64dartwag
Member
I wish I had the cash for the Dutra Duals and that manifold setup. I currently have a 4bbl Offy intake that i got for 40 bucks, but i like the dual 1bbl better.
Hughes Whiplash Camshaft
- Thread starter 64dartwag
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Central California fires in the last 2 months
ugh. That's just terrible. I hope he didn't lose too dang much. They still have their lives I assume.
The house was standing but nothing else apparently. Everyone is safe.
Oh and mill the block to get in the 8.8:1 range. Mine was about 7.6:1 from the factory
. I took 0.060 off to take the stock sealed power pistons from 0.190 down in the hole to 0.130 down.
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64dartwag
Member
don't they respond better with higher compression? That's one reason I was looking to build the long rod motor.
I meant cam selection is not driven by compression. Decking the block is more cost effective for street type compression.
Yup that is why I am hanging on to it!
I had been talking to Doug via PM on the other site about cam selection for my engine just before the fire, he never did answer my last PM though I am assuming he read it as it isnt in my "outbox" any more. I have 2 PMs out to other members there (about different topics than what I was talking to Doug about) that are older than that last PM to Doug but still in the "outbox" meaning as yet unread by the other end.
After I found out about the fire, I didn't press the issue of Doug not getting back to that last PM, I figured he had bigger fish to fry.
I thought I was locked in on a good cam choice for the rest of my combo, and was asking Doug of his thoughts and he suggested the reverse pattern cam. That last PM that is as yet unresponded to, was about the how different my engine will run with all else being equal between his RV10 and his RV15.... In the beginning I was asking his opinion of the Oregon cam 819, and he suggested "his" cam. but my engine is not destined for an A body, but rather, a D150. I pretty much have the rest of my combo ironed out besides the cam. I have heard it said that an engine can run quite different with all else being equal, but choosing a given cam over another "similar appearing" one. and Doug kinda went that direction with my idea of an oregon 819 for my build....as I remember something about his cams being a known quantity/quality.... to put something "close" in, my engine might run radically different from what I am after.
I will admit, cam profiles do nothing but confuse me. I dont get the difference in duration vs duration at 50, vs advertised duration, etc...
and wouldnt the "centerline" be the "centerline" under any conditions? I don't get the (for example) "ground on 108* centerline, installed at 112* wouldn't that mean that on the "other side" would only be 104*? (averages out to 108) and taking that 108 as an example, that 108 is the # of degrees between the max lift of the intake vs the max lift of the exhaust?
I remember back in the 80s when "Super Shops" was all the rage, and they carried Erson products extensively. Cams, springs, timing components, valve covers, all Erson/ who we hear nothing from these days. I remember my 1st 318 rebuild, and looking back now what I remember of the cam I picked out compared to what I see today, it appears that it was pretty close to a 340 stock replacement. the rest of the build was a basic re ring, all stock. and that motor was all noise, no go. it seemed worse than that engine had been stock, before teardown. it was my "guinea pig" engine in jr. college auto shop. Ever since I have been very leery of cam choice.
One of the best 318s I built was a stock (unrebuilt) bottom end, with a stock Melling 360-2 bbl cam in it// with a Magnum engine top end// and the 1.6 ratio of the magnum engines. topped with a plain Edelbrock Performer (not "RPM") and an Edelbrock 625. I don't want to make the same "super shops" mistake I made with cam choice back then with this engine. But I want better than stock.
Sorry for the thread jack, but the ideals I put forth here do seem to apply to some of what the OP was asking about..... if not adding a "What NOT to do".
After I found out about the fire, I didn't press the issue of Doug not getting back to that last PM, I figured he had bigger fish to fry.
I thought I was locked in on a good cam choice for the rest of my combo, and was asking Doug of his thoughts and he suggested the reverse pattern cam. That last PM that is as yet unresponded to, was about the how different my engine will run with all else being equal between his RV10 and his RV15.... In the beginning I was asking his opinion of the Oregon cam 819, and he suggested "his" cam. but my engine is not destined for an A body, but rather, a D150. I pretty much have the rest of my combo ironed out besides the cam. I have heard it said that an engine can run quite different with all else being equal, but choosing a given cam over another "similar appearing" one. and Doug kinda went that direction with my idea of an oregon 819 for my build....as I remember something about his cams being a known quantity/quality.... to put something "close" in, my engine might run radically different from what I am after.
I will admit, cam profiles do nothing but confuse me. I dont get the difference in duration vs duration at 50, vs advertised duration, etc...
and wouldnt the "centerline" be the "centerline" under any conditions? I don't get the (for example) "ground on 108* centerline, installed at 112* wouldn't that mean that on the "other side" would only be 104*? (averages out to 108) and taking that 108 as an example, that 108 is the # of degrees between the max lift of the intake vs the max lift of the exhaust?
I remember back in the 80s when "Super Shops" was all the rage, and they carried Erson products extensively. Cams, springs, timing components, valve covers, all Erson/ who we hear nothing from these days. I remember my 1st 318 rebuild, and looking back now what I remember of the cam I picked out compared to what I see today, it appears that it was pretty close to a 340 stock replacement. the rest of the build was a basic re ring, all stock. and that motor was all noise, no go. it seemed worse than that engine had been stock, before teardown. it was my "guinea pig" engine in jr. college auto shop. Ever since I have been very leery of cam choice.
