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 Looking for a PN or source for 12 point intake manifold boltsJump to page : 1 Now viewing page 1 [50 messages per page] | View previous thread :: View next thread |
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56D500boy |
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Exner Expert 10K+ Posts: 11182     Location: Lower Mainland BC | . In the process of solving a back-fire issue with my 56 Dodge D500, I've ended up removing the intake manifold and valley pan so I can check out the lifters (No. 8 intake lifter for starters). To remove the intake manifold, I used a proper 1/2" 12 point socket. Most of those bolts came out fine (I had test loosened them last year). *BUT* this time, there were a few that were reluctant to come out (not sure why) and they might have gotten a bit mangled when the socket slipped. Now that I am moving towards installing a new lifter and buttoning things back up, I am not liking a few of the sixteen (16) 1/2" 12 points that I took out. I wasn't paying attention but I am guessing that the ones that got a bit mangled on their way out (see photos below of one good one and one mangled one) were beside the blind water passages (2 bolts per passage x 2 passages per side x 2 sides = 8 bolts that might have wanted to stick. Plan B would be to file away some of the problem areas. Plan A might be new bolts. I can't find a PN for these bolts so I can't chase them. Any help will be appreciated (but no, I don't want to use 6 point bolts). When I do put the bolts (old and/or new) back in, they will have Never Seize on them (duh). Edited by 56D500boy 2026-03-16 6:09 PM (56DodgeD500IntakeManifold12PointBolts_1.jpg) (56DodgeD500IntakeManifold12PointBolts_2.jpg) Attachments ----------------  56DodgeD500IntakeManifold12PointBolts_1.jpg (207KB - 157 downloads) 56DodgeD500IntakeManifold12PointBolts_2.jpg (109KB - 123 downloads) | ||
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| JedRhule |
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Veteran Posts: 140 Location: Palm Beach County Florida | |||
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| 56D500boy |
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Exner Expert 10K+ Posts: 11182 Location: Lower Mainland BC | . This is what I found at McMaster-Carr. 12 point but only 3/8" head for a 3/8 x 16 threaded cap screw: https://www.mcmaster.com/products/screws/fastener-head-type~12-point... Same at a more local source to me (but they have no stock): https://www.grainger.ca/en/product/p/WWG2FA91?cm_sp=Catalogue-_-NA-_...  | ||
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| dels56 |
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Extreme Veteran Posts: 488 | |||
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| 56D500boy |
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Exner Expert 10K+ Posts: 11182 Location: Lower Mainland BC | . In the end, I decided to stick with the OE 1/2" 12 point intake manifold bolts. Only 2 or 3 were a bit mangled - which I improved using a triangular profile metal file. I cleaned all the threads up (3/8 x 16) with a die and after removing the old paint, I repainted them. My question now is, would it be wrong to install the 12 point bolts with thin stainless steel flat washers? I like the idea but I realize there might be a downside. (??) Here they are, ready to go (after I add some copper never-seize to their threads): (SlightlyRehabbed56D500_12PointIntakeManifoldBolts.jpg) Attachments ---------------- SlightlyRehabbed56D500_12PointIntakeManifoldBolts.jpg (147KB - 155 downloads) | ||
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| 56D500boy |
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Exner Expert 10K+ Posts: 11182 Location: Lower Mainland BC | . Off Forum, DelS (Dels56) advised my to NOT use stainless steel washers but use Grade 8 washers instead. I checked out local stainless steel flat washers and agreed that they were too thin. I didn't want to wait for Grade 8 washers so I went with zinc-plated steel washers. I had to trim some of them along one edge because the bumped into the intake runners, a bit. I think that I am happy with what I done. (DaveFs56D500IntakeDuringReinstallation_NewWashersUnder12points.jpg) Attachments ---------------- DaveFs56D500IntakeDuringReinstallation_NewWashersUnder12points.jpg (231KB - 144 downloads) | ||
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| wayfarer |
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Elite Veteran Posts: 940  Location: Peoples Republic of Oregon | That should work. now, about that broken coil mount bolt...  | ||
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| 56D500boy |
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Exner Expert 10K+ Posts: 11182 Location: Lower Mainland BC | wayfarer - 2026-03-29 2:59 PM That should work. now, about that broken coil mount bolt... You must have missed it Gary. I "bodged" my way to a solution awhile ago. http://www.forwardlook.net/forums/forums/thread-view.asp?tid=78349&... Not pretty but it works | ||
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| ronbo97 |
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Expert Posts: 4240  Location: Connecticut | |||
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| 56D500boy |
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Exner Expert 10K+ Posts: 11182 Location: Lower Mainland BC | ronbo97 - 2026-03-30 8:55 AM Are these 12-point bolts factory ? Every Mopar engine I've seen has had six-point bolts. They've also had the DPCD logo in the center. All I can say is every 1956 Dodge D500 315 double-rocker engine that I have seen (via photos) have the 12 point intake bolts. Most, but apparently not all, 315 polys have normal six-sided hex bolts. This is a least one exception: (56DodgeLancer315PolyWhiteBlueAndBlue_EngineBay_4.JPG) Attachments ---------------- 56DodgeLancer315PolyWhiteBlueAndBlue_EngineBay_4.JPG (178KB - 144 downloads) | ||
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| Powerflite |
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Exner Expert 10K+ Posts: 10542 Location: So. Cal | |||
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| 56D500boy |
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Exner Expert 10K+ Posts: 11182 Location: Lower Mainland BC | Powerflite - 2026-03-30 4:50 PM All three of the '57-'58 325 poly engines I have use these 12 sided bolts. They are pretty common on the Dodge of this era. You can probably get a set from John Fowlie at Big M. Thanks for that info Nathan. Turns out that despite having a few (3? 4?) bolt heads that needed attention (filing away some galling due to socket slippage), I have all 16 back in and, as of yesterday, torqued to spec. I found the tightening torque spec for the intake manifold bolts in the 56 Dodge FSM. It is 30 lb-ft. Hmm....my 1/2" drive torque wrench only goes down to 50 lb-ft and the 3/8" drive torque wrench that I have only goes up to 250 lb-in (not enough). So I went out Canadian Tire (think O'reilly's with sporting goods) to buy a 3/8" drive torque wrench that is good for 20 to 100 lb-ft. Previously, when I installed the intake the other day, I had tightened all 16 bolts with my "GuteUntTight" german spec with the 3/8" drive rachet (maybe a 12" handle). I thought that they were all very tight. I wasn't even sure that I needed a torque wrench to get this job done. (I was wrong) When I got back from Canadian Tire, I set the trip on the new untested torque wrench to 30 lb-ft, attached a short extension and one of the two 12 point 1/2" head JET brand sockets that I got at Lordco (think PepBoys) and gave it a go. Considering that I thought that I had the bolts very tight, I was surprised by how much I had to pull to move towards 30 lb-ft. In fact I got concerned that the torque wrench wasn't working properly (jammed??) and I was going to snap a bolt. So I quit trying and adjusted the new wrench down to 20 lb-ft and tried again. This time I got it to click. Yay. After tightening all 16 bolts to 20 lb-ft (each with a satisfying click), I re-adjusted the trip back to 30 lb-ft and continued tightening the bolts. This time, it didn't seem to require as much force as the first go. They all got a click at 30. so I was happy. The proof in the puddlng will be if I get any coolant leaks at the four blind water ports in the head. (Very strange design in my opinion). I was very careful and had zero socket slippage on what now appear to be very special 1/2" head 12 point bolts. Might even get the engine fired up today. Edited by 56D500boy 2026-03-31 3:57 PM | ||
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