951 Exhaust Manifolds

CJFusco · CJFusco's Garage

I got in a set of exhaust manifolds (bought from a Pelican member) to replace my cracked set (crack or bad gasket on the #1 cyllinder manifold).

The new set has a ribbed area (the word "baffle" comes to mind, but I'm not sure if that's correct) on the #1 cyllinder manifold, but my car's stock manifolds don't.

My car is a 1986, the first year for the 951. Is this ribbed area on the manifold simply an improvement that was made to the pipes' design over the course of the car's development? If so, what is the purpose of this ribbed area (I wouldn't doubt it if it had something to do with heat dissipation)?

ERAU944 · ERAU944's Garage

yes, it is a design improvement meant to keep from cracking, commonly referred to as a 'bellows' style manifold. i believe '87 and later were fitted with them.

CJFusco · CJFusco's Garage

Not surprising, considering that it is my #1 manifold that is cracked.

ERAU944 · ERAU944's Garage

aye... whatcha gonna do with the old ones?

TNT25169 · 06-02-2007, 08:42 PM

For the record CJ, I was a little concerned about the #1 header wiggling around a little by the baffle but I learned that's normal to prevent cracking when they heat up. Enjoy!

Aufgeladen944 · 06-03-2007, 07:09 AM

Hmm I think I need to buy a new manifold. Mine has a crack in it, too.

Funny thing is, it's the later style one that came on the Turbo S (I have a Turbo S engine). I was told $500 to fix it, or $1000+ for a new one.

CJFusco · CJFusco's Garage

I would recommend finding one from someone breaking down a 951...

Aufgeladen944 · 06-03-2007, 01:43 PM

Perhaps, but wouldn't buying a used one potentially have the same problem, or soon afterwards?

And how hard are they to get off of there?

ERAU944 · ERAU944's Garage

they are a PITA to get out of an N/A, i can't imagine removing from a 951 (sooner or later i'll get around to doing mine, not looking forward to it

). the ones he bought are the revised design, not (as) susceptible to the cracking/leaking

TNT25169 · 06-03-2007, 09:06 PM

A PITA? I removed the ones from both my '89 944 and my '87 951 with the engines still in the car in less than 30 min. I've had worse things to remove from the car....

ERAU944 · ERAU944's Garage

i guess i should say the *can* be a pita. one of the exhaust studs on the 951 is broken... i'm not looking forward to the job.

CJFusco · CJFusco's Garage

I am planning on tackling the job tomorrow (day off), and I was planning on just going in there, hitting the necessary bolts with some liquid wrench and an impact wrench, and then just pulling off the necessary pipes.

Is there anything else I should keep in mind? I can see why bolts might be a pain, but I'm not sure why taking off the pipes would be a HUGE PITA...

87944turbo · 06-04-2007, 07:26 AM

Quote:

Is there anything else I should keep in mind? I can see why bolts might be a pain, but I'm not sure why taking off the pipes would be a HUGE PITA...

The problem is getting enough room to get them off of the studs and out of the car. Some have found that unboltling the motor mount on the passenger side and raising the motor slightly provides the necessary clearance. Good luck, it is not fun.

I have found that taking the 2-3 off first and then the 1-4 works well.

CJFusco · CJFusco's Garage

ClarksGarage recommends removing the studs from the assembly by backing them out of the housing using two nuts. This, I suppose, would make removal easier.

The site also states that I MIGHT have to remove that coolant pipe that runs over the manifolds. Might? Has anyone had to do this?

87944turbo · 06-05-2007, 03:54 AM

Quote:

ClarksGarage recommends removing the studs from the assembly by backing them out of the housing using two nuts. This, I suppose, would make removal easier.

That is about the only way to remove the factory studs, but if you really take your time, you should be able to get them off w/out having to remove the studs. It can be done. Also, I am not a big fan of pulling and replacing studs in our aluminum heads. Its just too easy to strip the threads in the head since the aluminum is realtively soft compared to the studs, my .02.

Quote:

The site also states that I MIGHT have to remove that coolant pipe that runs over the manifolds. Might? Has anyone had to do this?

I really can't imagine trying to get the headers off w/o removing the coolant pipe. Once the headers are off and the coolant is drained to remove the coolant pipe, its a good opportunity to do your oil cooler housing seals as well!

CJFusco · CJFusco's Garage

Hmm. I wasn't planning on draining the cooling system, but I guess it's really no big deal.

The only coolant I really have in stock is the orange Dex-Cool stuff. There's no problem with using this, right?

87944turbo · 06-05-2007, 09:47 AM

Not sure about that. The coolant you want is the type that is phosphate free.

onZedge · 06-05-2007, 10:57 AM

GM Dex-Cool is fine, however, do not mix Dex-Cool with anything else but Dex-Cool in the future because it may gel when mixed with other antifreeze formulas. Prestone 5/150 is also acceptable, cheaper and compatible with other fluorescent green antifreeze formulas. I like to buy the 50/50 premixed versions as they are already cut with demineralized water. Do not use tap water in the radiator - and especially the battery. Mineral content of tap water is commonly too high.

CJFusco · CJFusco's Garage

thanks for the info; maybe you can help with my latest quandary:

Stumped!