4.0 SOHC Performance Motor Build

pazzo1969 · September 7, 2009

here ya go Jake
JE pistons

art #231316 377 4.000 bore 3.750 5.700 rod 1.425 compression height should yield 9.3 or so comp. w/68cc heads -16cc inverted dome 449 gr. weight ring # J100F8-4000-5
this is the same piston i have with the exception being mine are flat top

Limited02 · September 7, 2009

I think Eric is on to something. Forged 331 stroker with a single turbo

techieman33 · September 7, 2009

Limited02 said:
I think Eric is on to something. Forged 331 stroker with a single turbo

Might as well go to a 347 they're just as reliable. And if you want to go crazy a 414 is possible with the right block

Jakee · September 7, 2009

Guys - You buy the v8 and I'll race you. I bet I'll win.

Limited02 · September 7, 2009

If we are talking smallblocks here, why not a 468 based 351W?

techieman33 · September 7, 2009

Jakee said:
Guys - You buy the v8 and I'll race you. I bet I'll win.

I'll just say sometime next year I'll be happy to race you, and I won't need any of those spinny thingys either.

Jakee · September 7, 2009

techieman33 said:
I'll just say sometime next year I'll be happy to race you, and I won't need any of those spinny thingys either.

One condition - you have to finish on all four tires and not the roof.

CDW6212R · September 7, 2009

Jakee said:
Guys - You buy the v8 and I'll race you. I bet I'll win.

Ha Ha, I was laughing reading their posts, knowing it was "against the grain."

So the SOHC supposedly can go about .040, and 4.0 is a .050 over bore. I'd say you that a sonic check of the bore is mandatory, and the 4.0 should be possible. Some blocks will take that, some will not. Take a 460 block, all of those can go .080 without checking them. By sonic checking them, the best can go to about .160 over bore. Ford makes some blocks very thin, the Cleveland's are fortunate to not over heat with .030 over bores. 302's and Windsor's can take .030 easily, and some when checked will take .060 over. You need to have the block checked before getting pistons.

The camshafts are a huge factor in power for any engine. No matter what custom cams might cost, that gets you a lot of free power. Literally if you managed to get 500hp with the stock cams, you might see 575 with custom cams. Check with Alex about his 2002 Explorer and his new 4.6 stroker and blower. He has custom cams in the works from Jay, as I pointed him to him. Ask in PM's what those two will cost him. I'd guess that for a SOHC 4.0 it should be in the same ballpark. I know they aren't cheap, but the power is worth it.

I paid $400 for my one 347 cam, and that included his selecting the springs while he built my heads, so the springs and installation were no extra cost. So basically my custom cam was $100 or so more than some guess OTS cam.

The trick is to shop around and pick the best most important parts. You are getting there, and I want you to get there. Night,

Jakee · September 8, 2009

Technically, it's around .008" out of standard specs to bore to 4.00" but I agree, do the ultrasonic test, partial fill the block and go for it. If these plans will work, it will be a very cost effective build and might open doors for more like it.

I don't like crossing breads but some of the best dogs are mutts. It isn’t easy keeping a V6, trust me, but I wouldn’t be doing this if I didn’t think there was potential.

techieman33 · September 8, 2009

Jakee said:
One condition - you have to finish on all four tires and not the roof.

You just have to take all the fun out of everything don't you

I do really good going in a straight line, it was just my 3 trip around that corner that gave me a bit of trouble.

Carguy3J · September 8, 2009

CDW6212R said:
I'm not concerned about P/V clearance as that should be part of the piston and camshaft design. The cam designer controls P/V clearance as part of the cam design, another huge reason to only use a custom cam. A custom cam can be made to utilize big duration and/or lifts and stay far away from the pistons. An OTS cam is a crap shoot at best.......
............I've hinted as gently as I can, the valvetrain is critical, and a custom designed cam for a specific engine and vehicle is the best way to succeed. A top level custom cam will include valve spring specs that you can trust to work with the rest of the engine. Selecting each valvetrain part separately is very risky, and it does not save much money.

