spedrace35

Ok you guys I need your help yet again,
Ok so I am the guy that is having the problem with the 383 build. I am using 6” rods and I am concerned about the clearance between the rod and the cam. I wrote to summit and asked their tech guys about this question. Now I know if I use a small base circle cam that I will have more clearance between the rod and cam, that’s a good thing! But the guy from summit wrote me back and told me that I can only use the small base circle cam with a carbonated engine. So do you guys know if this is true and why that is? And if it is true what are my options, I want to keep the 383 and the fuel injected system, I just need to get the right cam. If you’re wondering what cam I have been looking at it is as follows: (This cam is not a small base circle, it is just the geometry of a cam that I would like to get or something similar to it, and I do not mind going with another company):

Comp Cams 08-430-8
Operating range: 2000 – 5000 rpm
Advertised Duration: 280 in/ 280 ex
Duration @ .050: 224 in/ 224 ex
Lift: .525 in / .525 ex
Lob 110*

I hope this is enough information for you guys. Thanks for helping me out once again.

Apeiron

A smaller base circle cam will only function properly with the sparkling effervescence of a carbonated engine due to the mechanical action of the rising bubbles.

I don't know what he's talking about, the cam doesn't care what kind of induction system you have on top.

Make sure your 6" rods have cap screws too for as much clearance as possible.

spedrace35

Thanks for your feed back. One question that I do have is what do you mean by sparkling effervescence of a carbonated engine due to the mechanical action of the rising bubbles.

Sonix

iTrader: (1)

I thought there was a smiley that was doubled over laughing so hard, but I guess not. that was hilarious....


it's not carbonated, that's what your pepsi is, with bubbles eh? you are talking about a carbureted engine.

one question that came to me was, cap screws? a cap screw is a BOLT correct? what would normally be there? (or do you mean, don't use studs?)

ede

damn now i need to clean my monitor, this is too funny to lock

Apeiron

On a stock rod, the cap is retained by a bolt inserted through from the piston side, with a nut on the cap side. Usually when there are clearance problems between the rod and the cam it's actually the head of the bolt that hits the cam lobe. When using cap screws, the rods are threaded so that no nut is needed and bolts are screwed in from the cap side, so that there's no bolt head protruding on the piston side to interfere with the cam.

Sonix

iTrader: (1)

oh! so you take away the press fit bolt in the rod (I recently disassembled a 350 here, so I can picture that..), and tap the holes and but a different bolt in from the other side eh?
hmm, any other complicated machine work involved in that, or special parts? or just grade 8 bolts and a tap?
Sounds like a nice way to upgrade your SBC rods bolts (apparently a weak point?) cheaply...

Apeiron

Rod bolts are a few grades beyond Grade 8. I don't know if it would be worth modifying stock rods. In his case, if he's using a 6" rod, then it's not a stock rod to begin with, so he could just get rods already set up with cap screws.

Sonix

iTrader: (1)

well, a tap is cheap, so tapping the holes should be pretty cheap...
grade 8 is 150k psi tensile... (going by mcmaster carr here...), and socket capscrews are 180k psi.... so socket capscrews should be good....

new rods are like $400+.... Just thought it'd be cheaper to mod the rods and use those socket capscrews compared to buying new rod bolts from ARP for $100 and needing someone to press fit them in for me...
then again i'd need the rods resized either way..

Apeiron

When a rod fails, it will destroy everything inside your engine. Is it worth trying to save a few bucks?

ede

damn this keeps getting better and better. i want to know how the DIY cap screw rods work out. my guess is great for something less than 30 minutes.

Apeiron

I'd be surprised if they lasted 30 seconds.

Sonix

iTrader: (1)

LOL... ok yea, that was just being cheap, sounded like a good idea at the time.... I realize that with a rod, when the cap has to be concentric, and precise to a fraction of a thou, then hand tapping *may* not be quite accurate enough....

Fine ! press fit freakin' ARP rod bolts for me.... stupid $100 for 16 bolts....

Apeiron

Compare it with the cost of just one failed rod bolt and it looks cheap.

ME Leigh

Cap screw rods don't cost $400. I have seen Scat I-beams with cap screws running $200-250.

Infact rods are so cheap now, rebuilding, reworking, or using stock rods makes no sense anymore.

Sonix

iTrader: (1)

well sure, $250 US, plus exorbidant shipping, border chargers, then into canadian funds.... Hence my $400 guess, based on ~$250 for you.
I thought re-sizing rods was in the range of $100 or so... well, i'll find that out soon enough...

ME Leigh

Buy them on ebay to lessen charges.

jimmy_mac

lol, this is why everytime I see someone telling someone else on the board to call the guys at technical support to get help I have to chuckle a little. I rarely hear of these guys at summit or jegs actually knowing what they are talking about.

To make you feel better, my brother has been running a small base cam from comp cams for a couple of years now in his factory cast iron block with no effervesense issues from the carbonation. And he is not easy on this motor at all. I'm assuming the concern is with the strength of a small base circle cam. I would think a grind from comp cams even on a smaller base would be strong enough to handle any stresses thrown at it considering the materials they use.

