Inliners International Forums General Discussion AMC/JEEP 195.6 OHV head sealing issues...

Hey, I posted up in the main "engines" forum (it doesn't say "chevy only" ... :-) about some advanced sealing issues with the old Nash/Rambler six... any help appreciated there!

I saw your post, try head studs for sure, they offer a greater clamping effect when torqued compared to bolts. That might help you in the long term also. The only other alternative you have for the head gaskets is to go with copper. They do require a little more engine prep to use them(o-ring the block), so that might not help you unless you plan a complete teardown.

It's a full teardown. Upgrades to the oiling system, better crankcase ventilation, alternator upgrade, might remove lumps from the intake (it's fairly terrible :-) and such.

Copper headgasket would be custom, I wonder if I could afford it. No one has ever made any performance part for this motor, ever. None, now or then. There was an Edelbrock aluminum head for the L-head version of this thing in the early 1950's, and Nash made a two-carb "Le Mans" head again for the L-head,(someone on this forum has one!) and THAT IS IT. No one's ever hot-rodded the 195.6 OHV motor to my knowledge.

I was gonna put EFI on this year, but the overhaul takes priority. I will replace the carb at least, the damn thing (Carter WCD) fuel-starves in every hard turn. Rally season is about 2 months away!

No performance parts? What was Barney Navarro doing with this engine? You mean that nothing is commercially available, i suppose.

i appreciate the work you've done on your website. i learned a lot about these cars.

God's Peace to you.

d
Inliner #1450

Navarro hot-rodded the 1964-up ("new") AMC six. That thing is the progenitor to the 4.0, and there's a fair amount of aftermarket for them.

The six I'm playing with is the old Nash design, that culminated in the 195.6 OHV that was the end of the evolutionary line. It shares nothing with the "new" AMC six, except the bellhousing pattern (until '72 when that changed).

I'd gladly stuff a "new" six in this car, except it's fully 10" longer and 6" wider and it would extend PAST the instrument panel in this car! The Rambler American prior to 1964 is a VERY SMALL car. With my palms on the steering wheel I can put my fingers on the windshield. Engine compartment is only 20" wide, 30" long.

What Navarro did though was his own custom work, there was no "aftermarket" for this motor in 1967... the motor was 3 years old then. He turbo'd the crap out of it. He had AMC cast him some custom heads too (I have one) but they're pretty much stock but ported insanely well.

Thank you for teaching me some more. i had forgotten that the Navarro experiment was based on the "late model" AMC six.

A few years ago i got to watch my friend Vic Holley build one of those tiny little flatheads with somebody's aftermarket head and two-carb intake manifold. i thought it might be a lot of fun in the right chassis. That's what you're after here, only without any of the pieces that they made for the flathead. What you're doing takes us back to a different time, before "hot rods" were a "business." i love to see that done well, by someone who knows what he's doing. i envy the skills and value the persistence.

God's Peace to you.

d
Inliner #1450

Wow! Yeah, that would have been fun. Edmunds and ??? made finned aluminum heads for the flathead in the 50's (it's an oooold Nash motor). There's the "Le Mans" head from Nash. There was just a thread about this on the amc-list. I was reminded by Frank Swygert (Farna, on this board) just low lo-perf those flatheads were.




Gosh thanks, but I do like this motor *because* no one else loves it, and they are around, so knowledge gained here may go further than just my motor.

But I take exception to the 'knows what he's doing' part -- I'm never sure if I have any idea I'm doing! It is fun though. Thanks for the kind words!

Another month passed -- but I pick up the short block tomorrow. It's been a trial finding all the parts and getting work done on a thing this old and this forgotten. Cost is killing me too. All the bearings etc come from Egge -- no one makes anything for this motor (195.6 iron OHV) any more, and old stock is disappearing.

That said, it should be a really nice motor. Polished up all the combustion chambers, took all the roughness off all the ports, only removed metal around the valve guides in the valve pockets. Static balanced rods, pistons, pins, and polished the piston tops. Identified and fixed a serious head-cooling design flaw.

My last big question, the full-flow oiling mod, I had a setback, the 1965 pump I was gonna use is too corroded (after a thorough second cleaning) so I'm back to a previous scheme. I'm nervous radically changing something so fundamental as the main oiling.

I'm documenting the whole thing, it has it's own website and I'll post it here when I get further along. Lots of pictures and notes.

