Projects Blown 430 MEL Build Questions

I am starting to gather the parts and pieces required for my next engine build and I need to pick the HAMB's collective brain on this. The end goal is to build a slightly nasty blown MEL to stuff in my '51 Ford Pickup for primarily street use. The motor will need to run on pump gas, no funny fuel, methanol, or anything distilled. Because of the pump gas requirement, I am thinking 8-12 lbs of boost max, and about 8:1 compression in the motor. I found an old Weiand LM671 Intake, and I have had a 6-71 core hanging on the wall for a number of years. My biggest question involves pistons, please give me your thoughts or suggestions.

Those of you who have dealt with MEL's know that the combustion chamber is defined by the piston dome and the heads are a plank style and milled at a 10 deg. angle to the bore centerline (just like a 348 / 409 Chevy). This means that the compression ratio can be altered by the geometry of the piston dome, and it turns out Ford altered the piston just about every year that the MEL was in produciton. This means that there are NO correct aftermarket pistons available. Companies like Egge and Kanter sell replacement pistons, but they are a flat top style that dramatically lower combustion ratio to around 8:1. I am pondering 2 options, and I would like the guys who have built and dealt with blower motors to weigh in.

Option 1: Order the flat-tops and run the stock crank and rods, this will get the compression ratio to a good point for a blown motor, but the quench and swirl characteristics may be awful. Also, will the generic flat-tops and/or stock rods live in a blown street motor???

Option 2: Offset grind the crank from the stock 2.6 in rod diameter down to BBC 2.2 and use 6.7 in long BBC H-beam Rods. This would require custom pistons, but the dome geometry could be defined so that the quench and swirl characteristics of the stock pistons are replicated. This option has the added benefit of netting an additional 58 cubic inches.

Obviously Option #1 is cheaper, but if it results in a motor with a short life span, it could get expensive very quickly.

Stock MEL Piston:


Generic Flat Top


MEL Cutaway

The Project Motor:

 

There are 2 other problems with this intake that will have to be over come. The first is distributor clearance. As in, there is none. It will require an offset distributor or something similar, suggestions are welcome. The 2nd is cooling passages. The stock 4 barrel intake takes water from the heads in the rear of the motor, and plumbs it forward, under the intake runners to the front of the intake where the thermostat is located. The Weiand has no provision for a thermostat, but it does have room for small water passages. I am thinking that a bit of plumbing and a remote thermostat will be in order, maybe a bit of welding and machining at the worst to enlarge the passages. Suggestions are welcome on both fronts.

Distributor hole.

 

That is what I was thinking too, but I figured it is better to ask first then to find out the hard way later. I would tend to assume the Kanter, Egge, et al buy their pistons from the same manufacturer??? I just don't see there being enough demand for MEL pistons for multiple manufactures to justify the tooling expense.

 

I'd look in to getting custom forged pistons, with a dome similar to the stock design, around 8.5:1 compression ratio. I have no idea if there are blanks available that would work for this.

Or run the stock type cast pistons, and go easy on the boost. 6-8 psi might be all you want.

The distributor looks like fun....I might be tempted to sneak an electronic crank trigger type system in there. Just because there is no room.

What size are the cooling fittings on the front of the intake? I have a pair of 1/2" npt fittings on the old Weiand intake on my blown 427 chevy, plumbed to a remote Offy thermostat housing. It gets kind of warm in the summer, but it mostly never boils over (stays below 230). It's not optimum, but it works.

 

I can't answer about your rods as I am not familiar with MEL stuff. I'll assume they are forged but don't know how strong they are in the rod bolt area. For the pistons I'd have to say not good! I'd go with forged($$$) and if you really expect 8-12# boost there is no other way. Maybe I'm giving something up in my combination but I took 11-1 LT-1 forgings and cut the domes off and then another .065 off the crown for approximately 8.5-1. Quench is horrible from a practical knowledge standpoint but it works great in every respect. Keep in mind my combo was intended for the street and highway right from the start and maximum performance was not a factor. I run a 6-71 15% under, two 600 vacuum secondary Holleys with inline, direct linkage, MSD 6 ignition and 31" tires with a 3.36 gear. Highway mileage is 17.5. Open the quads and give it some air and it's off to the races! Is it a drag strip killer? No way, but fun and practical for sure.

