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| I need more low end torque https://www.slantsix.org/forum/viewtopic.php?t=66103 |
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| Author: | '71Charger [ Wed Jul 28, 2021 3:15 am ] |
| Post subject: | I need more low end torque |
Hi Everyone , I'm new to the forum but I've been playing around with a slant for about a year and 7months . Id like some opinions please , I've done quite a bit of work on my cars engine : HEI ignition New 70amp alternator New performance plug leads New stainless steel headers (including 57mm stainless steel free flow) New Carter 2bbd New plugs skimmed 1.8mm off the head back faced the valves Re-seated the valves Ported and polished the head Gasket matched the exhaust and intake manifold Advanced timing Vacuum is perfect https://youtu.be/h8F2XEfwjSc However I still feel after all that the car isn't pulling like an inline 6 should I have fairly narrow tires 195 and I struggle to break traction on the rear . Is my next option a cam or is there something I'm missing ? Regards 71 Charger |
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| Author: | Rick Covalt [ Wed Jul 28, 2021 3:32 am ] |
| Post subject: | Re: I need more low end torque |
What is the timing set at? Verify that your vacuum advance is working What is the rear end ratio. I'm guessing you already adjusted the valves ? What are the goals for the car? |
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| Author: | '71Charger [ Wed Jul 28, 2021 3:56 am ] |
| Post subject: | Re: I need more low end torque |
Quote: What is the timing set at?
Hi Rick Verify that your vacuum advance is working What is the rear end ratio. I'm guessing you already adjusted the valves ? What are the goals for the car? The timing is advanced 12 deg My vacuum advance is fine The rear end ratio is stock (in the States its called a Duster) and yes the valves are adjusted My goal is nothing more than a street toy , but when I floor the gas I would like to break traction in a straight line I'm not sure this is even possible with a stock 225 with what I've done . Am I expecting too much ? |
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| Author: | Jase [ Wed Jul 28, 2021 7:09 am ] |
| Post subject: | Re: I need more low end torque |
Cut and paste below is from the engine build matrix. Was looking for a post from Aggressive Ted who had stated that he had trouble with wheel spin on his 1bbl Doug Dutra inspired torque build.. but could not find it And if the timing set is original and loose, It will retard cam timing and soften the low end grunt. Others who know more will chime in, but I would guess that a new timing set, or degreeing the cam would eliminate that variable. It sounds to me like you've got most of it covered, and additional turning (which includes cam timing) should create traction problems. Quote: I haven't seen anything added here in a while so I thought I would post. While this is not a full blown build, it is my experience with in-car bolt on performance enhancements.
My car is 1963 Dart 270 so it is relatively light weight. It has a '68 model 225, push button 904 and a 3.23 open 7.25 differential. I removed the head to repair a burned valve and had a three angle valve job done and .090" milled off. I added an Offy 4 barrel intake with adapter and a 500cfm holley 2V plus Clifford headers with Y pipe and Magnaflow single in dual out muffler and twin tail pipes. I performed the HEI mod and recurved my distributer. That's when this combination really woke up and ran 16.63 @ 83.4 mph on my G-tech.) Not fast but a huge improvement over previous low 19 second ETs it ran with only the headers and exhaust work. Traction is now an issue with the open differential and 195/70x14 tires. Again I know this is not a full engine build I thought it might be useful to members that want to add a little extra zip to an otherwise good running stock engine. |
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| Author: | SlantSixDan [ Wed Jul 28, 2021 10:21 am ] |
| Post subject: | Re: I need more low end torque |
Quote: Quote: What is the rear end ratio. [The rear end ratio is stockAlso1, pretty good odds your headers are working hard in a couple of ways against the low-end torque you want. Also2, "Advanced the timing" is not the way to get where you say you want to go, and 12° advance might very well be too much/working against you. You'd want to pay more comprehensive, informed attention to the initial, centrifugal, and vacuum advance curves. Also3, nothing in your list about the camshaft, its timing (degreed-in, or did we just glance at dots?), and the condition of the chain and sprockets. Also4, what is your altitude above sea level? |
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| Author: | Rick Covalt [ Wed Jul 28, 2021 2:08 pm ] |
| Post subject: | Re: I need more low end torque |
Is the car a 71 Charger? Or did I miss it? If it is you are moving a lot of weight. 3.55 gears will make everything feel better across the board. ( Except your gas gauge!) |
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| Author: | Greg Ondayko [ Wed Jul 28, 2021 2:44 pm ] |
| Post subject: | Re: I need more low end torque |
A valiant charger in australia is not the same as a north American B Body. Greg |
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| Author: | Rick Covalt [ Wed Jul 28, 2021 3:00 pm ] |
| Post subject: | Re: I need more low end torque |
Got it!
