Author Topic: Dolmar 7900 Porting Info  (Read 3796 times)

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Offline aclarke

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Re: Dolmar 7900 Porting Info
« Reply #150 on: July 06, 2014, 12:54:06 am »
Tim. Any sort of markings on the Raismann Platt jugs?   Taiwan mfg?

Offline 660magnum

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Offline KilliansRedLeo

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Re: Dolmar 7900 Porting Info
« Reply #152 on: July 06, 2014, 08:44:52 am »
Well RP sources stuff from all over the world. That being said, metallurgy is Brazil is some of the best in the world, not to mention Brazil is one of the largest aluminum producers in the world. There are NO marks on any of the components in the kit, has what appears to be a ductile iron ring (black), no split groove though. Decent earless circlips. Only mark on the piston is the EP arrow. Ports are nicely finished, and beveled, exhaust and intake spigots are nice and smooth, no casting flash anywhere. Looks to me to be virgin aluminum, no dark gray recast color to it.

Going to put it on an older Dolmar 7300 and run the snot out of it for this years shop firewood, so we will see what happens.
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Offline KilliansRedLeo

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Re: Dolmar 7900 Porting Info
« Reply #153 on: July 06, 2014, 10:01:23 am »
Adam, take a close look at the port pictures. I looked for bad spots in the plating on the dividers and above the ports but did not observe anything but I don't know exactly what you saw so, was shooting in the dark.

Also the plating and finish is way above that of the only Hutzl (Chinese) jug I have messed with in simple words the Hutzl jug is junk in comparison. Take a look at the squish band area on the Greek (for want of a better name) IMO it is on a par with what I see from Mahle on the new OEM cylinder I have.

I can't speak accurately of who made this jug but it is WAAAAY better than any of the other no-name stuff I've seen.
"When the people fear the government...you have tyranny....When the government fears the people....you have liberty"

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Offline Cut4fun .

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Re: Dolmar 7900 Porting Info
« Reply #154 on: July 06, 2014, 10:15:43 am »
Tim for the  nice full wrap 372   http://www.prosafetyproducts.com/Products.html
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Offline farmboy

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Re: Dolmar 7900 Porting Info
« Reply #155 on: July 06, 2014, 12:10:10 pm »
Yeah I was trying to figure out how to get the hole in the right place. I'll go with a plug!
There was an indentation in my 665 cyl cover where the side decomp would be.  Cut it out looks like it came that way.  Had to put a brass washer on the Husky decomp it bottomed out before it tightened up in the 7900 cyl.  I didn't try the Solo top decomp my deep well wouldn't go down deep enough to remove it.  KRL is getting it in the 665 cyl.
Shep

Offline aclarke

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Re: Dolmar 7900 Porting Info
« Reply #156 on: July 06, 2014, 02:42:34 pm »
Tim, you are correct.  The small chromed area between the two transfer had a small horizontal line in the plating.  I polished it out with a craytex wheel and all is fine.  I looks to me as though there was a low spot there prior to plating.  I noticed the squish "band" is only on the back half of the jug (intake side) this creates an area of higher squish velocity on the back side and poor squish velocity towards the exhaust.  Not ideal but it could be machined or improved with some sand paper on a mandrel.  Or just left!!! Lol.    I'll post a pic of the piston shortly

Offline aclarke

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Re: Dolmar 7900 Porting Info
« Reply #157 on: July 06, 2014, 03:05:22 pm »
piston from the AM 7900 jug.  Proper squish band would likely create a more complete burn if it was cut evenly. weird step on intake side   Whats yours look like Tim?

 



Offline KilliansRedLeo

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Re: Dolmar 7900 Porting Info
« Reply #158 on: July 06, 2014, 03:55:54 pm »
Adam, do you want to know what the squish band looks like or the piston. Don't have any after being run pictures because kit is not on a saw yet.
"When the people fear the government...you have tyranny....When the government fears the people....you have liberty"

Thomas Jefferson
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Offline aclarke

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Re: Dolmar 7900 Porting Info
« Reply #159 on: July 06, 2014, 11:04:48 pm »
Tim, I'll look at your cylinder pic again, but my cyl. has crescent shaped band on the FRONT of the squish band.  Kinda odd... Never seen that but it looks like it may be machined in?

 

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