You do have the benefit of the SOHC stock parts, many of which are great for your intended usage and rpm range. If you don't alter the rpm greatly, you can rely on the OEM followers and lifters, and all of the chains and sprockets. Just by maintaining the rpm range you cut down on custom parts to worry about. The pushrods need to be measured for and custom ordered(new cam specs). But the rest has proven itself well in the stock rpm range.....
.........I personally would work very hard to get a pair of custom cams made. I would as best I could sweet talk Jay into designing me a pair. I don't know if he can make those, but he has done countless other cams/applications. If he would I'd make a big bet that the power would jump a bunch from that alone. Regards,

CDW6212R said:
........... A set of custom camshafts will help the head flow more than anything else. Find a cam designer and work carefully with them about springs, pistons, compression, boost, and turbo specs. Not many cam designers can do all of that proficiently, and Jay of Camshaft Innovations can. I don't know his knowledge of the SOHC engine specifically, when you get away from common engines, it is harder to find good information. If it was a typical pushrod engine, he could nail down all of those things quickly.

You are rightfully searching for parts compatibility. But you should also put priority on the camshaft and getting input on the details which a camshaft needs to get the most from the engine. What I'm saying is, don't spend too much time picking pistons, rods, springs, turbo parts, without bringing in the cam designer. Don't tie their hands behind them by forcing them to make a cam just for your parts. Let them play a very big part in pointing you to the best parts, if they can do it.

I'd love to see you get 600HP or more from that SOHC, and I don't want you to leave power on the table. The cam designer is a huge part of a winning combination. I hope you are doing the SOHC to be different, because a 302 etc is an easy to do build. Money is obviously a key, big budget needed for any path. Regards,

CDW6212R said:
...........The cam has a lot to do with that also, let the cam guy pick those numbers. You have most of the specs and parameters you are working with.........

CDW6212R said:
Ha Ha, I was laughing reading their posts, knowing it was "against the grain."..........The camshafts are a huge factor in power for any engine. No matter what custom cams might cost, that gets you a lot of free power. Literally if you managed to get 500hp with the stock cams, you might see 575 with custom cams. Check with Alex about his 2002 Explorer and his new 4.6 stroker and blower. He has custom cams in the works from Jay, as I pointed him to him. Ask in PM's what those two will cost him. I'd guess that for a SOHC 4.0 it should be in the same ballpark. I know they aren't cheap, but the power is worth it...........

So, uuummmmm, what you're saying is that one should just scroll down to the bottom of the catalog page, and order the biggest off-the-shelf cam available right? I'm pretty sure that what you said?

I'm a little confused. Could you please clarify you're position on custom cams? It's not really very clear in your previous postings

CDW6212R · September 8, 2009

I meant what I posted, so if those quotes are right, then take that to mean I believe that a custom cam is critical to maximum power. If you want mediocre performance, pick any cam with a part number. I see them all as junk and not worth the time or money. Regards,

Carguy3J · September 8, 2009

Just joking....

CDW6212R said:
I meant what I posted, so if those quotes are right, then take that to mean I believe that a custom cam is critical to maximum power. If you want mediocre performance, pick any cam with a part number. I see them all as junk and not worth the time or money. Regards,

ummm, I was just being sarcastic. I just thought the shear number of uses of the word "cam" and it's variations was kinda humerous. That's all....

BUT, the off-the-shelf cam I put in my small-block 350 (w/vortec iron heads), in my '80 K20 p/u worked out pretty good. When I dyno'ed it, it put down 227hp and 292 ft./lbs. at the wheels, with 90% of the torque available pretty much right off idle. Since then, I made some tuning improvements, with some more to go. It's got a stock cheapo fuel pump, and it think it might be running out of fuel at the very top end.
It's a Comp "Dual Energy". Although, I think I was a bit conservative. Future plans call for a (slightly) bigger cam, with Rhodes, variable lifters to maintain the low end. It needs a bigger carb too. The Holley 670 just isn't enough. I'm going to put together a custom 750 vac secondary, or maybe an 800 w/ annular boosters......
But anyway... I wasn't really trying to start any debate or anything, but while I agree that custom cams might squeeze out some hidden horsepower, with something as well developed as a SBC, or SBF, the off the shelf stuff is pretty good, if you have a "normal" combo. On these motors, the money spent on custom cams could be better spent elsewhere.
Now, with something a little unusual, like a turbo 4.0L SOHC, maybe a custom cam might be more useful, if the guy doing is really a "motor guy" and not just an expert on one particular brand or design; Somebody who really understands engine theory, fluid dynamics as it pertains to both fuel and air,etc.....

Jakee · September 8, 2009

Maybe a SBC camshaft will fit the 4.0 SOHC? hehe

Carguy3J · September 8, 2009

Jakee said:
Maybe a SBC camshaft will fit the 4.0 SOHC? hehe

Well, with a welder, a grinder, and some duct tape......anything's possible.

techieman33 · September 8, 2009

Jakee said:
Maybe a SBC camshaft will fit the 4.0 SOHC? hehe

Maybe a 4.3 cam, they're just a sbc with 2 cylinders cut off after all. And what do you know your motor is going to be short 2 cylinders too

CDW6212R · September 9, 2009

I wasn't debating, and no harm at all or offense taken. I do state often that cams are far more important than people think. I state it because I know that it's true.

