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| Ideas on where to go next on my 225 https://slantsix.org/forum/viewtopic.php?t=59811 |
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| Author: | Skyla7z [ Wed Jun 22, 2016 5:33 pm ] |
| Post subject: | Ideas on where to go next on my 225 |
I'm not used to the whole forum thing so if this is in the wrong place or something let me know or just move it. I have a 1981 dodge d150 l6 225 it has msd 6al ignition with blaster 2 coil Offenhauser Intake 4 bbl holley 390 (stock new not jetted or any modification) i've upgraded the wiring for a 90 amp internal regulated alternator but world like advice on safe ampmeter intergration (took it off circuit) stock exhaust stock head 195 thermostat stock cam 8 1/4 rear end witch i think is stock in trucks not sure i havent messed with the ratio speedometer reads off because its manual and previous owners put 17" 255/r65 tires on it not sure how to fix this stock cam thoughts on vacuum canister after holley install? has 3 speed manual on the floor with over drive transmission A833 i think i took the fan off in place of electric fans Im looking to upgrade the truck as i have done but i don't want a race car just a very good daily driver that's fun to drive I do have occasional engine backfires when its running but i havet replaced the spark plugs or wire or messed with the carb at all really other than to set idle though it does idle at 2000rpms then it drops down to 500ish any help or ideas would be appreciated. |
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| Author: | ProCycle [ Wed Jun 22, 2016 5:47 pm ] |
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You didn't say how deep you are willing to dig into it but I'd say that the 4-barrel is not a good match for a stock head and cam. If it was me, I would freshen up the motor, install bigger valves and bump up the compression. Maybe a mild cam. Even with those things done it would probably be better off with a 2-barrel. |
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| Author: | Skyla7z [ Wed Jun 22, 2016 6:22 pm ] |
| Post subject: | |
I'm willing to do a great deal over time replace the head, manifold, and i'l working on the suspension but for now i'd like to keep it in reality and it really works great just have a slight occasional hickup and cam specifics would be great i don't mind having the head milled just getting a list o improve on what i've already done. |
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| Author: | ProCycle [ Wed Jun 22, 2016 6:46 pm ] |
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Keep reading around here. What you will find is that it's not a simple as getting a 'list of mods'. The first thing is to decide what you really want out of the motor. Then choose a cam (if necessary) that will get you there. With the cam chosen you can select pistons (if necessary) and calculate a desired dynamic compression ratio. That will tell you how much to mill the head (or block). There are plenty of folks who will tell you that a stock cam, milled head, good exhaust and a 2-barrel will make a very fun street motor. There are also folks who will say you don't need or want a 4-barrel unless you are building something much more like a race motor. Don't take my word for any of this. I'm still a novice when it comes to the ins and outs of slant 6 motors. Hopefully others with much more experience will chime in with their observations. |
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| Author: | Skyla7z [ Thu Jun 23, 2016 2:19 am ] |
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look my engine runs fine with the 390 holley honestly the stammer comes from it needing to be adjusted/jetted or a failing spark plug it's not my concern they were built for 6 cylinder engines and light v8s i'm really just looking for advice on cam duration and specifics. to say mild cam doesn't help me out that much and i'm not looking for a full list all i want is Ideas on good exhaust cam specifications for a nice daily driver with good performance without sacrificing to much fuel economy. based off what i have Specifications on jetting the carb if it's even needed best rear end ration for daily because i'm not sure of the stock were i can get the spindle piece for the transmission to fix the speedometer (it's off by like 15mph-ish) info on porting or milling if necessary the truck will only take premium or the engine diesels and has a hard time turning off that's due to the upgraded ignition or possible carbon build up (but it didn't do it before) |
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| Author: | wjajr [ Thu Jun 23, 2016 5:57 am ] |
| Post subject: | |
Welcome Skyla7z to the site. When it comes to carburetor selection one has understand that the engine is nothing more than an air pump its capacity limited by displacement and rpm. A stock 225 cid slant pump much air because of small displacement, and mid 4000 rpm limit mostly due to its restricted breathing characteristics. When Holley states their 390 4v is for six & small eight cylinder engines they list use on stock and modified engines; our slants fall into the latter. Here is a carburetor sizing calculator that one can play with inputting various engine parameters. A few of the disadvantages of an over carbureted engine are: engine can't move enough air or produce correct vacuum signal to fully open secondaries rendering that half of the carb as excess baggage; bog problems when transitioning off idle to main jets because of poor vacuum signal requiring excessive accelerator pump shot (this may or may not happen with a 390 where it's primary side is about the same as a super six set-up); transitioning to secondary operation having the A/F ratio go lean causing a bog; and perhaps poor fuel economy depending on measures taken (tuning) to alleviate some of the above drivability issues. Quote: i've upgraded the wiring for a 90 amp internal regulated alternator but world like advice on safe ampmeter intergration (took it off circuit)
Sometime about the year your truck was built I think Chrysler went to remote current sensing dropping the old stile gage which had full amperage flowing through it. If you have the later stile gage, I don't think it will be effected by the increased current flow rating of your alternator in the form of a melt-down. The old stile is not built or rated to take the increase amperage over a stock alternator and most likely cause gage failure by melting.Someone will chime in on when and if trucks went to the newer stile amp gage. Also it would be a good idea to increase the wire gage in charging circuit to handle alternator's output increase. Factory harness was barely able to handle full out put of stock alternator, and now that these vehicles are three to four decades old their harness are compromised by corrosion which causes increase resistance (read increase heat at each connection and voltage drop) in each circuit. |
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| Author: | Skyla7z [ Thu Jun 23, 2016 2:28 pm ] |
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I understand what ya'll are saying but i don't have bogging problems I've done my research and so far the carb works fine for what i plan to use it for it's not my problem if it becomes one it will be remedied. I was looking for cam suggestions and the various things i asked for previously. The wiring harness was melted when i got the truck because previous owners bypassed fusable links causing it to melt the wires through the firewall i've fixed the wiring to prevent anything over a certain amperage from going into the firewall period not my problem and no i don't have the newer gauges i don't believe i know it has a voltage regulator built into the cluster but i'm not sure if those wires even go to it and we're dealing with amperage a whole different animal all together. I was looking for a possible wiring diagram to safely make the ampmeter still functional with 0 worries about failure. |
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| Author: | DusterIdiot [ Thu Jun 23, 2016 5:48 pm ] |
| Post subject: | It's |
Quote: Someone will chime in on when and if trucks went to the newer stile amp gage.
Mopar went to shunt style ammeters in the cars in the 1976 model year, I think Trucks went the same way, so they don't get the full brunt of the charging circuit like the Pre-76 cars... at one time I thought Dan had a link on how to wire in a shunt style ammeter... If his engine is still stock he has a juice motor, so it would be a bit easier to buy another 1968-1980 225 and rebuild it to suit, since there are a few more cam choices on the mechanical lifter side...and headwork, increased compression, etc to support more cam would benefit from just starting from a fresh build than trying to pull your block and doing the bottom end, then coverting the top end.... IMHO. |
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