Lash Cap Talk/Update
Team Owner
Joined: Jan 2007
Posts: 29,063
Likes: 1,839
From: cookeville tennessee
Its a combination. Either some installed it on the pump and not the lifter, or, as in the case of Higgs, his pump broke off the bolts and as a result of the pump coming loose the lash cap went MIA.
If the lash cap is installed properly, and measurements are taken to ensure you use the proper size, you won't have an issue.
If the lash cap is installed properly, and measurements are taken to ensure you use the proper size, you won't have an issue.
Thanks buddy.
Racer
Joined: Feb 2005
Posts: 380
Likes: 33
I wanted to bring this back up again. So obviously you want the HPFP to have some kind of preload as always talked about on here but exactly how much preload are we looking for? I seen mittens mention.030, is this a good amount?
I'm Batman..
Joined: Apr 2014
Posts: 6,142
Likes: 921
From: Lehigh Acres FL
Tech Contributor
proper preload depends on the application. It is best to ensure you have some preload when on base of circle, but not so much to the point that it bottoms out the shaft on the eccentric. This should always be measured for each and every build.
Racer
Joined: Feb 2005
Posts: 380
Likes: 33
Thanks for the reply, right now I have .039” but I’m wondering if it should be more (as you said as long as it’s not bottoming out the pump). This is with a stock LT4 HPFP and an aftermarket cam with a 32% fuel lobe.
Last edited by WS6JJP; Feb 8, 2018 at 11:08 PM.
Racer
Joined: Feb 2005
Posts: 380
Likes: 33
Yeah i definitely measured and the .039 preload is where it’s sitting now with an LS7 lash cap. I’m just wanting to know what the correct amount of preload is. I’ve heard .030 all the way to .060. Anyone know for sure?
I'm Batman..
Joined: Apr 2014
Posts: 6,142
Likes: 921
From: Lehigh Acres FL
Tech Contributor
Thats not quite accurate. When I installed my cam with 32% lobe and LT4 HPFP a lash cap was -required- or I would have had zero preload.
Racer
Joined: Feb 2005
Posts: 380
Likes: 33
Do you remember what your preload measurement amount was by any chance? I know you’re supposed to have some kind of preload on the pump but no one ever says exactly what amount is correct. It’s always check your preload but nothing specific.
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Instructor
Joined: Sep 2017
Posts: 165
Likes: 17
From: Waterdown Ontario
I just ordered a complete cam package from Aaron at BTR stage 2 with 38% lope, the kit didn't come with a cap so I called BTR they sent me an 8mm cap.
LT1
LT1
Last edited by 16C7Z51; Feb 9, 2018 at 09:20 PM.
I'm Batman..
Joined: Apr 2014
Posts: 6,142
Likes: 921
From: Lehigh Acres FL
Tech Contributor
I do not. Im sure there is an “optimal” amount of preload, but im not sure that it will matter nearly as much having some preload vs not..
Racer
Joined: Feb 2005
Posts: 380
Likes: 33
Pro
Joined: Sep 2012
Posts: 592
Likes: 29
From: Bulverde, TX
That is interesting. I recently called BTR about a Gen V LT1 cam that has a 38% fuel lobe and he specifically stated it did not require a lash cap. I asked him about the lack of any preload and he stated several times "No lash cap is required". Confusing.....
I'm Batman..
Joined: Apr 2014
Posts: 6,142
Likes: 921
From: Lehigh Acres FL
Tech Contributor
Ant
Drifting
Joined: Apr 2015
Posts: 1,276
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If you don’t use the lash cap, the extra lift fuel lobe will be of no benefit, as the the extra lift comes from a smaller base circle. I’ve brought this up several times here and elsewhere. Talk to the cam manufacturer, not the guy selling the parts. Better yet, talk to the guys building and tuning them
John
John
I'm Batman..
Joined: Apr 2014
Posts: 6,142
Likes: 921
From: Lehigh Acres FL
Tech Contributor
If you don’t use the lash cap, the extra lift fuel lobe will be of no benefit, as the the extra lift comes from a smaller base circle. I’ve brought this up several times here and elsewhere. Talk to the cam manufacturer, not the guy selling the parts. Better yet, talk to the guys building and tuning them
John
John
Ant
Instructor
Joined: Sep 2017
Posts: 165
Likes: 17
From: Waterdown Ontario
If you don’t use the lash cap, the extra lift fuel lobe will be of no benefit, as the the extra lift comes from a smaller base circle. I’ve brought this up several times here and elsewhere. Talk to the cam manufacturer, not the guy selling the parts. Better yet, talk to the guys building and tuning them
John
John
Thread Starter
Safety Car
Joined: Nov 2005
Posts: 4,364
Likes: 931
From: Huntsville Alabama
I installed one with my cam swap... and pulled it back out. Changed the fan seettings back as well. we tried every setting in HP tuners, and that does not address the issue.
on the C7 the dash changes as the car warms up... with the lower threm it never gets to the 175 mark normally.. which results in the Dash always showing you its not all the way warm, a lower red line, and the Shift lights happen WAY early....
was more annoying to me to have the dash all messed up then the 20 degrees in cooling.
I have a thread on the issue as well.
Instructor
Joined: Sep 2017
Posts: 165
Likes: 17
From: Waterdown Ontario
Good luck with that 160 Therm..
I installed one with my cam swap... and pulled it back out. Changed the fan seettings back as well. we tried every setting in HP tuners, and that does not address the issue.
on the C7 the dash changes as the car warms up... with the lower threm it never gets to the 175 mark normally.. which results in the Dash always showing you its not all the way warm, a lower red line, and the Shift lights happen WAY early....
was more annoying to me to have the dash all messed up then the 20 degrees in cooling.
I have a thread on the issue as well.
I installed one with my cam swap... and pulled it back out. Changed the fan seettings back as well. we tried every setting in HP tuners, and that does not address the issue.
on the C7 the dash changes as the car warms up... with the lower threm it never gets to the 175 mark normally.. which results in the Dash always showing you its not all the way warm, a lower red line, and the Shift lights happen WAY early....
was more annoying to me to have the dash all messed up then the 20 degrees in cooling.
I have a thread on the issue as well.
Race Director
Joined: Jul 2007
Posts: 10,959
Likes: 2,641
From: Texas Hill Country
Good luck with that 160 Therm..
I installed one with my cam swap... and pulled it back out. Changed the fan seettings back as well. we tried every setting in HP tuners, and that does not address the issue.
on the C7 the dash changes as the car warms up... with the lower threm it never gets to the 175 mark normally.. which results in the Dash always showing you its not all the way warm, a lower red line, and the Shift lights happen WAY early....
was more annoying to me to have the dash all messed up then the 20 degrees in cooling.
I have a thread on the issue as well.
I installed one with my cam swap... and pulled it back out. Changed the fan seettings back as well. we tried every setting in HP tuners, and that does not address the issue.
on the C7 the dash changes as the car warms up... with the lower threm it never gets to the 175 mark normally.. which results in the Dash always showing you its not all the way warm, a lower red line, and the Shift lights happen WAY early....
was more annoying to me to have the dash all messed up then the 20 degrees in cooling.
I have a thread on the issue as well.