Offy 4 BBL Intake potential problem?

[DanR]

Here are a few PIC's I took of an intake manifold being installed on a 2.8 V6 Ford engine.

In the 1st PIC notice the point where the front portion of the "bottom" actually touches the timing cover.

The 2nd PIC is perhaps a bit more clear.

The 3rd and the 4th show the contact point as well.

The intake does not yet have the gasket between the engine and the "Bottom of the OFY manifold. But there is not a lot of clearance after tightening the bolts to spec's.

Note: the manifold bottom is aligned properly and spaced with bolts (temporary) holding in place.

Has anyone else encountered similar contact with their OFY Manifold?

DanR

As a solution I am planning to grind a small portion from the manifold to ensure adequate clearance.

 

[DanR]

Additional Comments of OFY installation

After receiving the proper Bolt Kit for the OFY Intake, I proceeded to "fit" before final installation.

Here is what I encountered with the process.

1st PIC Shows a bolt sticking up just before the threads make contact. It is all the way down in position, just before threads begin holding.

2nd PIC Shows a bolt in another hole of the manifold that does not stick up just before the threads make contact. It is all the way down as the first. Note also that the other two bolts ( a total of for utilized for fastening the "bottom" in place) are same as the second.

The bolts are identical in length. All start threading easily all thread down the same (number of threads) I counted by careful measurement.

Only there is a definite difference which I have not been able to determine.

Is it possible for the casting of the engine block to be "higher" in this particular spot and cause this difference.

What started me questioning was when I attempted to tighten the four bolts in position and one would not secure the bottom manifold. I actually removed the other three and tried the one by itself to prove to myself that it would not hold the intake in place.

Not yet satisfied, I did however shorten one of the bolts to compensate the difference for the time being..... Might be a permanent solution though?

Makes me wonder if something similar could happen to another engine and not be suspect?

 

[phyrman]

I wonder if the threads are cut into the block further down due to them being stripped earlier?????

BD

 

[DanR]

Bruce, All four holes are the same depth.... The threads do not appear to have been worked or reworked in any way.

DanR

 

[MikeH]

Did you mill the heads at all? What about the block, anything beyond decking. If you did, I remember reading somewhere (maybe the Pruett book) that the intake would need to be machined to correct it for the difference. I'll have to go back and look for the information.

Edit. I went back and found a section called Manifold Angle Correction, page 87 in the Pruett book. I think Jim E mentioned something about it when he did my heads. I will go back through those emails and PMs that I saved.

You also mentioned the gaskets were not in place. That could make a difference.

 

[DanR]

Bolt Kit Problem RESOLVED !!

Through trial and error I learn alot

This time it took a while to come up with a solution that is very simple.

First let me explain from the beginning, Ordered two bolt kits (2 top and 2 bottom), because I have more than one Ofy 4 bbl to install.

Bolt kits arrived and I open one of the packs to start the "fitting" process. That is when I discovered one of the bolts would not fasten down. Went thru all sorts of trials and could not come to a logical solution.

Cut one of the 4 bolts (8 mm 1.25 100mm lg) to 93-94 mm so that it would fit.

After POST'n on the Forum and sitt'n over night I went back and reviewed teh day before.

Nothing new.

Pulled the second bolt kit out of the package and Guess what? Three short bolt 90mm and one 100mm ? Why three short and one long was a question I could not get an answer to!

Took one of the short bolts (90mm) and tried in the hole that I had shorten a bolt the day before.... Bingo! fit nicely.

Why did I get three short bolts? in one package and four long ones in another?

Started looking and examining the valve lifter valley and discovered that the one threaded hole in the block sits about 10mm taller than the other three.

Next I went to several other blocks and discovered the same thing.

PROBLEM RESOLVED At least for me from now on.

Called the OFY outfit and discussed with them the short and long bolts, the gent said he would send me (one) 100mm bolt. End of discussion.

I have read and re-read the the "HOW TO BUILD AND MODIFY FORD 60 degree V-6 Engines but haven't read anything that refers to the difference in the "FOUR BOLTS" that fasten down the bottom piece of the OFY. I can see where it "could be overlooked" in the tightening process and cause some problems later on down the road.

I've included three PIC's, the 1st two are showing the "raised" threaded portion of the lifter valley on one side of the engine between the # 2 & 3 cylinder side. The other three thread holes are same height. (3rd PIC shows two front holes).

DanR

 

[DanR]

Did you mill the heads at all? What about the block, anything beyond decking. If you did, I remember reading somewhere (maybe the Pruett book) that the intake would need to be machined to correct it for the difference. I'll have to go back and look for the information.

Edit. I went back and found a section called Manifold Angle Correction, page 87 in the Pruett book. I think Jim E mentioned something about it when he did my heads. I will go back through those emails and PMs that I saved.

You also mentioned the gaskets were not in place. That could make a difference.[/QUOTe
MikeH, Thanks for your help and references.... All good info but not applicable in this case as a solution to the problem I had, My mistake was explained in the above POST I just made about the different height of one threaded hole in the lifter valley.

