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| Depress Clutch - Car Stalls | Rate Topic |
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| Posted: 04-03-2024 10:06 pm |
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1st Post |
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JH12947 Member
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I'm getting close to the finish of my 2 year restoration. Today I pushed the car out of the shop to get it started with fuel from its own tank for the first time. It starts and idles fine. Needs some tuning, but that's expected. However, under idle or slightly higher RPMs, pushing in the clutch pedal causes and immediate stall. I did manage to get it into first and creep forward if I rode the clutch and kept the RPMs high. Revs drop - stalls. I plan to get under it and check the clutch fork and adjustment, but would like to know if anyone has an idea of anything else to check. I'm aware there may be a crankshaft/thrust bearing issue, but hopefully not. As background, I had the flywheel skimmed, and the disc was relined. I installed a new spigot bearing and the throwout bearing seems smooth and fine. I did the initial adjustment according to the manual and installed a new cable. The car will move through all the gears when the car is not running, and the transmission is engaged since the rear end is locked. Any suggestions welcome, Corey
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| Posted: 04-05-2024 02:37 am |
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2nd Post |
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vnavaret Member
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Hoo boy, Could be many things. Is the engine ground strap connected? Might be getting the ignition ground through the clutch cable - depressing the clutch causes the ignition to cut out. When it stalls, does it stumble, slow and then stall, run rough for an instant, or display any other behavior? Or does it act as if the ignition switch has been shut off? A few clues might help us identify the issue. Vance
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| Posted: 04-05-2024 02:48 am |
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3rd Post |
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JH12947 Member
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Thanks for the reply. The engine is well grounded - it does not seem like an electrical issue. The engine stumbles but does die fairly quickly. If I keep the revs high it will engage the tranny and pull forward, but will die as soon as the revs drop. I'm going to do some more tuning tomorrow and see if that helps at all. I did check the crank pully endplay crudely with a prybar and didn't really detect any perceptible play so I'm hopeful it's not a thrust issue. All the clutch related stuff at the bell housing seems right. If you can think of anything else to check I'm all ears.
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| Posted: 04-05-2024 12:51 pm |
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4th Post |
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noomg Member
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Corey, Under the heading of trying the easy things first I'd pull the plugs and turn the engine over with a wrench or socket on the crank. It should turn smoothly with no compression then as your turning it have someone depress the clutch pedal. If you encounter resistance you'll know where the problem lies.
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| Posted: 04-05-2024 01:49 pm |
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5th Post |
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JH12947 Member
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Thanks noomg - I'll give that a go. Your post jogged my memory of what may be causing the engine to bind. When I replaced the rear seal I found the a PO had secured the seal housing with phillips head machine screws (see attached pic). I ordered some cap head screws to replace the fasteners, but found that when I torqued the flywheel some of them would bind. I ended up reusing the screws in a few spots and everything moved freely. It could be that the clutch pressure is enough to cause binding in this area, although it certainly seemed that clearance was adequate. I should know more after I do as you suggested. Attachment: seal cover.jpg (Downloaded 51 times)
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| Posted: 04-06-2024 12:51 am |
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6th Post |
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JH12947 Member
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Bit of an update.... I guess it's better to know but neither the fix nor the root cause is obvious to me. I took the dust shield off the bell housing and used my borescope to look at the rear seal cover bolts. As you can see from the photos, the clearance is minimal or non-existent and there is evidence of contact with the flywheel. So obviously the tranny is coming off so I can deal with it. I'm left to wonder why this would happen and what the clearance between the flywheel and these bolts normally is. Perhaps stock bolts (which seem unavailable) had thin heads. Unless he crank in this engine is actually sitting forward of where it should be it's hard to imagine that it's anything to do with my change of the seal and reassembly. New gasket thickness should not cause this. My options as I see them are to grind the heads smaller or have a few mm skimmed off the flywheel. I'd love to see the clearance in other engines and specs on the proper bolts. Attachment: IMG_0146.JPG (Downloaded 48 times)
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| Posted: 04-06-2024 12:51 am |
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7th Post |
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JH12947 Member
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Another bolt. Thinner washer would help but still wouldn't be comfortable with it. Attachment: IMG_0145.JPG (Downloaded 48 times) Last edited on 04-06-2024 12:53 am by JH12947 |
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| Posted: 04-06-2024 03:36 am |
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8th Post |
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JH12947 Member
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I found this photo in another thread on this forum. Since it shows a similar collection of bolts and machine screws, perhaps mine was not incorrect after all. Of course, this does not explain why mine is now binding. I'm sure it must have been running ok when it was taken off the road. Attachment: alternate pic.jpg (Downloaded 48 times)
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| Posted: 04-07-2024 12:34 pm |
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9th Post |
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redracer Member
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Sounds like your thrust(fore-aft movement of the crank)is too large. I do not know if you rebuilt the engine, but the 2 half-moon washers should give0.003'-0.008", with 0.005" is what I shoot for. The larger thrust washer is placed in the front side just to be sure of the clearance problem you have. When depressing the clutch pedal, the forward movement of the flywheel from the pressure will move the flywheel into said bolts. With no pressure on it, the crank will "float" to its least resistance, so Two other items come to mind: the earlier flywheels were "flat" since they used a rope seal and thus no mounting piece to hold the later rear main seals. The later flywheels had to have some material removed to accommodate this extra material. I have replaced the 4 phillips screws with standard hex bolts with no problem. And finally, I assume you put the clutch disc in the correct way as it is labeled with "flywheel" side on it.
