just checking injector block gasket sequence

[Alan L]

Just checking what I got for gasket sequence on Al injector blocks. I am sure this is as Chris (TK) suggested, but it does seem odd. I have a gasket at the base on the head intake port, then phenolic spacer then Al injector block on phenolic spacer - no gasket (seems odd) then gasket between manifold/injector block. The only interface without a gasket is the manifold/phenolic spacer. It seems to work, but seems to be asking a lot in terms of leakage under boost. Just checking while I have it all apart at moment.
Thanks
Alan

[T77911S]

thats what he told me too. i put a gasket there anyway.

you need to look at how the gaskets go on. they do NOT all go on the same direction.
flip the intake manifold over and lay the gaskets on the manifold. with them on there one way there is a very thin area that is covered by the gaskets, the other covers more area.
same with the insulator blocks.

i have nver liked how the gaskets fit. the port hole is way too big. i think this is par tto do with why the plastic ones crack. my plastic ones were "distorted" in the center where there is no gasket.

[RarlyL8]

I had custom gaskets and spacers made for the aluminum blocks we machined. I wanted the holes to all be the same size as the blocks.

[JFairman]

As long as putting a gasket in between each surface doesn't raise the intake manifold up so much that it affects the throttle linkage or how the turbo air pipe plumbing lines up it seems like a good idea.

If Chris says don't put a gasket there then I would do as he says and just smear a thin layer of Hondabond sealant on both surfaces, install the manifold, and torque down the nuts to 18 foot pounds.

Hondabond, Yamabond, and Threebond sealant are all the same stuff. They make high temp versions too but the regular stuff works fine on the intake.
Some people use Loctite 574 on intake gaskets and it works too but it's more expensive and a real pain to clean off if you ever have to.

[T77911S]

that is what i was worried. about but figured it was not enough to worry about.

then i ended up having the surface of my intake machined.
due to the gaskets not fitting as in the ports of the gaskets were bigger than the intake/block ports, the manifold itself "warped" around the ports. IE they were kind of concave plus had some minor pitting.

[Alan L]

Jim, The sealant sounds like an excellent idea. Thanks.
T77911S, yes - well aware of the gasket orientation issue. I posted on it once a while back while trying to find an issue with my engine. Wrong way around and you get about 1mm of sealing area. A recipe for frustrating problems. Trick for young players as they say.
Regards
Alan

[flightlead404]

Originally Posted by JFairman

As long as putting a gasket in between each surface doesn't raise the intake manifold up so much that it affects the throttle linkage or how the turbo air pipe plumbing lines up it seems like a good idea.

If Chris says don't put a gasket there then I would do as he says and just smear a thin layer of Hondabond sealant on both surfaces, install the manifold, and torque down the nuts to 18 foot pounds.

Hondabond, Yamabond, and Threebond sealant are all the same stuff. They make high temp versions too but the regular stuff works fine on the intake.
Some people use Loctite 574 on intake gaskets and it works too but it's more expensive and a real pain to clean off if you ever have to.

Titeseal is an option here too. I've used it in similar applications with good results

[proffighter]

So I have to tell my 2 cents here too (to let you guys know I am still there :-) ):

There is no chance to tell me, a phenolic to aluminum surface is durable seal. Using some stuff like whateverbond is not a good idea as long it's silicone based, as it will have contact with fuel gas/fog and soak, then swell.

Better than bond is a gasket or (big effort needed) O-ring in a groove.

[Alan L]

[QUOTE=proffighter;8918423]

There is no chance to tell me, a phenolic to aluminum surface is durable seal.

I would have to agree but it seems to work. And you would have to put some weight on the voice of experience of Chris (TK). He must have advised that for a reason. But now I pull it down, it does make me nervous, just looking at it. I wonder how I could expect it to seal. What I don't know is what reason Chris would advise against a gasket. (I do wonder if there is enough thread to accommodate a gasket).
Regards
Alan

[JFairman]

I've been using 40mm aluminum injector blocks and forgot about the original phenolic resin ones... because they suck.

And, Honda and Yamaha air cooled motorcycle engine cases are put together with Hondabond or Yamabond rebranded Threebond sealant without gaskets and you rarely see them leaking oil.

I installed the cam towers on my 930 motor with Hondabond 4 and it doesn't leak oil.
It also cleans up with laquer thinner on a rag or paper towel easily.
It's nothing like generic silicone sealant most people are familiar with.
No need for special solvents like MEK or industrial grade paint remover to soften it.

When installing the aluminum injector blocks I used PMO phenolic heat insulators between them and the heads a long with factory gaskets in between each surface so that was 3 gaskets for each one. I used a thin layer of blue hylomar gasket sealent on each gasket because it never dries and it ignores gasoline. Hylomar is not easy to find in the states anymore so I would use Hondabond on those gaskets if doing it again because
i have a tube of it and it works well.
At the same time a little wheel bearing grease smeared on those gaskets would probably work if using aluminum injector blocks with or without the approximately 10mm thick phenolic resin heat insulators.

[Alan L]

I better see if I can find some of that Hondabond/Threebond.
The name is not familiar to me here, but hopefully we have an equivalent under another name.
You guys have great access to a range of stuff we struggle to find sometimes.
Regards
Alan

[Alan L]

We got Threebond available - they have a range of RTV gasket material and liquid sealants.
Any idea which one I am after, or what colour?
Thanks
Alan

[JFairman]

I'm not sure which type of Threebond is the same as the Hondabond 4. I think the 4 digit number type begins with 3 and Henry over on the engine forum would know as he recommends it.

Here's a link the Hondabond 4 I'm familiar with. I bought a tube of it at the local Honda dealer for around $6.
It's grey in color.

In the description it says it resists gasoline...

Dirt Bike Pro Honda Hondabond 4 | MotoSport

With a search you may find it local to you if Honda or Yamaha motorcycles are sold and serviced near you.

Semi-drying liquid gasket.
Seals irregular surfaces with a tough, elastic film.
Solvent-based for easy removal; also resists gasoline.

[Alan L]

That should be enough info to track it.
Thanks
Alan

[930/66]

For TK Al Blocks:

[930/66]

I'm just rebuild / upgrade my ignition at the moment, for that my pankake is actual not installed.
No leaks!

[T77911S]

should have powder coated that intake. it would look good. i did mine.

i did what Jfairman did. 3 gaskets. cant remmeber if i used a sealant. i do have some non hardening sealants,just dont remember what i did.

you dont want anything that you would have to scrape off the phenoloc blocks.

i think TK told me the surfaces are machined so precise you dont need a gasket.

[Alan L]

Looks like you can get away with no gasket/sealant. That is what I did first time, and no issue. Just this time around it looks like an area that may cause problems - so I am going to use some Threebond - insurance.
Thanks
Alan

[TurboKraft]

Hi,

This ain't rocket science, nor is it terribly critical.

A sealant isn't necessary.
22 years of making and using CIS blocks like that, no leak problems with no seal between the insulator and manifold.

If you want to use a sealant, you may. We don't, but if it makes you more comfortable, go for it.

Why not add an o-ring seal in manufacturing? Because it hasn't proven necessary. Adding an extra step that doesn't solve a problem is just adding another step.

Happy building -

[Alan L]

Thanks Chris.
Alan