Revised 70 LT-1 valve setting numbers

[Dennis D.]

Decided to farm out some work on my 70 LT-1.
Diff fluid, carb tuning, valve seals (umbrella).
Going to need to set the valve clearance once the seals go in. Want to use the Duke/John method. Aside from hearing how well it works, I like no mess on setting cold.
Cant find the latest, revised paper. What are the int- exh settings?

[James G.]

Re: Revised 70 LT-1 valve setting numbers

.016 Int
.023 Exh

[Dennis D.]

Re: Revised 70 LT-1 valve setting numbers

.016 Int
.023 Exh

Thanks James

[Duke W.]

Re: Revised 70 LT-1 valve setting numbers

You want the latest 9/08 revision, which is here:

http://www.metroli.org/pdf/WHITE%20PAPER_Solid%20Lifter%20Cam%20Valve%20Adjustment.pdf

Be sure to follow the indexing procedure, and let us know how you like the tighter settings. Some do, some don't. You will likely have a bit less idle vacuum, some loss of low end torque, less valve train noise, but a smoother sounding/feeling engine at high revs and maybe a bit more power.

But the real reason for the tighter lash is to ensure that the valves are opened/closed at no more than clearance ramp velocity, and that's why the valve train is quieter. If fact, some might think it's a hydraulic cam.

Duke

[James G.]

Re: Revised 70 LT-1 valve setting numbers

I have adjusted the last 3 solid lifter engines by the DUKE JOHN method and swear by it.

*Ramp velocity - I spoke at length with Dave Crower when I had him design a solid roller for a 302 Chev. he stated with stock 186's he designed the cam with a 424 lobe lift which drops the valve quickly but not 100% closed... the tail of the lobe lets the valve touch the seat slowly. He said it's easier the heads and valves.

[Duke W.]

Re: Revised 70 LT-1 valve setting numbers

I'm glad you like the results. The Corvette Forum for the most part seems to hate those settings. I've had to deal all kinds of grief over them.

Duke

[Ed H.]

Re: Revised 70 LT-1 valve setting numbers

LOL, well I'm there, and I like them. Maybe that I like them is why I had a sabattical. ;-)

[Ed H.]

Re: Revised 70 LT-1 valve setting numbers

Duke, I have a 72 LT-1 where I have adjusted the valves with the Duke/John method and I swear by it. The engine is smoother; I think actual mid range torque is better and seems to have endless pull at the higher rpms.

Ed H

[Paul Y.]

Re: Revised 70 LT-1 valve setting numbers

I'm glad you like the results. The Corvette Forum for the most part seems to hate those settings. I've had to deal all kinds of grief over them.

Duke

Duke, I have around 8K miles on my engine and I love the sewing machine sound and the way it stays sounding. I don't miss any low RPM torque as the LT-1 has enough after advancing the cam at the crank. I can not be any happier with your and John's recommendations. Thank you for your paper and contribution. Pqul

[Duke W.]

Re: Revised 70 LT-1 valve setting numbers

Thanks for the positive comments, guys. I took the liberty of starting a thread over on the CF and copied and pasted your comments. No names or emails, of course, so you don't get any hate mail.

It's been kinda boring over there lately, so it's time to stir up the pot!

BTW, Paul, the as ground IPOML of the LT-1 cam is 110 deg ATC. What did you advance it to? Also, is it a real 350 LT-1 or a 327 with a LT-1 cam?

Duke