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| New Engine, Bad Result https://slantsix.org/forum/viewtopic.php?t=36019 |
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| Author: | Reluctant Dodger [ Sun Jun 28, 2009 12:20 pm ] |
| Post subject: | New Engine, Bad Result |
My son's 63 Dart GT is now a Hangar Queen in my garage. He has been restoring and using it as a daily driver. He finally saved enough to replace the engine. A shop that he had used numerous times before did the "job". 5 weeks later they still couldn't get it to run right. They replaced distributor, carb, battery, coil, etc. They lost interest in the job and just let it sit. So my son (who lives about 90 miles away) had it towed to our house. Symtoms: The car starts easily hot or cold but runs very rough (a lot of vibration) If you drive it it feels like its fuel starved. The mixture has to be much richer than it should be. What have I done: Rebuilt the rebuilt carb, replaced fuel filter, jumped a line from battery to coil, tried a known good coil, replaced ballast, adjusted valves numerous times, replaced "new" distributor with used known good one, set timing ,points, checked for vacuum leaks, replaced int/exh manifold gasket, removed rocker arms and checked for bent push rods. It's got the Holley 1920 carb. My instincts keep saying a valve timing problem so I went to the trouble of checking the timing chain and there is one thing that puzzles me...when the dots on the gears are lined up at their closest point (and the chain is on correctly) it is not on #1 TDC, if you rotate the crankshaft one complete turn then you get #1 TDC the dots are lined up thru the centers of the shaft but they are not adjacent. This doesn't seem quite right but the book doesn't specify that when the dots are adjacent it's #1TDC. The head is 75 or later and I can't make out the date for the block. Mom is starting to apply extreme pressure and I'm worried about losing my know-it-all reputation. Thanks for any insight. |
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| Author: | slantzilla [ Sun Jun 28, 2009 1:07 pm ] |
| Post subject: | |
IIRC, when the dots are lined up correctly the motor is actually on TDC on #6. Sounds to me like the intake is not sealed to the head very well. |
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| Author: | 65Dodge100 [ Sun Jun 28, 2009 5:27 pm ] |
| Post subject: | |
Have you tried a compression test? Danny |
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| Author: | 66aCUDA [ Mon Jun 29, 2009 6:26 am ] |
| Post subject: | |
Dot to dot is correct for TDC #1 (I have an engine on the stand now) or real close. Where are you is someone close. Often 2 heads are better than one. Do you have a known good carb to put on? On another note did your son get his money back??? That IS the responseablity of the shop. Frank |
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| Author: | SlantSixDan [ Mon Jun 29, 2009 7:00 am ] |
| Post subject: | |
Quote: Dot to dot is correct
Not so fast. There've been timing sets manufactured such that the dots align on the far sides of their respective sprockets when everything's installed correctly. That is, both dots are at the ~10:00 clock position (guesstimate off the top of my head). Years ago, this question came up in the old "Slant-6 News". I don't recall which tech rep said "Let monkeys line up dots...you use a degree wheel!", but he was right. It's best to use a wheel, but even if no wheel is used, it's better to trust the position of valves vs. position of piston than just to go by the dots.
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| Author: | 66aCUDA [ Mon Jun 29, 2009 7:06 am ] |
| Post subject: | |
Quote: Quote: Dot to dot is correct
Not so fast. There've been timing sets manufactured such that the dots align on the far sides of their respective sprockets when everything's installed correctly. That is, both dots are at the ~10:00 clock position (guesstimate off the top of my head). Years ago, this question came up in the old "Slant-6 News". I don't recall which tech rep said "Let monkeys line up dots...you use a degree wheel!", but he was right. It's best to use a wheel, but even if no wheel is used, it's better to trust the position of valves vs. position of piston than just to go by the dots.Frank |
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| Author: | Doc [ Mon Jun 29, 2009 11:10 am ] |
| Post subject: | |
As already noted, most "dot to dot" are at #1 TDC Exhaust stroke. That is where the overlap event is happening so it allows the builder to get a better view of cam position. The Iintake & exhaust lobe centerlines are also closer to TDCE then TDC compression stroke. From a valve movement standpoint, nothing is happening at TDC, all the "action" is at TDCE. As for this engine... I would check the overlap event to see how well centered it is over TDC. Do you know what cam and compression ratio was built into this engine? |
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| Author: | Reluctant Dodger [ Mon Jun 29, 2009 2:33 pm ] |
| Post subject: | Thanks for your input & a little more info |