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| Author: | SlantSixDan [ Wed Jul 28, 2021 7:55 pm ] |
| Post subject: | Re: I need more low end torque |
Dude hasn't got an Australian Charger; those didn't come with 225s. He has a 1971 Chrysler Valiant Charger Sports Coupé, which is a '71 Demon with right-hand drive and bilingual (English/Afrikaans) controls and displays, sold by Chrysler South Africa. |
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| Author: | Reed [ Wed Jul 28, 2021 11:48 pm ] |
| Post subject: | Re: I need more low end torque |
Quote: bilingual (English/Afrikaans) controls and displays, sold by Chrysler South Africa.
That would be interesting to see. I know its nothing special to people who live on the veld, but I've never seen one.
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| Author: | '71Charger [ Thu Jul 29, 2021 12:13 am ] |
| Post subject: | Re: I need more low end torque |
Attachment: Screenshot_20210729-085640_Video Editor.jpg [ 229.15 KiB | Viewed 4466 times ] This is my car @slantsixdan is 100% correct "He has a 1971 Chrysler Valiant Charger Sports Coupé, which is a '71 Demon with right-hand drive" My diff ratio stock is 3.23 Altitude is 400ft above sea level But to be honest I have only learned what I know in the last year , I don't know what Camshaft timing , initial , vacuum curve are in details , I have an idea but this is the first time I've tinkered with engines . I did all these mods myself using Youtube and Uncle Tony's garage and a mate of mine whose been a great help as he has a Slant 6 powered Valiant and a V8 Polara . So in a nut shell , I did all the mods listed above , Set the timing , set the carb with a vacuum gauge and run low octane unleaded fuel (All that's available here in SA) The car isn't snappy but instead feels lazy, I mean it goes but it feels like I'm missing something . What I would like if possible is a step by step tune up guide for my setup ? |
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| Author: | DadTruck [ Thu Jul 29, 2021 1:21 am ] |
| Post subject: | Re: I need more low end torque |
Even a Duster is somewhat heavier than an early a body. Going on the comment from the OP that the engine feels lazy. 1) .070 was cut from the head, assuming the original engine had a thin sheet metal gasket and that was replaced by a Fel Pro head gasket, about 1/2 of the head trim was lost in the gasket change. Was the head cc’d and actual static compression calculated? 2) Was the cam changed from the original? Was the cam removed? If removed how was the cam timing set when reinstalled? Was a new timing set installed? The OE cams are not aggressive, the lobes can wear with time. The timing chains and gears certainly wear with use and retard camshaft timing. 3) Have you checked engine compression? Was anything done to the cylinder bores and pistons - rings? 4) What do the spark plugs look like? Do they look out of tune lean or rich? 5) Do you have flow number after the head porting? How extensive was the porting? Did you get good race style multi angle valve seats cut in? These are stock sized valves correct? Personally I think that headers, a super six and a light head mill should wake up a slant, but won’t make it a tire burner. I think you will need more C’s : carburetor-cam-compression. After that converter and a lower final gear ratio. More detail on what was and what was not done on the engine would be helpful. Great looking car! |
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| Author: | '71Charger [ Thu Jul 29, 2021 3:52 am ] | ||
| Post subject: | Re: I need more low end torque | ||
Quote: Even a Duster is somewhat heavier than an early a body. Going on the comment from the OP that the engine feels lazy.
