Pulling truck engine "again" BBC

[randy331]

I got a BBC engine in a guy bought for his pulling truck, for the same class we run our truck in.
Got it tore down and we're deciding on direction.

It's got a Eagle 4" stroke crank, and stock length Eagle rods. Can't find anything on the pistons, so not sure what they are, but are a .030" over bore, 1/16 1/16 3/16 rings and the bores look decent. So probably just get few strokes with a hone.
Lots of TQ to turn the short block over, so it'll get something lower tension for rings.
He's got a vacuum pump in the budget, so rings can be lower for sure.

Does Eagle contract with someone to provide a plain label piston for their rotating assy? I can't find anything on them. They have a dome on them and with the open chamber heads compression is 12.8-1 as things are now.
I've used Eagle rods/cranks before but never a rotating assy. Always got pistons from someone else.

I don't see any signs of contact,.... so my thinking is tighten up things in the chamber a little with a thinner gasket? LOL
Things get ugly in this cube BBC open chamber to get up in the Comp.

Cam,.. it currently has a Comp Cam RX intake lobe and Rt ex lobe.
Current Valve events as it is installed are,
IVO= 28* BTDC
IVC= 69* ABDC
EVO= 71* BBDC
EVC= 33* ATDC
What events would you like to see different??
He's up for a cam change, so that may be in the cards.
Currently got 3/8 stem valves. Don't know why these things get built with that kinda valve?
It weighs 158 gram, but,.. sounds like he's up for titanium intakes, so things could change on the intake lobe. Only .725" lift as measured the way it was ran before. I'd like some more lift in it.

Got a new Whitener 1.98 venturi x 2.250 throttle carb on the way for it.
Will be ran on VP blue, Sunoco supreme, or Q16.
Maybe I could get Mark to send me 2 carbs and keep the one that makes the most power ? LOL
Kinda like a sponsorship!! LOL

Haven't done anything with the heads except took them apart, but they are open chamber rec port.

Anyway, thought some may be interested in it "even though it's for a pulling truck" lol, since it's not a theoretical engine and gonna get dyno time and go in a truck and compete.

Randy

[CGT]

More lift. Current cam cant be that far off. Then.....the usual things lol. Titanium valves seem to be almost a must to be competitve. Could maybe use more exhaust lobe. Jmo moo...big block chevies of that cube suck btw lol

[Walter R. Malik]

I got a BBC engine in a guy bought for his pulling truck, for the same class we run our truck in.
Got it tore down and we're deciding on direction.

It's got a Eagle 4" stroke crank, and stock length Eagle rods. Can't find anything on the pistons, so not sure what they are, but are a .030" over bore, 1/16 1/16 3/16 rings and the bores look decent. So probably just get few strokes with a hone.
Lots of TQ to turn the short block over, so it'll get something lower tension for rings.
He's got a vacuum pump in the budget, so rings can be lower for sure.

Does Eagle contract with someone to provide a plain label piston for their rotating assy? I can't find anything on them. They have a dome on them and with the open chamber heads compression is 12.8-1 as things are now.
I've used Eagle rods/cranks before but never a rotating assy. Always got pistons from someone else.

I don't see any signs of contact,.... so my thinking is tighten up things in the chamber a little with a thinner gasket? LOL
Things get ugly in this cube BBC open chamber to get up in the Comp.

Cam,.. it currently has a Comp Cam RX intake lobe and Rt ex lobe.
Current Valve events as it is installed are,
IVO= 28* BTDC
IVC= 69* ABDC
EVO= 71* BBDC
EVC= 33* ATDC
What events would you like to see different??
He's up for a cam change, so that may be in the cards.
Currently got 3/8 stem valves. Don't know why these things get built with that kinda valve?
It weighs 158 gram, but,.. sounds like he's up for titanium intakes, so things could change on the intake lobe. Only .725" lift as measured the way it was ran before. I'd like some more lift in it.

Got a new Whitener 1.98 venturi x 2.250 throttle carb on the way for it.
Will be ran on VP blue, Sunoco supreme, or Q16.
Maybe I could get Mark to send me 2 carbs and keep the one that makes the most power ? LOL
Kinda like a sponsorship!! LOL

Haven't done anything with the heads except took them apart, but they are open chamber rec port.

Anyway, thought some may be interested in it "even though it's for a pulling truck" lol, since it's not a theoretical engine and gonna get dyno time and go in a truck and compete.

Randy

Just a few questions:
What heads, (990 ?), and intake manifold are you using ...?
Does the engine have a really good power oil pan...?
What headers will be used ...?
What is the LOWEST RPM this thing will encounter ...?
Are there any compression or valve lift rules ...?

