rev or grenade??

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alfred e numan

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Here is the little F-270. Non stuffer crank, Nachi bearings, set to 0.019" squish, lightened flywheel, Lightened ported piston. I will try the WT-771 with 1" velocity stack. 9,500 clutch spring. Jet-pro rear mount modded for more top end. This could be a pretty good set up for the light XB. just a guess---
 
engine photo.

Darned phone rang-distracted me. I really do not know about the 771. it has no high speed check valve in the bore. Just a hole. I did mod a butterfly valve slightly. DDM sells a modded version of the 771 - says it for the bzm.- i am guessing that this carb could have a lighter pop off spring? This stock 771 is used on the ssk? marine engine according to what i have read about.- Yea, I bolted up a zen clutch -shoes- bolts-washers. never ran this clutch before- only one way to know---
 
I did not use the piston pin circlips that are shown in the piston photo. I did not like the way they fit. Gitzmo has The oem zen circlips- these seem to be higher quality than the CY stuff-- harder to install than the CY- stronger steel. I would have had this build done- but the piston is zen- had to order zen 28x8 mm pin bearing- bearing -washers from DDM.- arrived this morning.
 
I like the sound of this engine hope it rips. Yeah CY and zen piston pin are different size. There are some small difference between the two motors.
 
Re: rev or grenade??

Looks very nice. Can't wait to see some results. I seen a piston like that on eBay is that where you got that
 
yup, i installed the engine yesterday evening- done @ 7 pm. let the loktite cure overnight. Thought i would break in gently- have heat cycled 2 times, letting it cool down now. next start i will blip the throttle, see if the clutch is in correct order- then drive it. its set slightly rich on the hsn- so far so good. shure sounds diffrent than the stock f-270 on the stand, almost like a snowmobile- 1 lunger that is--
 
hi folks-- After breaking in this f-270, Its quite impressive. I run alone here so thereis no body to hand over the controller to the other car and have a drag race- soo- just eyeballing-- the tb2 is heavy - bout 6-+ pounds more than the xb. It has a full mod gitzo 30.5 -813- pipe- geared lower than the xb.- both cars have the same tires.- The 270 has a wt 771 same air filter- On a stock 771, the standard pressure spring- This engine is a rev monster-Change the spring and it becomes a torquer - comparing it to engines on you-tube- it almost sounds like a case reed engine. Oh- the xb has a 9500 spring on the clutch- the gitzmo 30.5 has a 8000.- Agan, just eyeballing-- the xb will pull the big motor on a short drag race- hands down. Yea, there is 500.000 wt fluid in the center diff on the tb2- close to locked up.- Now- if there was a rolling start drag race- I really think the big motor would pull the f-270 for 30-40 feet- then when the reves kicked in on the f-270- it would walk the dog on the big motor-- just tru massive rpm-s. just saying--- One last thing- the 30.5 has a stuffer carak- the 270 does not--.
 
yes it is. when i said that changing the pressure spring on the 270 makes it into a torquer- what i mean- it pulls much harder - in the 10,000- 13,000 range- but it still reves to the moon-- Forgot to say- this was all done on a hard packed football field- the grass is just starting to grow- there are bare spots- the tires dig in to the roots on the surface- total velcro traction- much more than there would be on pavement.- The tires on both cars are grp bulldogs mediun compound- narrows all the way around-- I do have grp easy narrows- 2 full sets- both cars would spin almost out of control in a drag race- This piston is worthy- its far stronger than a stock long block. and revs higher also.
 
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