Is valve shrouding a concern in a 318 w/ 2.02 & 1.6 valves

[rumblefish360]

I'm Probly missing something, a stock bore x stroke 318 is not within %1 of 360...or did I misunderstand something.

Yes! Go back and read the original post. We're working on a 318.

YES valve-shrouding will be an issue.

I can't watch this sh*t show any longer...

A 2.02 intake valve on a 3.91 (or any over-bore possible there-of, even a 4.04" for goodness sake) cylinder wall with a low-RPM cycle (1200-2200) will SUFFER from lack of velocity with that big of an intake valve on a street car. Especially a 318, god*amn.

WTF, does everyone on this site assume people still race around the street like dick's from 1977 still or something?

2.02 intake valves were cool when 4.56 gears were too... at the f****** Sonic Drive-In back in '85 , dumb-dumb's.

Maybe he is. Maybe he is stuck in the '70's & '80's! He's crankin out the Zeppelin & Iron Maiden with a Gid aweful mullet and ripped jeans and a tiger stripes bandanna!!!

And after the drive in and chasing the chicks around the burger table, he's gonna race the back road strip. Gonna "kill'em all" with his insane in the membrain 318.

 

[Longroof]

Why not start with a 360 block, an aftermarket crank will be required for the hp anyways... offset grind the crank and destroke the crank running small block Chevy rod journal size your going to need to run an aftermarket rod too... and might as well get the lighter parts.. This way you can get you to the cubic inch you want with an over bore to 360 +/- 1% Much better piston and ring availability and hp potential. Good luck it sounds like an uphill battle.

 

[Woods74]

YES valve-shrouding will be an issue.

I can't watch this sh*t show any longer...

A 2.02 intake valve on a 3.91 (or any over-bore possible there-of, even a 4.04" for goodness sake) cylinder wall with a low-RPM cycle (1200-2200) will SUFFER from lack of velocity with that big of an intake valve on a street car. Especially a 318, god*amn.

WTF, does everyone on this site assume people still race around the street like dick's from 1977 or something?

2.02 intake valves were cool when 4.56 gears were too... at the f****** Sonic Drive-In back in '85 , dumb-dumb's.

Vote for best post rollin' on my 15" cragars... Total troll thread this was destined to be. :happy1:

 

[racerdude5]

Why not start with a 360 block, an aftermarket crank will be required for the hp anyways... offset grind the crank and destroke the crank running small block Chevy rod journal size your going to need to run an aftermarket rod too... and might as well get the lighter parts.. This way you can get you to the cubic inch you want with an over bore to 360 +/- 1% Much better piston and ring availability and hp potential. Good luck it sounds like an uphill battle.

You're probably right, if someone has an early 70s 360 block they don't need and live in Ventura County, I'd be happy to come get it. I don't really have the space at the moment either though. But in reality, at this point if there's a way to reduce or eliminate the valve shrouding, I might as well just stick with the 318 block that I already have. You know what I mean?

 

[swies]

I agree with a previous post.
Many on here will spend your money and tell you how stupid you are for not 'Just going to get..." (fill in the blank here) and doing it the Best way. I wish I would be so blessed as them to not have things like space and budget to worry about...
Why don't you just sell everything you have and go get a crate motor that is done and ready to go?!?!?!
Because I have a 318 and not a truck load of cash!!!
Seems pretty simple to me.
I do not have the answers for you but wanted to chime in some support.
I hope the smarter people on here can help but I am not one of them.
Good luck and don't let the "Just do this" people put a damper on you mission.
Racing is always worth it!

 

[racerdude5]

I agree with a previous post.
Many on here will spend your money and tell you how stupid you are for not 'Just going to get..." (fill in the blank here) and doing it the Best way. I wish I would be so blessed as them to not have things like space and budget to worry about...
Why don't you just sell everything you have and go get a crate motor that is done and ready to go?!?!?!
Because I have a 318 and not a truck load of cash!!!
Seems pretty simple to me.
I do not have the answers for you but wanted to chime in some support.
I hope the smarter people on here can help but I am not one of them.
Good luck and don't let the "Just do this" people put a damper on you mission.
Racing is always worth it!

