Unless your trying to ruin someones elses build - then it would be very deceiving.
L98 Heads
Le Mans Master
Joined: Jun 2004
Posts: 6,231
Likes: 65
From: Seattle WA
St. Jude Donor '14
*sigh* What you're missing out of simple unwillingness to read and learn is that we're not talking about MLS gaskets...we're talking about rubber-coated MLS gaskets which are completely different and far more tolerant of a higher Ra. They'll seal to just about any deck. I'm curious - did you even READ the PDF you posted regarding the Fel-Pro rubber-coated MLS gaskets? They state exactly what I've been saying:
"Traditional OEM type MLS head gaskets don't easily conform to surface irregularities and require an incredibly smooth surface to provide a satisfactory seal. But when the castings are old or resurfaced with a less than perfect finish, leaks result. To seal under these adverse conditions, Fel-Pro engineers have developed the exclusive PermaTorqueMLS design." They conservatively state 60 Ra, but I've used these and similar types of gaskets regularly and consistently with no issues at all - my recommendations are always based on personal experience.
As an aside, people do "tops" of stock blocks with aluminum heads all the time. The 1094 gasket is pretty much the industry standard for tops, since it provides ideal quench with the typical .020 - .025 deck height found in stock GEN Is.
The concepts your trying to put forward just aren't based in experience, fact or common practice... which frankly seems pretty consistent across your posts.
Still waiting for you to tell me how you tried to cc a cylinder bore with the engine in the car!
Last edited by billla; Jan 23, 2012 at 12:15 AM.
Instructor
Joined: Sep 2007
Posts: 198
Likes: 0
From: Colorado Springs Colorado
Here is some good information on what you can do with your L98 heads. It would be over the head of the average DIY'er, but some really great info to share with whoever is working on porting them. However, the author says you can do this at home, with common tools. Good reading if nothing else.
Porting L98 heads
Porting L98 heads
Thread Starter
Safety Car
Joined: Mar 2009
Posts: 3,558
Likes: 4
From: Oakland California
Here is some good information on what you can do with your L98 heads. It would be over the head of the average DIY'er, but some really great info to share with whoever is working on porting them. However, the author says you can do this at home, with common tools. Good reading if nothing else.
Porting L98 heads
Porting L98 heads
. Billa what is this "1094" gasket that you speak of?
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
Here is some good information on what you can do with your L98 heads. It would be over the head of the average DIY'er, but some really great info to share with whoever is working on porting them. However, the author says you can do this at home, with common tools. Good reading if nothing else.
Porting L98 heads
Porting L98 heads
Here is a link to a pretty good price for the 1094 gasket, and it has a little write up/advertisement for the gasket itself, it will give you a general idea what it's all about.
http://www.northernautoparts.com/Pro...tModelId=22765
Scott
Le Mans Master
Joined: Jun 2004
Posts: 6,231
Likes: 65
From: Seattle WA
St. Jude Donor '14
. There's no before/after flow numbers that would validate the work, and IMHO those are places where the work would deliver little genuine value. Cleaning up the bosses is fine, but the next location should have been the short radius of both runners.IMHO, it looks like about 20-30 hours of work for near zero benefit...and one slip of the grinder and you're screwed. Not saying a guy can't port at home, but the information in the article isn't the right place to start.
All just one guy's opinion
Last edited by billla; Jan 22, 2012 at 05:35 PM.
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Thread Starter
Safety Car
Joined: Mar 2009
Posts: 3,558
Likes: 4
From: Oakland California
I went ahead and registered. It's an interesting article, but IMHO there's no reason to register to read it. It centers on cleaning up around the bosses and doing some unshrouding work around the valves - and using a drill press and grinder to create a back-cut on the valves - seriously? . There's no before/after flow numbers that would validate the work, and IMHO those are places where the work would deliver little genuine value. Cleaning up the bosses is fine, but the next location should have been the short radius of both runners.
IMHO, it looks like about 20-30 hours of work for near zero benefit...and one slip of the grinder and you're screwed. Not saying a guy can't port at home, but the information in the article isn't the right place to start.
All just one guy's opinion
. There's no before/after flow numbers that would validate the work, and IMHO those are places where the work would deliver little genuine value. Cleaning up the bosses is fine, but the next location should have been the short radius of both runners.IMHO, it looks like about 20-30 hours of work for near zero benefit...and one slip of the grinder and you're screwed. Not saying a guy can't port at home, but the information in the article isn't the right place to start.
All just one guy's opinion
I was taking a look at the 1094 gasket, but it's 4.100in. so it won'y work with a standard bore block. I've checked Summitracing and jegs, but haven't been able to find one for a standard bore 350. Do you guys know of anything similar that I can use?
Drifting
Joined: Aug 2005
Posts: 1,682
Likes: 3
From: League City TX
That gasket will work just fine.
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
The Valve back-cut was also a surprise to me. That is pretty much all it is(what Billa stated).
I was taking a look at the 1094 gasket, but it's 4.100in. so it won'y work with a standard bore block. I've checked Summitracing and jegs, but haven't been able to find one for a standard bore 350. Do you guys know of anything similar that I can use?
