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stress cracks in camshaft cap

K

Kyle245

New member
Joined
Jul 6, 2016
Is a camshaft cap something I can buy new? Or am I going to a wrecking yard for this part? Yesturday I noticed a couple of small lines in the #1 cap (nearest to belt) while reinstalling the head. The cracks are very small but they are quite long. This is on my 92 volvo 245. Which I am struggling to get running well. I just had the head rebuilt and a used B cam installed last week. I appreciate any help! Photo coming.
 
Dan said:
Are you sure those are cracks? Seems like an odd place to crack.
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cap is the stressed half of things--valve springs pressing UP, an front-est-est cam the most-est stressed becuz of cam belt drive tensioner and stuffs>>

1 really nice motor motor which ironically was commissioned with 1 job in mind--beat B21T 8v Volvo Group A car--which it did massively---that motor has a ball bearing ON the camshaft just behind the cam belt drive pulleys..
That gives some indication on where the big stress is.. (cuase the guys that designed the head were/are the best head guys in the whole world AND world leader in machine processing and casting--holding several patents in production casting techniques..

It suggests where the stress is by it's uniqueness--as far as i can tell).
 
Would line boring be mandatory when changing camshafts? Seems like it should be... But wouldn't all the guides and caps need to be replaced? Below is a path to Volvo forums where I place a similar thread and attached photos of the cap. For some reason I don't have attachment access here.
b230-camshaft-cap-stress-cracks-found-94236



https://volvoforums.com/forum/volvo-260-760-960-28/b230-camshaft-cap-stress-cracks-found-94236/
 
Wren said:
I'll bet they are just casting tracks that look like cracks. Pretty common on aluminum oil pans from what I've seen.
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This. I've seen cam caps that had weird little casting marks in them before. They look almost like hairs in the aluminum.

OP, can you post a pic of what you're talking about?
 
Kyle245 said:
Would line boring be mandatory when changing camshafts? Seems like it should be...
Click to expand...

A good machine shop would check this for you if you let them know you're swapping cams.

Kyle245 said:
But wouldn't all the guides and caps need to be replaced?
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Guides need replacement whenever new valves are installed or if they cannot be knurled. Caps are rarely (never) replaced and shims should be set when reinstalling the cam.

Kyle245 said:
For some reason I don't have attachment access here
Click to expand...

Contributors do ;-)
 
So I studied the lines with four guys at work and 3 out of 4 think they are casting lines 1 just said, it sure doesn't look new. We were using a good magnifying glass and I were able to see much more. So basically, the cam is worked over pretty hard, you can see the stress, but the major lines that I thought were cracks do appear to be casting lines. Why does my cam have two casting lines right through the middle? I don't know? Friday at the factory perhaps. Thanks for the help!
 
you could take a die grinder with a sanding bit and polish it and if its a crack it will remain. If its casting line then it will disappear. You will have to seal off the rest of the head really-really well. Clean it with carb cleaner; use some really good duct tape. Personally I dont believe it is a crack.
 
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