I'd like to thank everyone who took the time to respond. Let me add a few things that I forgot in the original post. I checked the compression early on and I was just looking for a big variance...there was none. This morning I checked it again and actually recorded the numbers. They were all between 155 and 151. (I may need a bottle of 151 tonight). That seems pretty good to me. Vacuum is about 17in at idle and 19in at fast idle with the choke on. Re the intake connection: That was my thought early on and I torqued the manifold bolts-I found three that were stripped. I replaced those, cleaned up the threads on the rest, new gasket, even put sealant around the intake ports. (This was one of my "THIS has got to be it" moments), torqued the manifolds back down according to the book with the same sad result. Unfortunately, I don't know anything about the rebuild, my son is going to use it as a driver so I don't think the shop would or could go the hi performance route. Let me tell you about some of my crazier theories that I've checked out: I thought maybe they left a rag in the intake manifold, so I snaked it out with a hanger (No Luck) I thought perhaps this engine had hydraulic lifters so I adjusted (carefully) the lifters as if they were hydraulic (No Luck) I'm blotting the rest of them out of my mind, I'm starting to scare myself. Any insight is welcome. Thank you all again |
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| Author: | Doc [ Mon Jun 29, 2009 4:16 pm ] |
| Post subject: | |
Try a different carb, hopefully one that is in known working condition. Where are you located... hopefully there is another SL6 owner around that can lone you their carb just to see if that solves the problem. My next though, maybe there is a performance cam in the rebuild. Try loosing the valve adjustment as loose as possible to see if the idle smooths-out a bit. DD |
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| Author: | Reluctant Dodger [ Mon Jun 29, 2009 5:29 pm ] |
| Post subject: | Thanks Doc |
There is a guy fairly close with a 63 Valiant. I've been trying to hook up but he's never home...must have a job. I'll keep trying. About the valves, how loose is a good starting point? Thanks Again |
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| Author: | Joshie225 [ Mon Jun 29, 2009 8:20 pm ] |
| Post subject: | |
If it's a standard cam the lash should be .010" intake and .020" exhaust. Running them .002" looser is fine. So try .012" and .022". |
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| Author: | Dave95693 [ Wed Jul 01, 2009 9:20 am ] |
| Post subject: | Here's a possibility |
I've had two episodes of the same type of problem. Both times I spent what seemed endless hours with carbruation, valve adjustment and timing. Both times, it ended up being a points issue. The first was when the wire going to the points was wearing against the distributor shaft and was arcing out. Replaced the points and cured the problem. The second and most recent was on my Demon. Again, same simptoms. I checked the points and sure enough they were defective. Replaced those points and now it runs like a champ. In both instances, the points were new...one was my fault for not being more careful with the installation, the second was just bad luck in getting bum points. Good luck! |
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| Author: | snarl [ Wed Jul 01, 2009 5:59 pm ] |
| Post subject: | |
Are the spark plug wires on correct? |
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| Author: | Reluctant Dodger [ Thu Aug 20, 2009 2:41 pm ] |
| Post subject: | Progress...Down to One Big Problem |
Well, I'm sure that you thought I'd either killed myself or set the Dart on fire. (I was thinking of doing these simultaneously) Instead I took Doc's advice and was finally able to ge a hold of the guy in my neighborhood with the 63 Valiant. He was good enough to come by and try his carb on the Dart. Major improvement. Then all I had to do was find a good rebuilt carb. Got one, paid too much, bad experience with quote versus final price. But it made a huge difference, so I've almost forgotten about it. I also had some other issues: When I removed the timing case cover and reinstalled it, I screwed up the oil pan gasket and of course it leaked badly. Oil Pan Gasket Replacement, That's a real fun job! The guys who did the engine ran rubber lines from the tranny to the radiator periously close to the exhaust manifold. I put metal lines in but routed them at a right angle toward the driver side and down the rail to the tranny with a rubber line across. Now my last problem...Vibrations. Once I got it tuned up and was able to bring the idle down there was still vibration inside the car. At idle the steering column shook badly. Looking at the engine it was apparently idling smoothly, it looked fine. I went back and checked the mounts and on the passenger side there are two bolts embedded in the rubber , the back side one the nut was about to fall off. Once again I thought I finally had it. When I started the car it was now smooth at idle. Time for a test drive and a return to tears. The car runs good, good power, good throttle response, but there is very bad vibration once over 1000 rpm and that's sitting in the garage or going down the street. It feels like there is an imbalance in the engine or Tranny. So I've got 3 possibilities in mind: Even though the mounts are new (all 3) they're bad, Something wrong with the harmonic balancer. Flex plate loose. (Just throwing that out there) I look forward to any assistance or similar experience that you may have. Thanks for your help |
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| Author: | terrylittlejohn [ Thu Aug 20, 2009 4:46 pm ] |
| Post subject: | |
even with torque bolts loose it won`t shake just knock.if balancer is good check converter for balance weight, somebody might have a 360cid converter in there. |
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