Apeiron

What are you complaining about shipping for? You're living in a city with how many speed shops?

Sonix

iTrader: (1)

haha, yea, you miss it yet? So far i'm using canadian tire (driverfx.ca ) and their selection is pretty brutal, and their knowhow is awful, but they're open late.. I'd rather not have to take a day off to go and buy something from a speedshop that's open 9-5 M-F....
oh, that reminds me, thanks for the tip on D&W, they sound like a really good shop, and i'll probably be going with them... (ps, they said they do deliver/pickup for blocks etc, but right now their trunk broke down.... uhh, bad omen?)


I'll have to make some calls later, upon closer inspection at ebay, some scat 6" rods (and therefore probably 5.7") with ARP wave lok bolts, ~$165 US, say $270 canadian, at the max. If I paid $140 for the bolts here, then $100 to resize, I'd save $30, by using old factory rods rather then brand new 4340 ones....
k, point well made Leigh.

Apeiron

Hell no, Calgary sucks. And they have this new thing now every week, it's called Saturday.

Sonix

iTrader: (1)

I'll head over to MOPAC on saturday then
I think i'll end up getting most of my lower engine internals from the shop that does my machine work... let them double check that i'm buying the right stuff, since it's most crucial...
C-tire and it's wonderful cheap-ness and convenience will be left to accessories

spedrace35

Hey guys,
Well I just came back to this post to see if any more new info was posted. And now I feel like a dumb a** for not spelling carbureted correctly. So let me get this straight, if I use the small base circle cam I can still use my fuel injected induction system. This is the response that the guy from summit told me:

Response (A.C.) - 09/12/2005 02:20 PM
The cam selected is not designed to be used with fuel injection. The lobe separation is too wide. Cam selection is based on installation, whether or not a computer is being used, and vehicle use. The only rod that will clear the cam with no problem is the stock 400 Chevy rod which is a 5.565" length. The 350 block was never originally designed to be used with a 3.75" stroke so clearances must be made as necessary. The oil pan rail of the block must be machined and rod to piston clearance checked. This is required with any rod longer than the 5.565" unit. The rod must be clearanced or a small base circle cam used to stop the rod from hitting the camshaft.

This is the reason that I am so confused about why I can’t use a small base circle cam. O and I wish I know about cap screw connecting rods a couple of months ago. The balanced rotating assembly that I bought from Eagle Specialty Products did not come with cap screw connecting rods putting me in a bad situation. Let me know what you guys think.


O and one last thing, the guy from summit said that the lobe was too wide (the cam I was looking at had a lobe separation of 110*). If it is too wide then what lobe separation should I be looking for in a fuel injected motor.

Thanks

spedrace35

OK sorry you guys one more thing,
This what the very first response I got from the guy at summit

Response (A.C.) - 09/12/2005 08:39 AM
You will have to contact our Sales department at 1-800-230-3030 with the part number of the cam. Sales, in turn, will contact Comp Cams to have a part number assigned to it with a small base circle. This is also assuming the vehicle will not be fuel injected.

This is one of the main reasons that I posted my question to begin with. Let me know what you guys think

Apeiron

Ok, he's saying that it's not for a carbureted application because of the LSA, not because it would be ground on a small base circle.

Too tight of an LSA will bleed off too much cylinder pressure at idle and make the stock computer unhappy.

84z28350

FYI Sonix, canadiantire orders from ekeystone.com which has a hella lot more stuff and a bit cheaper than driverfx.ca even though they are both the same company...

spedrace35

What would be a good LSA for my application. Street & strip. Will see the strip only a couple times a year. I do plan to get the computer worked on.

ME Leigh

What cam are we talking about here? The base circle size doesn't matter. It sounds like you are wanting to use the wrong cam for your FI application. You need one more appropriate for FI, with a larger LSA and less overlap.

spedrace35

what LSA and overlap would you guys recomend that I use for my fuel injected egine.

spedrace35

would you guys like to give a list of everything that i have gotten for this engine so far. Would that make it easier for you gusy to give me a more clear cut answer.

84z28350

would be nice to know where your powers at and if your running an auto what stall.

Get me some specs on the engine and i can punch them into dd2000 and i can get you some numbers of approx what youll be putting out at the flywheel.

