Critique my engine build
Thread Starter
Drifting
Joined: Feb 2005
Posts: 1,583
Likes: 5
From: Richardson Tx.
Critique my engine build
Chevy 350 Bored out .020 - Block was not decked.
HypereutecticPistons: (flattop) Sealed Power# H345NP
Flat Top; 4 valve reliefs
Compression dist 1.560
Deck Clearance .025
Skirt Clearance .0010
Compression ratio by CYL head CC
Part
number CID 64.cc
H345NP 350 9.24
FelPro Gasket Kit 260-1045- Not sure of head gasket thickness
New 64CC Vortec Heads - not modified
Gm Cam # 24502476 - Hydraulic Flat Tappet - 212/222 .435/.460.
Performance Products Vortec Cyclone #52006 (Edelbroc Performer Clone) –Dual Plane
Q-Jet Carb rebuilt by Lars
Timing set to 32 deg. per Lars for Vortec heads.
3.36 Rear End gears
2.5 True Duals- no cats
Stock Exhaust Manifold
4 speed B/W S/T10 trans.
All emission stuff removed
I thought that I would have better acceleration than what I have from this. My guess is that I am 0-60 in 7 seconds.
My goal was to have a quick snappy car with a good idle. I don't care about top speed at all.
Are there any changes that you would make? I know that some of you are going to say headers - I agree, but what else would you change? I may do it.
HypereutecticPistons: (flattop) Sealed Power# H345NP
Flat Top; 4 valve reliefs
Compression dist 1.560
Deck Clearance .025
Skirt Clearance .0010
Compression ratio by CYL head CC
Part
number CID 64.cc
H345NP 350 9.24
FelPro Gasket Kit 260-1045- Not sure of head gasket thickness
New 64CC Vortec Heads - not modified
Gm Cam # 24502476 - Hydraulic Flat Tappet - 212/222 .435/.460.
Performance Products Vortec Cyclone #52006 (Edelbroc Performer Clone) –Dual Plane
Q-Jet Carb rebuilt by Lars
Timing set to 32 deg. per Lars for Vortec heads.
3.36 Rear End gears
2.5 True Duals- no cats
Stock Exhaust Manifold
4 speed B/W S/T10 trans.
All emission stuff removed
I thought that I would have better acceleration than what I have from this. My guess is that I am 0-60 in 7 seconds.
My goal was to have a quick snappy car with a good idle. I don't care about top speed at all.
Are there any changes that you would make? I know that some of you are going to say headers - I agree, but what else would you change? I may do it.
Race Director
Joined: Sep 2002
Posts: 10,362
Likes: 5
From: San Diego - Deep Within The State of CONFUSION!
What's your compression ratio? Why did you use hyper pistons? I would not have used them if it's a motor that I drive hard (like I do) although I realize a lotta guys don't push their engines like I do. I run all forged all the time.
I know that's not gonna help diagnose your performance issues but if you could start with telling us what the comp ratio is, it would help.
I am also a staunch supporter of Dyno Tuning if there's a shop by you. Sure, I know that Lars built the carb and you have max timing set properly. But what about the curve? Do you have any idea at all what your air/fuel ratio is at cruise or under load?
All these things are adjusted under load on the dyno, during a tuning process. It is not to be confused with Dyno Testing, which is strictly a horsepower/max RPM run. Dyno tuning when done properly, will consume at least a half tank of gas and take a few hours to really dial in an engine.
I know that's not gonna help diagnose your performance issues but if you could start with telling us what the comp ratio is, it would help.
I am also a staunch supporter of Dyno Tuning if there's a shop by you. Sure, I know that Lars built the carb and you have max timing set properly. But what about the curve? Do you have any idea at all what your air/fuel ratio is at cruise or under load?
All these things are adjusted under load on the dyno, during a tuning process. It is not to be confused with Dyno Testing, which is strictly a horsepower/max RPM run. Dyno tuning when done properly, will consume at least a half tank of gas and take a few hours to really dial in an engine.
Last edited by SanDiegoPaul; Aug 20, 2010 at 04:02 PM. Reason: whydoyathink?
