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Wed Jul 28, 2021 2:35 pm

I have a couple of questions after reading about how to seal cylinders.

Cylinder to Head
Am I right that I should not have any sealant between head and cylinder,
only lap with valve grinding compound?
I read SGKent uses copper spray gasket on the head mating surface too help until there is carbon buildup to help seal properly.

I have a couple of scratches on my head mating surfaces,
I'd like to know if this will be a problem and cause leaks or not.
Or if these scratches warrant some kind of sealer to even out even though you normally shouldn't use a sealer?

see pic below

Cylinder to Case

When it comes to cyliner to case, I am not able to lap the cylinders, since I still have the mounting bolts for the cylinders and heads screwed into the case. I'm afraid that if I unscrew them I wont get them back without opening the case.

Will I still be able to seal without lapping cylinder bases?

As for sealant, I have Curil T2, Hylomar Blue and Permatex aviation no 3 at my disposal.
It is my understanding that most people use High temperature RTV though.

I don't have High temp RTV yet (as always its a bit hard to find the brands that are popular in the US here in Sweden so hard to know what is good quality)

will something like this do?
https://www.wurth.se/produkter/kemi/fogmassa/silikon/hogtemperatur/rtv-silikon-super-rtv-plus/#/

Or will it work just as good to use Curil T2, Hylomar or Permatex no 3?

When using either Curil T2, Hylomar, RTV on cylinder bases, should I apply on one side or on two sides of the shim?

Also I read that Curil T2 has replaced both Curil K2 and Curil T. Haven't heard it mentioned before on the forum so I thought I'd just mention it.

Thank you for helping me!

Wed Jul 28, 2021 2:42 pm

The cylinder slips into the head, that's not the mating surface.

I just built a new Type 1 engine and used Permatex Right Stuff on the base. It's good to 500*F and doesn't shrink.

Wed Jul 28, 2021 3:16 pm

Yup, those scratches don't matter for sealing - not the sealing surfaces.

This stuff is great:

https://www.autozone.com/sealants-glues-adhesives-...520940_0_0

Wed Jul 28, 2021 11:57 pm

You lap the cylinders to the heads and not to the case. If the heads have been resurfaced then lapping to cylinders to the heads should not be necessary.

Thu Jul 29, 2021 8:27 am

Wildthings wrote: You lap the cylinders to the heads and not to the case. If the heads have been resurfaced then lapping to cylinders to the heads should not be necessary.
Ok, thanks then I'll skip the lapping procedure, maybe lapping by someone inexperienced would do more bad then good in this case.
Glenn wrote: The cylinder slips into the head, that's not the mating surface.
Aha, that's good then, was worried that my head builder had done a bad job, but I was wrong then, phew!

About cylinder base sealant;

I'm deciding between "the right stuff" and Curil T2 non-hardening.
One factor is how fast I have to slap heads + cylinders together.
Since I'm a noob I'm thinking that if Curil has a slower "hardening" time I have more room for mistakes. However I'm not sure what time curil has, but TRS seems to cure VERY fast. The instructions in the online store specifies it hardens in 1 minute and has a temp range 59 °C till 232 °C (temporaraly 260 °C).
Curil T2 is up to 270 °C but seems to have longer curing time. Is is non-setting though.

:arrow: So what to choose?

Also there will be a shim so I guess I'm going to have to apply Curil T2 or TRS to both sides of the shim, right?

About oil pump

Also while I'm at it, may I ask; I have ordered loctite 518 for the oil pump but it still hasn't shown up :evil: , so I'll be forced to use something else.
I have access to Curil T2, Hylomar, Permatex, paper gasket from gasket set, and can buy "the right stuff" i a store easily.

:arrow: What to choose?