I was taking a look at the 1094 gasket, but it's 4.100in. so it won'y work with a standard bore block. I've checked Summitracing and jegs, but haven't been able to find one for a standard bore 350. Do you guys know of anything similar that I can use?
Scott
Le Mans Master
Joined: Aug 2008
Posts: 5,578
Likes: 61
From: Austin TX
I went ahead and registered. It's an interesting article, but IMHO there's no reason to register to read it. It centers on cleaning up around the bosses and doing some unshrouding work around the valves - and using a drill press and grinder to create a back-cut on the valves - seriously? . There's no before/after flow numbers that would validate the work, and IMHO those are places where the work would deliver little genuine value. Cleaning up the bosses is fine, but the next location should have been the short radius of both runners.
IMHO, it looks like about 20-30 hours of work for near zero benefit...and one slip of the grinder and you're screwed. Not saying a guy can't port at home, but the information in the article isn't the right place to start.
All just one guy's opinion
. There's no before/after flow numbers that would validate the work, and IMHO those are places where the work would deliver little genuine value. Cleaning up the bosses is fine, but the next location should have been the short radius of both runners.IMHO, it looks like about 20-30 hours of work for near zero benefit...and one slip of the grinder and you're screwed. Not saying a guy can't port at home, but the information in the article isn't the right place to start.
All just one guy's opinion
Thread Starter
Safety Car
Joined: Mar 2009
Posts: 3,558
Likes: 4
From: Oakland California
Sounds good, but now the only things that will worry me is the compression ratio. What do you guys think? I might give it a try depending on the Compression ratio. Would it put me in the 11s?
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
Here is a link that does a pretty good job of explaining Dynamic Compression Ratio, which is what's really important. At the bottom of the page is a link to a really good compression ratio calculator. Download it, install it, and monkey around with it. If you have any trouble, give us a shout.
http://cochise.uia.net/pkelley2/DynamicCR.html
Scott
http://cochise.uia.net/pkelley2/DynamicCR.html
Scott
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
That gasket is .051 compressed thickness. Combined with a piston .025 in the hole gives you .076 quench. Your better off using a .015 rubber coated steel shim gasket. This will increase compression but the .040 quench will offset the compession increase in reguard to detonation resistance. Check existing piston to deck clearance.
http://www.summitracing.com/parts/FEL-1094/
Edit . Found piston volume -3.5 CC
Calculated compression. using -3.5 volume for piston, .025 in hole, 4.100 gasket bore, 4.0 bore, 5.7 rod 3.48 stroke, comes up 10.2 to 1 with .051 gasket and 11.2 to 1 with .015 shim. Both are trouble. Disregard my post above. Look for different heads.
http://www.summitracing.com/parts/FEL-1094/
Edit . Found piston volume -3.5 CC
Calculated compression. using -3.5 volume for piston, .025 in hole, 4.100 gasket bore, 4.0 bore, 5.7 rod 3.48 stroke, comes up 10.2 to 1 with .051 gasket and 11.2 to 1 with .015 shim. Both are trouble. Disregard my post above. Look for different heads.
Drifting
Joined: Aug 2005
Posts: 1,682
Likes: 3
From: League City TX
There is a gasket offered by Clevite that is .026" thick. http://www.summitracing.com/parts/CLE-5746/
You would end up with a quench distance around .050", which is a bit wide but not too horrible.
That gasket would get your compression down to roughly 10.9:1.
Between the aluminum heads and the long camshaft seat duration you could possibly get that to run OK.
Also, since you plan to have your combustion chambers polished anyway, a couple of cc's of metal removed from the chambers would put you at roughly 10.6:1.
I would be pretty confident that you could live with that on pump gas.
You would end up with a quench distance around .050", which is a bit wide but not too horrible.
That gasket would get your compression down to roughly 10.9:1.
Between the aluminum heads and the long camshaft seat duration you could possibly get that to run OK.
Also, since you plan to have your combustion chambers polished anyway, a couple of cc's of metal removed from the chambers would put you at roughly 10.6:1.
I would be pretty confident that you could live with that on pump gas.
Le Mans Master
Joined: Jun 2004
Posts: 6,231
Likes: 65
From: Seattle WA
St. Jude Donor '14
You keep hitting the same rock - which is the heads aren't right for the application. There are a lot of tweaks you can use to make a force fit, but they're all compromises and there's no way I can see to ensure everything works. My guidance is still to dump 'em before you toss even more good money after bad.
Thread Starter
Safety Car
Joined: Mar 2009
Posts: 3,558
Likes: 4
From: Oakland California
You keep hitting the same rock - which is the heads aren't right for the application. There are a lot of tweaks you can use to make a force fit, but they're all compromises and there's no way I can see to ensure everything works. My guidance is still to dump 'em before you toss even more good money after bad.
Le Mans Master
Joined: Jun 2004
Posts: 6,231
Likes: 65
From: Seattle WA
St. Jude Donor '14
I know. I was thinking about selling my 300Z to finance an LS swap and just daily drive the Vette. I'm putting together a plan to do so and, probably just sell these heads, and whatever I have left over. I'm gathering up the info for the swap, and have been reading the threads on the topic. I'm thinking about an LS1 and T56.
A set of E-Streets or iron heads would add power and be a cheap swap.Daily driving a C3 can get interesting unless it's in tip-top shape throughout...