Rocker Shims
#1
Rocker Shims
So I ordered a set of Rocker Shims from Rimmer brothers 3 weeks ago and have been patiently waiting the 5-15 business days for them to arrive as the website says. Well today was day 15 since they shipped and still no shims. So I called and was told, oh well air mail is talking 5-6 weeks now. So now I have wasted 3 weeks with this project sitting idle and I can't really wait 3 more weeks. Does any one know where I can get the shims in the USA?
#4
#5
@zacharyz28 What RPI fails to mention is most hydraulic lifters do not need adjustment. If they do normally you have 1 of 4 problems :
Read through this https://www.enginebuildermag.com/201...ifter-preload/
Getting the preload right takes a lot of time
- Lifters are shot
- Cam is worn
- Pushrods are mushroomed
- Rockers are worn
Read through this https://www.enginebuildermag.com/201...ifter-preload/
Getting the preload right takes a lot of time
The following users liked this post:
matt3502 (07-29-2021)
#7
@zacharyz28 Hmmm you should not have to shim after that, but it is possible that an accumulated wear has got you there.
#8
I don't understand how wear in the valve train can be the cause. If there was excessive wear on the lifters, cam or rockers then that would show up as less clearance in the lifter . Since I cut the cylinder head, the push rods would be forced down further then they were previously and would push the plunger down into the lifter further creating more clearance.
#9
You may have a collapsed lifter.
https://itstillruns.com/signs-sympto...-10045359.html
Additionally, the RPI kits are not OEM parts so shims may be needed. As pointed out by another poster, RAVE does not mention anywhere about shims during rebuild as they assume you are using OEM components.
https://itstillruns.com/signs-sympto...-10045359.html
Additionally, the RPI kits are not OEM parts so shims may be needed. As pointed out by another poster, RAVE does not mention anywhere about shims during rebuild as they assume you are using OEM components.
#10
Anything that increases the overall distance from the rocker cup to the lifter cup can change preload. The idea of hydraulic vs solid lifters is that hydraulic can compensate for a few thou of change.
Wear in each component can cause the distance to increase, heading truing or cutting causing the biggest change in general but even then it should be in thou's
For example a mushroomed push rod is slightly shorter, as is a worn cam lobe.
Weary lifters do not pump as well so shorter
Worn cups in the lifter or rocker can be slightly deeper
Good heads and a thicker head gasket can change it too
We do not have tight tolerance performance engines so we can get away with more "slack" in the system which why shims are not generally needed.
You do no harm by checking the pre-load just make sure you use a consistent process, but you can drive yourself crazy with it
Wear in each component can cause the distance to increase, heading truing or cutting causing the biggest change in general but even then it should be in thou's
For example a mushroomed push rod is slightly shorter, as is a worn cam lobe.
Weary lifters do not pump as well so shorter
Worn cups in the lifter or rocker can be slightly deeper
Good heads and a thicker head gasket can change it too
We do not have tight tolerance performance engines so we can get away with more "slack" in the system which why shims are not generally needed.
You do no harm by checking the pre-load just make sure you use a consistent process, but you can drive yourself crazy with it