Budget pulling truck engine named (Tommy Boy)

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randy331
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Re: Budget pulling truck engine named (Tommy Boy)

Post by randy331 » Sat Nov 04, 2017 11:48 pm

GARY C wrote:
Sat Nov 04, 2017 11:39 pm
What compression?
Probably end up 14.5-15 to 1 Not sure exactly what it'll be yet.

I'll take 15.5-1 if I can get it without compromising too much.

Randy

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Re: Budget pulling truck engine named (Tommy Boy)

Post by GARY C » Sun Nov 05, 2017 12:04 am

randy331 wrote:
Sat Nov 04, 2017 11:48 pm
GARY C wrote:
Sat Nov 04, 2017 11:39 pm
What compression?
Probably end up 14.5-15 to 1 Not sure exactly what it'll be yet.

I'll take 15.5-1 if I can get it without compromising too much.

Randy
Here is the 113 if you dont already have the specs.
SPECIFICATION
R+M/2 (Octane) 113
Color Green
Oxygenated
MON 109
RON 117.5
RVP 7.96
Specific Gravity 0.721
Fuel Type Leaded

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Re: Budget pulling truck engine named (Tommy Boy)

Post by randy331 » Sun Nov 12, 2017 11:17 am

New pullin truck engine to replace Tommy Boy

4.155 bore x 3.875 stroke SBC
14.5-15/1 comp
Targeting 7200-7300 for peak HP rpm ( that's where the head/induction looks like it's sized for) GMPP vortec bowtie heads
Wanting it to hang on as good as possible past peak HP rpm
2.08 in 1.58 ex valves
1.7 in 1.6 Jesel shafts
Dart SHP Pro block so it's big block cam journal and .904 lifters

lookin at Comp cams lobe # 1839 for intake and # 1960 for the EX. ??

Those lobes look ok for pullin truck engine ??


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Re: Budget pulling truck engine named (Tommy Boy)

Post by Old School » Sun Nov 12, 2017 12:49 pm

randy331 wrote:
Sun Nov 12, 2017 11:17 am
New pullin truck engine to replace Tommy Boy

4.155 bore x 3.875 stroke SBC
14.5-15/1 comp
Targeting 7200-7300 for peak HP rpm ( that's where the head/induction looks like it's sized for) GMPP vortec bowtie heads
Wanting it to hang on as good as possible past peak HP rpm
2.08 in 1.58 ex valves
1.7 in 1.6 Jesel shafts
Dart SHP Pro block so it's big block cam journal and .904 lifters

lookin at Comp cams lobe # 1839 for intake and # 1960 for the EX. ??

Those lobes look ok for pullin truck engine ??


Randy

My inexperience with pull engines doesn't lend much credibility to my thoughts but....

The lobes should be a good compromise between power and relialibility. A 272 intake lobe will give a 65/66 intake closing point on a 112 lobe separation advanced 2/3 degrees. That's not to say that's where it should be but a starting point. The 286 exhaust should keep the power from falling off the cliff. My first instinct would be 112LS but again just a starting point. Someone with more experience will have a better recommendation. Based on the lobes the cam should peak in the 7300/7500 area if the induction can support the flow needed.

Will the 1.7 rockers, larger cam core and the .904 lifters add a little duration to the .050 and up? Still you've got to start somewhere.

How much power do you hope to make at peak? Average power between 7000-7800? The average will be worth more than the peak.

Looking forward to your build and results.. best of luck Billy

PS Don't tell the lobes they are going in a pulling engine, that way they will not have a preconceived idea of what they should do.

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Re: Budget pulling truck engine named (Tommy Boy)

Post by CGT » Sun Nov 12, 2017 2:13 pm

randy331 wrote:
Sat Nov 04, 2017 11:48 pm
GARY C wrote:
Sat Nov 04, 2017 11:39 pm
What compression?
Probably end up 14.5-15 to 1 Not sure exactly what it'll be yet.

I'll take 15.5-1 if I can get it without compromising too much.

Randy
What were you thinking for lobe separation?

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Re: Budget pulling truck engine named (Tommy Boy)

Post by randy331 » Sun Nov 12, 2017 2:17 pm

Old School wrote:
Sun Nov 12, 2017 12:49 pm

My inexperience with pull engines doesn't lend much credibility to my thoughts but....

The lobes should be a good compromise between power and relialibility. A 272 intake lobe will give a 65/66 intake closing point on a 112 lobe separation advanced 2/3 degrees. That's not to say that's where it should be but a starting point. The 286 exhaust should keep the power from falling off the cliff. My first instinct would be 112LS but again just a starting point. Someone with more experience will have a better recommendation. Based on the lobes the cam should peak in the 7300/7500 area if the induction can support the flow needed.

Will the 1.7 rockers, larger cam core and the .904 lifters add a little duration to the .050 and up? Still you've got to start somewhere.

How much power do you hope to make at peak? Average power between 7000-7800? The average will be worth more than the peak.