Thanks for the support, it really is amazing how quickly people are to oppress the ideas of others. I find it kinda funny honestly; I makes no sense to criticize someone's thoughts and ambitions unless you first ask why they are doing it. I'm not stupid, I've done countless hours of research and planning. Thanks Rumblefish360 also, for the support.

 

[racerdude5]

For those of you who would like to continue to discuss more than just the valve shrouding; I started a thread for those who want to support me in building this sprint car.

http://www.forabodiesonly.com/mopar/showthread.php?t=343040

 

[273]

First how much hp do you need there's a big difference between 625 and 725 how much is everyone else running?

 

[mguner]

Cylinder reliefs do make HP and are factory on the 273. I use them on my 0.060 over 440 because I had compression to spare. If you want all you can get in the higher RPM ranges and can afford the loss of volume it is a plus. If you are trying to get every ounce of compression you can and need the low and mid range more then I wouldn't.

 

[racerdude5]

First how much hp do you need there's a big difference between 625 and 725 how much is everyone else running?

Some guys say 600, some guys say 700, some say 750 hp. Obviously I need to make as much as I can with what I'm able to get.

 

[racerdude5]

Cylinder reliefs do make HP and are factory on the 273. I use them on my 0.060 over 440 because I had compression to spare. If you want all you can get in the higher RPM ranges and can afford the loss of volume it is a plus. If you are trying to get every ounce of compression you can and need the low and mid range more then I wouldn't.

Thanks for the valuable insight. I really appreciate it and I will take that into consideration. Does anyone have any used aluminum cylinder heads they'd be willing to see for a decent price?

 

[AJ/FormS]

So I'm following along with a great deal of interest.
But it seems to me, machining costs and custom parts are gonna be a drain, so the less of both the better. Starting with a teener, to save the cost of a bigger bore core-block, seems to me will cost more, in the end. And still be slower.And have less torque potential.A teener is about 13% down on cubes.I know you just wanna have fun, but throwing 13% away, right outta the gate? That might be like dragging around an extra 200 pounds on that chassis.How much fun can running at the back, and being lapped regularly,be? It's one thing to be the Mopar underdog, but you are not giving yourself much of a top placing chance, much less a win. I really like to root for a Mopar every time I see one at an event, but if a guy shows up at a gunfight, with a knife, well that's an awfully stacked fight; and it's really hard to root for the guy who's brandishing the knife, however boldly.

 

[racerdude5]

So I'm following along with a great deal of interest.
But it seems to me, machining costs and custom parts are gonna be a drain, so the less of both the better. Starting with a teener, to save the cost of a bigger bore core-block, seems to me will cost more, in the end. And still be slower.And have less torque potential.A teener is about 13% down on cubes.I know you just wanna have fun, but throwing 13% away, right outta the gate? That might be like dragging around an extra 200 pounds on that chassis.How much fun can running at the back, and being lapped regularly,be? It's one thing to be the Mopar underdog, but you are not giving yourself much of a top placing chance, much less a win. I really like to root for a Mopar every time I see one at an event, but if a guy shows up at a gunfight, with a knife, well that's an awfully stacked fight; and it's really hard to root for the guy who's brandishing the knife, however boldly.

I'm lucky to have a friend who has CNC machines, and another who owns an engine shop. So I don't have to worry about those costs thankfully. I'm going to have to get custom pistons either way; Wiseco asked for my formal proposal so I'm going to send them that this weekend. My buddy with the engine shop is good friends with the people at Ross Pistons as well; so hopefully that will work out. I understand what you're saying, but 13% displacement difference doesn't necessarily mean a 13% power difference. Right now, the biggest concern is valve shrouding; that would be the only benefit from running a 360 with a 4 inch bore. I'm not gonna go out and buy a 360, I have a 318 already. If somebody has a 360 block they want to give me; well then we'll see what we can do.

 

[yellow rose]

I want to get on the track! I love racing, I've been off the track for a year and a half. Having a Mopar Sprint Car has been my goal for quite a few years now. I can always make it better and faster as I go. I'll worry about cubic inches later, having a shorter stroke and smaller bore means less rotating mass and better throttle response for the time being.