 

I just saw Jim Forbes post and I agree completely about the cooling system. I drilled the front of my heads for 3/8 NPT and run -6 hoses and fittings to an Offenhauser divorced thermostat housing, works great.

 

The cost of the custom forged slugs doesn't scare me and gives me a good excuse to offset grind the crank and run the BBC rods. A 487 ci blown MEL backed by a 5 spd Tremec could be a ton of fun in a 3000 lb pickup. If I wanted cheap and easy, I would slap the blower on top of a BBC and order everything from Summit.

The water ports are currently 3/8" NPT but there is room to enlarge them to at least 1/2", maybe even 5/8". I will have to look into the Offenhouser Thermostat housing.

A crank trigger ignition system is on my radar, that may be something I have to dig deeper into.

 

Better check with some blower experts on that compression ratio, if you want to run pump gas and 8 - 12 PSI it will have to be pretty low. I was going to suggest crank trigger ignition. It sounds like a hell of a motor.

 

We run a crank trigger on our dirt modified motors but still use a distributor to distribute" the spark from the coil to the wires (all msd stuff) , he may need individual coil packs? Or you could drive a distributor with a timing belt as did mercury outboards

 

on the rods....there may be a good reason to run aftermarket rods, but I don't see much reason to go fancy on them on a blown motor. My guess is the heads will be the HP limiting factor, so you won't need to spin it real fast, and probably won't make much more power by making a lot of boost. I'd just leave the bottom end mostly stock, aside from the pistons. But then, I'm a cheapskate.

oh...5 speed? you won't get much use out of first gear.

 

I'm in to watch this one, as I have 2 of these in 383 form. Maybe Beep will chime in, I think he has a liking to MEL

 

I can't find exact numbers, but there are multiple sources that state the '58 and '59 Lincoln (I have a '58) heads flow about the same or a bit better then a stock 428CJ, so in that 275 to 300 cfm range at 28" of water and 0.600" lift. They do have big ports with big valves (2.14" Intake and 1.77" exhaust).

I have no illusions that it will ever rev past 5500, and 4500 will be a more normal daily redline. I agree, 1st gear will be for parades only, even with a tall rear end ratio and big diameter tires.

The BBC 6.7 Rods are cheaper, readily available, and reasonably close dimensionally to the stock rods to make the switch justifiable (especially with custom pistons). The engine had been sitting outside for far to long, and I most likely will have to grind the crank anyways, so there isn't a significant cost penalty to offset grind it and run the new BBC rods then it would be to undersize it and re-work the 60 year old rods (assuming there are still 8 good ones in there).

The added cubes will help keep the boost manageable as well. I like the idea of keeping it down closer to 8 psi.

Thanks everyone for all the help and suggestions, please keep them coming this is my 1st blower motor build and it will take a bit of time to get everything together.

 

Stock MEL heads flow in the 240-250 range, about like an unported CJ. With a lot of work you can get them up to a tick over 300 cfm.. Actually the later 462 head flows better despite the large ports on the early head.. The later head has a raised floor which improves the short turn radius in the port. If you are going to put a blower on it I would not worry much about quench.. You will need a flat top to get compression low enough.. A combo that I have used is the following.. Offset grind the crank to about 3.98 , BBC 6.7 rod, BBC .100 over 427 piston.. It is a flat top with one valve relief.. This combo gives about 9.5 compression and 475 inches. Those pistons are off the shelf and can be had either hyper or forged.. Stay away from the Egge cast pistons. There are only suitable for a stock rebuild. plus they cost 2/3 the price of a custom forged

 

Thanks for the clarification on the cylinder head flow, it all helps put the picture together.

Brechlrl, I will look into the 427 +0.100 pistons. The only thing I could find that shares a bore with the 430 is 472 / 500 Caddies, and those pistons don't look like they would work at all (big dish).

