Dauntless Exhaust Swap Leak HELP...

I'm posting this thread after having searched this site for answers and having not found them.

Here is my issue, I did the Saginaw steering swap a few weeks ago and in doing so I changed the stock front dump exhaust manifold with a later model rear dump manifold that I purchased on Ebay. I'm wondering if I somehow got the wrong replacement manifold.

I first installed new gaskets from the year of my engine and they leaked right away, I noticed that the new manifold port profile is square and definitely different from the old manifold and head ports so I next made a set of gaskets that I thought would work but they began to leak after a hundred miles or so, I then replaced the home made gaskets with a factory gasket from a mid 80's 231 and again they are leaking after only 100 miles or so.

I put a straight edge on the manifold and it seems to be flat as does the head so... did I somehow get the wrong manifold? is there a better match or what. Has anyone else had this issue?

The new manifold certainly bolts up to the head just fine...

Help

 

Could be that you got a later "high port" manifold from an even fire engine. Not sure if one of those will bolt onto an odd fire though. I'll have to read a bit. Otherwise, I don't know why it would keep leaking if everything is installed properly and you're using good quality gaskets. It is important to recheck the manifold bolts after installations. The heat cycles work on them and they can come loose.

ed.: It is possible to interchange early low port head exhaust manifolds with later, high port head manifolds.

" Since all Buick V-6s share the same exhaust manifold bolt pattern and relative port shape, either headers or stock manifolds will fit universally." -Pat Ganahl, "V-6 Performance"

Not sure that any issue would arise from using a later manifold, though since they are similar in shape.

 

I have re-tightened the bolts to insure they are snug so I don't think that's the issue.
Is there a known rear dump manifold that has the same exhaust port profile as the front dump?

 

I believe the same vintage Commando used rear dump driver side manifold. Or, any '76 or earlier Buick that had the V6. '77 was something of a transition year for the V6. '78 and later were high port heads and even fire engines. Maybe post an ad in the classifieds. Someone here may have what you need.

 

Jeepster rear dump are hard to find but they are out there. I believe Dave is right on the year of the high port. I recall someone over at the Jeepster forum using the high port manifold but I can't remember now what gasket they used.

 

In the jeep world you are looking for a V6 model with factory Saginaw power steering. Basically the 71 model year but since it is jeep possibly a late 70 of an early 72.

 

OK I think I have this thing figured out. I'm finding that there is a lot of bad information out there, I think it comes from well meaning people who read or hear bad information and then pass it along as if it were chapter and verse... As it looks the option for rear dump manifolds are fairly wide as long as the manifolds come off of mid to late 1970's 231 oddfire engines typically found in many different models of GM cars. Around 1980 it appears that GM went to the "high port" exhaust manifold which just happens to bolt perfectly to the older heads but doesn't cover the ports properly and eventually leak... I haven't found any photos of the manifolds that are suppoe to fit but I have ordered one online and should have it by the end of the week if all goes well... I'll update you when I get it. If anyone has any photos of these manifolds I would certainly appreciate seeing them.

 

"....... '79 and up high port head......" -again from Ganahl's book. So, '78 and earlier should provide the correct low port head exhaust manifold. I was off a bit. Sorry.

 

Exhaust manifolds off a 71 Jeepsteer with a 225



These are off a late 70's 231

 

Question,

The heads off the late 70's 231, will they work on a 225?

These look identical to the heads that I have purchased but have not installed.

Thanks

RVS

 

These are the ones on my 225, I do not run manifold gaskets and do not have any leaks. My uncle always told me a manifold should not need one, and most did not from the factory. Every time I tried run a gasket I blow it out, he told me to knock it off and I have not looked back since. Headers OTOH need them.

 

in the earlier photo post the ports on the "newer" manifolds in the photo look just like the high port manifolds to me... Are they actually different? Do these manifolds seal to the 225 heads?

 

Now these are the same ports I need, What did these manifolds come off of?

 

The '79 heads will not work on the 225, without modification. They changed water passage shapes and locations in '77.

 

I have the same problem just reversed. I have a set of 79 heads and 75 manifolds. The ports are high on the head and the manifold drops a 1/4 to 3/8" below the head sealing surface. There is no way to seal it with out welding the lower edge of the manifold and having the manifold resurfaced. I guess I will be looking for another set of manifolds soon.

 

I agree with jeepfreak81 in that I don't use manifold gaskets. I have had mine off/on several times in the 43 years of owning this 225 and never a leak.

 

Well my Saga continues for the time being, I found an exhaust manifold in New Hampsire and had them send it to me but they sent me the wrong one... They are now sending the correct one so we will see when it gets here.

I have no problem running without manifold gaskets as long as they don't leak but it's been my experience that if the maniold wasn't mated to the head when they both were new or newly surfaced that they don't seal very well at all so that's my only hesitation there.

 

Hallelujah, I'm off the road again... ;-) after receiving 2 incorrect manifolds for my jeep I finally got the one I needed. It works great. The best part was that it not only bolted up to the engine correctly but with the heat riser in place it also fit perfectly to the exhaust pipe so there was no need to mess with that. I want to thank everyone here who helped me out with this project. I am somewhat surprised with the number of years that modifications like this have been done that there isn't a comprhensive guide somewhere online that outlines step by step and part by part what will be needed so the mistakes that I made would never have to happen. Thanks Again; Kevin

 

Any body know where I can locate rear dump stock manifolds for both sides of my 225