AND as I said, there's 2 options;

1) a spec head: Brodix ASCS B1BA which can't be modified

2) open: whatever you want as long as the valve angle is within 1 degree of factory.

If you can run ANY head with 1 degree of stock the only heads I would look at are the W-2, the W-5 series. There i s no way a Pcar will run with those. that B1BA won't run with either the W-2 or W-5.

I can't tell you how many times I have seen this. you want to race so bad, that you are willing to do it wrong, just to do it. Get a PLAN, on PAPER. Get a BUDGET on PAPER.

just because I,m curious, how many magneto fired, alcohol injected engines have you tuned.

I'm not trying to pee in your cereal. Just want to save yo much grief and many $$$$$$$$$$$$$$$$.

 

[yellow rose]

I'm lucky to have a friend who has CNC machines, and another who owns an engine shop. So I don't have to worry about those costs thankfully. I'm going to have to get custom pistons either way; Wiseco asked for my formal proposal so I'm going to send them that this weekend. My buddy with the engine shop is good friends with the people at Ross Pistons as well; so hopefully that will work out. I understand what you're saying, but 13% displacement difference doesn't necessarily mean a 13% power difference. Right now, the biggest concern is valve shrouding; that would be the only benefit from running a 360 with a 4 inch bore. I'm not gonna go out and buy a 360, I have a 318 already. If somebody has a 360 block they want to give me; well then we'll see what we can do.

Like I said, not trying to talk you out of anything. I don't care what you do.

You are correct in the 360 main bearing size. It's too big for what you want. BUT, I never like to give up bore size. Don't kid yourself, bore size makes HP.
If you are ok going out and being a back marker and having fun, so be it. But, when you come to a forum and ask advice about something so simple as valve shrouding but not giving exact details, you are going to get answers all over the map. You are not just asking about valve shrouding. You are asking about compression ratio, cam timing and all that.

THERE IS NO WAY I WOULD CALL COMP AND GET A CAM FROM THEM ON THIS DEAL. I know all the comp fan boys will hate my guts and flame me up for it but I don't care. You need to call somewhere that you get to talk to the guy who grinds the cam, or who is not some snot nosed kid just starting out. If you have an inside connection at comp then go for it. Otherwise, you need to call Jim at Racer Brown, or one of the guys at Cam Motion, or Mike Jones at Jones cams. The guys at Bullet are good too. Call them all and see what they say. Deal with the one who YOU get on with best.

BTW, you can put billet caps on a 318 (or a 340 or a 360) and it is just a waste of time. The cap is NOT the issue. The blocks are weak. Girdles do not help either.


Best of luck to you.

Keep us posted.

I'd love to see you succeed.

 

[moper]

Here's my opinion for what it's worth... The way you get big horsepower in this package is from rpms. The block won't care. Personally I'd buy caps for it for numbers 1-4. The 273 crank is a good part. But it's stock. And more important it's heavy. Stock rods won't take the abuse - so you need rods. Cheap rods are the fuse on the dynamite. It's either long or short. I'd go aluminums. Cheap & light and will last a season or two with care. Figure the rods out before you order pistons. At high compression ratios piston to head clearance is critical and aluminum rods will need more clearance at the rpms you will need to spin it. Shrouding will affect your output. I'd go as far as saying by a fair amount. Ring package will be critical too. As will oil modification and bearing clearances. You are asking a LOT of a stock block. So ultimately, assuming you do get it up and running, eventually you will lose it due to the block.

 

[racerdude5]

Like I said, not trying to talk you out of anything. I don't care what you do.

You are correct in the 360 main bearing size. It's too big for what you want. BUT, I never like to give up bore size. Don't kid yourself, bore size makes HP.
If you are ok going out and being a back marker and having fun, so be it. But, when you come to a forum and ask advice about something so simple as valve shrouding but not giving exact details, you are going to get answers all over the map. You are not just asking about valve shrouding. You are asking about compression ratio, cam timing and all that.

THERE IS NO WAY I WOULD CALL COMP AND GET A CAM FROM THEM ON THIS DEAL. I know all the comp fan boys will hate my guts and flame me up for it but I don't care. You need to call somewhere that you get to talk to the guy who grinds the cam, or who is not some snot nosed kid just starting out. If you have an inside connection at comp then go for it. Otherwise, you need to call Jim at Racer Brown, or one of the guys at Cam Motion, or Mike Jones at Jones cams. The guys at Bullet are good too. Call them all and see what they say. Deal with the one who YOU get on with best.