One of the best 318s I built was a stock (unrebuilt) bottom end, with a stock Melling 360-2 bbl cam in it// with a Magnum engine top end// and the 1.6 ratio of the magnum engines. topped with a plain Edelbrock Performer (not "RPM") and an Edelbrock 625. I don't want to make the same "super shops" mistake I made with cam choice back then with this engine. But I want better than stock.
Sorry for the thread jack, but the ideals I put forth here do seem to apply to some of what the OP was asking about..... if not adding a "What NOT to do".
I admit I have no experience driving a /6 yet
.... but the modeling I was doing for Doug seemed to match his real world experience with his grinds. The RV10 is what I would use for something that you just want to drive. The RV15 breaths a little more above 3500-4000RPM but gives up a good 10-15 ft-lbs below 2000 RPM. Other than that they are close.. The Oregon Cams is in the middle... Is the one you are quoting the 2106? Do you have the data for it? I can run it in the model. In the model the sensitivity to similar cams is not high, my prediction is the under normal conditions I would predict you could not tell the difference between the RV10-RV15 and OG 2106 unless you where in a place where you were kicking it in the butt to pass someone and the RV15 would not die out as soon.You are correct there i a lot of smoke and mirrors in spec sheets and the way cam companies talk about/spec out their products. The duration at 0.050" lift was one attempt at making it apples to apples but as you state there are other terms the companies use that make it confusing and make their stuff look better.
Well sure. putting the long rod in them makes it much easier to get higher compression. Of course, you can also mill the block and head. On an inline six, that doesn't pose some of the alignment issues you run into on a V8 engine. Some say the long rod engine is good, some don't. Too late for me now, as I have a fresh long rod short block on the stand. lol
I admit I have no experience driving a /6 yet
You are correct there i a lot of smoke and mirrors in spec sheets and the way cam companies talk about/spec out their products. The duration at 0.050" lift was one attempt at making it apples to apples but as you state there are other terms the companies use that make it confusing and make their stuff look better.
What was the one that was the reverse grind everybody was raving about? I think it was a 270 duration grind if I remember right. I kinda always wanted to try that one.
I am not finding the link in my PM's from Doug but what he did was copy the idea from the Mopar cams where they extended the duration of the exhaust lobe. What it does is makes some difference above 3500 RPM but robs a bit at the lower end. So what Doug was doing was using the RV10 on stock 1 barrels since they are limited by CFM at higher RPM anyway. He then liked RV15's on 2 barrels because they could breath more and the RV15 moved the peak hump up about 1000RPM so you could take advantage of the CFM. The RVP gave you a bit more at the high RPM but took away less at lower RPM than any thing else you could do. For someone like me who takes an engine above 4000RPM once a year, maybe, I would stick with the RV10 for the low. I put oversized valves in which gave me the higher RPM with the RV10 that the RV15 gave without loosing the low RPM. The Dutra Duals with the "Y" behind the transmission crossover with the RV10 (or OC 106) picked up the torque 20 ft-lbs + across the band.
I probably run mine to 4K every time I shift to out of 2nd, but it's a 170 and it likes to rev.
Yes a short stroke 170 is a different beast! The intake runners of the Hyperpak are perfect length for the RPM a 170 can achieve on the track but do nothing by the time the 225 explodes!
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I would have to jump over to teh /6 site to get specifics, but I was looking at going with Oregon's #819. I was also looking into possibly one of a couple of "Howard's" cams I discovered on Ebay.
I thought the #2106 was a hydraulic grind? I am staying with solid lifters.
I thought the #2106 was a hydraulic grind? I am staying with solid lifters.
Ok found it:
Oregon's grind #819
219/219 @ .050", 264/264 adv, .437"/.437" lift, 110 sep
The 2106 is very close to the RV10 and is what Ken at Oregon recommended when I talked to him.
210/214 @ .050”, 254/254 adv, .434”/.444” lift, 108 sep
Basically the same grind. The 110 sep will give you a bit more at high end (if the rest of the build is not choking it off there) and the 108 will give you a bit more low end. You can see that in the model results below.
Dart Build in the graph is as follows:
- 8.8: 1 compression
- Oversized Valves
- Dutra Duals
- Collector behind the cross member for the 2 banks (BIG BANG FOR THE BUCK OVER HEADERS for low end torque)
- Offy Dual Carb (just modeled total CFM so a 4 barrel with the same CFM would model the same).
- Low restriction exhaust (second order effect)
- OC 2106 or OC 819
64dartwag
Member
What kind of CFM #'s are you getting from the dual 1bbls?
they are about 185 CFM each so 370 CFM overall. Perfect for what I am after in low end response and under 4000 RPM
Just thinking outside the box......have you thought of making the linkage progressive? Think of the fuel economy you might get. lol
you can’t really as one carb feed 3 cylinders. I think that would run like crap
Really? I thought the plenum was open on that intake. Is it not?
Jim, I am almost 100% certain that intake has a common plenum. It will run on one carburetor. The fact that it's off center will have very little effect. Now if the plenums are isolated I could see it, but I don't think they are.
The plenums are isolated. One carb for 3 cylinders. Offy Offenhauser dual carb intake manifold for Slant 6 Mopar | eBay
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