Thanks for the reply , Everything else is how it came out of the factory , I never removed or changed anything from the bottom of the engine only worked on the head . Stock cam and I haven't done a compression test . 1) .070 was cut from the head, assuming the original engine had a thin sheet metal gasket and that was replaced by a Fel Pro head gasket, about 1/2 of the head trim was lost in the gasket change. Was the head cc’d and actual static compression calculated? 2) Was the cam changed from the original? Was the cam removed? If removed how was the cam timing set when reinstalled? Was a new timing set installed? The OE cams are not aggressive, the lobes can wear with time. The timing chains and gears certainly wear with use and retard camshaft timing. 3) Have you checked engine compression? Was anything done to the cylinder bores and pistons - rings? 4) What do the spark plugs look like? Do they look out of tune lean or rich? 5) Do you have flow number after the head porting? How extensive was the porting? Did you get good race style multi angle valve seats cut in? These are stock sized valves correct? Personally I think that headers, a super six and a light head mill should wake up a slant, but won’t make it a tire burner. I think you will need more C’s : carburetor-cam-compression. After that converter and a lower final gear ratio. More detail on what was and what was not done on the engine would be helpful. Great looking car! As I mentioned before I'm a weekend hacker getting by with some youtube vids and advise from friends 1 yes I removed the steel gasket but didn't want to remove too much stock incase I needed a skim later on . Static comp was not tested . 2 no nothing removed or changed all still stock 3 havn't checked compression and left everything in place , bores still looked good with no scoring 4 the plugs are new and last time I checked were running a little rich but I leaned that out 5 I didnt do a flow test I watched the episode on UTG where Tony just cleaned up the ports and bowls removed all the sharp edges where flow could be compromised . Attachment: IMG_20210219_132202.jpg [ 22.48 KiB | Viewed 4445 times ] Attachment: IMG_20210219_132202.jpg [ 22.48 KiB | Viewed 4445 times ]
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| Author: | Jase [ Thu Jul 29, 2021 6:00 am ] |
| Post subject: | Re: I need more low end torque |
I'm not running UTG down, but wanting to suggest that you listen to his advice only as a starting point for investigation and learning. He covers lots of topics which is helpful, in bringing awareness to the topic. That is a good beginning to investigate more. For example: I have seen one of his videos suggest that locking out the ignition advance is the way to go for a snappy response on the street. Such advice MAY be useful for a vehicle with 4:11 rear gears, but not helpful for a heavy vehicle with 2:73 rear gears.. Ask around here who has a locked out ignition on their street car, and I would fall over backwards if you found anyone with a 'quick' street car and a locked out ignition... Now back to the issue at hand: Seems like a compression test would be useful information to begin with.... as readings of 110 PSI across the cylinders will point in one direction, and readings of 160 will point in another direction.. finding out what you have will help identify where to go next. |
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| Author: | DadTruck [ Thu Jul 29, 2021 6:03 am ] |
| Post subject: | Re: I need more low end torque |
Nothing that you did mechanically was wrong, you just did not do enough to make a change in the engines performance, or address issues that may exist that are causing the engine to feel lazy. The terminology used to describe some of the changes is not correct. A little polish on the side walls of the ports is not porting and I do not see a functional back cut on the valves. Gasket matching is the last thing that one would do to get the last bit of performance out of a precise and thoughtful built performance motor. Means about nothing on a near stock motor. Some tips: * If you are going to take the time to mill a head, prior to that you should cc the head, measure piston recession and use an online calculator to plan how much to cut to get to the desired compression ratio. There are lots of compression calculators on line, here is one https://www.rbracing-rsr.com/compstaticcalc.html * Cleaning up stock valves really does little to help port flow on an engine. As the engine runs the valves sink into the head, that recession really hurts flow at low lift. One of the real advantages to installing oversized valves is that causes the valve seats to get re cut. If you have a machinist that knows what he is doing that allows the new valve seat to be higher in the head, and that helps flow the larger diameter also helps flow. Buying the best multi angle valve seat that you can get is money well spent. * If the motor has many miles - kilometers at all and the timing chain has not been replaced, that will retard timing and that will cause the engine to feel lazy. * Stock slant six cams are not known as performance cams. Don't go crazy big as a bigger cam will get you more torque and horsepower, but that will raise the rpm level where that occurs and cut tq and hp in the lower RPM's. There are plenty of cam posts on this forum, I would go with something in the 210 to 220 duration, 106 LSA installed 102 ICL. * A distributor recurve will also help, not as a fix to your current issue but as a component of the fix. Look around your area and see if there is someone with an old time Sun distributor machine. Maybe check with local car and hot rod clubs. * Investigate the possibility that your transmission is slipping when the car pulls away from a stop, 904's and kick down linkages need maintenance to. * the posting above mentioning doing a compression test is absolutely on track. * Consider getting a desk top dyno package like Dyno Sim. You can use that to see the effect of changes made to the engine prior to buying and installing the part. I use one. http://www.proracingsim.com/dynosimmainpage.htm Poke around in the FAQ section in this forum and continue to post and ask questions. https://www.slantsix.org/forum/viewtopi ... 19&t=38446 You have a great car to start with, keep learning. |
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