301 Big Nasty

[Whitetrashrocker]

I might have missed it, but what are you doing about spark timing? Offset key or no key and lap the flywheel?
I found a cool bracket from Vegas karts for an adjustable coil holder. It was for the 212 but I made it fit the big block with some mods. Made it easy to find where the engine liked it.

 

[Rat]

I might have missed it, but what are you doing about spark timing? Offset key or no key and lap the flywheel?
I found a cool bracket from Vegas karts for an adjustable coil holder. It was for the 212 but I made it fit the big block with some mods. Made it easy to find where the engine liked it.

I've read its better not to offset a 301, and if you do DO NOT EXCEED 6°.
Idk if I'm going to bother, I've got a 2° and a 4° key somewhere though if I change my mind

 

[Whitetrashrocker]

I've read its better not to offset a 301, and if you do DO NOT EXCEED 6°.
Idk if I'm going to bother, I've got a 2° and a 4° key somewhere though if I change my mind

What would be any different on the 301? Or does that apply to large displacement engines in general? More torque and power to shear the offset key?

You said this was a balls to the wall build now. You know the tricks to making hp. Air flow, compression, and proper spark.

You might want to clay the valve clearance. I kept the stock cam and didn't have an issue. Not sure what your lift is. I read some where a guy cut .100" off the head but I'm sure there were many other things on that build.

I also tried a washer under the spring but failed there. Got coil bind. Maybe I shouldn't be so cheap and buy parts that work.

 

[panchothedog]

I put a 4 degree key in mine.

 

[Rat]

What would be any different on the 301? Or does that apply to large displacement engines in general? More torque and power to shear the offset key?

It's not recommended to use more than a 6° key on any engine unless the crank is keyed way off. The Big Blocks are a little more consistent than the small blocks as I understand it.

You said this was a balls to the wall build now. You know the tricks to making hp. Air flow, compression, and proper spark.

You might want to clay the valve clearance. I kept the stock cam and didn't have an issue. Not sure what your lift is. I read some where a guy cut .100" off the head but I'm sure there were many other things on that build.

I'm not terribly concerned with clearance, but putting the head on naked is an automatic 0.045" shave, and that's plenty (possibly too much) considering the decided billet rod is going to be +0.020"

I also tried a washer under the spring but failed there. Got coil bind. Maybe I shouldn't be so cheap and buy parts that work.

Well stock big block springs are 30lb, and the lightest upgrade I come across was 45lb, most common seems to be 50lb, and there are also 90lb.

 

[Rat]

I put a 4 degree key in mine.

That's where I was at, 275 cam, 50lb springs, naked head, and a 0.020 Conrod. I've got to get the stock valves out and clean out the ports still

 

[panchothedog]

With the longer rod you might want to check valve to piston clearance. You said it was a hemi, didn't you. Do you already have the 275 cam? I'm sure you know that's when to.check ( with cam installed ). You'll be + .045" lift over stock with that cam, and another + .020 with the longer rod. Not all that much, but the duration of the cam could come into play. Also ( my experience anyway ) very limited supply of head gaskets available. Only thing I could find was stock, and had to order a complete engine set. None of the kart supply shops I checked carried any gaskets for the 301. This was almost 2 years ago. Maybe that has changed. You can find head gaskets for the 212's in at least 5 different thicknesses and 3 different materials. I think the 301 is the ugly step child. Everyone wants a 420.

 

[Rat]

With the longer rod you might want to check valve to piston clearance. You said it was a hemi, didn't you. Do you already have the 275 cam? I'm sure you know that's when to.check ( with cam installed ). You'll be + .045" lift over stock with that cam, and another + .020 with the longer rod. Not all that much, but the duration of the cam could come into play. Also ( my experience anyway ) very limited supply of head gaskets available. Only thing I could find was stock, and had to order a complete engine set. None of the kart supply shops I checked carried any gaskets for the 301. This was almost 2 years ago. Maybe that has changed. You can find head gaskets for the 212's in at least 5 different thicknesses and 3 different materials. I think the 301 is the ugly step child. Everyone wants a 420.

I haven't ordered anything major like that yet at all.
The 301 is the smallest big block and apparently has the nickname "the middle block" despite clearly being a big block bottom end.

As stated by Pancho, the internals are very 212by design, just beefier. I'm sure you can imaging my surprise to find the governor on the crank cover instead of the usual location.

UNLIKE a Ducar212 or a Predator Hemi 212, this has a dished piston like a wedge head always has stock... +020 will bring the crown edge flush to the deck leaving the center 80-85% of the piston 050 below deck level.

I'm definitely not one of those dumb@sses that slaps everything together and fires an engine up on the assumption I know everything.

It will be at the very least hand rolled over without a plug feeling for anything that feels like a problem then proceed with caution from there.

As for clearance checking, I prefer play-doh; it sticks less than that greasy modeling clay crap... even a pad wet folded paper towel is better IMHO.

