thanks!

[52PLOWERWAGON]

Here's some more #'s:
Swept Volume: 629cc
Volume between piston & deck: 5cc
Volume of valves: -2cc
Volume of head gasket: 19cc
Volume of current 218 head's chamber (casting #1326304-11): ~86cc

If you're bored and run the #'s it should work out to 6.8:1 CR. This with the small chamber 218 head!
A new M37 chamber my buddy Mark "The Texas Tornado" measured was ~101cc.
To get to 8:1 CR I'll need to get the 218 chamber (1326304-11) down to 68cc. Tomorrow we'll look at how much material would need to be milled from the head to get there.

Edit: It looks like it will take around .120" to get the chamber volume to 68cc. If I go .100" with the current bits this leaves .045" between the valves and the head.

I'm thinking I may have to deck the block and I may look into angle milling the head.

If anyone knows some of the limits of these blocks and heads as far as "too thin" please post! I don't the $ for too much "R&D" .

Andy

ps. just me, thanks for asking, I was able to get a bracket from Storm.

heres the head you need http://edgyspeedshop.com/

[RMS]

[ashyers]

It's completely apart! We removed the guides today and the block is completely bare. We'll finish detailing it tomorrow.

Here's what we found:
Bores are 3.250" + wear and skuffs
Cyl. #6 is sleeved
Rod #6 has been replaced
Pistons #1 and #6 are Silvolite pistons the remainder are Dodge
The block has been line honed
Tappets and cam were OK and are off to Delta Camshafts to get cleaned up
Valves and guides were toast
Crank is -.010/-.010 and likely will be -.020/-.020 due to taper and roundness

I've found that the head we intend to use is a Plymouth passenger car head from '52 with 7:1 CR. I'm looking for a proper fitting head gasket. The Fel-pro "universal" head gasket is miles off and thick. The Best head gasket is thinner, but I don't have a sample to check the fit around the chambers.

I've done some digging and found that Egge sells pistons that have a compression height of 2.000" as compared to Sealed Power at 1.980" and Silvolite at 1.978". This is worth .2 in CR and more importantly gets the piston up closer to the head for improved squish and detonation resistance. I'd like to get to .040" but I'm limited by the head gasket thickness and how much is safe to cut off the block to get there. If all goes well I'm hoping to get some of the stuff out for machining next week. I have not decided if I'll run Chevy exhaust valves or not. The Manley Street Flow valves are popular on the Ford Flatheads and their valve sizes are similar. It would enable me to get a good quality waisted stem valve for a reasonable price. I could go 1.5"I/1.5"E or 1.6"I/1.5"E. Well see.

We have not begun the balancing yet, some joker stole my scale !

Andy