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Requesting input for LG motor "recipe"
https://slantsix.org/forum/viewtopic.php?t=64194		 Page 2 of 3
Author:  justa170 [ Wed Nov 13, 2019 6:02 pm ]
Post subject:  Re: Requesting input for LG motor "recipe"
Quote:
My 170 will turn 6500 with mild cam...
Nice!!

I think I need to sit back and wait for an equal-ish-intake-runner-length manifold to pop up at an unreasonably low price. I like the Offenhauser 5041, and the Aussiespeed stuff looks great, but the prices make me flinch a bit. (I'm not saying they're not worth the money; I'm saying I don't want to spend that much right now.)
Author:  justa170 [ Fri Feb 21, 2020 11:24 am ]
Post subject:  Re: Requesting input for LG motor "recipe"
Quote:
1.50" exhaust valves are overkill. The exhaust port works pretty well compared to the intake port and so the bigger intake is most of the benefit...
Thank you. There's won't be a shrouding problem with the 0.060"+ overbore, but I might still ask the machinist to decrease the diameter of the 1.5" exhaust valves, if the extra 0.05" is counter-productive.
Author:  justa170 [ Fri Feb 21, 2020 11:32 am ]
Post subject:  Re: Requesting input for LG motor "recipe"
Many thanks to all who have provided input for this ongoing LG Stroker project! I'm back, with yet another engine recipe question. Here is the current plan. Still aiming for a displacement of 205-210ci and a CR of ~9.5.

LG block (overbored 0.060-0.80)
198ci crank
Offy 5041 dual-carb intake* w/Raso manifold heat system
matching Carter BBS carbs
oversized valves
head port/polish
upgraded valve springs (haven't selected these yet)
dual exhaust manifolds
custom windage tray

* I know this isn't the smart/practical way to go, but WOW is it cool-looking.

This motor will go into a lightweight custom roadster with a manual transmission. The car will be driven (enthusiastically, but safely) on the street.

QUESTION: I knew nothing about cams. I bought one book, I read it, and now I know *almost* nothing about cams. :wink: I'm considering this #2106 regrind (hat tip to SlantSixDan). Is this the way to go? (This is the Dutra RV10-RDP, right?)
https://drive.google.com/file/d/1CprcLK ... sp=sharing
Author:  drgonzo [ Fri Feb 21, 2020 11:44 am ]
Post subject:  Re: Requesting input for LG motor "recipe"
With a manual trans, 9.5 CR and a light car, I would go a lil bigger on the cam.
Author:  hyper_pak [ Fri Feb 21, 2020 5:39 pm ]
Post subject:  Re: Requesting input for LG motor "recipe"
On my 170, Hyper Pak intake and Hyper Pak exhaust manifolds, I had to clearance the rib on the back of the water pump. Also my mini starter, Dakota manual trans, can not be removed without taking the rear manifold loose. I think you will have more room with Dutra manifolds. Headers also will give you more starter room.
Author:  justa170 [ Fri Feb 21, 2020 9:06 pm ]
Post subject:  Re: Requesting input for LG motor "recipe"
Quote:
...Also my mini starter, Dakota manual trans, can not be removed without taking the rear manifold loose. I think you will have more room with Dutra manifolds. Headers also will give you more starter room.
I think I have that same starter (Remy 16054). I'm hoping "dual duals" will clear.
Author:  DusterIdiot [ Sat Feb 22, 2020 6:41 am ]
Post subject:  Re: Requesting input for LG motor "recipe"
Quote:
I knew nothing about cams.
FYI. Since the 170 is a zero deck motor, and if your build is possibly going to be positive deck, you may have to assemble the block,
and test fit the head and check the valve clearances to the piston face to make sure that the larger cam's lift won't allow the valve
to conflict with the piston face...
Author:  justa170 [ Sat Feb 22, 2020 8:01 am ]
Post subject:  Re: Requesting input for LG motor "recipe"
Quote:
FYI. Since the 170 is a zero deck motor, and if your build is possibly going to be positive deck, you may have to assemble the block,
and test fit the head and check the valve clearances to the piston face to make sure that the larger cam's lift won't allow the valve
to conflict with the piston face...
Indeed! We're going to mock up the build and see where things sit. I'll definitely want pistons with a shorter-than-stock wrist-pin height.
Author:  Charrlie_S [ Sat Feb 22, 2020 8:05 am ]
Post subject:  Re: Requesting input for LG motor "recipe"
Quote:
I'll definitely want pistons with a shorter-than-stock wrist-pin height.
Why?
OK, forgot about the 198 crank.
Author:  justa170 [ Thu Oct 26, 2023 11:08 pm ]
Post subject:  Re: Requesting input for LG motor "recipe"
Here's the current plan. I've got everything except the retainers, the harmonic damper (I just ordered it), and the headers/exhaust, which will be mocked up and fabricated when we're further along.