 

your 9.5:1 motor....that one didn't have a blower on it, did it?

 

Yea, 9.5:1 is probably a bit high, but it may be possible to tweak the offset on the crank grind a bit so it is lower in the hole at TDC. That will drop the compression a bit at the expense of a few cubes. Going to have to start playing with the calculator and figuring out the geometry. Can anyone confirm that the listed deck height for an MEL of 10.482 is at the center of the bore and not at either the outside or inside edges?

 

Maybe the dished Caddy pistons are what you need to lower the compression.

 

Deck height is measured on the valley side of the cylinder wall for purposes of determining rod,stroke, compression height of piston. That side of the bore is your 0 deck point.
My 9.5 motor is not blown.. Runs OK on the street with 92

 

Send a PM to Brian,Beep here on the HAMB...He lives in Highland Village(Dallas)Texas He runs a strong blown MEL in his Gizzlehopper .(on fuel too)

 

Thanks brechlrl.

Just doing some quick research, but after finding a reasonably priced hypereutectic Kieth Black flat top at 4.350" (0.050" overbore) and a compression height of 1.645". That means with a 6.7" rod and a 4.1" stroke (full offset grind from 2.6" journal down to 2.2") there should be a chamber left over with a volume of 7.77 ci. This assumes a 0.040" gasket thickness, and a 10 deg deck with a deck height of 10.482 on the short (intake) side. With a swept volume of 60.9 ci per cylinder, that should yield a compression ratio of 7.9:1 if I did my math correctly.

 

What power Rang are you looking to have , & total compression under boost ?
( RPMs 1,000-5,500). 13:1 under boost for 93 octane, safe
Intake cooling problems are easy to overcome with Imagination , no big deal same with distributor .
J&E can make any piston , stay away from hyperTech pistons , with blower ( more then 5pd's boost )
And any rod can be made buy a few companies.
Mild build , Heads are not a big deal , you can be surprise what blower can do on a non-ported head , but depends on how much horsepower do you want to make . (Not Over 500 @ flywheel )
You can change compression with head gaskets ,
Not familiar with a MEL but with a Chevy (sbc /BB) you can make 500 hp on a cast crank with blower & live .
How about pic's of intake , & sitting on block , heads for distribute thought's.

 

I was told there would be no math today!
In all seriousness, that is quite an undertaking. About as traditionl as they come I'd say.
This is how the pioneers of racing did it, someone had to be the first to blow something up before they knew for sure it would work.
I'm in.

 

XX2. This is """"""SO TRUE!!!!!!"""""""

 

Pm sent , Out side of the box thinking !!! ( distributor )

 

I wonder what Ted Cyr, and Rodney Singer used for pistons ?

 

Slover Porting service in Ca makes a finned aluminum timing cover that can be drilled for a cam mounted distributor

 

i am with squirrel on this as far as utilizing some sort of distributor-less system; This company makes it easy:
https://electromotive.com/
They can even custom make a trigger wheel to fit with any harmonic damper.

Now if you wanted to stick with a distributor to keep traditional, then i have no idea what to do in this situation.

Could you provide a link to this?

 

Marty,back in the days of Ted Cyr and Rodney Singer,,FORGED TRUE was the hot ticket,

 

George... I am a little uncertain why we are considering intake flow of the heads on a blower motor. Usually the exhaust side is much more critical...you can pack an elephant through a pin hole under pressure but once hes through.... how to do you get him out ?... The only thing as far as intake volume to consider is how hard you will have to drive the blower to fill the cavity of the cylinders .... usually supercharged engines are more forgiving on the intake side .... now i will continue reading on... the rest of the thread. Oh... If I were this guy...I would be more concerned with bottom end strength and longevity than anything....

 

just athought about the 430. (we used to run them at the local 1/2 mile dirt track). the oil passage at the top of the heads that feeds the rocker shafts needs to be drilled and tapped for a restrictor. i think drilled it to 1/8", maybe less. Set the huge main bearings at .003 to .0035" we had an Isky EE-500 cam, rapped it to 7,000 on the straights. lot of power for back then.