BTW, you can put billet caps on a 318 (or a 340 or a 360) and it is just a waste of time. The cap is NOT the issue. The blocks are weak. Girdles do not help either.


Best of luck to you.

Keep us posted.

I'd love to see you succeed.

Okay, you seem to think it's much more simple than it actually is. A 4.00 bore does not automatically equal a podium finish, a 3.91" bore does not automatically equal a last place finish. The block I have is bored .030 over already, I'm planning on boring it another .010. That means 328.5 c.i. and a 3.95" bore, that means that the bore will be 1.25% smaller than that of a 360. The displacement will be about 8% smaller. However, the 3.31" stroke and 6.123, 6.125, or 6.00" rod has a better rod/stroke ratio than 360s 3.58" stroke. In fact, the 318s factory rod/stroke ratio is 1.85 approximately, with 6.00" rods it is 1.81; almost perfect. The 360's rod/stroke ratio is 1.71 approximately. If you were to run 6.00" rods on a 3.58" crank, the ratio would be 1.675, not good. The 318 crank weighs less due to less material for the shorter stroke and smaller journal sizes, the pistons will weigh less, the rings will weigh less, to get an optimum rod/stroke ratio; the rods will weigh less because they will be shorter than the 360s equivalent (to get a rod/stroke ratio on a 360 of 1.81 you would need to run rods that are 6.5" long). There's a lot more to making power than displacement; at least when you're dealing with high performance racing engines. The 360 will have more torque. It's just a sacrifice I'm going to have to make, and it doesn't mean that I'm going to be in the back of the field. Like I said, if you have an R3 block you want to give me or a 360 block, or even a 340 block, maybe I can change my plans. The valve spacing on most small block heads is 1.87". 1.87"+ 1.025" (half the diameter of the intake valve on a B1BA) + .8 (half the diameter of the exhaust valve on a B1BA) + .375" (to avoid valve shrouding a clearance of 3/16" between the valve and the cylinder wall is recommended) would equal a bore of 4.07" which is a 340 bore .030 over (assuming the valves are centered in the bore).

 

[yellow rose]

Okay, you seem to think it's much more simple than it actually is. A 4.00 bore does not automatically equal a podium finish, a 3.91" bore does not automatically equal a last place finish. The block I have is bored .030 over already, I'm planning on boring it another .010. That means 328.5 c.i. and a 3.95" bore, that means that the bore will be 1.25% smaller than that of a 360. The displacement will be about 8% smaller. However, the 3.31" stroke and 6.123, 6.125, or 6.00" rod has a better rod/stroke ratio than 360s 3.58" stroke. In fact, the 318s factory rod/stroke ratio is 1.85 approximately, with 6.00" rods it is 1.81; almost perfect. The 360's rod/stroke ratio is 1.71 approximately. If you were to run 6.00" rods on a 3.58" crank, the ratio would be 1.675, not good. The 318 crank weighs less due to less material for the shorter stroke and smaller journal sizes, the pistons will weigh less, the rings will weigh less, to get an optimum rod/stroke ratio; the rods will weigh less because they will be shorter than the 360s equivalent (to get a rod/stroke ratio on a 360 of 1.81 you would need to run rods that are 6.5" long). There's a lot more to making power than displacement; at least when you're dealing with high performance racing engines. The 360 will have more torque. It's just a sacrifice I'm going to have to make, and it doesn't mean that I'm going to be in the back of the field. Like I said, if you have an R3 block you want to give me or a 360 block, or even a 340 block, maybe I can change my plans. The valve spacing on most small block heads is 1.87". 1.87"+ 1.025" (half the diameter of the intake valve on a B1BA) + .8 (half the diameter of the exhaust valve on a B1BA) + .375" (to avoid valve shrouding a clearance of 3/16" between the valve and the cylinder wall is recommended) would equal a bore of 4.07" which is a 340 bore .030 over (assuming the valves are centered in the bore).

