Camshaft Movement Hello All,
MercMarc here with a question. Facts as I know them: 1953 239, dual carb, Isky 88 cam, Adjustable lifters, Aluminum cam gear, EAB heads, stock bypass oil filter style. 1950 239, dual carb, Isky 88 cam, Adjustable lifter, Fiber cam gear, EAB heads, full pressure oil filter upgrade. Both engines experienced failure with in 10 hours of run time due to the cam shaft walking forward into the cast iron timing gear cover, eating the aluminum cam gear sending metal particle throughout the engine. The second engine has a fiber gear and was caught earlier so little cam gear damage but the cast iron cam gear cover was ground away by the 4 cam bolts. Both engines were professionally built by an west coast shop. Turn key engines, both engines started and ran great, a noise was heard radiating from the distributor area sounding very similar to a dist rotor hitting the inside of the dist cap. After removing the dist cap there was no evidence of the parts hitting each other. Note: The first engine was replaced in totality without question or disassembly by the shop when I told them I was having trouble with the engine. Question: What would cause a camshaft to walk forward on these engines? Thank you |
Re: Camshaft Movement Using a cam meant for a pre-8BA engine? (They thrust the opposite way.)
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Re: Camshaft Movement Hi Marc, just out of curiosity whose lifters did you use, were they the original Johnson's OR just Johnson "styles".
If possible look VERY closely at the lifter adjusting nuts where they contact the valve tips, see if they are perfectly "flat" or if they are "radiused" some?? Thanks, Gary in N.Y. P.S. I'll also come back later with a way to help keep the cam "where it belongs" so to speak! The very simple method will work providing you have no other underlying issues? |
Re: Camshaft Movement Dont get it. The dist drive gear would contact the cover before the bolts and in any application the bolts aren’t proud of the front of the cam gear. What ever you have going on it sounds like the wrong timing gear set was used
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Re: Camshaft Movement Since they both are 8BA generation putting in an early camgear doesnīt matter...will just put trust back againt block.
8BA should have the cam rest against the front cover...but if you start to increase the load on the cam with stiffer springs so does the forward force. So did someone by chance put an early ignition on it ?? With a proper ignition cover cam would have to eat a hole in the center before the gear hits the cover... |
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Thank you all for jumping in on this thread, all very helpful. I am trying to post a picture or two so please stand by
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Here is a picture showing the cam gear rubbing on the cover as well
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Re: Camshaft Movement Thank you Tubman, I will try to confirm the cam application
Hello GOFAST, I only have pictures from the first engine and that one had as it turns out non adjustable lifters. I requested adjustable lifters for the second engine but I do not have a picture to review. Hello jetmek, Hopefully the pictures better explain what I am looking at. Hello flatheadmurre, I was told the valve springs are of the Lincoln Zepher type and rating. This may be nothing more than the wrong cover on two engines then. If I am understanding correctly, on 8BA motors, the dist drive gear on the cam actually rubs the front cover as it appears to do? I would hope cam thrust would be towards the block. Again many thanks to everyones input, time and help Respectfully Marc |
Re: Camshaft Movement Looks like a bolted on dist drive adapter for an early cam??? Its making the bolt heads way too far fwd and contacting the cover
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Re: Camshaft Movement Hello etmek,
Would this also explain the cam gear rubbing the cover as well? |
Re: Camshaft Movement That is a result of bolting togetter the wrong parts...
A bit of grinding and checking axial play of the camshaft...or getting the correct cam...or going for an aluminum cover with bottom support for the distributor...many solutions... All comes down to the same bottom line...the guy assembling it didnīt check his work...that cam must have made noise from start...or the adapter is to short with excessive endplay. |
Re: Camshaft Movement Normal for the dist drive gear to contact the machined boss in front cover
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Re: Camshaft Movement Hello jetmek, thank you for confirming the drive gear contact is normal.
Hello flatheadmurre, I agree on all accounts of your latest reply. And yes the engine did make noise from the beginning albeit subtle most of the time. Very similar to a rotor and cap click, until literally, one day the noise became quite profound and I stopped running it. I challenged the builder on the noise and was told he never heard of such a thing. |
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Thanks, Gary in N.Y. P.S. Here's a shot of an easy way to avoid the cam or gear from making contact with the cover! That is a Comp Cams (SBC) nylon "button" with the end play checked and adjusted as needed! |
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Re: Camshaft Movement Hello Gary in NY, Many thanks for the picture and follow up.
Thank you Ronnieroadster, for the direction of cam thrust. To everyone who has jumped in on this thread THANK YOU. I am waiting to hear from the builder to discuss options if any and to share with him what has been learned so he does not repeat the same mistakes again to anyone else. Respectfully and Sincerely Marc |
Re: Camshaft Movement FORDBARN FORUM
WHAT A GREAT TOOL AND GIFT OF FRIENDS Marc |
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Re: Camshaft Movement IF the crank and cam gears are new aftermarket, check to see if the gear has been marked on the wrong side, the crank gear timing dot should be on the side with center flush with the gear face, there is about 1/8 inch offset on the rear of the crank timing gear, it may be mis- manufactured and marked on the wrong side while running the gears may be trying to correct the centering by moving the cam gear forward. I would check the cam gear also , I find some of the name brand parts have been shipped before the mistakes were realized thus creating a hair pulling problem . is it possible the add on dist. drive is incorrectly made ? Having two engines in succession with the exact same problem sounds like some mis-manufactured parts . Keep us in the loop.
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