Le Mans Master
Joined: May 2006
Posts: 9,993
Likes: 1,136
From: League City Tx
I would put more cam in it for sure. Those Vortec heads flow pretty decent...ofcourse they are spring limited so I am not sure if you got the Vortecs that were machined for the bigger springs or not but......I would put a little more cam in it to make good use of those ports. I think this more modern cam would give you better power across the powerband and still drive very mild.
http://www.lunatipower.com/Product.aspx?id=1984&gid=287
Ofcourse headers and a good 2.5" exhaust system. Like Paul said, dial in the carb and timing on a chasis dyno to know what you "really" have for a tune up...(or better yet, tune it for mph at the drag strip).
You will have a pretty strong running combo there...I would say an honest 350-375 crank hp, maybe 400hp with an RPM air gap intake and Holley 650/750 double pumper carb.
Should be good for low 13s, maybe even high 12s on sticky tires if you can drive..(if it's a stick)
http://www.lunatipower.com/Product.aspx?id=1984&gid=287
Ofcourse headers and a good 2.5" exhaust system. Like Paul said, dial in the carb and timing on a chasis dyno to know what you "really" have for a tune up...(or better yet, tune it for mph at the drag strip).
You will have a pretty strong running combo there...I would say an honest 350-375 crank hp, maybe 400hp with an RPM air gap intake and Holley 650/750 double pumper carb.
Should be good for low 13s, maybe even high 12s on sticky tires if you can drive..(if it's a stick)
Race Director
Joined: May 2003
Posts: 10,956
Likes: 409
From: California
that cam is very mild, the compression is low, clones seem to never work as well as the real stuff...
I would guess more like 250hp at the wheels, 330 at the crank... max
S/B good for 15's.... imho
I would guess more like 250hp at the wheels, 330 at the crank... max
S/B good for 15's.... imho
Drifting
Joined: Jun 2007
Posts: 1,404
Likes: 1
From: Ansonia/NYC CT
I have the same set up, cept with shorty headers, GMP intake for vortec, no new pistons, and a lunati bracket master 2 cam.
It seems slow, but here's the thing. It only wants to pep up after 3,000 rpms, under WOT. I think 1st gear in our T10s are too long for decently cammed motors. Kind of an expensive fix, I think, but one I'm planning in the next couple of years or so.
It seems slow, but here's the thing. It only wants to pep up after 3,000 rpms, under WOT. I think 1st gear in our T10s are too long for decently cammed motors. Kind of an expensive fix, I think, but one I'm planning in the next couple of years or so.
Race Director
Joined: May 2003
Posts: 10,956
Likes: 409
From: California
I have the same set up, cept with shorty headers, GMP intake for vortec, no new pistons, and a lunati bracket master 2 cam.
It seems slow, but here's the thing. It only wants to pep up after 3,000 rpms, under WOT. I think 1st gear in our T10s are too long for decently cammed motors. Kind of an expensive fix, I think, but one I'm planning in the next couple of years or so.
It seems slow, but here's the thing. It only wants to pep up after 3,000 rpms, under WOT. I think 1st gear in our T10s are too long for decently cammed motors. Kind of an expensive fix, I think, but one I'm planning in the next couple of years or so.
that cam is more of an idle to 5500rpm cam.
this is an edelbrock performer cam, NOT and RPM..
ENGINE: CHEVY 265-350 V8
RPM RANGE: Idle-5500
Duration at 0.006" Lift: Intake: 278° Exhaust: 288°
Duration at 0.050" Lift: Intake: 204° Exhaust: 214°
Lift at Cam: Intake: 0.280" Exhaust: 0.295"
Lift at Valve: Intake: 0.420" Exhaust: 0.442"
Timing at 0.050" lift: Open Close
Intake: 5° ATDC 29° ABDC
Exhaust: 44° BBDC 10° BTDC
Centerlines: Lobe Separation - 112° Intake Centerline - 107°
and it runs idle to 5500rpm...
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Race Director
Joined: Jan 2000
Posts: 12,399
Likes: 247
From: San Jose CA
...GM puts hyper eutes in the LS7s from the factory... and they handle 7L and 450rwhp pretty well...
