Riser gasket replacement

[Worthing skier]

(1993 Prostar 190 Inmar 285 hp).

Hi all

Just doing a bit of the winter maintainance replacing the riser gaskets , I am sure I read some were that these only go on one way , but cannot see this .
I have bought 2 new gaskets from my local main dealer ,when I offer them up it does not seam to make any difference .
Also there was some rtv type sealant on the original old gaskets , is it recommended to apply a sealant , if so do i use an exhaust type high temp operation sealant or a water proofing sealant ?.
Last question , is there a recommended torque setting for the retainer bolts .

Many thanks


Kevin

[mikeg205]

I changed my riser gaskets this year on my '95. I used the Permatex Copper sealant for slight imperfections in the mating surfaces. I went with fellow team talker Lumberg's torque spec - good and tight. I used the anti-seize on the bolts so they come out easier next time.

Mine fit both ways...there were no special instructions when in my package...I had some pitting in mating surfaces so I will be checking every other season to make sure I don't get any water intrusion. It was so easy...even taking the exhaust hose was not a big deal.

Besides it will give me something to do during the boring Chicago winters.

[Cloaked]

Originally Posted by Worthing skier

(1993 Prostar 190 Inmar 285 hp).

I am sure I read some were that these only go on one way , but cannot see this .
I have bought 2 new gaskets from my local main dealer ,when I offer them up it does not seam to make any difference .
Also there was some rtv type sealant on the original old gaskets , is it recommended to apply a sealant , if so do i use an exhaust type high temp operation sealant or a water proofing sealant ?.
Last question , is there a recommended torque setting for the retainer bolts .

Many thanks


Kevin

You have read about the PCM setup and the gasket does go in one direction but the gasket in your picture is not that PCM gasket and according to your decsription of being an Indmar, there is no specific direction. Only the PCM engine has a directional gasket installation. The Indmar has no blockout and according to DIM, the gasket you show is the correct gasket for the Indmar unit. http://www.skidim.com/products.asp?dept=1109


Picture below of the starboard side of the PCM engine (this is an older project I worked on a few years back, but same application as the 93) is the correct configuration and direction for the PCM, the blockout going to the exhaust end of the engine.

For your question, there is no directional requirement for the Indmar.

Get four or eight new hex head threaded bolts for the new install. Also clean the mating surfaces to a shine (or there abouts) and you should not need any sealant or additional goop. While you have it apart, inspect the inside of your exhaust hose for any deterioration. Bottom link in my sig line will show you what you could encounter. Put antiseize on the threaded connections (as stated above) and also on the exhaust hose connection to the riser. Makes an easy change out if necessary later on, especially on the hose.


.

[mayo93prostar]

I concur with cloaked that you do not have the type of engine or gasket that need to go a certain way. I also have a 93 with Indmar ford engine and have same looking gasket that you have. It does not matter which way it goes. the first time I replaced my gasket 2 years ago, I did not use any gasket sealant because your not supposed to need with that gasket. However, mine leaked so I replaced them again last year and used permatex red gasket sealant and no leaks. Both times I cleaned the mating surfaces up very well by scraping and sanding them. I replaced the bolts with stainless steel hex head screws but I have heard of some replace with bolts with regular heads, not sure if you have room to get a wrench in their or not. Good luck.

[Worthing skier]

Thanks for all the answers ,

While doing this I have had 1 of the the riser to manifold alan bolts shear , so as the gasket faces are not perfect I have removed the manifolds to recover the broken stud and get the faces cleaned at my local machine shop.
My next question is there no gasket between the manifold and head , it just appears to be a smear of sealant .
I do not think this has ever been apart before .

Also I have got a couple of distributor advance springs to replace and the light gauge one is very rusty , have you got any tips on this as they do not come past the advance plate , do I need to take the disy out and strip it , or there an easier way .

Many thanks

Kevin

[mikeg205]

Regarding the manifolds...there should be gaskets there..sorry about the sheer on the bolt.

http://www.skidim.com/prodinfo.asp?number=49-1006 is the part for the manifold to head union.

Advance springs? Nothing about those in my Indmar manual - picture - or someone with more knowledge needs to helps with this.

[Worthing skier]

Hi

Pic of the distributor attached , also pic of the faces where there was no gasket , the white spray on the head is just spray grease to stop the face rusting while I do the repair .

[Lumbergh]

I would contact Pertronix about distributor springs.

http://www.pertronix.com/

As for the riser bolt shearing, I live in fear of that happening. That is why I replaced all of mine with new SS and new manifold bolts too when I removed mine. Steel and long term exposure to water and humidity = bad things happening.

Hope you have no further problems.

edit: skidim sells a complete manifold install kit, cheap.

[mikeg205]

Probably obvious for others...is this a 351W? - But I am pretty sure you need a gasket for the manifolds...at least my gm has gaskets...looks like gasket sealant like permatex copper was used...I see some residue in your pictures.

[Bouyhead]

Gaskets are optional at the manifold to cylinder head. I run a little hi temp sealant and call it a day.