 

[crs]

Dan,
Glad to hear that you figured it out.
My Offy four barrel manifold went on without issues as my mechanic would have said something if there were problems.

PLUS - when the engine was documented and hopped up to 3/4 race specs, the heads were milled and that was never an issue either.
All this reminds me that we have no rain forecast here for several days, so I should take the car for a spin. Just to charge the battery , you know.

 

[Ken Ellis]

Ahh, "solar" battery charger... for the cells and the operator.

 

[DanR]

crs,

Quote: My Offy four barrel manifold went on without issues as my mechanic would have said something if there were problems. Unquote

That is exactly what I'm thinking with my Commodore Blue V6 !

Hoping my Machine Guy "caught"the difference in the 4th bolt needing to be 10mm shorter than the rest

You can actually tighten the bolt in question down into the recessed hole, but, not secure the bottom Ofy piece

Perhaps my V6 is done properly also. I have tried to test for leaks in and around the manifold to resolve my idle problem. To date none! The car runs on the open road very nicely but still will not idle under 1250 RPM.

All the suggestions and recommendation for the Forum Members have not been fully tested yet! I am continually testing them.

Thanks to one and all,

DanR

 

[crs]

"The car runs on the open road very nicely but still will not idle under 1250 RPM."

You know, I had that same idle issue with my Holley 4bbl.
IIRC, it had to do with the slow idle setting and I had to talk to folks (Jose, my garage owner friend, and another mechanic that had worked on the final stages of the engine swap) before I figured it out myself. The resolution was in the manner the slow idle was to be adjusted.
I will try to remember and if not will look into my voluminous V6 files.

Right now I am off to pick some peaches off our trees. YUUUMMM!!!

 

[DanR]

Sounds like something 260 was saying for me to do....I've still some of those suggestions yet to do.


DanR

 

[crs]

Dan,
Did you receive my reply to your PM?
When I tried to send it, I received a message that my PM storage was full.
That may have caused my message to be lost.
Since then I have cleaned out most of the stored messages.

Bottom line = I did not follow Jose's cam recommendations. We went with a well known local hot rod shop for the rebuild of the V6 block we had. The owner and I had to talk my son (who was paying for the engine work) out of a full race cam - thank god we did as the thing is a handful as is.

If you get out this way, let me know and we can take it for a spin; but no popping the clutch and no flooring it before we get the revs up! !

Then, if you really want a thrill, Colin can take you for a ride in his 800 HP 370Z done by http://jotechracing.com/ . He has been wanting to take the Alpine to Jotech to put it on their dyno, but he has not offered to pay for that.

 

[Cactusmasher]

Offy Intake bolt problem

Dan: There is a reason for the different length bolts. If my recollection is correct, The four longer bolts are installed two in the front and two in the rear of the manifold connecting it to the heads. Try fitting the manifold with gaskets in place....if that doesn't eliminate the contact between the manifold and the block the old hot rodder trick would be to judiciously grind away some of the aluminum at the contact points. The manifold is beefy enough that a little trim here or there won't affect the operation of it. That's my 2 cents worth.

 

[DanR]

Jim, The Kit is supposed to have three 8-1.25 100mm and one 90mm because of the "raised" area in the lifter valley. The PIC's in Pruitt's book and the PIC's I took of the three different blocks I have all show that "one" threaded riser located between the no 2 & 3 cylinder (passengers side USA) being about 10mm taller than the other three.

Ofy Parts sent me a mixed bag of bolts. I now have what it takes.

Fitted with gaskets in place the bolt situation is the same. 3 long and 1 shorter does the trick.

I did grind a bit from the lip of the Ofy bottom piece where it touched the timing cover. All is well.

I paid about $28.00 for the bottom bolt kit 6097 BBK which consisted of 4 8 mm bolts. Found them at Fastenall for 1.00 ea. Any one needing them I have a bag full $1.00 each

DanR

 

[DanR]

crs, I did get your pm....

I bet you guys had a time talking your son out of the race cam

When I come thru I'll give you a call.

The Delta Rep I spoke with said I had a full race cam so I can attest to the fact it is a hot one.

If I intended to race it would be excellent, but for a frequent driver one a bit milder would really make me happy. The next engines, two of which I am now building will have a more milder street version.

DanR

P.S. I think I'll pass on the 800HP

 

[mike_also]

Recently bought a used Offy with an unopened accessory pkg and it did not contain enough 8.25X100 bolts to hold down the manifold. No problem, the local Tru-Value carries shapes and sizes of fasteners to put Home Depot and Lowes to shame. Bought 4 more and shortened the length of 2 for the corners and grind a scintilla from the circumference of the hex heads for the 4 interior hold-down bolts. The bolts hold the intake manifold in place securely.

 

[DanR]

Hi, Mike_also, KNOWING WHAT BOLTS TO USE IS IDEAL........

Like you I eventually found them at Fastenal.

I have a whole bag full now Save about $20....Should any one need some, I have them $1.00 a piece

DanR