351w Rebuild |
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jpage
Newbie Joined: July-16-2014 Location: Atlanta,GA Status: Offline Points: 29 |
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Posted: February-12-2015 at 1:25am |
Just pulled the motor out of my cough MasterCraft '84 . For a bad head gasket and excessive crank pressure. About to do a full rebuild and figured you guys would like to see the progress as it goes. New parts are as follows
Edelbrock E-street heads Harland sharp 1.6 rockers Wielend Stealth Intake Lunati Voodoo cam/lifters/pushrods Dish +12cc pistons along with all the other internal bits and pieces. |
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MrMcD
Grand Poobah Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3605 |
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When you invest in Piston Rings buy Ductile Iron Moly rings, actually this is for the Top Ring, the second ring can be standard cast and the oil ring won't change but the top ring will be exposed to more power and potentially exposed to detonation. The Ductile Iron ring will live far longer in this environment. Might cost $35. more but worth every penny. Keep us posted as you go.
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JoeinNY
Grand Poobah Joined: October-19-2005 Location: United States Status: Offline Points: 5696 |
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I mean ya know if you're in there and all you might as well stroke it a Lil bit...
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Waterdog
Grand Poobah Joined: April-27-2006 Location: United States Status: Offline Points: 2020 |
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Come on Joe "a little bit" to funny from the King ! |
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jpage
Newbie Joined: July-16-2014 Location: Atlanta,GA Status: Offline Points: 29 |
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I would love to do that. But as a college student that just doest fit in my buget at the moment. I can alway set up a GoFundMe page if yall are willing to donate a little $ |
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21133 |
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I don't know much about those heads but its safe to say I'd spend what budget I have on a stroker kit (or at least a roller cam) before spending $$ on aluminum heads.
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backfoot100
Platinum Member Joined: January-03-2007 Location: United States Status: Offline Points: 1897 |
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+1 If you're on a tight budget, you have to look at what will get you the biggest bang for your buck for every part you put in there. Aluminum heads really won't give you near the ROI that a stroker kit would and they would probably be very close in price. You would have some extra costs for the machining and then some much more reasonable cast heads but that's still pretty minimal in the overall cost of the build. If you're still insistent on not stroking it, at least go with much cheaper cast heads on a budget. Then put the extra money you just saved toward a roller cam like Tim suggests. You'll be much happier in the long run. |
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When people run down to the lake to see what's making that noise, you've succeeded.
Eddie |
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jpage
Newbie Joined: July-16-2014 Location: Atlanta,GA Status: Offline Points: 29 |
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I got the heads from a friend for a great price they are 60cc with 2.02 valves. If I was doing a stroker I would need at least $1500 for a heads alone that would flow enough. I have just that much total in this one. I do have a spare block laying around that I could build up piece by piece as funds allow. In these motors and the RPM's that we are turning roller cams don't mean that much more in power. You just need to be more selective with the hydro flat tap cams and use roller rockers. The link bar lifters that make it roller are around the $500 mark.
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phatsat67
Grand Poobah Joined: March-13-2006 Location: Indiana Status: Offline Points: 6149 |
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The 3 guys that quoted above you know more about ski boat marine engine performance than most anyone in the world. I suggest you take their advise when working inside your budget.
Eddie, Tim, and Joe have boats running so well they make most everything else in the world look stupid. |
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21133 |
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Yes, the tie bars are pricey (small block stuff might be a little closer to $400), but machining for a spider retainer and some stock (used) roller lifters would probably be a bit less $.
I disagree entirely on the potential of a roller... I would have agreed with you prior to going down both roads in 2 of my correct crafts. The reliability concerns are worth the extra cost alone, IMHO- but the power gains are real, and significant. Going roller on a LH engine is a no-brainer... And still worth the effort on a RH, though the cost goes up quite a bit. |
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phatsat67
Grand Poobah Joined: March-13-2006 Location: Indiana Status: Offline Points: 6149 |
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Fraction of the cost and much easier than roller in a RH. Thats mostly why the hi-po guys are using 1.23 transmissions to run LH engines vs RH. |
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jpage
Newbie Joined: July-16-2014 Location: Atlanta,GA Status: Offline Points: 29 |
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IF i was to go Full Hydro cam what cam specs should i be looking at?
