I have done several NWP Big Bore conversions. This is my first OEM Mahle. This steel head gasket is crimped and has got a hump. I am assuming the gasket is installed with the hump up.
6401 to 7901 Crimped Steel Head Gasket (Assuming Hump Goes Up?)
- Thread starter JimmyT
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mtngun
Addicted to ArboristSite
No experience with the 7901 OEM gasket, but the IPL shows it having a tab on one side only. The tab should point toward the muffler. Is that what you mean ?
Not the Tab
Mtngun, the oem steel gaskets are crimped, one side has a ridge or a hump running all the way around the inner edge of the gasket and the other side has an indention.
Mtngun, the oem steel gaskets are crimped, one side has a ridge or a hump running all the way around the inner edge of the gasket and the other side has an indention.
I have a dolmar 7900 repair manual dated from 2005 and it shows the tab in the pic towards the exhaust, but says nothing about a crimp or indentation. It just says to use a new gasket and gives the part #.
Crimped Gasket
Aftermarket gaskets are flat on both sides and the tab is inslalled toward the exhaust port or muffler. These oem steel gaskets have a ridge running all the way around the perimeter of the gasket on the inner edge and they are not marked for top.
Aftermarket gaskets are flat on both sides and the tab is inslalled toward the exhaust port or muffler. These oem steel gaskets have a ridge running all the way around the perimeter of the gasket on the inner edge and they are not marked for top.
Dolmar 965-531-160
I ordered the Dolmar OEM gaskets from Kyle at Edge and Engine maybe he knows.
I ordered the Dolmar OEM gaskets from Kyle at Edge and Engine maybe he knows.
That is the part # on the ipl that I have for the gasket yet the repair manual shows 965 531 121 which is a good number according to E & E website. :msp_confused:
Stihl-Pioneer, I got a 50-50 chance of installing it upside down.
Is there a way to see which way it is when assembled? I could check my 7900 later for you. Taking the wife out right know for her birthday for dinner. I will check back in later.
It came with a flat fiber gasket with no ridges.
IthacaMan
ArboristSite Operative
I recently did the oem 79cc on my saw.My parts were from E&E.I know what you mean about the gasket looking humped or bowed up on one side.I think it is from when thy are stamped out the metal becomes bent slightly.I snaped mine onto the base of the cylinder before I started it onto the piston.
IthacaMan, These gaskets are punched out at the factory but they are also crimped for some reason. Thanks for your input.
eichen323
ArboristSite Operative
I'm in the process of the same upgrade and the only reason I found the answer is because I discovered a tear in the rubber intake boot. While looking up the part # in the most revised IPL (I got mine from the Makita website) There are Tech Bulletins on all the updated parts. The crimp faces up and the "hump" points to the exhaust.
TECHNICAL INFORMATION 2008/03
2008-03M Cylinder gasket DCS7900_GB.doc, 25.03.08, Page 1 / 1
Subject Metal base gasket with circular crimping
For Models DCS6400, DCS6400H, DCS6401, DCS6401H, DCS7300, DCS7300H,
DCS7301, DCS7301H, DCS7900, DCS7900H, DCS7901, DCS7901H
Country Worldwide
Description The material of the cylinder base gasket has been changed from paper
to a metal gasket with circular crimping.
CURRENT NEW
paper gasket
965.531.121
metal base gasket
965.531.160
Interchangability (I/C)
Old part Description I/C New part Description
965.531.121 Paper gasket Yes 965.531.160 Metal base gasket
Remarks
Fixing position of the cylinder base gasket:
The "nose" of the gasket shows in direction of the exhaust port. The
crimping shows upwards.
Implementation Into serial production from December 2007
Available on stock with immediate effect
This was a cut and paste. Hope it helps.
TECHNICAL INFORMATION 2008/03
2008-03M Cylinder gasket DCS7900_GB.doc, 25.03.08, Page 1 / 1
Subject Metal base gasket with circular crimping
For Models DCS6400, DCS6400H, DCS6401, DCS6401H, DCS7300, DCS7300H,
DCS7301, DCS7301H, DCS7900, DCS7900H, DCS7901, DCS7901H
Country Worldwide
Description The material of the cylinder base gasket has been changed from paper
to a metal gasket with circular crimping.
CURRENT NEW
paper gasket
965.531.121
metal base gasket
965.531.160
Interchangability (I/C)
Old part Description I/C New part Description
965.531.121 Paper gasket Yes 965.531.160 Metal base gasket
Remarks
Fixing position of the cylinder base gasket:
The "nose" of the gasket shows in direction of the exhaust port. The
crimping shows upwards.
Implementation Into serial production from December 2007
Available on stock with immediate effect
This was a cut and paste. Hope it helps.
mtngun
Addicted to ArboristSite
Excellent info, eichen323. :msp_thumbup:
Right Stuff
eichen323, Your the man, would you consider being the technical guardian for AS. Me and Makita will sleep good tonight knowing that the head is not going to explode when I crank it.
eichen323, Your the man, would you consider being the technical guardian for AS. Me and Makita will sleep good tonight knowing that the head is not going to explode when I crank it.
sawfun9
Addicted to ArboristSite
I had the same question, but figured the embossed hump as you call it, goes up and that worked for me. The original gasket on the 6400 was either paper or asbestos. and was .015 thicker than the new stamped metal one.
sawfun9, I guess it is actually called a crimped ridge. All the other head gaskets that I have installed were flat on each side. I read that Makita and Dolmar started putting these steel gaskets on saws that had 24" or longer bars because they were blowing the fiber gaskets.
My 6400 was ordered from the distributor with a 24" bar but when it came to the dealer, the saw was built with a 20" bar and the distributor had put the 24" bar in the box. It says 20" on the id plate.
eichen323
ArboristSite Operative
I'm hardly qualified for that title but thanks for the faith:msp_tongue:
It's just luck that I came across that info. I'm just glad that I could help.