I get EXACTLY what you are saying. What I am saying to you is that you can do all the math you want (considering valve shrouding here) and I can't tell you how many flow tests I have done regarding valve shrouding, including in the chamber. There is more than one way to skin a cat. You can be closer than 3/16 (don't know where you got that number) and NOT lose flow. But you need to look at the valve job, back cut ( I almost NEVER backcut a valve anymore as it may gain flow but LOSE power) and the shape of things. All are important.

I get all the rod ratio stuff and I'm with you. I'm about the only guy I know who thinks a 360 is a waste of time (going to catch holy hell for that) because all your math on that is correct. I get it. But don't step on your wiener here. I'm not even considering valve shrouding, because there are ways around it. I'm talking about HORSEPOWER. While your percentages may look like bore size is minimal in HORSEPOWER, it is HUGE. Not necessarily in peak power, but power under the curve. If you take a .030 over 340 (4.07) verses a .060 over 318 (3.970) you are talking about a pretty big swing. You are talking about .100 of an inch. Don't think about shrouding now. Think about how much more PRESSURE is exerted on a piston that has a bore that is .100 larger! That is where the power comes from. The exact same cylinder pressure on a 3.97 bore will make LESS horsepower than the exact same cylinder pressure on a 4.07 bore. And the 318 will have thinner cylinder walls!

I don't have any spare 340's or I'd give you one. I see them here on FABO all the time for fairly cheep coin.

That 273 crank is PERFECT...........................IF IF IF you use a light piston and rod. Get the bobweight down and it is very nice. My last drag engine I did for my self had a 1680 gram bobweight. And I used a 273 crank. Turned it 8500. And made power. The crank is NOT an issue IF IF IF you keep the bob weight down AND get a good damper on the crank. I always use fluidampers. I'm not a fan of elastomer type dampers (that is a whole 'nuther thread) for many reason. But your crank is the least of the issues you have.

I suggest finding a good used 340 block and not putting any money in the 318. You will be better off in the long run. And it will make more HP.

And like you, I did the math on the 360 in 1979. Didn't like it then, don't like it now. The small amount of torque you lose, I make up with gear ratio.

 

[racerdude5]

I get EXACTLY what you are saying. What I am saying to you is that you can do all the math you want (considering valve shrouding here) and I can't tell you how many flow tests I have done regarding valve shrouding, including in the chamber. There is more than one way to skin a cat. You can be closer than 3/16 (don't know where you got that number) and NOT lose flow. But you need to look at the valve job, back cut ( I almost NEVER backcut a valve anymore as it may gain flow but LOSE power) and the shape of things. All are important.

I get all the rod ratio stuff and I'm with you. I'm about the only guy I know who thinks a 360 is a waste of time (going to catch holy hell for that) because all your math on that is correct. I get it. But don't step on your wiener here. I'm not even considering valve shrouding, because there are ways around it. I'm talking about HORSEPOWER. While your percentages may look like bore size is minimal in HORSEPOWER, it is HUGE. Not necessarily in peak power, but power under the curve. If you take a .030 over 340 (4.07) verses a .060 over 318 (3.970) you are talking about a pretty big swing. You are talking about .100 of an inch. Don't think about shrouding now. Think about how much more PRESSURE is exerted on a piston that has a bore that is .100 larger! That is where the power comes from. The exact same cylinder pressure on a 3.97 bore will make LESS horsepower than the exact same cylinder pressure on a 4.07 bore. And the 318 will have thinner cylinder walls!

I don't have any spare 340's or I'd give you one. I see them here on FABO all the time for fairly cheep coin.

That 273 crank is PERFECT...........................IF IF IF you use a light piston and rod. Get the bobweight down and it is very nice. My last drag engine I did for my self had a 1680 gram bobweight. And I used a 273 crank. Turned it 8500. And made power. The crank is NOT an issue IF IF IF you keep the bob weight down AND get a good damper on the crank. I always use fluidampers. I'm not a fan of elastomer type dampers (that is a whole 'nuther thread) for many reason. But your crank is the least of the issues you have.

I suggest finding a good used 340 block and not putting any money in the 318. You will be better off in the long run. And it will make more HP.

