Engine assembly but Piston hits valve... help
Thread Starter
Teching In
Joined: Feb 2018
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I think it's time to bolt down a head with a used gaskets and the lifters as they should be (not converted to solid) and measure preload and valve clearance and see where you're at. And what you need.
I gonna take a wild guess and guess that you're valve clearance will be fine and that you'll be around .080 preload with the 7.225's. But you'll have to measure to see.
The preload wont actually change your valve clearance, in and by itself, but the squish that comes from running them will actually reduce your lift a little and increase valve clearance a little. But very little and should never be considered a safety margin because there may be times the lifters don't deflect any of the lift.
I gonna take a wild guess and guess that you're valve clearance will be fine and that you'll be around .080 preload with the 7.225's. But you'll have to measure to see.
The preload wont actually change your valve clearance, in and by itself, but the squish that comes from running them will actually reduce your lift a little and increase valve clearance a little. But very little and should never be considered a safety margin because there may be times the lifters don't deflect any of the lift.
let me soak the lifters and do as you said.
I’ll get back to you guys.
as always, thank you for the help.
Essentially what I was saying before is hydraulic lifters don't always maintain 100% of the cams lift, they yes can give you more valve clearance if they don't maintain the lift, but you should measure as if they did.
To do this with a solid lifter you need a pushrod or checker set at zero lash with the solid lifter, you did that buy you added preload of .070 which opened the valve .070 while on the base circle of the cam, which increased lift at all points by .070
To do this with a solid lifter you need a pushrod or checker set at zero lash with the solid lifter, you did that buy you added preload of .070 which opened the valve .070 while on the base circle of the cam, which increased lift at all points by .070
Thread Starter
Teching In
Joined: Feb 2018
Posts: 23
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Essentially what I was saying before is hydraulic lifters don't always maintain 100% of the cams lift, they yes can give you more valve clearance if they don't maintain the lift, but you should measure as if they did.
To do this with a solid lifter you need a pushrod or checker set at zero lash with the solid lifter, you did that buy you added preload of .070 which opened the valve .070 while on the base circle of the cam, which increased lift at all points by .070
To do this with a solid lifter you need a pushrod or checker set at zero lash with the solid lifter, you did that buy you added preload of .070 which opened the valve .070 while on the base circle of the cam, which increased lift at all points by .070
I kind of sold myself on the roller to rockers and this was the first time I did that... wonder if it was really worth all the effort and money. I guess time will tell.
thanks again for walking me through this guys. Much appreciated.
I should say bolting down the rockers and setting the rocker to zero lash with your solid lifter and using the length checker is best for checking the valve clearance, but with a light spring like darth said.
Or technically you could use no valve spring. Extra precaution would be needed there but technically that could be done but would likely be a pain in the ***.
If nothing else grab a spring from something and make it work as a light (soft) valve spring. Like a carburetor spring or throttle/brake pedal return spring.
Many ways to do this man.
Or technically you could use no valve spring. Extra precaution would be needed there but technically that could be done but would likely be a pain in the ***.
If nothing else grab a spring from something and make it work as a light (soft) valve spring. Like a carburetor spring or throttle/brake pedal return spring.
Many ways to do this man.
Check springs at Summit...I keep these in the toolbox. You’ll use them more than you think...
https://www.summitracing.com/parts/crn-99881-2
https://www.summitracing.com/parts/crn-99881-2
Originally Posted by Urocmyiroc
I do want to know how the preload on these solid lifters is going to work out when I install the hydraulic lifters... does it mean I’ll have more than the PTV I’m showing now?
If so, is a thinner gasket advisable?
or should I opt for the next size up (7.230) on the pushrods since I needed 7.226 and I went with the 7.225 Due to it being closer in value.
If so, is a thinner gasket advisable?
or should I opt for the next size up (7.230) on the pushrods since I needed 7.226 and I went with the 7.225 Due to it being closer in value.
That said if you have 070 clearance with an overly long pushrod on a solid lifter you will have about two miles of clearance when you install the hydraulics - which you should have with that cam. You should have plenty.
Thread Starter
Teching In
Joined: Feb 2018
Posts: 23
Likes: 2
Check springs at Summit...I keep these in the toolbox. You’ll use them more than you think...
https://www.summitracing.com/parts/crn-99881-2
https://www.summitracing.com/parts/crn-99881-2
Ok. Preload is for hydraulic lifters. When checking with a solid lifter DO NOT add preload. All that does is lift the valve.
That said if you have 070 clearance with an overly long pushrod on a solid lifter you will have about two miles of clearance when you install the hydraulics - which you should have with that cam. You should have plenty.
That said if you have 070 clearance with an overly long pushrod on a solid lifter you will have about two miles of clearance when you install the hydraulics - which you should have with that cam. You should have plenty.
I’m going to install the The LS7 lifters That I got for this build along with these new pushrods tomorrow and do a clay measuring. Glad I don’t have to fly cut the pistons. I’ll get back to you guys tomorrow.
Thanks to everybody that helped me along.
Originally Posted by Urocmyiroc
I just ordered a set. I’m sure I’ll use them down the road.Are you saying that I should use a thinner gasket? lol
I’m going to install the The LS7 lifters That I got for this build along with these new pushrods tomorrow and do a clay measuring. Glad I don’t have to fly cut the pistons. I’ll get back to you guys tomorrow.
Thanks to everybody that helped me along.
I’m going to install the The LS7 lifters That I got for this build along with these new pushrods tomorrow and do a clay measuring. Glad I don’t have to fly cut the pistons. I’ll get back to you guys tomorrow.
Thanks to everybody that helped me along.
And you do not need to redo the clay with hydraulics. Just install, get your 7.2xx pushrods, and send it.
Thread Starter
Teching In
Joined: Feb 2018
Posts: 23
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I have a .041 Cometic gasket and a .051 GM OE gasket to use. How much power would I leave on the table using the larger gasket. I’m asking because I like the GM stuff better Because it looks higher quality.
It's not so cut and dry as "thinner HG is worth exactly 284.73628 hp". and obviously, that's not how much it's worth. It's about timing and detonation. Thinner HG allows you run more timing, tolerate higher compression without detonation. That kind of thing. It's better for your engine. Are you going to gain 1.3 seconds at the track from it? no.
TECH Resident
Joined: Jun 2011
Posts: 936
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It's not so cut and dry as "thinner HG is worth exactly 284.73628 hp". and obviously, that's not how much it's worth. It's about timing and detonation. Thinner HG allows you run more timing, tolerate higher compression without detonation. That kind of thing. It's better for your engine. Are you going to gain 1.3 seconds at the track from it? no.
Last edited by 68Formula; Oct 26, 2020 at 12:28 PM.