Can you torque a head if using a Cometic MLS gasket more than once?

[deerjoe]

I know this subject has come up before, but I couldn't find it...I'm in the middle of a 95" build, and need to check squish height...I have a new Cometic .030 MLS head gasket, and don't want to ruin it just to torqe the head down to check squish height, but I feel it could be important enough that I will if I have to....buy a new one (choke) to do this.  Has anyone run into this dilemma before, and if so, what was the outcome?  Everything is going well so far,  got the new Torrington inner cam bearings in and the cams changed, getting ready to install the new pistons and bored jugs tomorrow.  I cc'd my Hildreth performance heads out to 83 and 84, just need to install new jugs and pistons to see what height the pistons come up to to see if I need to mill the heads a little or not...going for 9.5 to 1 compression to match up with my SE 203's.  I got a goal for a good squish height from the NHRA site...they recommend .030-.035 squish.  So that's what I'm shooting for.  I'd like to try some Singh grooves as well, and read on here somewhere that that'll probably add at least 1cc to my chamber volume.  Anybody see any flaws in what I've said so far...any advice?  Thanks in advance from a first time twin cam rider....just not as easy as workin on my old shovelheads....j

[Tre_11 FLHX]

Do you still have the old stock gasket?  If so You can use it and subtract the difference. Or no gasket and add the .030-

[GoFast.....]

As far as I know you can Tq them down and reuse them if you do not start the bike, but Most people use a sodering wire. Measure it, place in the piston where the there is no dome with a little vasiline put the head on, turn it over , take the head off and mesure it.

Mike 52 had a great picture of this on the old htt. Mike where are you. HAPPY NEW YEAR TO ALL MY HTT FREINDS

[jsachs1]

Providing you don't put any heat in the motor,YES, you can !!!!
John

[Hillside Motorcycle]

No problems whatsoever on the re-use.
Damn good gaskets.

[Mike52]

As far as I know you can Tq them down and reuse them if you do not turn the bike over but Most people use a sodering wire. Measure it, place in the piston where the there is no dome with a little vasiline put the head on, turn it over , take the head off and mesure it.

Mike 52 had a great picture of this on the old htt. Mike where are you. HAPPY NEW YEAR TO ALL MY HTT FREINDS

Happy New Year to everyone.  Barry, is this the pic you're looking for.

Mike

[attachment removed after 60 days by system]

[Jim Bronson]

When I was doing mine, I tried to find an answer to this question, and they were all over the map. Local HD tech said I should not reuse them, so I installed new for the final assembly. Cometics are metal, so it's probably not necessary to replace if you don't start the bike until you're finished. If I was doing it today, I'd probably reuse them.

[Faast Ed]

I keep a set of used ones in my garage just for that purpose.

[deerjoe]

Thanks a lot for the ideas guys....I just looked at the old gaskets...they separated when I took them off, so I think I'll just trust in other's past experience and install the new MLS gaskets and torque them down but not start up.  I'm pretty far from starting up anyway! ;0   But I'm gettin there....I'm in mid-Missouri, and the weather sucks here right now anyway.  We get a 50 degree day every once in a while, but that usually means rain's comin, too.  I'm just takin my time and trying not to f- this up!  So far so good...  Right now, I'll be happy to just get the "holes" covered back up so nothing crawls in! 

[les]

Joe, I don't quite understand.  If you're concerned about nothing going wrong and you've got all the time in the world then why are you considering reusing head gaskets?  The cost of a set of head gaskets is less than an oil change.

[Faast Ed]

Along that line, (time is on your side), ask around for somebody who has some used ones laying around that they can give to you.

I could not see paying for two sets of gaskets just to measure squish with one set.
Would also feel less than comfortable reusing the new ones, but I'd likely do it if I had no other options.

[Showdog75]

I re-used mine , no problems after 10,000 hard miles .

[Sonny S.]

If it makes ya feel better torque it to 38lbs to measure squish, then 42 final assembly.
I've never done that but does anyone see any problems?

[deerjoe]

les....these Cometic MLS big bore head gaskets are $40.00....that ain't hay to me.  I've time, it's true, but money is another subject...hoping to avoid buying another set.  Thanks for your input, though.  I'd also like to thank Mike for the pic of the solder on the piston....gonna do that.

[GoFast.....]

As far as I know you can Tq them down and reuse them if you do not turn the bike over but Most people use a sodering wire. Measure it, place in the piston where the there is no dome with a little vasiline put the head on, turn it over , take the head off and mesure it.