And like you, I did the math on the 360 in 1979. Didn't like it then, don't like it now. The small amount of torque you lose, I make up with gear ratio.

Thank you Yellow Rose Now that's information I can work with :burnout: What you're saying about power under the curve (which is what really matters) makes complete sense and I can see where my numbers may be misleading me. People have so many claims without any supporting theories and or evidence behind them, I don't listen to those because most people don't know what they are talking about; so please forgive me if what I said was rude or obnoxious.

Haha I appreciate it, that's probably the best option; I agree. If my budget allows me to find a 340 or if somebody has a crusty one that they don't feel like messing with and they want to give it to me; that's what I'll do. Otherwise I'll just have to stick with the 318 for the time being until I get some more cash and can swap everything over to the 340 block. Going for a 340 block makes total sense, but everybody was arguing in favor of a 360 block which is a step backwards in my opinion.

Awesome, I'm planning on getting the crank magnafluxed and polished soon. I hope it's a good piece as one of the rod journals is kinda rough. I actually want to have a bead welded around the journals on the filet (or the space between the journal surface and the web) so I can have it machined and it will have radiused journals for extra insurance.

 

[racerdude5]

As far as the crank goes; if I can't use the one I have and nobody has a good forged one they'll sell to me fairly cheap, I'll probably just buy a billet crank out of a NASCAR R3 along with the matching connecting rods and call it a day. That would be the most economical way to go if I have to buy something.

 

[AJ/FormS]

The 3.97 versus 4.07, works out to over 5% additional force with the same cylinder pressure; 12.378 inches sq for the small bore vs 13.01 on the larger. Very significant.

 

[forphorty]

I only have one question: If money is so tight, then why not race in a more budget oriented class for now? If it takes everthing you have just to get the car build, what happens if you blow the motor ,crash, need tires etc? I don't know much about sprint cars but I'm under the impression that even if the car was free, it is a VERY expensive car to campaign.

 

[273]

I don't get how you are gonna manage to pull this off I've done a quick research and unless I'm looking at the wrong engines they go for about $30,000 in your class and that's Chev probably can add another $10,000 for dodge. It's not that 650 hp is exactly a hard number to hit especially on methanol but the reason these engines cost so much is there built for endurance and even with all the best parts they only last 15 or so races.

I'm all for the under dog, I agree the 340 would be the better engine to start with but 318 is what we got so let's move on you've pick your engine so valve shrouding is a non issue it's all about trying to make it work now.

The biggest hurdle now is cylinder heads what's the plan there ? Probably your best bet there is to find 2nd hand ported out W2's

 

[yellow rose]

I don't get how you are gonna manage to pull this off I've done a quick research and unless I'm looking at the wrong engines they go for about $30,000 in your class and that's Chev probably can add another $10,000 for dodge. It's not that 650 hp is exactly a hard number to hit especially on methanol but the reason these engines cost so much is there built for endurance and even with all the best parts they only last 15 or so races.

I'm all for the under dog, I agree the 340 would be the better engine to start with but 318 is what we got so let's move on you've pick your engine so valve shrouding is a non issue it's all about trying to make it work now.

The biggest hurdle now is cylinder heads what's the plan there ? Probably your best bet there is to find 2nd hand ported out W2's

A few of us said shrouding was an issue. And it is. My point was we can deal with the shrouding issue in several ways. He can never make up for bore diameter.

I'd certainly pick the 318 over the 360 every day.

As for "ported out" W-2's... you can buy them used, untouched all the time. IIRC there is a pair on FABO right now for pretty decent change.

While you think you may be saving by buying some else's port work, you may end up with a pile of scrap. Cheap used PORTED heads usually are. No one I know give porting away for cheep because it is so expensive. I would never buy ported heads WITHOUT letting some I trusted look them over very close, had them mag'd or pressure tested if aluminum (you can pressure test iron too and it's not a bad idea) and preferably FLOW TESTED. Otherwise I prefer to port my own stuff.

 

[273]

A few of us said shrouding was an issue. And it is. My point was we can deal with the shrouding issue in several ways. He can never make up for bore diameter.

Why I said that cause he's gonna build a 318 basically no matter what so I agree it's an issue but it is what it is. Its gonna make less than a similar built 340 but that the situation we got.