LIFTER SHIM SWAP FOR BETTER CONDITION
#1
Instructor
Thread Starter
Join Date: Dec 2016
Location: Silverton, OR
Posts: 117
Likes: 0
Received 0 Likes
on
0 Posts
LIFTER SHIM SWAP FOR BETTER CONDITION
Okay, I can't get my head around why everyone says to keep our Lifter / Shims in the same location. They are designed to move in a circular rotation, as not to be worn unevenly by the cam or valve repeated contact.
It doesn't make logical mechanical sense to me.
If someone can come up with a logical reasoning as to why it is a good idea to keep them in their original home please see question #2.
#2. What if you had a "bad Lifter / Shim" and needed to buy a "brand new one". Would you have to throw the whole engine away? What would happen mechanically?
My theory is this is logic from push rod motors and is just something passed along from shade tree mechanic to shade tree mechanic. Maybe I am way off base and the collective knowledge on this amazing site will enlighten me.
I have some that are pitted on top and have 32 nice ones from the bad engine to choose from. Planning on taking them all apart and cleaning them.
Here are some pictures of my progress. Maybe I should be posting this progress in 1 thread, but like the idea of seperate thoughts and questions for searchability. I am guessing I am not the only one to have questions on these maters.
It doesn't make logical mechanical sense to me.
If someone can come up with a logical reasoning as to why it is a good idea to keep them in their original home please see question #2.
#2. What if you had a "bad Lifter / Shim" and needed to buy a "brand new one". Would you have to throw the whole engine away? What would happen mechanically?
My theory is this is logic from push rod motors and is just something passed along from shade tree mechanic to shade tree mechanic. Maybe I am way off base and the collective knowledge on this amazing site will enlighten me.
I have some that are pitted on top and have 32 nice ones from the bad engine to choose from. Planning on taking them all apart and cleaning them.
Here are some pictures of my progress. Maybe I should be posting this progress in 1 thread, but like the idea of seperate thoughts and questions for searchability. I am guessing I am not the only one to have questions on these maters.
Last edited by Ryan Thompson; 01-11-2018 at 09:25 PM. Reason: can't spell
#3
Rennlist Member
Its a strong best practice...every shim will look like an LP record album, but with totally different tracks on it than another...there is a per-lobe very individual wear pattern.
If you have to change one, its not the end of the earth, unless you had deeper problems with that cam lobe to begin with.
If you have to change one, its not the end of the earth, unless you had deeper problems with that cam lobe to begin with.
#4
Team Owner
best bet is to have the head welded JB weld is a last resort for this surface.
NOTE read the WSM before you do anything to the head so you can see how much surface is available for cutting
lifter and cam lobes all wear into each other.
swapping them will change the wear curves of the parts thus making the wear increase rapidly.
NOTE read the WSM before you do anything to the head so you can see how much surface is available for cutting
lifter and cam lobes all wear into each other.
swapping them will change the wear curves of the parts thus making the wear increase rapidly.
#5
Instructor
Thread Starter
Join Date: Dec 2016
Location: Silverton, OR
Posts: 117
Likes: 0
Received 0 Likes
on
0 Posts
best bet is to have the head welded JB weld is a last resort for this surface.
NOTE read the WSM before you do anything to the head so you can see how much surface is available for cutting
lifter and cam lobes all wear into each other.
swapping them will change the wear curves of the parts thus making the wear increase rapidly.
NOTE read the WSM before you do anything to the head so you can see how much surface is available for cutting
lifter and cam lobes all wear into each other.
swapping them will change the wear curves of the parts thus making the wear increase rapidly.
Trending Topics
#8
Rennlist
Basic Site Sponsor
Basic Site Sponsor
Like said above, the cam lobes and lifters "wear in" together. There will be tiny variations of wear on each individual lobe and lifter....not something you are going to see with you naked eyes or feel with your fingernail.
I mark each lifter and return it to it's original position when I re-assemble, instead of shuffling them like a deck of cards and sticking them anywhere. However, if I find a bad lifter (very rare) I will replace that lifter with a new lifter.....there's nothing else that can be done, in that case.
In your case, if you have pitted lifters, the cam lobes are also going to be bad (The lifters are much harder than the camshafts. Wear always starts with the cam lobe, which then damages the lifters), so it doesn't really matter what lifter you put on which lobe.
Mix and match as you please.
Sell it quick.
I mark each lifter and return it to it's original position when I re-assemble, instead of shuffling them like a deck of cards and sticking them anywhere. However, if I find a bad lifter (very rare) I will replace that lifter with a new lifter.....there's nothing else that can be done, in that case.
In your case, if you have pitted lifters, the cam lobes are also going to be bad (The lifters are much harder than the camshafts. Wear always starts with the cam lobe, which then damages the lifters), so it doesn't really matter what lifter you put on which lobe.
Mix and match as you please.
Sell it quick.
__________________
greg brown
714 879 9072
GregBBRD@aol.com
Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
Free consultations will no longer be available.
Will still be in the shop, isolated and exclusively working on project cars, developmental work and products, engines and transmissions.
Have fun with your 928's people!
greg brown
714 879 9072
GregBBRD@aol.com
Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
Free consultations will no longer be available.
Will still be in the shop, isolated and exclusively working on project cars, developmental work and products, engines and transmissions.
Have fun with your 928's people!
#10
Instructor
Thread Starter
Join Date: Dec 2016
Location: Silverton, OR
Posts: 117
Likes: 0
Received 0 Likes
on
0 Posts
https://rennlist.com/forums/928-foru...corrosion.html
I also found this thread to backup what the machine shop and my logic was telling me. Again, not a sealing surface.
I also found this thread to backup what the machine shop and my logic was telling me. Again, not a sealing surface.
Last edited by Ryan Thompson; 01-11-2018 at 10:29 PM. Reason: Didn't hyperlink
#11
Instructor
Thread Starter
Join Date: Dec 2016
Location: Silverton, OR
Posts: 117
Likes: 0
Received 0 Likes
on
0 Posts
So by looking at the lifters in question, I should ascertain the cam is bad. Correct?
It is on one cam that all the lifters / shims are worn. I have an extra cam or whole head from the bad motor (owned 928 3 weeks and found torque tube pulling on thrust bearing killing motor) . Should I look to swap the cam and lifters to this head or whole head swap?
It is on one cam that all the lifters / shims are worn. I have an extra cam or whole head from the bad motor (owned 928 3 weeks and found torque tube pulling on thrust bearing killing motor) . Should I look to swap the cam and lifters to this head or whole head swap?
Last edited by Ryan Thompson; 01-11-2018 at 11:21 PM.
#14
Rennlist Member
I would avoid sanding the lifter as you will reduce cam lift among other things.
#15
Instructor
Thread Starter
Join Date: Dec 2016
Location: Silverton, OR
Posts: 117
Likes: 0
Received 0 Likes
on
0 Posts
Thanks so much for your help!