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Forrest
04-25-2001, 08:28 PM
I'm finally getting the new 383's back in the Magnum 27 Sport. After building the engines with a bunch of good parts, I decided to ditch the cast-iron Volvo style manifolds and buy a couple of pair of Stainless Marine small-block exhaust manifolds. The potential problem is that these engines are mounted only 30" apart as measured to each engine's center-line. When I bolted up the two inside exhaust-manifolds with no gasket for a test fit, you could just slide a credit card between the two stainless-steel band clamps on each manifold. Next, I decided go for it and bolt 'em using the supplied exhaust manifold gasket - and now they touch, but not hard. I will add that these engines are mounted to heavy-duty steel, under-engine one-piece offshore-race type engine mounts and don't move at all.

http://imagehost.auctionwatch.com/preview/bo/bowtiekid/SMexhaust1.JPG

http://imagehost.auctionwatch.com/preview/bo/bowtiekid/SMexhaust2.JPG

What do you think? Am I going to have problems with these manifolds since the band clamps touch??

Also, those are madpoodle's standard SM risers that you are looking at, but I really need a set of standard risers with the "Volvo" down angle. I understand that Stainless Marine make 'em. Does anyone know where I can find a "deal" on a set of four?

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Forrest

[This message has been edited by Forrest (edited 04-25-2001).]

RickR
04-25-2001, 08:38 PM
Can you adjust the engine mounts 1/8"?
How about milling the clamps?
Will the blocks expand when they come up to normal operating temp?
If you were really concerned you could mill the manifolds.
She's LOOKIN' GOOD!!

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RICKR
mailto:riggerb@aol.comriggerb@aol.com</A>

[This message has been edited by RickR (edited 04-25-2001).]

Gearhead99
04-25-2001, 09:05 PM
Forrest,

I think they are too close. You know that the manifolds will expand when they get hot. I would find out about milling the manifolds some. When they touch or barely touch you will get some noise and ring. Like a cat. conv. going bad on a car.

I also don't think that moving the motor mounts is the way. Then you'll mess up the alignment to the drives. You have to mill the manifolds just a tad.

How about a full pic of the engine bay. The little sneek pic you gave sure looks good.

boldts
04-25-2001, 09:28 PM
This may be a dumb question, but if you mill the exhaust manifold, will the valve covers height now get in the way? Hard to tell how much space is between the valve covers and the exhaust manifolds in the picture.

Scott Boldt

BERTRAM BOY
04-25-2001, 09:51 PM
Forrest,
I think you need to get rid of that Magnum.... that would definetly solve your problem.........have I got a deal for you !!!!!!
BERTRAM BOY

Formula Jr
04-26-2001, 05:40 AM
Don't move at all? Cool. You could have a single exhaust manifold tied to both banks.
Only cost ya about 12K. http://www.donzi.net/ubb/smile.gif

Real dumb question here - how the heck did you bolt those on?

Looped
04-26-2001, 07:31 AM
After milling the manifolds you can always buy the valve covers that have the angle on them so that it gives better clearance. Here is a picture that has the angle on the topside of them but they do make ones that have it on the outer topside of them.

http://www.paceparts.com/images/sbvc2.gif

Craig

Forrest
04-26-2001, 09:52 AM
Now that's the kind of advice that I'm looking for, guys. You know when I'm doing about ten-thousand different things at once, every now an then I get a brain fart . . . Paralysis through analysis! Right now there is about 1/16" between the manifold clamps and the valve covers. I'm thinking that if I mill a little off of the manifolds, the clamps will hit the valve covers, but I can deal with valve covers either by going to another style of valve cover, or as thick as those Holley valve covers are, I can do a little work with a die grinder to make 'em fit. The owner of the only real machine shop in town just retired and liquidated everything, so now I have to trust these babies with an unknown machinist. Gulp!!!

Oh yea Ownen, the first manifold is easy to install, the second is a b-i-t-c-h! No really, all you do is position the gastket on the head with a some gasket adhesive, then put the four bolts through the manifold, work the manifold into position without loosing the bolts in the bilge, and finally tighten the bolts with a box-end wrench. At least they don't weigh 90+ lb. each like the original iron.

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Forrest

[This message has been edited by Forrest (edited 04-26-2001).]

MattM
04-26-2001, 10:56 AM
Forrest, could you post a picture of your "offshore style" engine mount. I'd like to fab something for my 18, but am not sure what it shold look like. Also, if you mill your manifolds maybe milling a degree or two of angle on that face would let you keep more meat while angling the tops in a little giving you plenty of clearance.

Jamesbon
04-26-2001, 11:19 AM
Hmmmmm....maybe milling the manifold ports......

What'd you powder coat everything red? Looks REEAAAl GOOOOOOD!!!

Yeah, I second MattM's request for pics of the engine mounts.....

Forrest
04-26-2001, 03:36 PM
Nate, I used a super-secret paint formula that I could only find in a spray can at Lowes . . . are you ready . . . Krylon Epoxy Enamal - Color: Cherry Red. Price $3.29 /can. Everything was primed with zinc-chromate primer. I hope it last a while.

I think I have at least one pic of the motor mounts with one engine out . . . I post it here tonight.

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Forrest

BERTRAM BOY
04-26-2001, 03:59 PM
But seriously...... I was giving this some thought today. Depending on how far away you can get the manifolds, how about using one solid motor mount on each engine, toward the middle of course. I don't think that you'd want to use two per engine(too much vibration), but one would limit the travel under acceleration. I don't think that's going to solve the problem completely, but would probably help.
BERTRAM BOY

Forrest
04-26-2001, 05:29 PM
Cliff, that's exactly what it is, a one piece mount for each engine. Let me get that picture . . .

. . . I had to hang the camera into the bilge so this is about the best that I can do . . .
http://imagehost.auctionwatch.com/preview/bo/bowtiekid/.mids/mountcenter.JPG

http://imagehost.auctionwatch.com/preview/bo/bowtiekid/.mids/mountpad.JPG

http://imagehost.auctionwatch.com/preview/bo/bowtiekid/.mids/firstenginein.jpg

http://imagehost.auctionwatch.com/preview/bo/bowtiekid/Red383front.JPG


. . . also, I just found this GIL single engine race-mount on eBay (http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=1137163388) that you may want to check out.
http://abacus.sj.ipixmedia.com/abc/M28/7f554be60246ec5716734d1c/i-1_T.JPG
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Forrest


[This message has been edited by Forrest (edited 04-26-2001).]

[This message has been edited by Forrest (edited 04-27-2001).]

BigGrizzly
04-26-2001, 08:29 PM
mill the headders at 3-4 deg bevel, that will giv you about a1/4 inch at the clamp. If you think that is close. I saw a skater with inetertwined pipes. I didn't beleive Custom Marine did it but they did.

Randy

Scott Pearson
04-27-2001, 06:12 AM
Forrest,
Do you have a picture of those Manifolds off the boat? Or can you get some posted after you remove them? I have an Idea and I dont know if it will work or not. I would have to see what they look like.

(NJ)Scott

Looped
04-27-2001, 12:12 PM
Hey Forrest,
Here is a better shot of what type of v-covers with the angle I was trying to describe but they are real tough to find for sbc's. These are made from IMCO for BBC's maybe they make some for small blocks too?
http://www.flatlanderracing.com/images/vc46.jpg

Craig