Tappet Replacement Required???

AJenson

AJenson

Diesel Mechanic
Joined
Oct 5, 2008
Messages
290
I am in the middle of doing a p-pump conversion and I am installing a 181/210 106.5 LSA cam while I am there. The engine has 65K miles and I was wondering if replacing the tappets is necessary with the new cam. Also, I have read about CR tappets being beneficial due to the larger foot but also have read about not being able to use CR tappets with cams that have the fuel pump lobe (which mine has) due to clearance issues I assume. Is this true? Thanks.


Austin
 
The 24v tappet is close in diameter to the CR, so it is not nearly as beneficial of an upgrade as going to a CR tappet in a 12v.

IMO it is a good idea to either resurface the existing tappets or put new ones in.

Hope that helps.
 
Tappet replacement is required to maintain warranty on the cam. Zach has posted that on here before
 
even at " only 65k miles" the tappets you have are mated to the current cam, placing them in and running them on the new cam would cause wear, swap em.
 
CR tappets can interfere with the lift pump lobe. Zach recommends 24v tappets for 12v cams.

Snedge can get you a good price on them.
 
The 24v tappets are 1.3" and are a good bit lighter than the CR and just a bit more than the 12v. I don't have my notes on me and my gram scale is in storage but I believe the 12vs are only 10 grams lighter than the 24v and the CR is about 25-30 grams heavier.

They (24v tappets) are easily capable of handling any cam that we produce at this point( our new .420" Cam lift will require 1.5").

They are lighter than the CR tappets which is important when you are at high rpm with the 12v's.

They will work even in CR applications

They never have clearance issues with the cam journals or the lift pump lobe.

Although at 65k you should not have much wear, tappets are not a place you want to skimp, because if there is an issue, it will wipe a lobe and require another cam and a new set of tappets along with 6-10 more hours of labor.

Sorry it took so long to get back to you, I was on a bobcat all day and not near a computer.


Zach
 
Hamilton Cams said:
The 24v tappets are 1.3" and are a good bit lighter than the CR and just a bit more than the 12v. I don't have my notes on me and my gram scale is in storage but I believe the 12vs are only 10 grams lighter than the 24v and the CR is about 25-30 grams heavier.

They (24v tappets) are easily capable of handling any cam that we produce at this point( our new .420" Cam lift will require 1.5").

They are lighter than the CR tappets which is important when you are at high rpm with the 12v's.

They will work even in CR applications

They never have clearance issues with the cam journals or the lift pump lobe.

Although at 65k you should not have much wear, tappets are not a place you want to skimp, because if there is an issue, it will wipe a lobe and require another cam and a new set of tappets along with 6-10 more hours of labor.

Sorry it took so long to get back to you, I was on a bobcat all day and not near a computer.


Zach
Click to expand...

That is ok. I ordered set set of CR tappets yesterday. I just wanted to make sure that I wouldn't have any clearance issues with the fuel pump lobe. Thank you for the peace of mind. I wont be turning over 4k with my p-pump conversion.
 
The CR tappets will potentially interfere with the lift pump lobe in a 24v 98.5-2002 block, especially if the cam gear is not pressed on all the way. If you remove the lift pump lobe from the cam then you can run a CR tappet in a 12 or 24 valve all day long.
 
Most will not have problems, but once in a while I see CR tappets hit the lift pump lobe on the 12v and 24v engines.

I apologize, I never meant to give you peace of mind about running CR tappets in a 12v or 24v. Occasionally they can have issues.

On dieseltruckresource.com, you said you had talked to Zach and he said it was alright to run the CR tappets, My name is texashghways on there so I am the one that said just run the 1998-2002 1.3" tappets.

Zach
 
I made sure that I have the gear pressed on all the way. If I end up having clearance issues, I will return them to cummins and get a set of 24v tappets.

Sent from my DROID3 using Tapatalk
 
Hamilton Cams said:
Most will not have problems, but once in a while I see CR tappets hit the lift pump lobe on the 12v and 24v engines.

I apologize, I never meant to give you peace of mind about running CR tappets in a 12v or 24v. Occasionally they can have issues.

On dieseltruckresource.com, you said you had talked to Zach and he said it was alright to run the CR tappets, My name is texashghways on there so I am the one that said just run the 1998-2002 1.3" tappets.

Zach
Click to expand...

Ahhh gotcha. Ill call cummins real quick and see if I can swap my order.

Sent from my DROID3 using Tapatalk
 
Hamilton Cams said:
The 24v tappets are 1.3" and are a good bit lighter than the CR and just a bit more than the 12v. I don't have my notes on me and my gram scale is in storage but I believe the 12vs are only 10 grams lighter than the 24v and the CR is about 25-30 grams heavier.

They (24v tappets) are easily capable of handling any cam that we produce at this point( our new .420" Cam lift will require 1.5").

They are lighter than the CR tappets which is important when you are at high rpm with the 12v's.

They will work even in CR applications

They never have clearance issues with the cam journals or the lift pump lobe.

Although at 65k you should not have much wear, tappets are not a place you want to skimp, because if there is an issue, it will wipe a lobe and require another cam and a new set of tappets along with 6-10 more hours of labor.

Sorry it took so long to get back to you, I was on a bobcat all day and not near a computer.


Zach
Click to expand...

So no issue's running 24v tappets in a cr? Guess I'll be going with 24v tappets then.
 
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