Increasing Looper Compression

[doogall]

it is not constant bleed off. after about 4000 rpm engine speed. no compression really bleeds off. I do agree that plugging idle reliefs gives a much better hole shot and midrange. but I do notice that it sounds like a barrel of marbles when you back off the throttle. it would be nice to have a ratcheting lower unit like a mercury has. I plug mine and cut the heads to get 130 psi. I forget what side. but port or starboard head needs to be cut .025 more to even the compression.

Since it is for the bottom end I'm looking to increase ill go with the reliefs as I can always cut the heads later.

[doogall]

I bet that would be ok to use. Marine Tex isn't high temp that I am aware of.

The main thing you got to worry about is it hardening in the bore. When I plugged my idle reliefs with marine tex, it was tough getting the excess off the bore. So have plenty of shop towls handy.

This is what I'm considering using. It seems to be suitable for the job and might be easier to use than a liquid epoxy.

http://www.jbweld.com/product/j-b-highheat/

thanks Craig

[JohnR]

I used JB Weld rebasing some headlight bulbs a few years back and though they get pretty hot they held up fine.

[baja200merk]

Since it is for the bottom end I'm looking to increase ill go with the reliefs as I can always cut the heads later.

AGAIN... Do not cut the heads if you dont have to. Your engine calls for the thick gaskets 88-92. When you pull the heads to plug the reliefs put thin gaskets from 93-up loopers on it. We gained about 15psi on an old wore out looper by plugging the reliefs and going from thick to thin gaskets.

Kevin

[Lockjaw]

I used JB Weld rebasing some headlight bulbs a few years back and though they get pretty hot they held up fine.

I used it to hold an AN fitting bolt on the side of my old pan for the hot side drain on oil for my turbo before. And it worked.

[Lockjaw]

This is what I'm considering using. It seems to be suitable for the job and might be easier to use than a liquid epoxy.

http://www.jbweld.com/product/j-b-highheat/

thanks Craig

That will probably work as long as you can get it to seal to the sides of the idle relief hole. FWIW, I took some stuff like that one time, wadded it up, and stuck it on the side of a cinderblock wall. I believe the block would have broke off if I beat on the wad of the stuff. It was hard as a rock.

It will flat mess up a ring I bet, so just go slow, be careful, and make sure none is in the bore or protruding out of the idle relief hole. In fact I'd try to pack it into the hole a little bit, so you don't have to worry about it being to close to the bore.

And yes, the marine tex epoxy was a challenge. It was alot like working with silicon caulk.

[doogall]

Thanks guys for the advise. I now have a plan to work to over the winter months here.. Roll on the spring. Cheers Craig

[baja200merk]

I used jb quick stick on a couple of them. Works fine

[frederick55]

Plain soap and water with remove most any epoxy before it hardens. Works great for smoothing out MarineTex.

[jdw2u]

Does anyone have the part # for the thin gaskets?

[baja200merk]

340919

[wanagofass]

340919

What is the 0345257?

[wanagofass]

Nevermind, looks like a superseded number for the same part.

[jdw2u]

Thanks!

[doogall]

AGAIN... Do not cut the heads if you dont have to. Your engine calls for the thick gaskets 88-92. When you pull the heads to plug the reliefs put thin gaskets from 93-up loopers on it. We gained about 15psi on an old wore out looper by plugging the reliefs and going from thick to thin gaskets.

Kevin

Thanks Kevin, I'll go down the path of the relief holes first. Is there any problems with fitting a closed deck head gasket 93-up to an open deck motor? Will it have any effect on cooling water flow into the head? I seem to recall Racer saying once to stick to the gasket that suited the block.

Craig