Increase Compression Ratio/Eliminate Head Gasket
- Thread starter Russ2251
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Russ2251
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Did you not read 1st post?
for what that wont ever work for a head gasket.
sideways
Unfinished projects king.
That's what Russ recommends, I have my doubts too but its possible, many small engines use the same stuff for bottom ends and so on.
Thanks
Hayden
#28 FASTGRASS
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Or as an alternative...see you local cemetary grounds keeper / person / funeral home who looks after the final resting place's and see if you can get you hands on a piece of ground & polished hard granite headstone, or dress stone which has been broken or otherwise no longer needed, this will do the trick and is more than flat enough for lapping.......(the thicker the better)
Note: Highly recommend and concur with Russ's methodology here, esp. if you get some flat granite from the cemetary DO-NOT lapp in a 666 motion the engine beast may come out
(and nor will it be flat!) the only advise I could add would be to gently file off any burrs with a millsaw or flat bastard file first that should help speed things up too.GOOD POST RUSS!
OzFab
New member
Yeah, that's not a good idea, you can actually do more damage doing that.
1. Carbon build up is what causes preignition or detonation. The carbon heats up to create a false ignition source.
2. If the carbon weakens, it can cause a hole on the casting
1. Carbon build up is what causes preignition or detonation. The carbon heats up to create a false ignition source.
2. If the carbon weakens, it can cause a hole on the casting
Thanks for telling me that, it hasnt caused trouble for me yet on any of the egines i have taken the head gastkets off of yet. I had probably better fix a few things on them then lol
Russ2251
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Post #1 links updated (7/26/13).
Just an FYI for the guys that were talking about valve lapping. The practice is no longer done because of using an interference angle of 1° between the seat and the valve. What this does is let the valve and seat perfectly seal after the engine has run. It is a better way to do it and that might be why they don't lap. But I would think they should have been able to explain that to you.
Russ2251
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Out of the thousands of 4-cycle anchors that have passed over my workbench, only a handful benefited from lapping.
Doc Sprocket
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This really is proving to be an eye-opener. Today, I am trying this for the first time, on a 28 CID Briggs L-head vertical. The head looked pretty good with a known straightedge. Yeah... Right!
I managed to lay hands on a slab of granite from a custom stone work place I did some renovations in, and finally decided to give this a shot.
For a head that looked straight, it sure wasn't. I've been working feverishly to flatten the whole thing out. The gasket surface surrounding the intake valve area was all "low" and is taking me awhile to work out. With a good head gasket, this engine had no issues. I can see now that eliminating the gasket, or simply using a thin copper one would have been a failure.
Maybe I'll put up a couple pics later. For now, still working away at it...
EDIT- Head's done, block, too. The block went more quickly- which is merciful because it was pretty awkward and required some effort to hold down flat against the drag of the grease and grit while shakin' may moneymaker.
I managed to lay hands on a slab of granite from a custom stone work place I did some renovations in, and finally decided to give this a shot.
For a head that looked straight, it sure wasn't. I've been working feverishly to flatten the whole thing out. The gasket surface surrounding the intake valve area was all "low" and is taking me awhile to work out. With a good head gasket, this engine had no issues. I can see now that eliminating the gasket, or simply using a thin copper one would have been a failure.
Maybe I'll put up a couple pics later. For now, still working away at it...
EDIT- Head's done, block, too. The block went more quickly- which is merciful because it was pretty awkward and required some effort to hold down flat against the drag of the grease and grit while shakin' may moneymaker.
At least you're trying to eliminate your head gasket.... I just popped the head off of an old Lifan 2.8hp I'm rebuilding, and there was no head gasket present. No evidence of gasket solution or anything, heh. It's not flat either, but there is a crap ton of carbon on top of the piston head/intake valve/combustion chamber. Guess I broke that "carbon seal" when I popped the head
Sorry... back to topic.
Sent from my XT1060 using Tapatalk
Sorry... back to topic.
Sent from my XT1060 using Tapatalk
Doc Sprocket
*********
I had a bugger of a time trying to photograph this: the flash kept washing it out. This pic is before completion. Look closely around the intake valve area (around the plug boss) and you can just make out the warp that gave me such a hard time. Also shown is the block.
Attachments
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head.jpg -
block.jpg
OzFab
New member
You're not gonna want to hear this but, maybe you should've cleaned off the carbon buildup before sanding, a bit like porting before cutting valve seats; you now risk damaging the flat surface while cleaning out the carbon...
I see the area you're referring to, at the end of the head between the top & centre bolt holes
I see the area you're referring to, at the end of the head between the top & centre bolt holes
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