Dino cam wear | FerrariChat

Dino cam wear

Discussion in '206/246' started by barchettaboy, Jul 30, 2016.

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  1. barchettaboy

    barchettaboy Rookie

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    Darryl Fling
    #1 barchettaboy, Jul 30, 2016
    Last edited by a moderator: Sep 7, 2017
    I am working on a customers car and was checking cam timing ( per customers request ) and have found some sketchy looking cams, nothing terrible has happened yet, but I sure do not like what I am seeing. and there are chunks missing from the aluminum head around the tappet, it almost looks like some of the lobes have been hitting ( I cannot believe that that is the case ) I assume that was from someone trying to pry out the tappets. I know I have read on this forum about cam wear. so I thought I would share these with the forum. by the way the car has 70K kilometers ( Euro car )
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  2. GIOTTO

    GIOTTO F1 Rookie
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    #2 GIOTTO, Jul 31, 2016
  3. Dino Club Germany

    Dino Club Germany Formula Junior

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    #3 Dino Club Germany, Jul 31, 2016
    The Cams are maybe THE weak point on the Dino V6 engine. When the cold start happens it take too long from the oil sump to the farest away location (cams). Even in the 5 years of production Ferrari did a lot of modification on the cams to improve this like small grooves to guide the oil where it is needed. The later Filters with the stand pipe where also introduced to keep some oil on half way between oil pan and cylinder heads to shorten initial oil distribution. If you feel around the corner it is getting sharp as sign of missing material. Today improvement is to replace the cams and modify the with a 0.7 mm hole which will make the oil quick available where its needed.
     
  4. TonyL

    TonyL F1 Rookie

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    #4 TonyL, Jul 31, 2016
    Difficult to tell from the photo but the marks look like where someone has used the lever tool to force down the bucket prior to removing the shim. Bit heavy handed!

    Always change the shims by flipping over if correct the gap is measured, if you don't see the thickness imprint when you flip over then you know the shim has possibly been used and no good.

    Use a good magnetic stick to pull the shim out or compressed air
     
  5. swift53

    swift53 F1 Veteran
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    #5 swift53, Jul 31, 2016
    Remains of silicone (rtv) anywhere on an engine if that were the case, (or is it red assembly lube?), are not exactly signs of good mechanical practices,
    along the other heavy handed manners in dealing with other issues.

    In such cases, one never knows what else lurks inside....

    Regards, Alberto
     
  6. garybobileff

    garybobileff Formula 3
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    #6 garybobileff, Jul 31, 2016
    The real issue here is that the cams need to be removed, rebuilt, rewelded , and then installed. In it's present condition, you are wearing the cam lobes and shims, because the cams have worn thru their surface hardness. As this happens, you are ingesting steel particles into the lubrication system, which is death to the motor. All the Ferraris' built in that era had this problem, 275/4, Daytona's, 246's, C/4's. In 1975 the metallurgy changed with the 365 BB and 308's, and now the problem rarely exists.
    Gary Bobileff
     
  7. barchettaboy

    barchettaboy Rookie

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    #7 barchettaboy, Aug 1, 2016
    I completely agree, with the cams starting to wear to this degree, is the start of cascading wear everywhere. And yes there was silicon everywhere. But my biggest concern is that besides the disturbing wear on some of the lobes, there appear to be very small chunks missing from the edges of some of the lobes as well. It seems like some of the lobes have made contact with the raised perimeter of the tappet instead of the shim, which if all of the geometry is correct, should obviously not be able to happen.
    But thanks to GIOTTO post, it mentioned that at 3.40 mm or less the cam lobes can kiss the tappet edge instead of the shim. So it looks like what I suspected may be true. Has anyone else found this to be true ? So if that is really the case then just replacing the cams will not solve the problem. But the heads would have to come off, and all of the valve geometry dealt with. Anyone with any experience with this issue ? I would like to have as much knowledge as possible to share with the owner, to help him make the right decision.
    So now I have to break the bad news to the owner.
     
  8. fastradio

    fastradio F1 Rookie
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    #8 fastradio, Aug 1, 2016
    Between the post referenced and the comments made by Gary Boblileff, you have input from some of the most knowledgeable, experienced folks in the Ferrari world. I am the David that Rob refers to in that post. Installed valve height is critical. If your shims (ideally) fall between 3.85-4.15mm, there little to be concerned with. Otherwise the heads need to come off and problems corrected. The cams; their condition is pretty obvious. There are no mysteries in what you are seeing or what the proper repair should be.
     
  9. daviekj

    daviekj Formula Junior
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    #9 daviekj, Aug 1, 2016
  10. barchettaboy

    barchettaboy Rookie

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    #10 barchettaboy, Aug 22, 2016
    Thank every one for sharing your knowledge with me. So I have pulled the engine and heads off and I am going to get new cams and have the heads reworked, replacing the original sodium fill exhaust valves and whatever else is needed. But I need to know the installed height is supposed to be, so that I wind up within the safe range as far as shims, I have the factory book and it gives lots of the dimensions regarding valves, except I cannot find any measurement of the installed height.

    Any help out there ?
    I will be posting more pictures as I go

    Darryl
     
  11. daviekj

    daviekj Formula Junior
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    #11 daviekj, Aug 23, 2016
    Darryl, Try the bar chart with dimension f in post 29 of the above link. Kevin
     
  12. barchettaboy

    barchettaboy Rookie

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    #12 barchettaboy, Aug 26, 2016
    Does anyone have a line on valves, ( for a reasonable cost ) I am replacing all the valves, ( and everything else ) it still has its sodium filled exhaust valves which are quite worn. As are the intakes as well. I checked Superformance ( as they usually have the best prices and there parts seemed to be vetted well ) but even their prices seem pretty high ( to the customer and me ) I have my machinist looking for better pricing, but I am sure that some of you guys have already done this and found the best deals on valves.
    So any leads ?

    Thanks for all your help

    Darryl
     
  13. Nuvolari

    Nuvolari F1 Veteran
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    #13 Nuvolari, Aug 26, 2016
    Superformance pricing is about the best you are going to find and they are also a one stop shop for all of the head items you will need. Moreover they stand behind their product and will get it to you quickly. Shopping around piecemeal on this job is a false economy and you will waste a ton of time in the process. This is not a Small Block Chevy where valves are $5 and engine re-builds are priced in the hundreds. Get ready to spend but there are a few things you can do to minimize runaway costs:

    1. Get the cams re-built by Web Cams: Web Cam Inc. - Performance and Racing Camshafts They have outstanding service and their work is second to none. Much cheaper than getting new camshafts and they have all of the Dino specs in their records.

    2. If the intake valves are not worn then they will likely not need to be replaced. Get them inspected before just throwing new ones in.

    3. Replace the valve springs. A full set is cheap and yours are likely past their best.

    4. Reference the Dino blog (Dino 246?Home) for the information on blueprinting the heads and give this information to your machinist. If he can't do it then get someone else this is not hard but vitally important to get the most from the rebuild.

    5. Be sure to check the valve lash one last time AFTER the heads are torqued. Believe it or not they do change from on the bench to on the engine.
     
  14. dino clay

    dino clay Karting

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    #14 dino clay, Aug 29, 2016
    too much wear, have cams reground by competent cam grinder. Lobes must be welded and profile reground. Would send to San Rafael calif. If have interest, will supply phone # CLAY
     
  15. swift53

    swift53 F1 Veteran
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    #15 swift53, Aug 30, 2016
    Is it the guys by Smith Ranch Road?

    If so, verrry expensive, but flawless reputation.

    Regards, Alberto
     

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