FWIW 1.3mm might be a bit thick for our needs. We really need to get a piston in an engine to check the setup height. Then the gasket thickness can be determined. Granted 95% of the setups will not really matter just what the squish area turns out to be but it would be nice to have it right.
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Old Colt
Originally posted by Nessism View Post
FWIW 1.3mm might be a bit thick for our needs. We really need to get a piston in an engine to check the setup height. Then the gasket thickness can be determined. Granted 95% of the setups will not really matter just what the squish area turns out to be but it would be nice to have it right.
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I can get an OEM 650 gasket shipped off to Thailand asap & wait until after we have all received our pistons to order the MLS I suppose. We can have Mike sell the 25 year old Wiseco NOS gaskets to those who don't care enough to wait for a piston-in-hole deck height measurement. I generally always mill a skim coat off of the deck and the head to ensure trueness and an excellent mating surface, so 1.3mm may not be bad. The compressed thickness will be slightly less, fwiw.
Old Colt, I was hoping you would chime in a good bit on head gasket technical specifications, thank you. Please voice any other concerns or suggestions you have.
I could also send dimensions to Cometic for a composite quote, but I think they are around $80 each for a small batch if I recall correctly from forum posts from here a few years ago.'77 GS750 920cc heavily modded
'97 Kawasaki KDX220R rugged terrain ripper!
'99 Kawasaki KDX220R rebuild in progress
'79 GS425 stock
PROJECTS:
'77 Suzuki PE250 woods racer
'77 GS550 740cc major mods
'77 GS400 489cc racer build
'76 Rickman CR1000 GS1000/1100
'78 GS1000C/1100
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Old Colt
It would be nice to get a clay imprint between the head and piston just to see what the chamber looks like at TDC and what the true squish is.
At an estimate of $80 for Cometic the Gaskets to go might be very competitive, might be damn nice gaskets too and for me much less work than making an O-ringed copper gasket.
I am thinking I should get my azz in gear and assemble the bottom end of this motor. I am thinking I am glad I never contoured the chambers to fit the OEM 750 pistons.
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Here ya go!
Originally posted by John @ GasketsToGo.comHi Chuck,
Cost to make your gasket as a 1.3 or 1.4mm MLS head gasket would be as follows:
1-4 pcs: $119.95/ea.
5+ pcs: $79.95/ea.
Lead time is 3-4 weeks at the moment.
We can work from a scale scan you make (more info: www.gasketstogo.com/scans)
Or you can send your pattern to me (www.gasketstogo.com/mailing)
If you decide to order I would send you a PayPal invoice you can pay by credit card once we are ready to proceed.
I will attach an info sheet for MLS gaskets to this message.
Regards,
John
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Regards,
John M. Baker
Owner
In my hot rod/musclecar days with my GTO fanatic dad, I had learned in that community that in a water cooled small block chevy v8, .039"-.045" quench height was preferred to keep you clear of detonation concerns. Could be that these air cooled engines that run much hotter (270 degrees vs 210 water cooled) need more quench/squish band height due to different operating parameters? Heat of compression and latent heat combined is what causes detonation (like how a diesel operates intentionally).
I will research this more.'77 GS750 920cc heavily modded
'97 Kawasaki KDX220R rugged terrain ripper!
'99 Kawasaki KDX220R rebuild in progress
'79 GS425 stock
PROJECTS:
'77 Suzuki PE250 woods racer
'77 GS550 740cc major mods
'77 GS400 489cc racer build
'76 Rickman CR1000 GS1000/1100
'78 GS1000C/1100
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Old Colt
The engines I build which are considerably smaller than that old big iron are run considerably tighter clearance. Common practice is around 0.030 clearance. Most of my engines are in the 0.015 to .020 range.
With this piston setup the clearance up in the chamber needs to be checked as well as the outer squish area.
Those prices are good. Obviously there are other costs involved such as shipping in and out.