The only engines which should ever get an OTS cam are bone stock engines, thus a cam with a part number. Any change from stock throws airflow figures far out of norm, and OTS cams are made simply to make money.

OTS cams are all built as compromises, mainly in that the steel is cast, weak, and cannot take the higher spring pressures that a custom billet cam can. The valvetrain is far less stable with OTS cams and weaker springs and the weaker steel of the cam. Above 4500-5000rpm's all SADI cams(cast steel) begin to not spin true, which affects the whole valvetrain.

Almost all engine failures which include valvetrain damage, they begin from valvetrain issues. Too much spring pressure, not enough, too little lash, too much, springs not compressed enough, or too close to binding, cheap valve seats, etc, etc.

Tons of things in the valvetrain can kill an engine. Bone stock engines have been engineered with specific parts to last a long time, but not for the most power. A billet cam allows much more duration and lift, with a stronger spring, to obtain much more power at every single rpm point.

These are not guesses or IMO like you read on the Corral and dozens of sites. These are facts which happen to be very uncommon, too many people have been wrongly taught. People think that any engine which doesn't blow up, must be great, it has the perfect set of parts already, or very close. The truth is that very very few engines(non stock) which do run for years are anywhere near close to optimum.

The best possible power starts with a billet cam, designed for a specific head, specific intake etc, with specific valve springs, and properly set up. That is a lot of things to get right, and has nothing to do with bolting an engine together. If you think about it for a second, you should realize that most of this work is done before any parts are bought. You make the complete list, buy the parts, machine work, then slowly assemble the engine. Assembly includes many mock up steps, installing parts and removing them again for further work. Most of that is for the valvetrain and intake.

All of this is the difference between a 227HP engine and a 350HP engine. My 347 engine is going to be down on measured power due to the small intake, TB, and exhaust. I know that ahead of time, but my heads, cam, and shortblock are excellent as is. With better intake etc, stuck in a Mustang, this is a 400RWHP 347. There are dyno sheets to see of combinations like that. The key is the cam, heads, intake, and valvetrain. Try a custom cam some time, stop "saving" money(wasting HP).

Limited02 · September 9, 2009

There are plenty of OTS parts out there to make a 400hp 347 that runs reliable and can be run hard. I believe it's the mixing and matching of different manufactors that will start to cause you problems.

I am not saying a custom cam is a bad idea because it is essential to the motor, but for the average Joe an OTS cam is more than enough and more affordable. So if you are trying to squeeze every ounce of power out of your combo, then a custom cam is the way to go(followed with supporting parts)

CDW6212R · September 9, 2009

You see, that's where 99% of everyone is wrong. The custom cam is worth tons of extra power and driveability. It is not a minor thing. All OTS cams are a source of possible failure, due to the inferior SADI core and design, and typical poor valvetrain set up.

Any valvetrain which is not bone stock, with absolutely no aftermarket parts, they all require special assembly, which 90% or better or people do not do. That is the source of tons of poor performance(at best) and noises and mysterious symptoms, failures.

There are not tons of OTS parts which can make a reliable 400HP 347. It takes special skills and very specific parts to reach 400HP with a NA 347. I paid to have my geometry done right, and the parts(besides my intake/exhaust) were chosen by the cam pro, not me.

It is not as easy as you think, and keep suggesting. I continue to try to help everyone, by pointing you towards real experts. As long as you think that you are smarter than the experts, and everyone on 99% of the internet thinks they are an expert, the minority of us will win at the track. Night,

Limited02 · September 9, 2009

Not saying I am an expert, or even smarter than the experts. But you can easily build a 400 pump gas 347 with OTS parts. I guess I am thinking "peak" HP at the flywheel, you may be building towards an "average" HP at the flywheel. It's not rocket science to build a 400hp 347 and it's not cheap either. But it can be done with OTS parts.

We can see from our debate that the motor I will build with off the shelf parts will make less power and maybe not even last as long. But how much less power and how much less long it will last is the question.

I am not calling you out and I am not saying you are wrong, I am sure you know a lot more than I do. I am saying that getting everything "custom" is not always the correct path. Plenty of smiles and miles can be had with OTS parts

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