To Lap or Not To Lap, That is my question |
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To Lap or Not To Lap, That is my question |
Allan |
Nov 6 2004, 06:49 PM
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#1
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Teenerless Weenie Group: Members Posts: 8,373 Joined: 5-July 04 From: Western Mesopotamia Member No.: 2,304 Region Association: Southern California |
Just got my heads back from Rimco and bought a new set of Mahle p/c's. Do the cylinders still need to be lapped? (IMG:style_emoticons/default/confused24.gif)
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JoeSharpOld |
Nov 6 2004, 06:52 PM
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#2
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Does it seem cold to you Group: Members Posts: 361 Joined: 29-April 04 From: Camping in Neverland Member No.: 2,001 |
Allan: I don't do it. Do you have your cast off yet?
Joe |
Allan |
Nov 6 2004, 06:54 PM
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#3
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Teenerless Weenie Group: Members Posts: 8,373 Joined: 5-July 04 From: Western Mesopotamia Member No.: 2,304 Region Association: Southern California |
Yep, I made then take it off after 2 weeks because it started to smell like rotting meat. I think it got wet from being out in the rain. Once they got it off I talked the doctor into putting me in a cam walker that I can take off to shower and sleep.
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skline |
Nov 6 2004, 07:38 PM
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#4
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Born to Drive Group: Members Posts: 7,910 Joined: 26-December 02 From: Costa Mesa, CA Member No.: 17 Region Association: Southern California |
Your choices are simple, install using the factory head gasket or lap them in. I would lap them in to be sure of a good seal. If you dont, any kind of imperfection could turn to a burned head or cylinder, most likely, the head.
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newdeal2 |
Nov 6 2004, 07:49 PM
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#5
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Unregistered |
This is how I lapped mine [per a Porsche mechanic]
Apply valve grinding compound to the end of the cylinder, place it into the head and with even pressure rotate the cylinder back and forth a few times. Make sure you wash the residue of of the surfaces when done and keep each lapped cylinder in the same location on the head. DO NOT install the gaskets , they will leak. |
newdeal2 |
Nov 6 2004, 07:52 PM
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#6
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Unregistered |
Oh, by the way....do install the metal gaskets on the case side and use a case sealer.
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Joe Ricard |
Nov 6 2004, 08:01 PM
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#7
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CUMONIWANNARACEU Group: Members Posts: 6,811 Joined: 5-January 03 From: Gautier, MS Member No.: 92 |
Lapped the used cylinders to used heads 1.7L engine. Ran living piss out of it hours of Freeway travel near 4000 RPM and then Autocross it banging the rev limiter. Got it hot ran t more. When I pulled the motor apart the heads showed evidence of a perfect seal.
LAP THEM it is easy and well worth it. I also did not use a head gasket or base shim. The compression ratio was just a little higher (IMG:style_emoticons/default/rolleyes.gif) |
skline |
Nov 6 2004, 08:05 PM
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#8
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Born to Drive Group: Members Posts: 7,910 Joined: 26-December 02 From: Costa Mesa, CA Member No.: 17 Region Association: Southern California |
(IMG:style_emoticons/default/agree.gif) I dont use a base gasket either but did put some sealer on it. Otherwise, it will leak eventually.
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Joe Ricard |
Nov 6 2004, 08:14 PM
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#9
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CUMONIWANNARACEU Group: Members Posts: 6,811 Joined: 5-January 03 From: Gautier, MS Member No.: 92 |
All depends on the deck hieght. and the compression ratio you desire. Maybe you could put some stupid big ass copper rings inbetween the head and cylinder, Oh and make sure the ring is an 1/8 th inch smaller the the head diameter.
Oh sorry that is what the P.O. did to the project engine. Can you imagine the leaky head this thing had. one side of the ring was completely burnt. |
newdeal2 |
Nov 6 2004, 08:28 PM
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#10
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Unregistered |
I used the base gasket w/sealer per Jake's video. I didn't think that what, .006 or so of gasket would add much compression and I am using flat top pistons and a Webcam so life will be good...if I didn't screw anything up internally that is (IMG:style_emoticons/default/wacko.gif)
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Elliot_Cannon |
Nov 6 2004, 09:18 PM
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#11
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Senior Member Group: Retired Members Posts: 1,922 Joined: 26-March 03 From: Orange County Ca Member No.: 480 Region Association: None |
Put the cylinder in the head and rotate it back and forth for 2 minutes. Turn it 90 degrees and rotate it for 2 more minutes turn another 90 degrees etc. etc. Very important to get ALL the valve grinding compound cleaned off the cylinder and head surfaces. This method takes awhile and is very tedious but insures a good seal.
Cheers, Elliot |
Allan |
Nov 6 2004, 09:40 PM
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#12
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Teenerless Weenie Group: Members Posts: 8,373 Joined: 5-July 04 From: Western Mesopotamia Member No.: 2,304 Region Association: Southern California |
Something that I should probably know but don't is, does it matter which cylinder goes where. They all look the same to me.
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newdeal2 |
Nov 6 2004, 09:46 PM
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#13
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Unregistered |
They all have a flat side [finned area] that faces in and the piston arrow should point towards the flywheel. Do the number 4 cylinder first so you can get the circlips in and work your way around.
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Allan |
Nov 6 2004, 09:55 PM
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#14
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Teenerless Weenie Group: Members Posts: 8,373 Joined: 5-July 04 From: Western Mesopotamia Member No.: 2,304 Region Association: Southern California |
So it dosn't matter which cylinder goes where?
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newdeal2 |
Nov 6 2004, 10:06 PM
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#15
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Unregistered |
No. But keep the piston with it's cylinder. By the way...follow the last suggestion on lapping. I didn't take that much time but it's probably better to go the whole 360 as he described.
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Allan |
Nov 6 2004, 11:50 PM
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#16
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Teenerless Weenie Group: Members Posts: 8,373 Joined: 5-July 04 From: Western Mesopotamia Member No.: 2,304 Region Association: Southern California |
Thanks guys. You have been really helpful. Now as soon as the bearings get here it's time to put it all together.
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