Type of bolts used to fix aluminum exhaust manifold on cylinder block

[darengr]

engine model 4.3L LX Gen+ 1996-97
Hi,
I decided to change my old cast iron exhaust manifolds with aluminum ones this time.
My question is, what type of bolts do I use, the old iron ones, or the new that are within the box of the manifold (HGE aluminum HGE 9746-A)?
There is a note within the box (http://www.manifoldwarehouse.com/mes...edure-Rev4.pdf), which instructs to use teflon tape, but it does not specifically mention to use it on the bolts that fix the manifold to the cylinder block. As far as I understand it, it refers to the riser to manifold fix bolts.
Any ideas please?
Thanks!

 

[gm280]

:welcome: aboard darengr. Nice to have you join us here at ibaots...

Your questions are a little hard to answer because they are not the usual boating type question changing from standard parts to aftermarket parts. I think your absolute best idea is to contact the manufacture of the exhaust manifold and get their suggestions. Maybe even log on to their website to see if they make any reference to your question about bolts... JMHO!

 

[grewvin1]

Al. bolts can corrode dissimilar metal galvanic action and upon next removal, threads can gall in cast iron and bolt snap off. Always add anti-seize to threads for everything unless tech manual calls for Loctite. My practice is to install grade 8 bolts zinc plated, (overkill from the usual grd.5 plated). My favorite as a builder of very large oil and gas machines is to use whenever possible socket head cap screws with washers. They are very hard strong and always come out with an allen key never snap off.

 

[Bondo]

My question is, what type of bolts do I use, the old iron ones, or the new that are within the box of the manifold (HGE aluminum

Ayuh,..... Welcome Aboard,.... For the manifolds to head connection, just use the stock bolts,....

I use perfect seal or form-a-gasket #3 on the threads, insteada never-seize, since Don S convinced me a few years ago,....

Before ya go to far, slap a straight edge against the manifold at the riser gasket surface, 'n make Sure it's good, 'n Flat,....

Chinese manifolds are known to need resurfacin' to get 'em Flat, before ya mount 'em,....

The pipe dope is because those holes are open to the coolin' water, just like Chevy head bolts,....

 

[darengr]

thank you all very much!.. I really appreciate you help and suggestions.

I did contact the manufacturer before this post via their site and hope to a response.
I am also pro using the stock iron bolts, I did not have the slightest problem taking them off, after 8 years from last manifold change @ 2007.
They were installed dry at that time, as far as I can remember, and some of them were OEM new and have had red threadlocking material on them, it is still visible.

I do have handy some grey loctite gasket maker, but such a material (or like the one Bondo is mentioning form-a-gasket#3) is this really recommended for threads in an anaerobic environment? Another idea was to use blue threadlocking, so I thought it will be easier to remove the bolts in a couple of years, for manifold inspection.

UPDATE: furthermore, although there are instructions to prepare the bolts and plugs with teflon tape, there is a red bottle with a chinese anaerobic adhesive within the risers box!... What could be its use, to place it on top of the teflon-tape wrapped bolts???
Has anybody installed the aluminum HGE risers and manifold set and used this adhesive together with the teflon tape?

I also checked the pairs for flatness (I placed the riser on the manifold very carefully), they look fine.