Mike 52 had a great picture of this on the old htt. Mike where are you. HAPPY NEW YEAR TO ALL MY HTT FREINDS

Happy New Year to everyone.  Barry, is this the pic you're looking for.

Mike

it is Mike, what kind and size where you usein

[hotbo]

as stated by hillside

YOU CAN RE-USE THEM    as long as there is no heat put to them.i have done this several times no problems,call cometic they will tell ya the same thing.they are multi layered metal.hell i have re-used other h.g.s before doing the same thing , no problems just dont heat cycle the gaskets.i hope this helps you.  beyond me why some might think you cant

happy new year fellas.hope to learn more this year with all the good group pf guys on here.be safe.travis

[les]

Of course, if the gasket works then it works.  I think about the crush of the gasket as being the functional element that makes a gasket seal.  Once the crush has happened then there is a possibility that crush can be a one shot deal.

In terms of my point...I'm not saying you "can't".  I'm saying I "won't" in order to be on the safe side.

[Jeffd]

I thought when this came up on the old htt site Cometic said you could torq them down as long as the motor was not run.
That being said I have a new one that I use to check squish that i will send you if you promise to send it back.  You only need one because you do one then the other. 

[Mike52]

As far as I know you can Tq them down and reuse them if you do not turn the bike over but Most people use a sodering wire. Measure it, place in the piston where the there is no dome with a little vasiline put the head on, turn it over , take the head off and mesure it.

Mike 52 had a great picture of this on the old htt. Mike where are you. HAPPY NEW YEAR TO ALL MY HTT FREINDS

Happy New Year to everyone.  Barry, is this the pic you're looking for.

Mike

it is Mike, what kind and size where you usein

Barry, that particular solder is plumber's solder, is .093" thick, you can use whatever kind or thickness as long as the solder is thicker that the measurement you're shooting for.

Regarding using the Cometic gasket after torquing to check squish, the Cometic gasket in my pic was reused in the engine for final assembly, the engine has 10.8 CR and made over 120hp and it's still running strong 2 years later, see Showdog's post. If you want to waste money buying another set of Cometics, or listen to the rocket scientist that know it all, it's up to you, but you've been told numerous times by people who have done it more than once, you can reuse Cometic MLS head gaskets after torquing as long as the engine was not run and heat built up.

Mike

[Faast Ed]

.....or listen to the rocket scientist that know it all,.......

Sure are plenty enough of THEM around!


Deerjoe,  It seems that reusing you gaskets is a safe bet according to the majority of posts. However, if it will help you feel safer, you can PM me and I'll send you a set of used gaskets to measure your squish with.

[txtech]

i reused the same .030 cometics thru 2 flywheel changes,about 5000 miles apart. i"m sure they where HEAT CYCLED plenty,no problem. thinking about reuseing the again next week when i change pistons. i know your not supposesd to but i was to lazy to drive 80 miles and pay 50 bucks for new ones.

[deerjoe]

Heyyyyy.. Faast Ed.. Thanks for the offer of the loaners, but I saw enough positive info on here to go ahead and check my squish with the new gaskets.  Now I have what could be a dumb question...here goes...If your piston is flush with the top of the cylinder and your head gasket is .030 thick, it seems like your squish would be the thickness of your gasket???   Mine came in at .035... I've seen recommendations of .030 to .035, so I'm thinking I'm good.  I only torqued to 35ft/lb in respect for the new gaskets.  I just double and triple checked my cc's on the heads, and am taking them to the machine shop tomorrow to adjust to 82cc's.  I'm using .00723  per cc as a number for material removal.  Can't wait to get them back and put 'er back together!   

[Faast Ed]

If your piston is flush with the top of the cylinder and your head gasket is .030 thick, it seems like your squish would be the thickness of your gasket???

Yessir!

While your "per cc" is a close aproxamation, it's 'better if they can cc the heads as they mill them. No need to have 1/2 a cc more in one than the other. But you should be in the ballpark.

[GoFast.....]

they must of been .005 down in the hole if it came out .035

[Jeffd]

Some say .035 is ideal.  Some say .030 is ideal, either way better than .050-.070 LOL.

[deerjoe]

Roger that....005 down in the hole.  I didn't have a feeler gauge that small.  Tried to catch a fly to pull out one of his chin hairs to use for one, but the little bugger got away.  I shined a light under my straightedge, and my finely honed eye thought we were flush.  Guess I need to go rehone my eye.