Sonix

iTrader: (1)

geez, go out for dinner and the thread gets huge...

ekeystone.com eh? I asked about special orders at c-tire and they told me that "oh, yea, keystone..." he told me I couldn't find out what keystone has, that's just for them, but to use driverfx.ca since it's virtually the same... (the prices are usually within 5% difference...)
driverfx.ca charges bigtime on shipping, I just use it to find the p/n, then go in to cantire and get them to order it. No shipping charges as they just get it in their normal shipping...
EDIT: also, if you were to look under say, exhaust, then to fit your car, selection is awful. just either look under brands (also bad), or easier, go to the website of your brand, ie. compcams, then find the part #, then search on keystone to see if they have it, and price, then go in to c-tire to get them to order it. bit of a hassle, but cheap.
-> also, looks like ekeystone is just for distributors... only businesses can sign up.... have you successfully used them?


speed: yea, a list couldn't hurt, we (and by that I don't mean me...) could tell you if you already bought something wrong...

mainly, are you running a stock computer and chip? speed density injection? if so, you must have a relatively stock type of cam to not upset it, or get used to burning proms....

larger LSA (ie 114* ish) will be ok with a stock computer, and anything with a powerband rating in the range of below 5500RPM would probably work ok.... (don't take this as gospel, i'm no FI expert...) but IMHO you should start burning proms, then nothing is holding you back from whatever cam you need.

and finally, looks like you now have the choice of getting a small base circle cam (is that significantly more expensive? and block work...) to avoid your rods, or different rods, which would allow you to sell your current rods.... (ps, I may be in the market for rods

spedrace35

Ok here is the list.

383 Fully Balanced rotating assembly from Eagle specialty products
stroke 3.75 x bore 4.060
6” rods (non cap screw)
Cam – yet to be determined as well as push rods

Heads – Pro Topline Pro lightning heads with 74 cc chambers
200 cc intake runners that have been polished
2.02 Manley intake valves
1.60 Manley exhaust valves
Comp cams springs retainers all the good stuff
Set pressure 130# open @ .50 lift 350#
Complete 1:6 Roller rockers
Heads were put together at a performance shot in my home town

Intake for the time being Ill be using the stock tpi system but Ill upgrade shortly to the TPIS Mini Ram

Headers- SLP 1 ľ” coated

Ignition – Stock but will up grade shortly

Torque Converter – I have hard many things about going to a high stall, I heard it will kill my gas mileage a lot. If I do get a new stall I want to keep it fairly low

Trans – 700-r4 with shift kit

Rear end 4:11

Computer - its stock, when I bought the car it already had a chip. I am planing on getting the chip reporgramed or I will get a new chip if it is not reprogramable. I would like to wait till my car is running and take it to the dyno and have it tuned there.

That is all that I can think of right now.
Remember that my intentions are for street use mostly and little strip use, probably only a couple times a year.

And I do not plan on having a screaming high RPM motor, that is the reason why I wanted to go with a stroker. I would like to have my power from low to mid RPM’s , I don’t want to go above 5,500 RPM and the most I would want to push my engine is 6000 RPM.

I hope that this helps sorry that it took me so long to write back I had leave the house for a wile.

WhiteHawk

When I built my stroker, my rods were hitting the cam. I choose not to grind my rod bolts since I paid $250 to get everything balanced. I just returned the cam and got a small base circle cam and it wont hit (it will hit still, but if it is timed (timing chain) it wont). Holy parenthesis.

Apeiron

There's a lesson in there on the value of trial-fitting the assembly before balancing.

spedrace35

WhiteHalk,
I know what you mean I dont want to grind mine because of the same reason. For your timing how do you have it timed, do you have the intake valves opening a little before top dead center or right at top dead center. If your timing in not right at top dead center can you tell me how many degrees before or after your vlaves are opening from top dead center. And by how far are the rods going to miss the cam? And are your rods in your 383 6"? Thanks for you input

spedrace35

Sonix,
Hey thanks for your imput, I really dont know about prices for the small base cam or if it requires any modifications does anyone here know that answer? I dont know if I am going to be selling the rods, if I get new rods then I have to rebalence the whole thing and to get the rods I want from Eagle its going to cost me a couple hundred more bucks!! I still dont know what I am going t be doing. First I just want to find out the cam that I want to run then find the prices and if there is any additional work required on my block. But if something turns up I will let you know. Thanks for your imput

84z28350

Sorry to thread jack but if you want a little bit more parts to look at go to

www.ekeystone.com
user: 88923
pass: tires

it was an account set up to check pricing so dont bother trying to actually order stuff because it wont work. The pricing is what your local CT "should" charge but the end price is up to them.

Ahhh the joys of being a partsman... lol

WhiteHawk

What I meant by timing it correctly was, that I set the crank so that the rods would hit a normal cam. I then installed the small base circle and rotated it. It still hit, and I got nervous. Then I installed the timing chain and lined up the dots. The cam did not hit. To accurately measure where the cam is I would have to install a degree wheel and get the actual degrees. Timing gears have been known to be off, as my teacher checked his and it was 10 degrees off!!!! I guess it would be trial and error if the cam still hits you may have to jump a tooth or try another timing chain. I am about to upgrade to a larger lift cam...I am scared.

WhiteHawk

Thank you for reminding me although I fully understood my mistake and won't every build a stroker without clearancing first.

spedrace35

I learned my lesson about building a stroker also!!!!!

Apeiron

These kinds of things aren't unique to strokers. Surprises can be expected any time non-stock parts are used.