Spacer on exhaust manifold needs replacing.

rdm · 11-12-2002, 07:10 PM

Well we have another small bug to fix before we leave this weekend. Our 325 has an exhaust leak that I thought was the donut between the manifold and exhaust system.
Turns out the leak is at the cast spacer used to replace the heat riser on the manifold on the P 30 chassis.
Any ideas about sourcing this part. the local parts stores seem to be at a loss.
Thanks Ray

Silver Bullet · 11-12-2002, 07:35 PM

What motor do you have? Oscar

PeterH-79MH · 11-12-2002, 07:36 PM

Ray,
since it is only a spacer and not the heat riser, do yourself a big favor and make an appointment at your local muffler shop.
Have them take the spacer out and cut your pipe back 8-10 ". Then they will slide a bigger pipe over the old one,weld it and mount it directly to the manifold. Also have them replace the manifold studs with shorter ones and ask them to use a metal donut.
It should cost no more than $80.- to 100.- and will fix it for good.

rdm · 11-12-2002, 08:37 PM

Just got an update to my spacer question.

It is the heat riser that is worn out. Also the manifolds are original and are well aged. The chimney that connects to the air intake is missing. The choke appears to have been sticking partially open as there is a lot of carbon visible with the manifold off.
Also the air pumps are well corroded.
Our mechanic suggests replacement manifolds and possibly working on the carb.

Questions
1 Comments on new manifolds what kind GM or thorley (we put on a flowmaster exhaust system on earlier this year ).

2 Should I put on a rebuilt carb at this time.

Thanks everyone for help
Ray

Still hoping to leave for South Carolina saturday

Silver Bullet · 11-12-2002, 09:03 PM

Manifolds- If they are not cracked and are cast iron, do not do ANYTHING but have them surfaced to fit flush with the block! Any automotive machine shop can do this. Iron that has been heated and cooled over a period of time is known as "seasoned" meaning the stress has been removed (kinda' like heat treating but, periodically over time"). They will last longer than new ones.
Carb.- Buy a rebuild kit at NAPA and a 1 gallon bucket of "Gunk" carb cleaner and do it yourself. Follow the instructions on the rebuild kit and it will run like new. Oscar

PeterH-79MH · 11-12-2002, 09:53 PM

If you have to replace the exhaust manifolds, consider the cost of new GM stock manifolds ($~250 each) versus headers.
I have never had a pleasant experience with buying a rebuild carb. Most of them are junk!
If you ever decide to replace the carburator go with a Edelbrock. They are sweet.

74Argosy24MH · 11-12-2002, 10:04 PM

Ditto on the headers. Cast manifolds can be a real headache with cracking. If you have already got a good open exhaust, you might as well get headers and take advantage of it. They will also be cheaper than cast manifolds.

John

Silver Bullet · 11-12-2002, 10:09 PM

That's what I run, Edelbrock aluminum carb. Good choice!

They are designed after the Carter carb only dissipate heat better. Oscar

rdm · 11-12-2002, 10:18 PM

Thanks for the help
Is there a difference between header makes such as heddman, thorley.
Also Peter what would cost of the edelbrock carb be.

thanks
Ray

Silver Bullet · 11-12-2002, 10:33 PM

From Summit Racing in Akron, Ohio.... 750 cfm Edelbrock carb, electric choke, $270.00. They are on line with catalog. Oscar

davidz71 · 11-12-2002, 10:46 PM

Does Banks sell their headers by themselves?

11-12-2002, 11:57 PM

i would not go with headers! they are prone to rusting out if they are not stainless....also the big thing is they leak! you have to check the bolts often or your gaskets will burn out and they will leak!......if your into tightening bolts all the time go for it. if you do not check them they will leak! the stock manifolds are best. i dont now how easly axsessable your manifolds (OR ENGINE) are but if they are hard to get to DO NOT GET HEADERS! instead of headers they should be called headeachs!

if i was going to change out my manifolds i would go to the GM stainless steal manifolds they would be the best! they are kinda like a header and they are a GM part. you do not need gaskets for(manidold to head) i have had headers on a couple of vehicals the dont last like the factory stuff and what i like about the stock manifolds, and the stanless GM manifolds is they dont use gaskets and they DONT LEAK. my personal opinion is that headers suck.

one more thing if your conserned about annoying noises headers are noisy!

as for the carb you must have a q-jet and the edelbrock is good. dont get a crappy rebuild! if yours is in good shape... i would rebuild it......also holly has a q-jet replacment.
or you could get a new Q-jet from GM. i think if i remember right they cost from 400 to 800 bucks.......the edelbrok is alot less.

say no to headers if you have all that emissions crap and air pumps and stuff its a waste of time to go to headers. headers dont give you a very noticable power gain. they are for high rpm 4 grand and up thats were you might notice a difference.......leave your engine alone. unless your building a race car engine.

I would open up your intake and the exsaust from the manifolds back.
just say no to headers

11-13-2002, 12:01 AM

hey isn't the heat rizer attached to the manifold? everyone i ever saw was. is possable or more likely your manifold is just cracked?
if so just replace the one... is your otherone in bad shape too?

davidz71 · 11-13-2002, 01:49 PM

Overlander,
I beg to differ with you concerning headers.

1. Older style headers did warp at the mounting flange which caused bolts to work loose and subsequent exhause manifold leakage. Newer models such as produced by Edelbrock, JBA and others have thicker flanges.
2. Headers come in various tube thicknesses so why go thin which will rust out or burn through faster.
3. Some headers can be purchased with a ceramic coating to lower temperatures and prevent/retard rust and premature wear.
4. Some headers have been manufactured which require NO gasket material between them and the block.
5. Just because you have emisssion control devices on the vehicle does not mean that headers are a waste of time. Anything that moves the exhaust gasses out faster is an improvement especially if the intake side has also beem massaged.
6. Header tube length and diameter determine whether the header helps in the lower end for torque or the high end producing rpms. Running a long tube race header is a bust on a vehicle which spends time in the lower rpms where torque is needed. Banks is one such company which has been testing manifolds for heavier vehicles such as MHs.
7. Yes, cast manifolds are much easier to deal with (until they crack) and the newer stainless from GM are free breathers but still not as good as a good quality header. I have the stainless manifolds on my 8.1 (496) gas engine but not sure I would want to buy new at $250 each if that is the price.

rdm,
Peter had the cheapest solution and that would probably be the one I would try first. If it doesn't look like that will do the trick then I would look for a quality set of headers from a reputable manufacturer who has designed that set specifically for MHs. Good luckl.