Boosted, Blown or doped?

massacre

massacre

#21
#21
Well our bikes are still using small wheels/tires, so RPM becomes more important if you wanna go fast/quick. I have taken my motor to 10k RPM a few times when i was still running a centrifugal clutch, motor has billet everything so it stayed together. Now I have the Polar clutch so around 8k RPM is about all i need.
Catch can becomes very important at high RPM as well
 
Augiedoggie

Augiedoggie

Well-Known Member
#22
#22
massacre said:
Well our bikes are still using small wheels/tires, so RPM becomes more important if you wanna go fast/quick. I have taken my motor to 10k RPM a few times when i was still running a centrifugal clutch, motor has billet everything so it stayed together. Now I have the Polar clutch so around 8k RPM is about all i need.
Catch can becomes very important at high RPM as well
Click to expand...
Sounds like a keeper. Let's hear your engine specifics if you don't mind sharing.
 
massacre

massacre

#32
#32
Blockzilla is just a factory Briggs block made especially for jr dragsters. Yes it is a flathead. Since i race it, i don't want to give away every detail. If you look up 8.90 jr dragster engines you'll get an idea of what is going on. Power is about 25 HP at the tire, had it on a chassis dyno. 33mm Mikuni carb, 3 stage header. Billet everything.
 
Augiedoggie

Augiedoggie

Well-Known Member
#33
#33
massacre said:
Blockzilla is just a factory Briggs block made especially for jr dragsters. Yes it is a flathead. Since i race it, i don't want to give away every detail. If you look up 8.90 jr dragster engines you'll get an idea of what is going on. Power is about 25 HP at the tire, had it on a chassis dyno. 33mm Mikuni carb, 3 stage header. Billet everything.
Click to expand...
Very good. Do you race a Jr dragster? What does 8.90 designate?
 
massacre

massacre

#38
#38
Just to be clear, Briggs only sold bare Blockzilla blocks. Needs machining still. Lots of builders sell complete engines though. And there are BZ1, BZ2, and BZ3 models. Bore is different between them, possibly other differences.

The inherent problem with Blockzilla design, is that the crank and cam are too close together. Lots of grinding necessary to fit a big cam. Other companies realized this, and moved the cam further away from the crank. This enables bigger cams, and bigger valves. So in this regard, the Blockzilla is somewhat obsolete compared to the newer designs.
A brand new, fully built jr dragster engine is not what i would call "affordable" necessarily, but lots of times used engines come up for sale when drivers move up to a faster class, or age out of racing all together.
 
sparkwizard

sparkwizard

#39
#39
We are Ebay shoppers. We have different project "buckets" so when we find deals, we buy parts and store them in different buckets for each project. Some day in the future, we will start putting these projects together.
We are labeling a Blockzilla bucket this week and placing it under the tree.:rolleyes:
 
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