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Fl Inboards
Grand Poobah Joined: January-20-2008 Location: United States Status: Offline Points: 2066 |
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Hopefully you dont plan on hanging cast iron exhaust manifolds off those aluminum heads?
Just checking! I just went through a engine replacement for a 81 Stars and stripes MC. As when the engine showed up here from Tenn it had been damaged in transport to the extent that the motor mount bosses on the block were broken off....So we got a rebuilt marine short block assy from Summitt. I had a set of GT-40 heads and we purchased a new performer intake and cam/lifter kit along with a new 4160 holley all said and done estimated HP in the 300 range for under $4500. |
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Hobby Boats can be expensive when the hobbyist is limited on their own skill and expertise.
1993 Shamrock "fat" 20. 2008 Nautique 196 5.0 |
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jpage
Newbie Joined: July-16-2014 Location: Atlanta,GA Status: Offline Points: 29 |
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Fl Inboards, i assume you would be the wise jody seal, what would the issue be of using the stock exhaust on aluminum heads?
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phatsat67
Grand Poobah Joined: March-13-2006 Location: Indiana Status: Offline Points: 6149 |
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Aluminum can't hold as much weight as steel.
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Fl Inboards
Grand Poobah Joined: January-20-2008 Location: United States Status: Offline Points: 2066 |
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Not sure I am as wise as cautious. Cant say I have hung a set off Aluminum Heads but have seen over the years many a cast Iron GT head crack at the water jackets above the head bolts. I think if I were to utilize aluminum heads I would find a set of aluminum logs and go that route... They look cooler anyway! Who knows depending how hard you run your boat the cast and aluminum heads may stand up! Then again!!!
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Hobby Boats can be expensive when the hobbyist is limited on their own skill and expertise.
1993 Shamrock "fat" 20. 2008 Nautique 196 5.0 |
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phatsat67
Grand Poobah Joined: March-13-2006 Location: Indiana Status: Offline Points: 6149 |
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I am pretty sure ford thinned up that outer wall later on the GT-40 stuff. Never seen cracks on any of the early lo-po heads but the GT-40 or later 2 bar heads generally crack or rust through right there.
If i were super worried I would just put a cross bracket on the manifold riser bolts to connect the two together. |
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jpage
Newbie Joined: July-16-2014 Location: Atlanta,GA Status: Offline Points: 29 |
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motor is getting built up as we speak, should the motor be put back in with the bell housing on the motor or trans?
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jpage
Newbie Joined: July-16-2014 Location: Atlanta,GA Status: Offline Points: 29 |
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Here is a little update, looks like will be finishing up next week
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jpage
Newbie Joined: July-16-2014 Location: Atlanta,GA Status: Offline Points: 29 |
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Update: going to go fire it up tomorrow.
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jpage
Newbie Joined: July-16-2014 Location: Atlanta,GA Status: Offline Points: 29 |
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Should I remove the carb spacer?
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mamigacz
Groupie Joined: June-08-2014 Location: Wisconsin Status: Offline Points: 96 |
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If you have clearance issues with the carb spacer you can replace the carb base with an Holley auto base (get rid of the carb spacer). There isn't anything marine about it, except that the input for the vacuum advance needs to be plugged. I did it when I ran a Holley with a Performer RPM intake.
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21133 |
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I am not sure we have definitively answered whether the base plate is marine specific or not. Some knowledgable folks have indicated that the throttle shafts are sealed, and while I've never confirmed that myself, the only ones I've seen leak are automotive versions.
