The Stovebolt Site Forums The Shop Area Engine Shop Offy & Fenton = poor fit

Patrick is right, these two guys didn't consult each other about thier respective manifolds. I've done a trial fit on them and after grinding and filing what seems like too much off the intake I am still not there. I'll get that part with enough patience but my question concerns the bolts and clamps used. On the end bolts what are you people using for the "clamp" that goes over the boss on each of the manifolds? The stock one's will need considerable modification to work on the uneven surfaces of the two bosses it pulls down over. The use of washers would look sloppy at worst and half-assed at best. Any other ideas?

Can you post pictures of the mis-match in flange height?

:mad: :mad: :mad:
Isn't that set up a pitiful mess!! :mad: I had to notch my clamps to make them work right between the intake and the headers. I ran that set up for awhile and everytime I looked at it, I became more and more unhappy. It did work fine, it just didn't look right. I finally bought a set of original headers when I found the flange on them to be more equal in thicknes to the flange on the intake, any intake!
:confused: I don't see where you can do anything else but to notch them.

A I recall, the Fenton flanges/ears are thicker than the Offenhauser ears/flanges. I slowly and carefully ground down the Fenton flanges/ears until they matched those on the Offy intake. Then I used the original bolts and "clamps" (actually I used the original clamps and stainless bolts from Totally Stainless).

The bigger problem I had was taking enough metal off the intake and exhaust manifolds so that they did not touch. Use paper (carbon paper if you can find it) to place between the tight edge to be sure they do not touch when you clamp them together to the head. As I recall, I ground metal from the Offenhauser edge but still had to cut a matching "groove" in the Fentons. They now match up fine.

I used a bolt with washer at each end of the Fenton/head, even though originally a stud was at each end.

Tim

My Clifford 6=8/Fenton set-up was just as pitiful. Grind and fit, grind and fit, grind and fit.

I had a Offy dual carb manufold and Fentons, required some grinding on the intake and I built up weld on those oval manifold clamps to get a good fit. Typical aftermarket parts,"custom fit" .Then I switched to a Clifford heated 4bbl intake, fit with no probems.
This grinding ,hammering and welding a challange,keeps the brain working.

tclederman, I see from your post that you are using the Totally Stainless bolts for your manifold setup. I have the same SS bolt kit for my engine, but I remember a post on one of these boards, which advised against using them for the manifold application due to some interaction of the SS with the cast iron head/heat.

Here is the post I saw: http://www.stovebolt.com/bboard/cgi-bin//ultimatebb.cgi?ubb=get_topic;f=2;t=002671#000001

cujo8,

I have read similar opinions and experiences regarding problems with stainless steel hardware. Totally Stainless hex head bolts are supposedly equivalent to grade 5 (non-graded stainless at hardware stores might be grade 2). Totally Stainless also sells a grade 8 equivalent line of bolts.

The bolts on my 261 have been in place for about 6 years and I have had the manifolds off a couple times over those years. I always use a stainless anti-galling compound. No galling, heat discoloration, or galvanic corrosion has been apparent.

Regarding galvanic collosion, maybe the lack of water/moisture in the location of the manifold bolts lessens the likelihood of this occurring. also, my understanding is that corrosion/loss would take place on the stainless part - if I see it happening, it is easy to change these bolts.

Bottom line is that I am concerned about these matters and am keeping an eye on it.

Tim

Manifold fitting is easiest to do with the head on the workbench. It's worth the time to pull it off the engine.

Stainless bolts that have known heat treat should be okay. I would use a high temp locktite to put them it, it should keep the corrosion down.

tclederman, What is the brand name of the "Stainless anti-galling compound" that you use? Is it the same stuff that Totally Stainless includes in their kit?

What kind of carb or carbs are you guys using? I have the Fenton and Offy set up with 2 single carbs but they seem to be a bit rich. I also had the same nightmare with the flanges.

I see everyone eles had a great time installing the Fenton/Offy setup too. I had already talked to someone prior to putting mine on, so I knew what to expect. The casting on the Fentons is awfull at the flanges. The muffler guy got a kick out of that. I've got 2 one barrels and they work all right. Leaky suckers though. I didn't install any heater on it. It doesn't get that cold here in So.Cal. [img]http://community.webshots.com/s/image6/7/30/30/92773030mWtEVi_ph.jpg[/img]

rat,

My 261 with Fenton exhaust and Offenhauser intake has two one-barrel Rochesters on it. After running it without a heated intake for two years, and experiencing hestitation at low revs, I installed a heating plate (water from the cooling system) from Tom Langdon's Stovebolt Engine Co. and it runs much smoother.

Are you heating your intake? I understand that it might be warm where you are (I dream of being warm at this time of the year) but the intake can get quite cold from latent heat of vaporization (I think that is what it is called). Supposedlly, an unheated intake can get so cold that it can cause the vaporized gas to recondense inside the manifold - this could result in a properly tuned set of carbs running rich at times.

Tim

I set the head up on the bench for ease of working with it. I had to grind some clamps and weld plate steel to others to take up the slack between clifford/fenton setup. But now it works really well, and I didnt grind on the manifolds or intake. I like my water heated intake and 4bbl. People freak when they see that hanging off a straight 6.

chip

Yes the fit is bad, you kinda worry as your grinding. Also had to clean up a spot or two on the fentons. The clamps are modified to give a step effect between the two. Mine are now in Williamson NY,after the water jacket opened on the 235 (swallowed a valve) now have an injected Vortec in the frame and running at this time. smo-o-o-t-h. Zeke

cujo8,

Sorry about my delay in responding to your question. I use the Anti-Seize Lubricant that I think I got it from Totally Stainless but I might have gotten it from MSC .

It is Permatex ANTI-SEIZE LUBRICANT, 133A.

Tim