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| Posted: 04-07-2024 01:16 pm |
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10th Post |
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JH12947 Member
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Thanks - The thrust issue is what I assumed is my worst case scenario. The car came to me with only 40k miles on it and ran fine on the stand so I assumed it to be ok and there was no scoring on the back of the flywheel to indicate there was an issue before. Of course, I don't know if the engine is original to the car, although the dates are close. I'll be pulling the tranny today to double check everything. It seems hard to think that the clearance to the bolt heads would be so minimal with correctly set thrust that anything other than a massive amount of slop would allow for contact. My other two thoughts are that perhaps the machine shop removed some material on the crank mating surface when they skimmed the flywheel, or, when I initially torqued the flywheel bolts on with the cap head bolts I was planning to use, the large heads on those caused the flywheel to physically pull the crank rearwards in the block. There seemed to be a bottom-end noise when I ran it the car that was not present on the stand. I'll post some photos of the teardown as I do it.
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| Posted: 04-07-2024 05:03 pm |
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11th Post |
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redracer Member
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At least put a dial gauge on the crank to see what the runout is. Also, put on the flywheel and push it forward to see if it touches the bolt heads, which would be an indication of worn/incorrect thrust washers
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| Posted: 04-08-2024 06:05 pm |
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12th Post |
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JH12947 Member
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Here is what I have found out. I pulled the tranny and removed the clutch cover and friction disc. All looked good there. I put a dial indicator on the flywheel and the runout was negligible. All good there. I pried the crank backward and forward using the crank pulley and the gauge reading for thrust was consistently "0.0055. This also seems good. There is also no scoring on the flywheel or bolts that would indicated there is contact. (though clearance is still too small for my liking.) What I did find is that the back of the flywheel is eating into the seal at the location shown in the photo below. Also in the following post there is a photo of the groove in the seal. You can see in the original photo in post 5 that there was very minimal contact with the seal in the prior installation. I was very careful to leave the 0.10" recess between the housing and seal when I installed it so either this seal was thick or it walked forward when I pressed the cover on. I guess my options are to install a new seal or have the flywheel machined slightly to reduce the step and increase the clearance. Thoughts? Attachment: Flywheeel.jpg (Downloaded 30 times) Last edited on 04-08-2024 06:08 pm by JH12947 |
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| Posted: 04-08-2024 06:07 pm |
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13th Post |
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JH12947 Member
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Seal with groove Attachment: seal.jpg (Downloaded 30 times)
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| Posted: 04-08-2024 09:34 pm |
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14th Post |
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redracer Member
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I can't be sure from the 2 dimensional picture, but that looks like the earlier('72 & '73) flywheel. If that surface is "sticking out" (i.e. to the front of the car), that will most definitely hit the seal cover. Better pix of that same are where the crank-to-flywheel holes are showing that "rubbing" surface would let me know definitely if you have the wrong flywheel in there. I recycled all the early ones I had as the later ones are fine and a little lighter. If you need one, I have plenty of good used ones
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| Posted: 04-08-2024 10:18 pm |
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15th Post |
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JH12947 Member
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Thanks - Here is an additional photo. The casting number is 7199397 if that matters. Let me know if you need another angle. BTW, engine number is 3077. Attachment: IMG_0158.jpg (Downloaded 29 times) Last edited on 04-08-2024 10:36 pm by JH12947 |
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| Posted: 04-09-2024 02:38 am |
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16th Post |
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redracer Member
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Hope these pix go through? The 2 i took of the later style show the circumference just outside the bolt holes is machined down, unlike yours. Again, yours looks like the earlier style which will not work with later engines that have the rear crank seal cover
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| Posted: 04-09-2024 02:38 am |
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17th Post |
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redracer Member
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Hope these pix go through? The 2 i took of the later style show the circumference just outside the bolt holes is machined down, unlike yours. Again, yours looks like the earlier style which will not work with later engines that have the rear crank seal cover
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| Posted: 04-09-2024 02:41 am |
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18th Post |
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redracer Member
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Hope these pix go through? The 2 i took of the later style show the circumference just outside the bolt holes is machined down, unlike yours. Again, yours looks like the earlier style which will not work with later engines that have the rear crank seal cover Attachment: J-H later Style flywheel(2).jpg (Downloaded 25 times)
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