Looking forward to your build and results.. best of luck Billy

PS Don't tell the lobes they are going in a pulling engine, that way they will not have a preconceived idea of what they should do.
Thanks for the reply.

I was kinda thinking 111* LSA and I think it will likely end up in at 106 ish when it's tested on the dyno, so puts IVC a bit earlier than the 65-66 you mentioned, but no way to know till it's tested. 62-63 ABDC IVC is kinda what I was thinking.

Hoping it will make 110 more HP and 110-120 more pounds of TQ. That will be 2.3 HP/cfm in the heads current state. But, I'm welding up the pushrod area and will widen it for more CSA there. Still a bit small there for 7200-7300 rpm 420 cube. And that CFM is on a 4.060 test bore, so it's likely they'd move some more air on a bigger bore.

My guess is you have as much experience with pulling trucks as I do. Only been involved in it for 2 years now. Before that I was just a beer drinking spectator now and then. :D

Maybe I should start a new thread for this build ?

Randy

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Re: Budget pulling truck engine named (Tommy Boy)

Post by GARY C » Sun Nov 12, 2017 2:28 pm

Maybe I should start a new thread for this build ?
That would be cool, you guys tend to produce above average power with parts that the average speedtalker can afford and would be a much greater benefit to the majority of the readers here.

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Re: Budget pulling truck engine named (Tommy Boy)

Post by CGT » Mon Nov 13, 2017 9:29 am

Intake Duration at .050 272°
Exhaust Duration at .050 286°
LSA: 112
Intake Centerline: 108°
IVO is 28.0 ° BTDC
IVC is 64.0 ° ABDC
EVO is 79.0 ° BBDC
EVC is 27.0 ° ATDC
55 Degrees of overlap @.050

I like the lobe choices and the valve events, on a 112lsa. But who knows, itll have to be dynoed to see. I'd be inclined to try the #1962 lobe, due to the rpm range, inches, compression etc. But..............

Chad

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Re: Budget pulling truck engine named (Tommy Boy)

Post by randy331 » Mon Nov 13, 2017 9:29 pm

LSA: 112
Intake Centerline: 108°
IVO is 28.0 ° BTDC
IVC is 64.0 ° ABDC
EVO is 79.0 ° BBDC
EVC is 27.0 ° ATDC
55 Degrees of overlap @.050

Those valve events are very close to what I'm thinking it needs.

For a 2 cam test try what else ??

Randy

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Re: Budget pulling truck engine named (Tommy Boy)

Post by CGT » Tue Nov 14, 2017 11:46 am

Intake lobe #1771
Exhaust lobe #1766

Intake duration at .050: 270 °
Exhaust duration at .050: 290 °
LSA: 113°
Intake Centerline: 108°
IVO is 27.0 ° BTDC
IVC is 63.0 ° ABDC
EVO is 83.0 ° BBDC
EVC is 27.0 ° ATDC
54 Degrees of overlap at .050

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Re: Budget pulling truck engine named (Tommy Boy)

Post by randy331 » Wed Nov 15, 2017 11:23 pm

CGT wrote:
Tue Nov 14, 2017 11:46 am
Intake lobe #1771
Exhaust lobe #1766

Intake duration at .050: 270 °
Exhaust duration at .050: 290 °
LSA: 113°
Intake Centerline: 108°
IVO is 27.0 ° BTDC
IVC is 63.0 ° ABDC
EVO is 83.0 ° BBDC
EVC is 27.0 ° ATDC
54 Degrees of overlap at .050
Bet there wouldn't be much difference in that cam vs the other one once both are moved around for best position.

If I was gonna test a different cam I'd be inclined to make it a bigger difference but may not be able to open intake earlier or close ex later with the pistons I have on the way.

Randy

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Re: Budget pulling truck engine named (Tommy Boy)

Post by steve316 » Thu Nov 16, 2017 8:53 am

the lobes on the cam in my 427 is 1720 in. 1960 ex. on 112 lsa with ls firing order. 273 & 286 @ .050. still about the same as your speck if you want to try it let me know. I run with 1.75 & 1.6 rockers Steve

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Re: Budget pulling truck engine named (Tommy Boy)

Post by CGT » Thu Nov 16, 2017 8:56 am

steve316 wrote:
Thu Nov 16, 2017 8:53 am
the lobes on the cam in my 427 is 1720 in. 1960 ex. on 112 lsa with ls firing order. 273 & 286 @ .050. still about the same as your speck if you want to try it let me know. I run with 1.75 & 1.6 rockers Steve
Steve. I'm not seeing the 1720 intake lobe. Which lobe series is that?

Chad

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Re: Budget pulling truck engine named (Tommy Boy)

Post by steve316 » Fri Nov 17, 2017 12:20 pm

1720 lobe is 306 @ .020 273 @ .050 lobe lift .485 @ .050 int. open 25 btdc close 67 abdc specs for 111 icl. It is in the same family as the 1722 witch is 2 degree larger

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Re: Budget pulling truck engine named (Tommy Boy)

Post by CGT » Fri Nov 17, 2017 12:36 pm

Oh ok. RX Pro lobe.

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