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350 Head Gaskets

Ribrickulous

Ribrickulous

Veteran Member
Joined
Jun 8, 2020
Total Posts
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Location
Brooklyn, NY, USA
Alright, so as I go into the build up of engine#2 I'm faced with a choice. What type of head gasket to use?

As I see it, I have three options:


  • The gasket in the top end kit
  • A NOS Honda gasket
  • A copper gasket

As I understand it, the pro's and cons are:


  • Kit Gasket
    • I have it already (Pro)
    • Ostensibly requires no sealer (Pro)
      • I'm still going to use some around the cam chain tunnel and oiling passages (Con...ish)
    • Varying quality depending on the brand (Con)
      • I have a Vesrah gasket and a no-name brand gasket. I'm planning on using the Vesrah.
  • NOS Honda Gasket
    • Expensive, comparatively (Con)
    • You know it'll fit (Pro)
    • Ostensibly requires no sealer (Pro)
      • I'm still going to use some around the cam chain tunnel and oiling passages (Con...ish)
    • If it's not in a sealed bag, I don't know how well they hold up over time (Big Con. All of the ebay ones are out of the packaging)
      • Also unclear if it's actually a honda gasket.
  • Copper Gasket
    • Sounds cool (Pro)
    • Not too expensive, but not free (Con/Pro)
    • Requires annealing (Con)
    • Requires Sealer (Con)
    • Better combustion seal than composite gaskets above (Pro)

Anyone have anything else to add? I saw somewhere on a car website that a copper gasket may require machining of the block to accept steel o-rings, but I haven't heard it mentioned elsewhere...
 
I'll say the Vesrah gasket. Known good quality item. I'd still add a very thin smear of Honda Bond around the oil pressure passages, even on the base gasket.
 
FWIW...The Vesrah top end gasket kit I ordered didn't have the 4 o-rings that sit behind the cylinder head side covers. It was a little frustrating when I found them missing during assembly.
 
The Vesrah head gasket is my vote as well.

almost every gasket kit you can find that’s not Honda will be missing some things, and/or contain the wrong size things.
 
Okie dokie, Vesrah it is.

And yeah, Jim - I was going either silicon or hondabond (threebond). Now I’m recalling that somewhere on another thread someone mentioned how if hondabond makes it’s way into the oiling system, it doesn’t clog up the works like silicon does.

I ordered the rocker pin o-rings from partzilla. I remember them not being in there from last time. It’s weird the assortment of stuff they give you in these things.


Ed
1972 Honda CL350
 
It is odd, but that seems to have evolved over the years as these bikes and engines get older and fewer working in the aftermarket industry are truly familiar with them. It does seem that they sometimes almost create a combo of o-rings and valve seals as if to cover many different engines, then dump one of each into the gaskets for each engine. I've bought 450 sets that had the tubular valve seals with the wire ring around them, totally not for the 450, not even close. As to Hondabond, I used it around the passages on the base gasket on my 450 and when I pulled the head to reseal it a couple years ago the cylinders stayed put, didn't break loose. I figured it would stay sealed so I left it alone and I was right, it did. You just have to be careful not to smear it on too thick because unlike silicone sealer, Hondabond will get firm and if too thick can keep the surfaces from coming fully together in that area. So if you use Hondabond, be quick about it. Silicone sealer scares people unnecessarily, if used properly it causes no trouble and later when you disassemble things (if you ever have to), everything comes apart cleanly with very little gasket remnants to scrape wherever it is used.
 
Right, I figure the Honda bond amount will be similar to what gets used when sealing the cases back together, and put on within minutes of applying it.

A thin smear, enough so you cover everything, but not globbed on. I’ll leave some space between the oil passages and the edge of the Hondabond so it doesn’t want to creep out and cover the passages.
 
Difference between smear and thin smear is a smear covers the area completely with a thin coat while a thin smear will show some gasket or surface coming thru.
 
Alright - so in that case it sounds like I’m going for a plain ol’ smear, yeah?


Sent from my iPhone using Tapatalk
 
One of the most pleasurable engine disassemblies I've done is where the PO used silicone on the gaskets. After reading ancientdad used it, I will definitely try and remember to give it a shot on my next build. I even went out and bought a tube of silicone from the hardware store... though no engine work in the horizon at the moment.


ancientdad said:
It is odd, but that seems to have evolved over the years as these bikes and engines get older and fewer working in the aftermarket industry are truly familiar with them. It does seem that they sometimes almost create a combo of o-rings and valve seals as if to cover many different engines, then dump one of each into the gaskets for each engine. I've bought 450 sets that had the tubular valve seals with the wire ring around them, totally not for the 450, not even close. As to Hondabond, I used it around the passages on the base gasket on my 450 and when I pulled the head to reseal it a couple years ago the cylinders stayed put, didn't break loose. I figured it would stay sealed so I left it alone and I was right, it did. You just have to be careful not to smear it on too thick because unlike silicone sealer, Hondabond will get firm and if too thick can keep the surfaces from coming fully together in that area. So if you use Hondabond, be quick about it. Silicone sealer scares people unnecessarily, if used properly it causes no trouble and later when you disassemble things (if you ever have to), everything comes apart cleanly with very little gasket remnants to scrape wherever it is used.
Click to expand...
 
I got a Vesrah gasket set I'll be using on my 350 when it goes back together soon. It includes the cylinder base o-rings and the valve cover o-rings. It does not include the found valve adjuster shaft o-rings

Thanks for the tip LongDistanceRider. I was thinking I would use Gasgacinch around the cam chain tunnel and oil feeds on both base and head gasket. Maybe Gasgacinch around the cam chain tunnel and Threebond 1184 (I have a recently opened tube on hand) for the oil feed passages?
 
Dunk said:
I got a Vesrah gasket set I'll be using on my 350 when it goes back together soon. It includes the cylinder base o-rings and the valve cover o-rings. It does not include the found valve adjuster shaft o-rings

Thanks for the tip LongDistanceRider. I was thinking I would use Gasgacinch around the cam chain tunnel and oil feeds on both base and head gasket. Maybe Gasgacinch around the cam chain tunnel and Threebond 1184 (I have a recently opened tube on hand) for the oil feed passages?
Click to expand...
Be aware that the cylinder base O-rings probably are too thick and you'll need the Honda part.
Yeah, just a light smear of Honda Bond on the gasket around the oil pressure feeds.
 
LongDistanceRider said:
Be aware that the cylinder base O-rings probably are too thick and you'll need the Honda part.
Yeah, just a light smear of Honda Bond on the gasket around the oil pressure feeds.
Click to expand...

Thanks for the heads up. I just measured each cylinder base o-ring from the Vesrah kit, diameter is 1.99mm-2.02mm. Original o-ring appears to be 2mm, so I think these are good.

Also, the head gasket is a graphite coated type. Honda bond or similar on the head gasket too, or just the paper/fiber base gasket?
 
I don't use anything on head gaskets, some people like the copper spray but a good coat of that negates the usefulness of the graphite impregnated gasket. If I was building an automobile engine that uses a different type of gasket I would consider it.
 
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