I have learned a lot about scope creep. :|

Pair of Carter BBS 7044s
Offy 5041 dual-carb intake
Raso manifold heat system
GM HEI upgrade
Stock valve cover
Slant Daily Garage valve cover load spreader
1970 head, ported/polished
Oversized valves - 1.72" intake and 1.45" exhaust
COMP Cams 901-16 springs
Retainers: not sure yet
Cam: Pattern #346, with 110-degree LSA, from Oregon Cam Grinders
JP Performance JP5613 timing chain
1961 LG block (overbored 0.065)
198ci crank
Romac 0224SA damper (IF it fits, and BOY do I hope it does)
stock 170ci rods
Silv-O-Lite P/N 1287-5MM pistons
Custom headers/exhaust
"Group Buy" windage tray
Author:  hyper_pak [ Fri Oct 27, 2023 7:59 am ]
Post subject:  Re: Requesting input for LG motor "recipe"
Glad to see you are still plugging along!
Looking forward to hearing what it sounds like.
Author:  justa170 [ Fri Oct 27, 2023 11:19 am ]
Post subject:  Re: Requesting input for LG motor "recipe"
Quote:
Glad to see you are still plugging along!
Full speed ahead on this project!
Image
Quote:
Looking forward to hearing what it sounds like.
Same!

I just unboxed the the Slant Daily Garage valve cover load spreader. It looks good:
Image
Author:  hyper_pak [ Fri Oct 27, 2023 11:35 am ]
Post subject:  Re: Requesting input for LG motor "recipe"
Quote:
Quote:
Glad to see you are still plugging along!
Full speed ahead on this project!
Image
Quote:
Looking forward to hearing what it sounds like.
Same!

Been there, done that.

Attachments:
Stans Colt s.JPG
Stans Colt s.JPG [ 72.01 KiB | Viewed 1014 times ]
Author:  SlantSixDan [ Fri Oct 27, 2023 11:59 am ]
Post subject:  Re: Requesting input for LG motor "recipe"
Quote:
Slant Daily Garage valve cover load spreader
Huh! What a cool product. Wish that had been around in years past.
Quote:
1961 LG block (overbored 0.065)
198ci crank
stock 170ci rods
I calc this out as 206 cubic inches. Interesting.
Author:  Charrlie_S [ Fri Oct 27, 2023 12:47 pm ]
Post subject:  Re: Requesting input for LG motor "recipe"
If my math is correct: and 170 theoretical deck clearance is .000
Your combination will have the piston .080 down in the hole. Most 170 engines have the stock piston about .010-.020 down in the hole, so add that to the .080. That means you will have to cut the deck .100 just to obtain the stock compression ratio (with a unmilled head). Now you need to cut valve reliefs if you are going to mill the head and install a bigger cam.
This just seems to be a lot of effort to get the same results from a LG engine, as you can by using a 198 RG engine
PS: I have an LG engine in my shop that someone else wound up cutting the deck about .170 to use some oddball combination of parts.
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