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Christmas Build, 3.2 Short Stroke, 10.1 CR. — 10.4 CR and twin Plug
After some misinformation and insistence from Total seal rings that they gave me the right rings, I noticed scratches in my cylinders during my last build. Ian and I went to total seal with the rings and cylinders and pointed out that the oil control rings were over by .004” , they insisted they were right and accepted no responsibility for the damage to my cylinder’s. We deglazed the cylinders again and built with Goetze rings. The deglaze ended in a RA of 7 but we still had verticle scraping. After 15,000 miles the engine had unacceptable leak down.
Due to a less than desirable leak down, I'm going a fresh build. Here goes. Crank polished, rods balanced, bearings coated. http://forums.pelicanparts.com/uploa...1735238824.jpg 993 Oil Pump. http://forums.pelicanparts.com/uploa...1735238824.jpg Mahle Pistons and Cylinders sharp edges softened, washed and prepped. http://forums.pelicanparts.com/uploa...1735238824.jpg http://forums.pelicanparts.com/uploa...1735238824.jpg http://forums.pelicanparts.com/uploa...1735238824.jpg |
How are the new ring gaps?
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The oil rings from total seal were out of spec by .004" in the height measurement , undersized, so the rings were cocking in the cylinder , thus scraping and marring the cylinders.
The new MAHLE rings are much better than the last set I installed , last set I had was riddled with many burrs and sharp edges , leading to 4 hours of ring prep. The latest set is much better , all ring gaps came pre set to .0175" and very few burrs. The pistons were standard no prep , valve pocket edges were razor sharp , so round off all edges . Ian |
Ian, we spoke a few times in real life at the hill country ralleye, a real pleasure.
Hope you are doing well! The engine looks nice. I was wondering if you have posted about the prep, you are doing sometime in the past? If not, would you elaborate a bit on the process and materials used to prep? I see a little 3 in 1 oil on the table and what looks like spongy sanding pads. I think I also see some red assembly lube maybe and I notice a bead of 574 I think. edit* I also notice nothing on the webbing as far as case sealant. Hopefully soon I will be at a similar stage, and I would be interested in your thoughts on best practices. Looking forward to seeing the rest of the build. Chris |
Lots of prep so far, measuring everything two or three times making sure that everything is sterile and within spec.
The prep so far has involve polishing, the crank, balancing the rods, cleaning and checking in the case, checking the mating of all gears. 6 hours into piston and cylinders, the pistons get a razor blade scraped on all sharp edges, then smoothed with 220, finished with 600, only the edges are touched up. The pistons and cylinders are washed with a high concentration of dawn dishwashing liquid in super hot water and rinsed completely, then checked with a clean microfiber towel. we’re installing rings now. |
Great info thanks y'all.
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Just the edges of the rings get light touch up to remove the sharp edges around the outer gap opening.
http://forums.pelicanparts.com/uploa...1735319811.jpg |
Rings installed.
Very nice, installed easily, they are perfect. http://forums.pelicanparts.com/uploa...1735321257.jpg |
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Or did you mean even with the deglazing, the vertical scraping was present before you put the Goetze rings in and did the 15000 miles... I'm thinking it was the latter? |
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Mike, after the oil ring scratched the Nicasil liners we ran an 800 grit aluminum oxide Hone and we’re able to do a fairly good job but the scratches still remained. We put the engine together with the understanding it would be less than perfect
That’s not to say that we didn’t add a pinch of hope for the possible outcome |
Great close up of the ring ends thank you for sharing.
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Shane, what did you run in the ultrasonic cleaner? Your parts look nice and clean.
I spray down with Dawn Power Desolver and run PineSol in the ultrasonic.. |
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Cheers |
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This is getting a wee bit confusing.....