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Ace07
Yeah those prices for those gaskets sound good to me. I have heard anything back from wiseco. I called them Friday and found out my contact, Ale, is gone until Tuesday. I always hate waiting. Ha ha ha
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Originally posted by Chuck78 View PostCould be that these air cooled engines that run much hotter (270 degrees vs 210 water cooled) need more quench/squish band height due to different operating parameters? Heat of compression and latent heat combined is what causes detonation (like how a diesel operates intentionally).
I will research this more.
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Ace07
Hey guys I think I messed up on grinding out my top case to make the 650 cyclinders fit. I was dumb enough to grind part of the case where the crank sits. If I found in half way will the case still work? I am such an idiot sometimes. I cut about a quarter into it.
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Forum LongTimerGSResource Superstar
Past Site Supporter
Super Site Supporter- Mar 2006
- 35583
- Torrance, CA
Post some good photos. Use photobucket or similar and post up the IMG code. Hopefully it's not too bad.Ed
To measure is to know.
Mikuni O-ring Kits For Sale...https://www.thegsresources.com/_foru...ts#post1703182
Top Newbie Mistakes thread...http://www.thegsresources.com/_forum...d.php?t=171846
Carb rebuild tutorial...https://gsarchive.bwringer.com/mtsac...d_Tutorial.pdf
KZ750E Rebuild Thread...http://www.thegsresources.com/_forum...0-Resurrection
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Ace07
I have never used photo bucket before, but I am sure it is not to hard. I will try to post some pictures. I just can't believe I did something that stupid. It was just one of those days for me
I also found some hair line cracks.
so I will probably just order a different caseLast edited by Guest; 06-19-2016, 12:21 AM.
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Originally posted by Ace07 View PostI have never used photo bucket before, but I am sure it is not to hard. I will try to post some pictures. I just can't believe I did something that stupid. It was just one of those days for me
I also found some hair line cracks.
so I will probably just order a different case
Last edited by Charlie G; 06-19-2016, 02:08 AM.sigpic
83 GS1100g
2006 Triumph Sprint ST 1050
Ohhhh!........Torque sweet Temptress.........always whispering.... a murmuring Siren
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Old Colt
That will not hurt the engine. The lines you point to are casting flow, not cracks. You did grind one bearing saddle in pretty deep though.
Doing this type of work you are much better off to do trial assemblies and let the parts talk as to what is needed to be done. The areas you ground, neither the pistons nor the cylinders go there.
On my engine case the 650 cylinders fit, tightly but they fit the 550 case. I did clean up some casting flash a bit so the cylinders set down easier is all mine needed.
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Originally posted by Old Colt View PostThat will not hurt the engine. The lines you point to are casting flow, not cracks. You did grind one bearing saddle in pretty deep though.
Doing this type of work you are much better off to do trial assemblies and let the parts talk as to what is needed to be done. The areas you ground, neither the pistons nor the cylinders go there.
On my engine case the 650 cylinders fit, tightly but they fit the 550 case. I did clean up some casting flash a bit so the cylinders set down easier is all mine needed.
The "cracks" are just casting lines as said. Not cracks at all.Last edited by Chuck78; 07-03-2016, 09:24 AM.'77 GS750 920cc heavily modded
'97 Kawasaki KDX220R rugged terrain ripper!
'99 Kawasaki KDX220R rebuild in progress
'79 GS425 stock
PROJECTS:
'77 Suzuki PE250 woods racer
'77 GS550 740cc major mods
'77 GS400 489cc racer build
'76 Rickman CR1000 GS1000/1100
'78 GS1000C/1100
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Since it's a roller bearing engine I would agree it's OK, I might be concerned if it was going to be a highly stressed engine abused in racing or something but I bet for normal use it will be OK. Hell it's probably OK anyway, the 550s are extremely overbuilt, as indestructible as any engine ever made.
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Originally posted by Old Colt View Post
On my engine case the 650 cylinders fit, tightly but they fit the 550 case. I did clean up some casting flash a bit so the cylinders set down easier is all mine needed.
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