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This is question for 4x4 high !

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454 blazer

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Ive stripped down my big block to put my 781 heads on and have found that one of my lifters has worn down about 3 or 4mm :doah:do you have any idea why this would happen ? also found that my # 4 piston had a bit of play :mad: . Also on the top of the head were the valve guides are should ther be a roller bearing in the exhaust valve and the fuel valve ? hope this makes sence to you. Any in put would be aprriciated as you seem to be a bit of a legend when it comes to bbs !!!:bow:
 
Pictures of the mentioned lifter
05052009171.jpg
 
What cylinders were these lifters in line with?

7 and 8 are known to have inadequate oiling as most problems lie in those two way at the back of the block. There are fixes for this problem.
 
The roller bearing is a exhaust rotator all of those heads have them. Its time for a new cam and a complete tear down to remove the lifter/camshaft metal. Sounds like you need a bore anyway. I would consider GMs hard faced lifters if going back flat hydr other wise roller.
 
Is it a sure thing that i need a new cam ! Ive only had it year , really dont want to do a tear down , and its bored over 30 as it is how far can i go with boreing ? Ive heard more boreing more heat is that true ?
 
More boring will lead to increased heat due to the cylinder wall becoming smaller.

As for the cam, it is a pretty safe bet with the wear on that lifter that the cam lobe will have been worn as well. Both the cam and lifter were starved for oil enough to cause that wear, and that means that you will want to do a new cam.
 
There is either something terribly wrong with that lifter OR it is a completely wrong lifter. It's hard to tell from the pic but is the face (that rides on the cam) flat or is it cupped?

Also the exhaust uses rotators and the intake just uses a shim under the springs. The very first thing you do when building a BBC with any kind of larger cam is to buy a set of rotator eliminators (spring spacers as some people call them). Comp cams makes them and IIRC they are part number 4779-8

EDIT: looking a little closer at that lifter is does look like it is cupped. The cam WILL need to be replace along with a NEW set of lifters. You also need to take a close look at the pushrods especially the one that was on that lifter to make sure then end(s) aren't damaged.
 
4X4HIGH said:
There is either something terribly wrong with that lifter OR it is a completely wrong lifter. It's hard to tell from the pic but is the face (that rides on the cam) flat or is it cupped?

Also the exhaust uses rotators and the intake just uses a shim under the springs. The very first thing you do when building a BBC with any kind of larger cam is to buy a set of rotator eliminators (spring spacers as some people call them). Comp cams makes them and IIRC they are part number 4779-8

EDIT: looking a little closer at that lifter is does look like it is cupped. The cam WILL need to be replace along with a NEW set of lifters. You also need to take a close look at the pushrods especially the one that was on that lifter to make sure then end(s) aren't damaged.
Click to expand...

Yes the lifter is cupped ! Im a bit bumed about putting in a new cam in.:( Ive only had it in a year.As for the rotator eliminators , are they only on the exhaust valves ? and it being an eliminator i assume it stops the spring turning, the cam i put in was a magnum 280 comp cam package, it included stronger springs timming belt lifters and cam shaft . what would you recommend as a new cam shaft ? Thank you for replieing 4x4 high :bow:
 
Why not keep the rotators with bigger cams, doesn't it help distribute the heat around the exhaust valve?

Regarding the cam/lifter failure, I think it sounds as a break-in error.
What procedure did you follow during initial start-up, when you installed the new cam?
 
Last edited:
It seems really weird that the lifter is so much shorter because of wear....

I would think that the cam lobe would wear it down in the middle, but at the extreme edges too??? It seems surprising that the lobe would ride that close to the edges to wear the entire surface down so evenly (except for a little cupping in the center).

:dunno:

Well, you're in good hands now. Scott will get you straightened out.



:usaflag:
 
Is the worn lifter sitting on a lower surface than the others? It looks to me like it is a different lifter, unless it is worn down on the top. If you look at the lifter in relation to the others (dont know proper lifter terminology) but the part where it indents and isnt shiny is lower than all of the others.
 
big dan said:
Is the worn lifter sitting on a lower surface than the others? It looks to me like it is a different lifter, unless it is worn down on the top. If you look at the lifter in relation to the others (dont know proper lifter terminology) but the part where it indents and isnt shiny is lower than all of the others.
Click to expand...

That was my first thought but it looks like thats just the camera angle. If you look close they look the same.
 
Fred_M1010 said:
Why not keep the rotators with bigger cams, doesn't it help distribute the heat around the exhaust valve?

Regarding the cam/lifter failure, I think it sounds as a break-in error.
What procedure did you follow during initial start-up, when you installed the new cam?
Click to expand...

Those rotators like to explode with extra spring pressures on them so that's why you should use the eleminators instead. Yes the rotators make the valves rotate with the engine running to help cool the exhaust valve.
 
Greg72 said:
It seems really weird that the lifter is so much shorter because of wear....

I would think that the cam lobe would wear it down in the middle, but at the extreme edges too??? It seems surprising that the lobe would ride that close to the edges to wear the entire surface down so evenly (except for a little cupping in the center).

:dunno:

Well, you're in good hands now. Scott will get you straightened out.



:usaflag:
Click to expand...

The cam lobe is not flat across the surface of the lobe just as the lifter isn't perfectly flat either. They both have a very small crown to them to make the lifter rotate on the cam so it doesn't wear in only one position. With the lifter being able to rotate on the lobe is why the lifter will wear evenly (relatively speaking) across the lifter body making it shorter.
 
4X4HIGH said:
Those rotators like to explode with extra spring pressures on them so that's why you should use the eleminators instead. Yes the rotators make the valves rotate with the engine running to help cool the exhaust valve.
Click to expand...

Ok, thanks for the info.
I'm in the process of building a 454 for my Camaro at the moment, so thats good to know.
 
Greg72 said:
It seems really weird that the lifter is so much shorter because of wear....

I would think that the cam lobe would wear it down in the middle, but at the extreme edges too??? It seems surprising that the lobe would ride that close to the edges to wear the entire surface down so evenly (except for a little cupping in the center).

:dunno:

Well, you're in good hands now. Scott will get you straightened out.



:usaflag:
Click to expand...
Ile have the cam out today , so ile put some pics up , i rotated it wilst still in the block and it looks pretty mangaled , when the engine was put together they seemed to have put the exhaust valve rotators on the fuel valves if that makes sence ? so my thinking is that this put extra presure on the springs (which were high pressure comp cam ones)and this may have chewed up the lobes. Im having a look today at a cam and roller lifters that some ones selling , not sure of the duration , but ile let you guys no.Thanks all of you for all your help on this one .
 
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