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Old 12-14-2010, 12:15 AM   #11 (permalink)
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thanks 1fastxc.this motor does have the shim under the cylinders,doesnt use the storm piston.maybe i will just have the slp heads reworked.when checking squish with the soilder should i be between 60 -65 thousand where is this measurment taken since the squish ring is tapered,then i guess the dome of the head has to be recut also.have a very good machinest here in m.d that can do the work ,but nobody here that can tell me how.lol.thanks for the help
1fastxc is probably right on the xcr heads.I had the stock ones reconfigured to bruces specs as he wanted like 300.00 for the new ones and i thought that was way to pricey at the time.60-65 thou is were you want to be for sure.take the solder and put it down the spark plug hole till it hits the edge of the cylinder wall.then roll motor over and take out and measure with a caliper the very end of the solder. this will tell you your squish.head cc i don't recall the exact number but i will look at my old paper work bruce faxed me to see what he recommended if i still have it.as for your pistons if i recall they are water craft pistons of some sort like 20 over or something.this was the reason they shimed the base. it was to get the cylinder up so the outer edge of the piston didn't travel over the top of the cylinder.it was cheaper to shim than having a company make custom pistons just for that application.
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Old 12-14-2010, 09:38 AM   #12 (permalink)
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I agree I want sure if XCR Cylinders had been used or the Cylinders for the Ultra had been bored.. the XCR Heads won't fit..

as an option to using solder I started using .090 STHL weed wacker thread for checking squish, softer than solder and the weed wacker thread does maintain the squish, a few bumps using the clutch.
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Old 12-14-2010, 11:04 AM   #13 (permalink)
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I agree I want sure if XCR Cylinders had been used or the Cylinders for the Ultra had been bored.. the XCR Heads won't fit..

as an option to using solder I started using .090 STHL weed wacker thread for checking squish, softer than solder and the weed wacker thread does maintain the squish, a few bumps using the clutch.

good idea roger.never thought of that one.do you have to measure right away or does it maintain its shape for quite awhile?
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Old 12-14-2010, 11:15 AM   #14 (permalink)
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It does hold squish quite a while, even days, I measured a couple right after the squish
and the next day nothing changed the squish was the same
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Old 12-14-2010, 06:47 PM   #15 (permalink)
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Why not just send your heads to XCR 1250(Don)? He cuts heads all the time at his shop. He'd be able to set you up. Not like he has anything better to do all day. (LOL)
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Old 12-14-2010, 11:24 PM   #16 (permalink)
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Question SLP heads

Tom Hold off on cutting up those heads!!! I have run into a little snag on my HTG build. I never knew there were so many different combustion chamber designs on these engines, I cc'd every one I had, all over the place. I just had a set cut and hit some bad porosity in two of them, one hole is 1/8" deep, Anyway I am sitting here 1 head short of a set in three different configurations, I have a line on some more stockers, to try again, but this is getting spendy... What are the SLP heads taken out to? I took these to 73.5, ended up with the lower ring pin in the center of the intake port same as the HTG/wiseco, don't like it but willing to give it a try. New pistons fit nice in the freshly bored and honed sleeved cylinders.
Can anyone give me an educated guess on what the timing would be if it was straight on the marks on a 96 case? Ii is set maybe a degree retarded, and thinking about going one or two more... looks like a piston was broke by detonation. any advise? this sled will be run 6000-9000 ft.
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Old 12-15-2010, 08:54 PM   #17 (permalink)
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Tom Hold off on cutting up those heads!!! I have run into a little snag on my HTG build. I never knew there were so many different combustion chamber designs on these engines, I cc'd every one I had, all over the place. I just had a set cut and hit some bad porosity in two of them, one hole is 1/8" deep, Anyway I am sitting here 1 head short of a set in three different configurations, I have a line on some more stockers, to try again, but this is getting spendy... What are the SLP heads taken out to? I took these to 73.5, ended up with the lower ring pin in the center of the intake port same as the HTG/wiseco, don't like it but willing to give it a try. New pistons fit nice in the freshly bored and honed sleeved cylinders.
Can anyone give me an educated guess on what the timing would be if it was straight on the marks on a 96 case? Ii is set maybe a degree retarded, and thinking about going one or two more... looks like a piston was broke by detonation. any advise? this sled will be run 6000-9000 ft.

on the 96 case with timing marks lined up it is 16 degrees btdc at 8600rpms.every pipe manf. for the 96 model recommends timming between 12-14 degrees at 8600 rpms.
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Old 12-19-2010, 11:33 PM   #18 (permalink)
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Default HTG 800 Heads

I just had a set of heads re cut and hit some casting flaws, some I just knocked off the sharp edges, one of the holes was very deep, might drill it out and weld it in, it is within a 1/2" of the sealing surface, afraid it is going to warp, may be looking for another head, I have 4 or 5 extras, but no more like these and no 3 the same to begin with, never knew there were so many configurations, I have one J head that looks pretty loose...
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Old 12-20-2010, 06:13 AM   #19 (permalink)
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I believe the "j" heads are the spx ones. Yes, there are a few different designs for the ultra. I just re-cut a new set myself and i used the "j" heads. The others were too shallow on the bowl for the design i was using.
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Old 12-20-2010, 07:41 AM   #20 (permalink)
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on the 96 case with timing marks lined up it is 16 degrees btdc at 8600rpms.every pipe manf. for the 96 model recommends timming between 12-14 degrees at 8600 rpms.
I believe stock timing for the 96 Ultra was 12 degrees at 8000. This was reported by Dyno Tech in volume 6, number 5

Most pipe manufacturers had to use less timing, unless they reworked the combustion chambers as PSI did in Volume 7, number 1. There, they overbored the cylinders, installed 750 pistons, and reworked the heads to narrow Rotax-like squish bands with "top hat" style combustion chambers. Timing was then set at 14 degs. Finally detonation free on 93 pump fuel.

I owned a new 96 Ultra with Dyno Port pipes, stock 12 deg timing, VF reeds, Boswell TMX flatslides. It ran very well.
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