Post by enigmas on Mar 6, 2024 2:32:33 GMT
There's been quite a lot of discussion during, since and post Covid with the manufacture of certain engine components. Obviously the pandemic in many ways affected both the production and quality of specific engine components. Camshafts and tappets whether hydraulic or solid were affected by quality control and production issues during this period.
If you're rebuilding an engine, vital components such as these need to be assessed carefully to ensure that they're fit for purpose.
A few particulars about these components to consider.
1. No flat tappet/lifter base (whether hydraulic or solid) is flat.
2. Lifter bases when freshly machined are "convex", generally with a .003" dome.
3. Camshaft lobes do not have a parallel top surface. The camshaft lobe is ground on a slight angle of approximately .003" - .004".
4. The lifter is slightly offset to the camshaft lobe when in situ.
Why?
So that when the camshaft rotates it also causes the lifter to rotate.
This action then causes the pushrods to rotate.
On an older running engine in good mechanical condition the pushrods can be seen to be rotating. If they're not seen to be rotating then the camshaft lobe is gouging a groove in the lifter base.
* That's evidence that the camshaft and lifters need replacing.
* Don't throw the baby out with the bathwater unless you know how to correctly assess the components. Just because they are used, it doesn't mean that they're not fit for service. Check don't guess.
* If dismantling an engine and wanting to reuse, the camshaft, lifters and pushrods ensure they are all marked so that they are returned to their exact locations on reassembly.
* When fitting a fresh camshaft and lifters use assembly lube liberally on all contacting surfaces. * Fill the engine with a "non-detergent" break in oil with adequate Zinc or ZDDP.
Why a non detergent oil?
Because a detergent oil will want to wipe off the zinc protection from the camshaft lobe and lifter mating surfaces.
Hope this assists.
The youtube video below by UTG is worthwhile viewing.
If you're rebuilding an engine, vital components such as these need to be assessed carefully to ensure that they're fit for purpose.
A few particulars about these components to consider.
1. No flat tappet/lifter base (whether hydraulic or solid) is flat.
2. Lifter bases when freshly machined are "convex", generally with a .003" dome.
3. Camshaft lobes do not have a parallel top surface. The camshaft lobe is ground on a slight angle of approximately .003" - .004".
4. The lifter is slightly offset to the camshaft lobe when in situ.
Why?
So that when the camshaft rotates it also causes the lifter to rotate.
This action then causes the pushrods to rotate.
On an older running engine in good mechanical condition the pushrods can be seen to be rotating. If they're not seen to be rotating then the camshaft lobe is gouging a groove in the lifter base.
* That's evidence that the camshaft and lifters need replacing.
* Don't throw the baby out with the bathwater unless you know how to correctly assess the components. Just because they are used, it doesn't mean that they're not fit for service. Check don't guess.
* If dismantling an engine and wanting to reuse, the camshaft, lifters and pushrods ensure they are all marked so that they are returned to their exact locations on reassembly.
* When fitting a fresh camshaft and lifters use assembly lube liberally on all contacting surfaces. * Fill the engine with a "non-detergent" break in oil with adequate Zinc or ZDDP.
Why a non detergent oil?
Because a detergent oil will want to wipe off the zinc protection from the camshaft lobe and lifter mating surfaces.
Hope this assists.
The youtube video below by UTG is worthwhile viewing.
