Putting a new hot street motor together for my 73 GSR/Sports Bug. It’s a weekend car, porsche-hunting mountain runner, and it turns as good as it scoots. Well, that’s the plan anyway. I know this will be a high strung motor and I plan on driving it hard, realistically I’m expecting ~50k from this build.
2165cc, 10.9:1 CR, ~180-190hp
CB Alu. super case
CB forged 78mm race crank
CB 5.5” Super race rods
Weisco 94mm pistons, total seal 2nd ring, Mahle barrels
CB 044 CNC Mini-Wedge port heads, 42mm/37.5mm, k800 springs, 49cc chambers, .031” deck
CB 1.25 forged rockers
CB 28mm lightweight lifters
Chomoly tapered pushrods
CB 2300 cam, Dur. @ .050'' 273°, Lift w/1.25 .537”
CB 30mm Maxi Full Flow pump
CB Ultra wide glide sump
DTM shroud
Welded Super Bee fan
CB 48mm TBs w/ port matched manifolds
MS3 fuel injection and spark
44mm vintage speed merged comp. exhaust
91 octane only
Does this look sound? Has anyone besides Pat run this much CR with a CB 2300 cam? Is this crazy?
Motor build sanity check
- Piledriver
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- Joined: Sat Feb 16, 2002 12:01 am
Re: Motor build sanity check
Why the gapless second ring?
If the TS gapless second ring actually worked as advertised, the top ring would reliably fail to seal.
Realize the second ring MUST leak some for the top ring to operate properly.
Many high end builders use a wider than "spec" second ring gap for that exact reason.
(particularly on boosted or high CR motors)
TS top ring almost makes (theoretical) sense. Second ring no bueno.
Suggest Napier type second ring.
I understand this borders on a religious argument so I will leave it at that...
No dry sump?
If the TS gapless second ring actually worked as advertised, the top ring would reliably fail to seal.
Realize the second ring MUST leak some for the top ring to operate properly.
Many high end builders use a wider than "spec" second ring gap for that exact reason.
(particularly on boosted or high CR motors)
TS top ring almost makes (theoretical) sense. Second ring no bueno.
Suggest Napier type second ring.
I understand this borders on a religious argument so I will leave it at that...
No dry sump?
Addendum to Newtons first law:
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
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- Posts: 192
- Joined: Sun Mar 09, 2003 12:01 am
Re: Motor build sanity check
I was told to use gapless 2nd ring for high boost/high CR engines, but gapless to top ring never came up. I ran a gapless 2nd ring on my turbo motor for that reason. Maybe I'll switch to a TS top ring for this setup.
I don't want to go dry sump if I can help it. I ran dry sump on the race bug with great results, but it always had changing issues even with high output alt. I'm hoping an extra 4 quarts in the sump are good enough for street duty.
I don't want to go dry sump if I can help it. I ran dry sump on the race bug with great results, but it always had changing issues even with high output alt. I'm hoping an extra 4 quarts in the sump are good enough for street duty.
- Piledriver
- Moderator
- Posts: 22518
- Joined: Sat Feb 16, 2002 12:01 am
Re: Motor build sanity check
Using a 356 size top pulley usually get the fan/alt back to ~stock speed when using a dry-sump pulley, but I understand, simple is good.
Addendum to Newtons first law:
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.