ICARP, are you and the OP (snbush67) working on the same motor? What tool are you using to file the end gaps? |
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All rings end gaps were perfect at .0175” so we didn’t file them further, we did lightly smooth the corners with 1000 grit sandpaper. |
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Curious if the hone may have caused premature wear of the rings or if it was the scratches or something else. |
Jeff, yep same engine , softening the the rings with foam block coated with 1000 grit sanding face of black paper. See pic above
The rings must be checked for burrs and sharp edges , attend to all. Leak down should be less than 1% in my book, they were 6%-8% leak down operating temp engine. Scratches from the incorrect ring set from Total Seal was the cause of the poor sealing . The scratches occurred from just turning the engine over by hand while setting the cam timing The pic of the 574 sealant is missing some around the 8mm through bolt like the breather has That line of sealant is enough to cause proper squish out around the whole case I BELIEVE IN NOT ADDING ANY SEALANT ON THE MAIN BEARING BOSS FACE ADDING SEALANT WILL DESTROY PROPER MAIN BEARING CLEARANCE |
Nice project…
Q any specs and or parts changing since you are back in there…? You guys got this…! This will be another eye opener build…! Carry on… |
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I think that this build is going to squeeze everything possible out of a 3.2 short stroke. Increasing CR from 9.8 , Mahle 10.1 CR pistons cylinders. We may be doing dual plugs. The heads are being ported with Icarp specs, Iconel valves, titanium keepers, drilled for dual plugs etc., Keeping the Knightrace75 Camshafts. The main and rod bearings are coated. Rockers faces, cam lobes and other surfaces have been Izumi treated. Keeping the PMO 46’s with 42 Chokes. Keeping the M&K headers and muffler. |
Very nice “tweaks” Shane….!! Thanks for sharing…
I anxiously await how this goes… Go get em’….! |
Did Ian tell you I'm running 200 PSI static compression with the M1 , no problem..
Nikkies cylinders with 9.5 CP pistons without the bottom shim. Deck was -.067 with shim, -.027 without shim. The valve relief cuts left me plenty of room for the M1 cam so I let the shim out. Zoom Zoom |
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The compression test was also done @10ft above sea level ian |
This mornings deck height with base gasket is at -0.047”.http://forums.pelicanparts.com/uploa...1735661346.jpg
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Nice… !
When you get back the heads, can you post pics of where you may of had them tweaked…? Are you staying with carbs? Carry on… Happy New Year to all involved in this Christmas build project… Bob |
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What does "fairly tight in the bore" mean? What were the actual measurements for those and what Pistons/Material?
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These were engines with iron cylinders and cast hypereutectic pistons. 4" bore, clearance .002".
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Better results with .010” base gaskets. - .037”’deck.
http://forums.pelicanparts.com/uploa...1735772455.jpg |
Heads are back.
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Decision time.
.037” deck = 10.47 CR .047” deck = 10.16 CR |
Shane, you're using twin plug heads, right? If so, I would go for the tighter squish--.037". I'm at .030", using Mahle pistons with the Carrera domes on them.
IMO, you get more reduction in tendency to detonation with reduced squish/quench clearance than the increase in CR tends towards detonation (but I wouldn't swear to it, because it also depends on combustion chamber shape). Nevertheless, it's a tight balance. If you have the capability, I would consider shaving the piston dome down a bit to get the CR back to 10:1. David Vizard has some excellent videos on YouTube about quench (he prefers that term), as well as all his other videos. I came across this info initially reading one of his books about 40 years ago, and I have strived to include it in all my types of engine builds since. |
Pete, yes twin plug heads. With the head torqued, deck came out to 0.040”, CR comes in around 10.1.http://forums.pelicanparts.com/uploa...1740270582.jpg
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I went with the .50 mm base gaskets. Pistons and cylinders are clipped in.
http://forums.pelicanparts.com/uploa...1740270706.jpg |
Ring size…
Looks like a great build. I have a similar build pending - early SC heads & CIS, Max Moritz P&C’s, M1 cams, SSI’s, M&K 2/1, etc..
I am having trouble finding Mahle rings for my build (1.2/1.2/3.0) and due to the hit or miss quality of Total Seal and Goetze rings, I’d really like Mahle rings. If your rings are original 1.2/1.2/3.0, where did you find them? Were they NOS? Thanks, Mark |
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I bought the Mahle Motorsports kit, it came with the ring pack. http://forums.pelicanparts.com/uploa...1740350131.jpg |
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