 

[panchothedog]

You're right. The clay is a PITA. My 301 is a hemi, but came with a flat top piston. Strange, to say the least. My ARC rod is standard length. Didn't measure how far down in the hole it sat. I have heard that on the predator 212 engines the hemi and non are manufactured by two different companies. I have bought 6 or 7 of them and have never even seen a hemi. All were wedge heads. The 301 I have came on a used Manco kart I bought from a 16 year old kid. Really a rough beater that he had just put a brand new 301 on, with a centrifugal clutch 14 tooth and it would hardly move. He gave up on it and put it up for sale. Don't know where he got the engine from, but he was in Southern California, as am I. Even now if I go to Harbor Freight for something, I check out the 301's they have on display, and they are not hemi's.

 

[Rat]

You're right. The clay is a PITA. My 301 is a hemi, but came with a flat top piston. Strange, to say the least. My ARC rod is standard length. Didn't measure how far down in the hole it sat. I have heard that on the predator 212 engines the hemi and non are manufactured by two different companies. I have bought 6 or 7 of them and have never even seen a hemi. All were wedge heads. The 301 I have came on a used Manco kart I bought from a 16 year old kid. Really a rough beater that he had just put a brand new 301 on, with a centrifugal clutch 14 tooth and it would hardly move. He gave up on it and put it up for sale. Don't know where he got the engine from, but he was in Southern California, as am I. Even now if I go to Harbor Freight for something, I check out the 301's they have on display, and they are not hemi's.

Basically same scenario with this 301 Hemi. I didn't even know Predator 301 was even a thing until seeing this oddball, only 301 Ive ever seen before was an 80's Briggs Flatty.
The Kart is a production kart that has been hacked on, molested, and bodged back together with frame flex like a plastic ice tray. It would go pretty good on the 14/60 set up (supposedly) but the cooked spring in the clutch tells me it never reached full lock... which if it was fast I can't imagine how scary it would have been. It was turned over to me for diagnostic and possible repairs... when I reported back that it was evident the tamper proofed carb was suspect and best replaced "F★ck it, let's get stupid" was the immediate answer.

I definitely found the dished piston odd, it's the 3rd Hemi I've had in my shop and only one without a flattop. The 212 Hemi got cannibalized for spares but it had other condition issues.

 

[Whitetrashrocker]

Got my 301 from HF new and it is a hemi head with a flat top piston.
Little basturd child

 

[Rat]

I've decided NOT to go full cowboy on the ports. I used a socket and C-clamp from valve head to spring cap to compress the springs and rattle out the split keepers it already has then had a think on it.
Seeing as I can fully compress the springs in one hand I know they are stock 30's because If they were 50lb upgrade I wouldn't get them more than halfway.

I just finished rubbing a radius to the sharp edges (no flash ridge) with a round, and a half round file. Good 'nuff... closer than government work.

 

[Rat]

You're right. The clay is a PITA. My 301 is a hemi, but came with a flat top piston. Strange, to say the least. My ARC rod is standard length. Didn't measure how far down in the hole it sat. I have heard that on the predator 212 engines the hemi and non are manufactured by two different companies. I have bought 6 or 7 of them and have never even seen a hemi. All were wedge heads. The 301 I have came on a used Manco kart I bought from a 16 year old kid. Really a rough beater that he had just put a brand new 301 on, with a centrifugal clutch 14 tooth and it would hardly move. He gave up on it and put it up for sale. Don't know where he got the engine from, but he was in Southern California, as am I. Even now if I go to Harbor Freight for something, I check out the 301's they have on display, and they are not hemi's.

I'm an idiot sometimes... or just have too much going on and too much crap on the bench. The 301 had a flattop, just found it with the iron flywheel and everything else pulled off or out of it.

Also the bore looks good, still has all it hone work showing... but I'm fairly certain the crank end shouldn't look like this.

 

[Whitetrashrocker]

Can you feel it? Looks excessive none the less.

 

[Rat]

Can you feel it? Looks excessive none the less.

Yes, a little flaked off too. By definition the engine doesn't even have enough operating hours to call broken in either.

 

[Whitetrashrocker]

What's the crank side look like. Looks like it went together with some crud in it.

 

[Rat]

What's the crank side look like. Looks like it went together with some crud in it.

Better but not by much

 

[panchothedog]

IF you are using the ARC billet rod, it will have a bearing insert. Polish the crank if it is scored up, get some plastic-gage to check clearance and toss that POS that you posted a picture of.

 

[Rat]

What's the crank side look like. Looks like it went together with some crud in it.

Because it's so centered, I'm sure your on point. I'm thinking chunks from the oil port being drilled but not debured

 

[Rat]

Getting there, waiting for the wallet to open again so the internals and flywheel can be gotten.

Going stock length ARC Con Rod
50lb springs and a 275 cam
PC from valve cover will be be given a double check valve and a filter (mostly to keep mud wasps out) although I did contemplate using the pulse pump fitting to feed the vent into the intake instead.


Yes the PJ tube is plugged so it's non functional. I do things a little differently when it isn't mine to modify and maul.