50mm bbk KABOOM!

[guen84]

well tryed switching the base gaskets to 1.33mm with 2 head gaskets, now the pistons hitting the head, it only a 50mm head so that option is out..

[guen84]

OUch dude. Ya you can go as rich as you want with high compression wont help unless the gas you use has a higher knock raiting. Maybe some turbo blue 110 or some 100 oct from sunoco then she would prolly like the compression more and pull some more torq, as well.

starting to look like thats my only option or get a 51mm head..

[Bear45-70]

OUch dude. Ya you can go as rich as you want with high compression wont help unless the gas you use has a higher knock raiting. Maybe some turbo blue 110 or some 100 oct from sunoco then she would prolly like the compression more and pull some more torq, as well.

starting to look like thats my only option or get a 51mm head..

Or have this head machined out to 51 mm. This would also lower your compression numbers.

[bakaracer]

ok with the 1.65 mm base gasket and 2-.5mm head gaskets my compression is 110... seems a little low, but what do you think? i could take out 1 of the .825mm base gaskets and put in a .54mm to raise compression a bit, but that will lower my port durations even more...


ohh ya and with 1 head gasket my compression is 135, thats what i had on the last grenade... [/quote]
with 110 it will be ok.as the revs go up, so will the compression.check your squish too. for your setup it should be no closer than .8mm

[guen84]

with 110 it will be ok.as the revs go up, so will the compression.check your squish too. for your setup it should be no closer than .8mm

looks like im getting almost 2 squish sizes, using the solder method, all the way at the tip im .54mm, then about .5mm in from there im 1.2mm im guessing that is because of the 50mm head... should i get the head milled?? or i can add another base gasket, will shorten port durations and lower compression more. any ideas?? just when i thought i was gettin some where...

[bakaracer]

ok so your at 1.65mm of base gaskets and 2 head gaskets right?

[guen84]

ok so your at 1.65mm of base gaskets and 2 head gaskets right?

yup thats correct...

[bakaracer]

so with the 1.65mm of base gaskets, the piston is flush or above the deck of the cylinder?

[guen84]

[quote="bakaracer"]so with the 1.65mm of base gaskets, the piston is flush or above the deck of the cylinder?[/quote

its flush.. but maybe not so flush when torqued down..

[bakaracer]

if the edge of the piston is below the deck of the cylinder then with the 2 head gaskets, your squish will be around .8mm or higher

[guen84]

heres my problem if you look at the very tip, the squish is very small like .62mm hard to measure, then goes to 1mm

IMG_20110725_161311 (320x240).jpg (68.76 KiB) Viewed 4531 times

[bakaracer]

out at the edge is where you should be measuring. ok so that means that the edge of the piston is past the deck. 2 head gaskets together is about .8mm thick. if your squish right now is at .6mm and your only getting about 110psi of compression, something esle is going on. a squish that tight will be up in the 180psi range with a mini stroke crank and 50mm bore

[guen84]

out at the edge is where you should be measuring. ok so that means that the edge of the piston is past the deck. 2 head gaskets together is about .8mm thick. if your squish right now is at .6mm and your only getting about 110psi of compression, something esle is going on. a squish that tight will be up in the 180psi range with a mini stroke crank and 50mm bore

ok well back at it then... ill take the head off tomorrow and see exactly where im at, ya know after you take the cylinder on and off 30 times with every possible gasket combo i might have been mistaken on the cylinder deck height..

[bakaracer]

note what base gasket thickness,deck height and the port durations are. also measure the diameter of the head area and make sure its not smaller than 49.5mm

[guen84]

note what base gasket thickness,deck height and the port durations are. also measure the diameter of the head area and make sure its not smaller than 49.5mm

ok heres what i got, base gaskets 1.65mm, 2 head gaskets =.95mm, intake 132 deg, exhaust 180 deg, piston rises bout .5mm past deck when i spin crank and compression is 120, squish is hard to measure but looks like .60mm area, cylinder height is 67.95mm... head bore diameter looks like 50mm aslo hard to measure...