Drifting
Joined: Jun 2007
Posts: 1,404
Likes: 1
From: Ansonia/NYC CT
That is not a big cam at all... and I to am running a T-10 and even with the old L82 225hp motor it would do a pretty good job,,,
that cam is more of an idle to 5500rpm cam.
this is an edelbrock performer cam, NOT and RPM..
ENGINE: CHEVY 265-350 V8
RPM RANGE: Idle-5500
Duration at 0.006" Lift: Intake: 278° Exhaust: 288°
Duration at 0.050" Lift: Intake: 204° Exhaust: 214°
Lift at Cam: Intake: 0.280" Exhaust: 0.295"
Lift at Valve: Intake: 0.420" Exhaust: 0.442"
Timing at 0.050" lift: Open Close
Intake: 5° ATDC 29° ABDC
Exhaust: 44° BBDC 10° BTDC
Centerlines: Lobe Separation - 112° Intake Centerline - 107°
and it runs idle to 5500rpm...
that cam is more of an idle to 5500rpm cam.
this is an edelbrock performer cam, NOT and RPM..
ENGINE: CHEVY 265-350 V8
RPM RANGE: Idle-5500
Duration at 0.006" Lift: Intake: 278° Exhaust: 288°
Duration at 0.050" Lift: Intake: 204° Exhaust: 214°
Lift at Cam: Intake: 0.280" Exhaust: 0.295"
Lift at Valve: Intake: 0.420" Exhaust: 0.442"
Timing at 0.050" lift: Open Close
Intake: 5° ATDC 29° ABDC
Exhaust: 44° BBDC 10° BTDC
Centerlines: Lobe Separation - 112° Intake Centerline - 107°
and it runs idle to 5500rpm...
Race Director
Joined: May 2003
Posts: 10,956
Likes: 409
From: California
What rear gears? I've got 3.08s. Specs on that cam are pretty close to my own. What hurts cam selection with stock vortec heads is lift. Can't have anything above .460, which eliminates most of the performance cam. What I find is that if I launch the car at around 2,500 rpms, then it's pretty quick, but who wants to do that on the street? Nobody. But if I don't, the sucker just bogs until around 3,000 rpms.
) but 35X??? anyway... so a little higher than yours which also helps. I am running the RPM retro roller cam and it pulls good from about 2000, but at 2500 it starts to lights up.... .460 lift is not a lot, my lift with the compcams RR is .546in .555ex and i wish now i was closer to .600 I did not know that about the vortec heads... good to know, thx
Drifting
Joined: Jun 2007
Posts: 1,404
Likes: 1
From: Ansonia/NYC CT
I understand how you feel.... i have a 4 speed stick, which helps, my gears are 352 (i think that is the number... for some reason , maybe getting old, im forgetting the exact number) but 35X??? anyway... so a little higher than yours which also helps. I am running the RPM retro roller cam and it pulls good from about 2000, but at 2500 it starts to lights up.... .460 lift is not a lot, my lift with the compcams RR is .546in .555ex and i wish now i was closer to .600
I did not know that about the vortec heads... good to know, thx
) but 35X??? anyway... so a little higher than yours which also helps. I am running the RPM retro roller cam and it pulls good from about 2000, but at 2500 it starts to lights up.... .460 lift is not a lot, my lift with the compcams RR is .546in .555ex and i wish now i was closer to .600 I did not know that about the vortec heads... good to know, thx
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
owing to piston chamfer & typical bore lead-in chamfer & typical composition gasket (~9cc) in kit ... I suspect you're closer to 9.53:1 with a poor, too-wide quench.
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felpro 1094 coated shim 0.015" (3.2cc) should put it just over 10:1 with a very good quench. you'll also need more cam
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felpro 1094 coated shim 0.015" (3.2cc) should put it just over 10:1 with a very good quench. you'll also need more cam
Race Director
Joined: May 2003
Posts: 10,956
Likes: 409
From: California
I have a 4 speed, too. There were two T10s that came with the vettes, one with "sporty" gearing, and one with longer gears. I'm pretty sure I have the longer gears. Sigh. Some day, I'll get me one of those sweat 5 speed conversions...and then a 3.57 rear end. I think that'll mate up perfect with my motor the way it currently is.
yea, i am also going to change to a 5 speed.... cursing at 85mph and tacking ~4000 rpm sucks.... especially for runs over 1 hour...
