PTV doing my head in???
Thread Starter
Staging Lane
Joined: Nov 2011
Posts: 51
Likes: 0
From: Australia
PTV doing my head in??? I have a 346ci LS1.
238/242 @ 108lsa, 0.603" 0.605" lift
Heads are 241 casting, have not been milled yet
Pistons are Mahle -4cc valve relief
Checked PTV with a dial indicator, checking springs installed and pushing down on the retainer. The dial indicator was mounted onto the rocker arm above the valve.
The figures I have just seem too big to me, and I cannot figure out why. Is it just because of the valve reliefs?
Intake
5BTDC - 0.435 "
TDC - 0.427"
5ATDC - 0.390"
9ATDC - 0.374"
10ATDC - 0.378 "
11ATDC - 0.380"
Exhaust
5BTDC - 0.325"
TDC - 0.309 "
1ATDC - 0.307"
2ATDC - 0.316 "
5ATDC - 0.321"
So my minimums are 374 intake / 307 exhaust
238/242 @ 108lsa, 0.603" 0.605" lift
Heads are 241 casting, have not been milled yet
Pistons are Mahle -4cc valve relief
Checked PTV with a dial indicator, checking springs installed and pushing down on the retainer. The dial indicator was mounted onto the rocker arm above the valve.
The figures I have just seem too big to me, and I cannot figure out why. Is it just because of the valve reliefs?
Intake
5BTDC - 0.435 "
TDC - 0.427"
5ATDC - 0.390"
9ATDC - 0.374"
10ATDC - 0.378 "
11ATDC - 0.380"
Exhaust
5BTDC - 0.325"
TDC - 0.309 "
1ATDC - 0.307"
2ATDC - 0.316 "
5ATDC - 0.321"
So my minimums are 374 intake / 307 exhaust
I have a 346ci LS1.
238/242 @ 108lsa, 0.603" 0.605" lift
Heads are 241 casting, have not been milled yet
Pistons are Mahle -4cc valve relief
Checked PTV with a dial indicator, checking springs installed and pushing down on the retainer. The dial indicator was mounted onto the rocker arm above the valve.
The figures I have just seem too big to me, and I cannot figure out why. Is it just because of the valve reliefs?
Intake
5BTDC - 0.435 "
TDC - 0.427"
5ATDC - 0.390"
9ATDC - 0.374"
10ATDC - 0.378 "
11ATDC - 0.380"
Exhaust
5BTDC - 0.325"
TDC - 0.309 "
1ATDC - 0.307"
2ATDC - 0.316 "
5ATDC - 0.321"
So my minimums are 374 intake / 307 exhaust
238/242 @ 108lsa, 0.603" 0.605" lift
Heads are 241 casting, have not been milled yet
Pistons are Mahle -4cc valve relief
Checked PTV with a dial indicator, checking springs installed and pushing down on the retainer. The dial indicator was mounted onto the rocker arm above the valve.
The figures I have just seem too big to me, and I cannot figure out why. Is it just because of the valve reliefs?
Intake
5BTDC - 0.435 "
TDC - 0.427"
5ATDC - 0.390"
9ATDC - 0.374"
10ATDC - 0.378 "
11ATDC - 0.380"
Exhaust
5BTDC - 0.325"
TDC - 0.309 "
1ATDC - 0.307"
2ATDC - 0.316 "
5ATDC - 0.321"
So my minimums are 374 intake / 307 exhaust
I got similar results on my build and never figured out why (was in a time crunch to get car done). I'm very interested in seeing what you figure out.
Thread Starter
Staging Lane
Joined: Nov 2011
Posts: 51
Likes: 0
From: Australia
Hi thanks for the reply guys.
I am pretty sure the cam is in correctly, I had a friend check the cam as this is my first time assembling - he told me it was good but I am going to double check myself for good measure (he has built a couple of BBC motors to 1000+hp)
Yes sure did get that decimal place in the right spot, hence why I am pulling my hair out.
I'd like to think it is just because of the valve relief's in the pistons, but I want to be very very sure.
I am pretty sure the cam is in correctly, I had a friend check the cam as this is my first time assembling - he told me it was good but I am going to double check myself for good measure (he has built a couple of BBC motors to 1000+hp)
Yes sure did get that decimal place in the right spot, hence why I am pulling my hair out.
I'd like to think it is just because of the valve relief's in the pistons, but I want to be very very sure.
Thread Starter
Staging Lane
Joined: Nov 2011
Posts: 51
Likes: 0
From: Australia
I checked the cam is degreed properly this afternoon and it certainly is.
Checked by putting dial indicator on the lifter bowl, and using the centerline method. Came back at 108 so is spot on.
Only other thing I can think of is pushrod length, so I am borrowing an adjustable pushrod checker for this weekend.
Checked by putting dial indicator on the lifter bowl, and using the centerline method. Came back at 108 so is spot on.
Only other thing I can think of is pushrod length, so I am borrowing an adjustable pushrod checker for this weekend.
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Thread Starter
Staging Lane
Joined: Nov 2011
Posts: 51
Likes: 0
From: Australia
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