The cam seems not right for a puller.

[travis]

A lot of the Eagle rotating assemblies come with Icon pistons, or KB’s for the lower priced kits

[Old School]

Best I can cipher by the valve events the cam is 109.8 lobe separation the intake installed on 110.5. The cam may not be ideal but is really isn't that bad either. More exhaust duration may carry the rpm's better and a wider separation might flatten the curve some. What about 1.8 rockers on the intake and trying the current cam, or get one with a little less intake duration 270-274, exhaust 282-286, lobe separation 112, net lift at least .780 on the intake with titanium valves and test the two cams when dynoed. At least that's my thoughts, may be completely wrong.

Your 50 degree seat will control some of the reversion at overlap. Compression, as you said, is very hard to get in a 468 without stuffing dome where it should not be in the chamber.

Does he have shaft or stud rocker arms? I always build this type of engine with a bracket drag engine mind set. However, best as I can tell, in pulling rpm is king and that should dictate the parts needed. That would be a good valvetrain, good windage control, and the best induction that rules allow. Course you know all that already. Best of luck.

Billy

[Carnut1]

If the pistons are in good shape you may be better off with an angle mill on the heads with appropriate gaskets. Depending on how high you want to go. Thanks, Charlie

[Truckedup]

Randy331, can a gas engine be built to pull as good as the modified Diesels? I'm assuming a well build Diesel puller, Cummins, has about 1500 ft lbs of torque ?

[randy331]

Ok, to try and answer some questions,

Heads are 026 casting
intake he has is a 454 victor but he bought a sniper jr to test and I have a sniper 2 here for a different engine we could try.
No compression or lift limits in the rules.
He has a set of mad dog headers for his truck, 2 1/8 x 2 1/4 step (I think)
RPM,... well usually not lower than peak TQ rpm at the end, but I've seen the winning truck get pulled back to idle, so... the engine needs power from idle to 9000 rpm. LOL
Currently it has a Jesel shaft rocker set up on it.

The cam is 110* lsa in at 110 icl I think, I rounded my cam findings to to full deg. Comp lists the RX lobe as 277*.

It'd probably made a bit more power in a little earlier.

As far as gas trucks pulling with the diesels, not under the current rules but maybe with the same rules, like they have to weigh 6200 Lbs like we do and we get a turbo like they do.

Randy

[CGT]

Randy, What are you thinking on the current cam?

[CGT]

since it's not a theoretical engine and gonna get dyno time and go in a truck and compete

I would just run it through a sim, should be within a few horsepower.

[CamKing]

Here's what we run on an engine that is similar.
273/283 @.050"
.500"/.485" Lobe Lift
112 LSA

[408swinger]

OP mentioned it taking a lot of Torque to turn the roatating assembly over.
How much is too much ?
The reason I ask is because I just assembled a 360 based 408 mopar stroker and noticed it took some muscle to rotate it... so I got my TQ wrench and measured... 95 ft/lbs

seemed like a lot !

[cgarb]

OP mentioned it taking a lot of Torque to turn the roatating assembly over.
How much is too much ?
The reason I ask is because I just assembled a 360 based 408 mopar stroker and noticed it took some muscle to rotate it... so I got my TQ wrench and measured... 95 ft/lbs

seemed like a lot !

Is that with the plugs in? That seems excessive if that's is just the shortblock assembly, I would be checking for problems. My dad taught me when building an engine to put everything together wrench snug first the torque all of the mains and rods at one time, not all the fasteners at once but all with one use of the wrench. As you are torquing the mains and rods give the motor a turn after you torque each main cap and rod, if you notice a significant change in effort to spin the engine, you probably have just found a problem somewhere. Loosen up what you just torqued and if it returns to spin freely, something is wrong.

[408swinger]

that was just the rotating assembly and cam... no springs or heads on.
Crank spun nicely after install , rings file fit to .016 on a 4.03 bore.. I just attributed it to the 4" crank.

[randy331]

that was just the rotating assembly and cam... no springs or heads on.
Crank spun nicely after install , rings file fit to .016 on a 4.03 bore.. I just attributed it to the 4" crank.

OP mentioned it taking a lot of Torque to turn the roatating assembly over.
How much is too much ?
The reason I ask is because I just assembled a 360 based 408 mopar stroker and noticed it took some muscle to rotate it... so I got my TQ wrench and measured... 95 ft/lbs

seemed like a lot !

That is a lot. This one took over 40lbs to get it broke free, but I could keep it spinning between 30-40 lbs,.. and that's too much.
Just the short block.

I did a BBC with .043"- .043" 2mm rings and it would turn over at about 18 Lbs.


Randy