PART #260 head gaskets

[Jim Morris]

what is the PART #260 head gaskets

[Eagle One]

27-814658-75 .75 MM thick gasket

[LARRY D]

The gasket that comes on a stock 260 is 27-814658-1 it is 1mm thick. pro marine has one 27-814658-75 it is .75mm thick. the pro marine gasket will not pass tech in odba or dsra it has to be the merc or promarine 1mm gasket. later Larry D

[Markus]

I thought the 260 used the thinner gasket, while the Drag used the thicker gasket.

[BUZZIN' DOZEN]

I'm pretty sure 1mm was standard 260

[Jay Smith]

The thinner .75MM is standard on all 260 as they have a recessed piston deck height of .004" lower than the deck height. The OEM part number for 260 head gasket is: 27 814656-1..

Now all Drag Motors with garloc gasketed heads( NON "O" RINGERS ) have the 1MM gasket head gasket because its pistons pertrude .004" higher than the deck needing more clearance to keep the piston from contacting the head as rod stretch at high RPMS WILL contact the head if the thinner gasket is used ( I've seen this many times ) Head gasket OEM Part number for the 1MM Drag motor is : 27-822844-1 BTW: This part number is the same as on most all the 2.5 200's too...

These part numbers straight outta da book...

Peace,
Jay

[BUZZIN' DOZEN]

The Pro-Marine catalog shows the 27-822844-1 as 1.2mm and the 27-814658-1 as 1mm:confused:

[Jay Smith]

I'm refering to OEM Mercury parts and their CORRECT numbers ....DUNNO about after market things;)


Jay

[BUZZIN' DOZEN]

<TABLE border=0 cellSpacing=0 cellPadding=10 width="95%" align=center><TBODY><TR><TD height=176 vAlign=top width="100%">Head Gasket - Standard, OE# 27-822844-1
1.2 mm thick
Price
$20
</TD><TD height=176 vAlign=top width="100%">
http://www.brucatosvs.com/L4sm.jpg (http://www.brucatosvs.com/L4.jpg)
click to enlarge (http://www.brucatosvs.com/L4.jpg)
<FORM method=post action=/cgi-bin/quikstore.cgi><INPUT value=html type=hidden name=store_type> <INPUT value=store_gaskets.html type=hidden name=page> <INPUT id="item-L4|20.00|Head Gasket - Standard|NA|2" value=1 size=3 type=hidden name="item-L4|20.00|Head Gasket - Standard|NA|2"> <INPUT border=0 src="http://www.brucatosvs.com/addcart.gif" type=image name=add_to_cart>
</FORM>
</TD></TR><TR><TD height=5 colSpan=2>
http://www.brucatosvs.com/yellowline.gif
</TD></TR><TR><TD height=176 vAlign=top width="100%">
Head Gasket - High Performance (thin), OE# 27-814658-1
1 mm thick
Price
$32
</TD><TD height=176 vAlign=top width="100%">
http://www.brucatosvs.com/HPL1sm.jpg (http://www.brucatosvs.com/HPL1.jpg)
click to enlarge (http://www.brucatosvs.com/HPL1.jpg)

</TD></TR></TBODY></TABLE>

[LARRY D]

Merc drag gasket 27-822844 1. .050 or 1.25mm
Merc extra thick gasket for HP 27-8280322, .060 or 1.5mm
Merc 260 and 225 pro max 27-814658-1, .040 ot 1mm
pro marine very high compression 27-814658-75, 030 or 75mm
the part # can be found on the s3000 parts guide the gasket sizes are on the parts list for the standard drag and the extra thick one. the 260 and 225 one i found on the dealer parts discriiption info. later Larry D

[Jay Smith]

MY Bad ... Been wrong for 14 years always thought the 260 was.75MM

Jay

[BUZZIN' DOZEN]

Jay, I wasn't tryin' to bust your balls there, I KNOW you have forgot more about these motors than I'll ever know,(as per our phone conversations)your actually the first person I ask advice from, just trying to get the right info to the original poster, I doubt the thin gaskets would have caused any grief anyways, Thanks for all your help and the invaluable info you share!!!:cheers:
Jeff

[LARRY D]

Jay, I wasn't tryin' to bust your balls there, I KNOW you have forgot more about these motors than I'll ever know,(as per our phone conversations)your actually the first person I ask advice from, just trying to get the right info to the original poster, I doubt the thin gaskets would have caused any grief anyways, Thanks for all your help and the invaluable info you share!!!:cheers:
JeffSame here, i have a friend that uses the 75mm on his progas- outlaw boat 290 plus lbs compression and never had one fail. later Larry D

[texasvector]

ive researched gaskets and coming up with mixed results .....just like above^^^....

i using a 27-814658-1 gasket with 34cc heads and comp a tad high.....i need to loosen it up a bit.....are the 844r-1M the merc gaskets i need????

thanks

[outasite]

The 844 should loosen you up 3-4 psi, the 1.5mm 5-6. But your squish will increase as well:confused:Just an idea but how about cutting a 2 degree angle on the squish band.It will inhance performance and increase effective cc area.

[texasvector]

I need to measure squish....this motor is fresh gonna try and get a tank through it fri using some 98oct

[eli]

would you still use 1 mm for angle squish or .75

[texasvector]

would you still use 1 mm for angle squish or .75

well im at 155lbs .....so not sure how much u would loose on angle alone??? eli ....you dont run a angle cut head?

[outasite]

The angle would start out @ zero.So it would still be possible to hit the head,right at the top outside edge of the piston.With heads that have been cut to 31-34cc a slight pocket of .010-.015 then a angle cut, will get ya back to a good useable pump gas head.

[texasvector]

I bought these heads to raise comp....was always told 34cc heads would be pump gas safe

my last build I ran c3 heads at 126lbs....wanted a lil more pop with this one

[outasite]

If your block was decked,that may account for some,Wizard pistons seem to be a few thou taller as well.If your ex port was not raised,or has a small radius cranking number will go up slightly.Was talking with a member the other day.He checks his running at idle.Battery,starter,ect will all play into a cranking compression number.

[90 5.0]

I bought these heads to raise comp....was always told 34cc heads would be pump gas safe

my last build I ran c3 heads at 126lbs....wanted a lil more pop with this one

34 is supposed to be 150 on the nose on a standard bore 2.5 with 1.0mm gasket.

Pistons oversised at all? That will raise it some

what are you trying to do with this motor? If class racing at all most classes do not allow angle cut heads.
Mae used to all the time on street cars and classes that would allow it. I know 4cyl vs 2cyl are different but it was always worth it when allowed.

[eli]

well im at 155lbs .....so not sure how much u would loose on angle alone??? eli ....you dont run a angle cut head?

Sorry not angle squish angle after

[texasvector]

34cc fresh cut heads..... 27 814656-1 gaskets.....015+ vertex cross the board.....im gonna break in tomorrow and then check with good gauge

just a river boat....no racing and dont wanna buy av gas everytime out....been thinking about running "aces" as well

[eli]

well im at 155lbs .....so not sure how much u would loose on angle alone??? eli ....you dont run a angle cut head?

Sorry not angle squish angle after