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| Cam and compression for mileage? https://www.slantsix.org/forum/viewtopic.php?t=55489 |
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| Author: | Sam Powell [ Mon Jun 02, 2014 7:08 pm ] |
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I really am enjoying these responses, and reading the other threads. This is a lot to absorb, especially the technical data about the cam profiles. Much of it is over my head. One of the posts in one of the threads, and I cannot remember which one now, and have not been able to find it, stated that oversized valves and porting would raise the peak torque by 500 rpm. How many think this is true? And, if so, over sized valves and porting would effect your choice of cam, and final ratio, so must be considered. I have already ordered the stainless over sized valves from ebay. I could not resist for $40. You eat an elephant one bite at a time. Sam |
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| Author: | Mr Zeal [ Mon Jun 02, 2014 8:29 pm ] |
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Which valves were they? I just ordered the last 1.70/1.44 set and they were the last set! I think they said they wait a couple of months for each order and then only a few come in. |
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| Author: | Tim Keith [ Tue Jun 03, 2014 1:07 am ] |
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An EFI manifold with equal length runners and port injection should help economy a little by evening out the fuel distribution. I don't think the custom manifold effort would pay off in economy, but you might get closer to the theoretical / mythical Feather Duster results and make more power. Maybe the FD results were a mistake, only teases me as I've never heard of anybody getting those results. If anybody produces that kind of manifold, I'll order one, and maybe get 30+ MPG. Also, welding the combustion chamber to heart shape might help a little. |
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| Author: | 1930 [ Tue Jun 03, 2014 2:34 am ] |
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Quote: Which valves were they? I just ordered the last 1.70/1.44 set and they were the last set! I think they said they wait a couple of months for each order and then only a few come in.
Curious what valves you are referring too. I just bought two sets of the engine builder oversize valves from e-bay. 1.70/1.4416 valves total, I bought two sets cause I plan to do two heads, one is a saver for a future build. Maybe Ill get a note from engnbldr saying that they no longer have them and sorry for the listing error? It did say last two avail. I thought I got the valves that everyone recommends which do not require excessive combustion chamber work. |
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| Author: | Sam Powell [ Tue Jun 03, 2014 4:27 am ] |
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Quote: Which valves were they? I just ordered the last 1.70/1.44 set and they were the last set! I think they said they wait a couple of months for each order and then only a few come in.
It was a set on Ebay. My son in law ordered them. The email I got from him said they might be here this week. That order was placed about 5 PM yesterday afternoon EST. I am always suspicious of listing that say "last set" or "only 5 available". WE will see. let me know if yours came. Am still wondering if bigger valves and porting raises peak torque 500 rpm. Sam |
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| Author: | Dart270 [ Tue Jun 03, 2014 4:59 am ] |
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500 RPM is an arbitrary number. I would guess you could get that, or another number, depending on how you port the head and how big the valves are and what your bore size is. Lou |
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| Author: | emsvitil [ Tue Jun 03, 2014 2:00 pm ] |
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500 rpm sounds about right..... I've played with desktop dyno, and keeping everything else the same; increasing the state of the porting (no porting, slight porting.....) will shift the power curve up everywhere, and to a slightly higher rpm. A slight bump in valve size does the same thing. |
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| Author: | 1930 [ Tue Jun 03, 2014 3:51 pm ] |
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Quote: Quote: Which valves were they? I just ordered the last 1.70/1.44 set and they were the last set! I think they said they wait a couple of months for each order and then only a few come in.
It was a set on Ebay. My son in law ordered them. The email I got from him said they might be here this week. That order was placed about 5 PM yesterday afternoon EST. I am always suspicious of listing that say "last set" or "only 5 available". WE will see. let me know if yours came. Am still wondering if bigger valves and porting raises peak torque 500 rpm. Sam |
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| Author: | Reed [ Tue Jun 03, 2014 3:55 pm ] |
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In all the reading and research I have done over the past decade about building a motor for torque for use in a truck or van, the conclusion I came to was that for a mileage or torque oriented engine build the best thing to do is run a single barrel carb and stock valves. Port the head a bit, but stock valves. Inrease compression (via head/block decking or forced induction) and get a better cam profile and improve exhaust flow. The valves may be sized for a 170, but a 225 won't outflow the valves at low RPMs. |
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| Author: | Rick Covalt [ Tue Jun 03, 2014 4:55 pm ] |
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Quote: I could not resist for $40
Sam, are you sure that you got a full set? Intake and exhaust. The last 3 sets I bought were about $80. If you got them from Ted (Enginebuilder) you don't have any worries. He is great to deal with.Rick |
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| Author: | Sam Powell [ Thu Jun 05, 2014 8:08 am ] |
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It said a full set. I do not know if it is the same guy, or the same product. My son in law ordered them. Sam |
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| Author: | SlantSteve [ Thu Jun 05, 2014 3:20 pm ] |
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There is a listing for a full set for about $80 and another listing for exhaust only got $40 or so ....maybe worth checking what going to turn up. |
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| Author: | Sam Powell [ Thu Jun 05, 2014 7:07 pm ] |
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Hmmmm. Yep. You are right. I'll have to order intake now. Thanks for the heads up on that. Sam |
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