Newer marine carbs have the vacuum port on the baseplate as well. |
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JoeinNY
Grand Poobah Joined: October-19-2005 Location: United States Status: Offline Points: 5696 |
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I would counsel against going to an automotive baseplate. First there is a difference in the shaft sealing between an automotive baseplate and a marine baseplate. When your float sticks and gas puddles on top of the butterflys you do not want the gas to pour out around those shafts onto your intake manifold. Second, you can quite easily locate a plug on that intake manifold that you can swap out for an elbow and give yourself someplace to hook up your pcv valve if you have clearance issues with the spacer in place (which I assume you will).
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phatsat67
Grand Poobah Joined: March-13-2006 Location: Indiana Status: Offline Points: 6149 |
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The bell cranks are nowhere near the same on an auto base either.
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 10727 |
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Here's a picture of a shaft from an auto carb on the left and a marine one on the right. This is from a post in 2008 titled "I replaced the Pro-Tec system" that somebody started and I amazingly still had the picture on my computer The marine one has 3 grooves at each end where it rides in the base plate. There are no seals of any kind that go in the grooves. I've had a number of them apart enough to see the shafts and every marine Holley was like this. There's really no reason to take the butterflies and shaft out, other than curiosity,it's a pain in the butt because the screws are staked and you have a good chance of screwing up the shaft threads taking the screws out or bending the shaft when you stake them again after they are back in place. Holley also says it is "slabbed" meaning that inboard of the innermost groove on each side only goes about halfway around and the rest (bottom part) is flat just like the part of the shaft that the butterflies hook to. Kinda hard to see this in the picture but that's how it is. A SMART person would not do this, a curious one would and may or may not cause some engine damage if one of those butterfly screws fell into the engine while it was running cause it wasn't staked properly. This pertains to let's say a 4160 from the 70's and 80's, don't know if there are any later model differences. I'd call it magic about how they prevent leakage but I'd guess it works like a labyrinth seal. Somewhere on the internet there is a Holley explanation of how it works. I found it once and didn't save it. Don't know when they started doing this to the marine carbs but they haven't always had the J tubes either. I had a 76 PCM 351 and the original carb new from the factory had no J tubes but did have the grooved, slabbed shafts. (List number 6576, it's hard to find this number in a Holley listing) Maybe somebody will have a good scientific explanation why this works but that is how they were built(at least the ones I've had apart.) I've heard that some newer ones have actual Teflon seals but that may have been an Edelbrock or Weber and I'm getting a little smarter and less curious so somebody else can look at that. KenO (I'm curious, not smart) |
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backfoot100
Platinum Member Joined: January-03-2007 Location: United States Status: Offline Points: 1897 |
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Excellent info Ken. Thanks for sharing. I've have read in numerous documents that there are shaft seals on marine carbs but this is the first time I've actually seen the difference. Many have questioned this fact and these are the same idiots who swear that they just add a "J" tube and an automotive carb magically becomes a marine carb. |
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When people run down to the lake to see what's making that noise, you've succeeded.
Eddie |
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jpage
Newbie Joined: July-16-2014 Location: Atlanta,GA Status: Offline Points: 29 |
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Here is a video of the start up last night, we got the cam broke in, now just to adjust the wiring and get it all fixed up and ready to drop in next week.
Start up video |
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skicat
Platinum Member Joined: May-18-2006 Location: Duluth, GA Status: Offline Points: 1128 |
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John- your video is set to private. Can't watch the motor start up you are going to put in that off brand boat!
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mamigacz
Groupie Joined: June-08-2014 Location: Wisconsin Status: Offline Points: 96 |
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I ended up swapping the primary shaft, secondary shaft, linkages and throttle plates from the marine base to the auto base. I didn’t see any seals either. However, the magical labyrinth seal is still part of my Frankenstein carb, since the marine carb shaft is part of it.
A PCV valve is constant vacuum leak when its open. Typically, the manifold port is used for applications that need intermittant vacuum for very short periods of time. Like the brake booster or transmission modulator. PCV inputs are always located before the intake runners, so the leak can be distributed to all 8 cylinders. When you use the manifold port, the leak is isolated to one cylinder. I would think this would cause a lean condition on that one cylinder. Has anyone tried this? If it works without problems, it’s definitely an easier solution than my carb base swap. |
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