Hot Rod Forum banner

1 - 17 of 17 Posts

·
Pure American Muscle
Joined
·
684 Posts
Discussion Starter #1
Hey everyone,

I got my new headgaskets today and as some of you remember I had to get thinner gaskets to meet qunech safe area. I got the 1094 Fel-Pro embossed steel shim .015 and I was reading the installation tips for it.

It suggest a surface finish of "55RA (60RMS) or smoother"
if surface is rougher to apply a sealer.

From what I gather RA is roughness average.
My question is how smooth is this in say terms of something like sandpaper or orginal block smoothness. Also what kind of sealer should be used.


Thanks again everyone,
Chris
 

·
Come Home Safe Soldier
Joined
·
846 Posts
Another question along the same lines that may prove helpful to strikingthrmatch.A sure way to clean any metal surface is a small air operated angle grinder with a Rol-Loc pad on it.But does that remove to much material on an aluminum heads? There are different types of Rol-Loc pads,on any metal surface I use the brown discs.What are the correct ones for aluminum useage?
 

·
Pure American Muscle
Joined
·
684 Posts
Discussion Starter #4
I'll take some pictures of the surface of the block there are no pits or anything of that sort in it but it has I don't know what you would call it but it looks like small cross hatch type marks on it. I am getting new alu. heads so I hope the surface will be pretty smooth since it is all CnC'ed What I really am worried about is the gasket sealing to the block. Also if I where to grind off an metal wouldn't that effect the quench?

I like what you where saying RC with Rol-Loc what might be a good way to clean up the surface of the block and make it nice and smooth for the gasket.

I''ll get those pictures guys! Hotrodding gotta love it lol.


Chris
 

·
Come Home Safe Soldier
Joined
·
846 Posts
I use the brown pads on a daily basis.But it is on metal parts.The aluminum may be reduced with the brown pads,as they are pretty abrassive.They are ideal for the block itself though.
 

·
Pure American Muscle
Joined
·
684 Posts
Discussion Starter #6
Where do you get the pads at RC. I did an internet search and didn't find anything. Go to home depot or something of that nature?


Thanks,

Chris
 

·
Come Home Safe Soldier
Joined
·
846 Posts
I get mine at work.Sort of the benfits package.You can get them at parts houses and hardware stores.The ones I have are 1" diameter.You can get them up to like 2.5".I like the 1 inchers though since they are smaller and tend to put more down on the surface instead of having the edges float.The Rol-Loc pads are made by3M.There are other brands though.

http://www.andale.com/stores/sf_cat...=6155891&mode=1&catId=1177103&pnum=2&psize=10





Here ya go
 

·
Pure American Muscle
Joined
·
684 Posts
Discussion Starter #8 (Edited)
Ok guys here is the pictures of the surface on it right now if I had to give it a feeling level I sould say it feels like a fine nail file.
Hope the picture helps.


Chris


The rest of the pictures are in my photo gallery and I will also post them in my project journal.
 

·
Registered
Joined
·
3 Posts
okay to answer your question about RA. Ra stands for Arithmetic Average Roughness Height. So basically the difference of "hills and valleys" above and below the centerline of the material. Now...On to the question about 55 RA and 60 RMS. 55 RA can be acquired by filing and turning on a lathe with slow feeds and fast speeds to produce a nice finish. The lower the RA the smoother the finish. For example lapping gives a surface finish of 1-2 RA. By the looks of your pictures...A honing stone and oil will be your best bet to acquire the 55RA. Right now your looking at roughness of about 125-150 RA . Hope This info helps.

The reason I mentioned using a honing stone is because the stone is almost a perfectly flat surface. Unlike the pads which have flex to them, which could cause waves resulting in a obviously smooth head surface but you will not create parallelism across the surface of the block.
If you are able to create parallelism across , the less sealer you'll need and the better the seal will be.
 

·
Pure American Muscle
Joined
·
684 Posts
Discussion Starter #12
Thanks madman That does really help. Im guessing that a 50Ra would feel pretty smooth and flat. What would be the best way to use the honeing stone to do this? I understand you want a even surface across the whole deck whihc makes sense that you would not want to use a pad that would create dip in one spot.

SO

1. How do you use the stone to do the surface.
2. What sealer would you use to seal it.


Thanks

Chris
 

·
Registered
Joined
·
3 Posts
Well,
You would want to use the stone in a "X" pattern creating a cross hatch design just like they do when you hone out your cylinders or when you prep a car for paint.
To reply on the sealer, buddy I really don't know to answer that one. I just happen to be going to school for manufacturing engineering so thats how I knew what you were looking for there on the surface finish. I'll keep my ears open for what type of sealer to use. I am going to give my racing buddy a call over the next day to ask him that question. I myself am doing head work on my 91 k5 blazer. Glad I could help.
-Chris

P.S. where is Saylorsburg, Pa Located?
 

·
Pure American Muscle
Joined
·
684 Posts
Discussion Starter #14
I started to go over the block and it does make it smoother and seems to be working well I just have to keep at it for awhile still it is smooth enough. Thanks for all your help it's good to know someone out there knows these anwsers. It's kinda funny that the gasket company assumes that everyone will know what a 55RA finish is and not tell you how to get one. lol

Saylorsburg is in the northeast part of PA up past Philly by about an hour or so.
By the way welcome to the Board!

Chris
 

·
Registered
Joined
·
24 Posts
RA surface prep

This ishotmetal800, You should just use the sealer because
there is no way that you can work flat enough, your machine shop needs to do this operation. I would use, for a sealer, a product called Hylomar HPF, item # 765-2692 from NAPA
This product comes in a spray can or tube and is applied to both sides of the cylinder head gasket prior to install.
 

·
Registered
Joined
·
4 Posts
Rol-Loc pads

these pads clean real well BUT be real careful they will remove material and create a poor surface area seen a John Deere diesel block ruined by a co-worker useing these pads. For aluminum 3m makes a pad with plastic like fingers one grade suitable for aluminum these work well , but with care hope this helps
 

·
Pure American Muscle
Joined
·
684 Posts
Discussion Starter #17
I was going to use sealer either way as an extra step to protect against leaks and other problems.

HotMetal
So the NAPA stuff is good? Have you ever used it for an job such as this one?


Lastly does anyone else have sealers they use for stuff like this.

Sorry for the questions but I don't think im the only one who runs into this problem and sure would like to save other people the trouble of findthing this out the hard way.

Thanks everyone!


Chris
 
1 - 17 of 17 Posts
Top