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Smoking Motor Fixed!

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  • Walter Muta

    Smoking Motor Fixed!

    Hello everyone. I'll be as brief as possible yet provide as much information as I can. The intake was installed and the motor fired-up - no smoke! Here's the short of it. I can describe to give anyone interested the long of it but only via private e-mail (so not to bore others....).

    - The galley was not the issue. The angles between the heads with respect to the bulkheads were a perfect 35-degrees. There was no twist either. I purchased a Felpro angle gauge that is simple to use and works well to verify the angles. The head surfaces were block sanded to be sure the surfaces were relatively flat and the sanding prepared the metal surfaces quite well before assembly. Hardly any metal was removed because 120 grit belt sanding material was used.

    - A word about the thickness of the metal around the ports.... The thickness on the face of the port surfaces should be no less that 0.125" for proper sealing. The interface between the intake and head requires at least this amount of metal.

    - The manifold was certanly the issue. The port surfaces were not flat in the length-wise direction within the specified 0.002". I used a belt sander to knock off the high spots over the heat crossovers then a hand block sander to clean-up the surfaces. The angle gauge was used to measure the manifold to be sure it was true also. Always block sand and NEVER use an orbital or other sander of this nature. These sanders have a tendancy to round off the recessed areas (like around the ports!) and may cause sealing issues when the gaskets are installed. Block sanding both surfaces (head and manifold) is a way to be sure the planes are flat and parallel.

    - The biggest issue was the bolt holes in the manifold. I found that the manifold was being held off the head surfaces causing incorrect sealing. The holes in the intake manifold were elongated to allow the manifold to drop into the galley creating proper seal on the gaskets. Indications are thread marks on the inside of the holes.

    - I found that the cardboard material used for picture mattes works the best to test the imprint between the intake and heads. The thickness is only about 0.010" shy of gaskets and doesn't affect the fit. Two 3" x 24" pieces painted with flat or semi-gloss black paint with holes cut-out for the bolts provide an imprint showing surface pressure and alignment. It's cheaper than going through gaskets and can be had for free from most art supply or picture frame shops. Ask for scraps.
  • Mark Ring

    #2
    Re: Smoking Motor Fixed!

    Walter,
    glad to hear you got it fixed. As you may remember, I had manifold sealing issues with one of my motors years ago and I am sure to agree that it is no fun at all. I had solved my problems back then by switching back to the original manifold but truing up the surfaces is another way to skin the cat. I know you put a lot of effort into fixing this problem and it looks like it paid off for you. Let us know how you like the motor now that you have it running right. Please send me the details when you get a chance as I would love to hear about it.

    -Mark.

    Comment

    • Walter Muta

      #3
      Re: Smoking Motor Fixed!

      Hi Mark.

      Thanks for your empathetic response. I do remember your posting about changing back to the original manifold. In fact, that posting lead me in the direction to think my manifold was causing the issue more so than the motor. I had no way to confirm that at the time.

      It feels great to have this beast - rebuilt by my own hands - running again.... I was really doubting my skills for awhile there. I procrastinated for a long time - the reason it took so long to make another attempt installing the intake. I didn't want to assemble again only to disassemble one more time. Whew! All the porting and polishing work, and the research, I think, paid off. The 461 heads flow great. (Next trick is to get 2.08" valves with a 1-degree offset working! - Just kidding.) The Comp roller cam and valve train kicks-in pretty well. The engine from the skins appears to be entirely stock, which was the goal.

      I just went out to lunch with a colleague. On the way back we were merging onto an expressway and I nailed it in 2nd gear and hit 3rd for a bit.... We were over 90 within a couple of seconds - at least that's what I can gather since by the time I looked at the speedometer we were doing 70 and I had been off the pedal for a couple of seconds. What a thrill. The guy almost s*** his undies....

      I'd be happy to take you through the whole experience. It's not pretty but there is plenty of learning and some things that were done added no value. In short, having the right tools is the key - as with any project.

      Thanks - grinnin' ear to ear,

      Walt

      Comment

      • Clem Z.
        Expired
        • January 1, 2006
        • 9427

        #4
        Re: Smoking Motor Fixed!

        glad you got it squared away.

        Comment

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