I was reading your posts and just thought I would toss in a few bits and pieces of information. I am sure most of the other memebers are more knowegable than me on the AMC six but here are a few things that I know. I have seen OHV 195.6 AMC/Nash engines with with 1,2 and even 3 carbs on them. The intake has a plate on the top that can be changed from 1 bbl to 2bbl which is what they called the power pack option and was rated at 138BHP. I have seen few of these on Ebay and from the looks of it they can be modified by a good machine shop to use differnt carbs. I have also seen a 50's era Nash Statesman with a 3 carb set up which was made by Eddy Edmunds. He also mad finned twin carb heads for the L Head engine. In the early 50's Nash made what is called the "DualPowerflyte" head for L Head engines which is what I am running on my engine. The Lemans engine was an OHV twin carb engine that was used in the Nash Healy and later in the Statesman and Ambassador series cars. I do believe I have seen cams for the OHV 195.6 engines but will have to look in my books to see who it was. In the case of my engine I sent the cam to Lunati cams in Mississippi and they gave me an upgraded profile with more duration and overlap to give me more mid range power. I am also stuggling with the full flow oiling problem on my engine but if I get it solved I will post the process for others to use. Best of luck in the build. Mike

Hi,

Man things go slow sometimes! Moving right along, just sloooow... the bottom of the engine is sealed up, should pick up the head tomorrow.

I've finally settled on oil pump mods for the full-flow cooler. Basically I made a replacement for the top cover out of 1/4" steel with a second piece welded to the top to provide the drive gear lube pocket and 1/2" of threads for the outlet. Basically, I plugged the pump's block outlet (which feeds the main gallery directly) and put the outlet in the cover.

The welded on section also provides additional stiffness. I am exceedingly paranoid about this mod, I can't afford to experiment with ruined engines working out oil mods! I wonder if I should have made it from 3/8" or 1/2" plate. It's only 60psi, but heat etc if the gear clearance jumps from .001" to .002" volume will drop.

I'm also dialing in the pump guts. I've ground the gear flat ends truly flat (emery paper on a ground cast iron plate) and made them the exact same height (NOS gears were nearly .001" height difference), ground the new end plate mirror flat (magic markered the plate, 600 grit paper on glass, 3 strokes takes the marker off 100% evenly). I'll grind the pump housing the same way to get gear to housing clearance .001" dead nuts.

I've got a "Cam Pro Plus RV1" cam, 202 duration no overlap! Moves torque DOWN a bit! I can't afford to make a 6000 rpm motor so I made a 4000 rpm motor :-)

I static/bench balanced the pistons+rods+pins within half a gram, polished the tops.

The ports and combustion chambers were very rough castings, so I polished them all (80 grit) and removed only some metal around the valve guides.

Weber 32/36 carb, on a *one barrel* top plate; I have a 2 bbl, but the 1bbl base was easiest to put a "Weber Jeep" kit and I blended them together and smoothed the sharp 90's into broad radiuses. That should be the (a) right carb for this engine, tiny primary, progressive linkage secondary. I've used it before, very nice carb to tune.

Also, I fit a Ford EDIS ignition to the (new) harmonic damper while the engine was apart. I welded a nice bracket for the sensor to the timing cover. I'll do the rest of the conversion later, after it's running.

I didn't know that LeMans motor was OHV! I thought it was a flattie. OK I have some reading to do... thanks for the pointer!

I wrote up another section on my hot-rod 195.6 OHV engine... here's the major stuff on the cylinder head modifications: http://wps.com/AMC/195.6OHV/Head-cooling/

I'm fairly sure I nailed the underlying problem. Time will tell of course. 200 miles on it now and it's working out fine so far.

Tom:
Thanks for these threads. Some of these ideas will likely be helpful on my f-161...oil pump comes to mind.

Sincerely:
Paul...aka xerxes

The oil pump I think is more of a 1950's thing than an "AMC" thing... heavy, overbuilt, simple, big fat clearances. Spending time on it is cheap reliability. Oil pressure at idle is "down" to 55 psi (250 miles) so I expect it to drop a bit more, but this indicates that the overall volume of the pump is way up.

I did check that the clearance at thrust at least doesn't jam the driven gear into the cover. If the gear thrusts back and forth in the housing, there will be X mils of clearance at the top or the bottom. Excess clearance == lost pump volume.


Your Willys motor, and mine, are in the same section of the Summit Racing catalog -- NOT FOUND :-) We gotta make our own parts!