Cam Degreeing/Checking Important

[GOSFAST]

I still find it hard to believe with all the emphasis on precision (especially in engine building) that a cam could be designed, cast, and machined that doesn't conform to spec in the most elementary way. What's worse is that obviously it happens enough that cam degreeing is a routine part of engine building. Is it really so hard to machine it in line with the spec?

Makes me wonder about other faults that are out there.

Hi Mike, you would not believe what we see here EVERY day, day in and day out, not only on these Flatheads??

I'll have more to add about the original topic, with respect to "controlling" the overall end play, a bit later today! Absolutely no different when building a SB or BB Chevy with a roller cam in the older units, with a cam button, end play MUST be "controlled". We set these at .003".

Read the P.S. below, this issue discovered yesterday has totally stopped us from assembling a forum members build. Of 4 Flathead builds going on at the moment two had a number of issues beyond our control and the other two we haven't begun assembling yet!

Thanks, Gary in N.Y.

P.S. Went to install a Speedway/Offenhauser "custom" timing cover on a "blown" unit here and discovered there is no way it's going on w/o some very major "surgery", I can't even get it started to go! The other issue I mentioned above was with a 100% defective pressure plate from a respectable clutch builder (they had to replace it, more downtime for us), you just can't take anything for granted, ALL must be scrutinized closely.

 

[Bored&Stroked]

I hear yah Gary . . . one has to check everything and there are usually issues to solve. This is why you can rarely build an engine and everything just "bolts up" and has the correct clearances . . . just doesn't happen!

Great Example: Friend bought a re-pop Winfield SU-1A cam and I was going to help him install it (new engine build). In my initial look at it, the journals seemed a bit small - so I took out my 1" - 2" mic . . . yep, .010 undersize. I check everything - regardless of where it came from or what I want to believe . . .

Many folks/shops would not even have checked it . . . then wondered why the oil pressure was very low with STD cam bearings!

Tis the nature of the beast . . .

 

[Ronnieroadster]

I hear yah Gary . . . one has to check everything and there are usually issues to solve. This is why you can rarely build an engine and everything just "bolts up" and has the correct clearances . . . just doesn't happen!

Great Example: Friend bought a re-pop Winfield SU-1A cam and I was going to help him install it (new engine build). In my initial look at it, the journals seemed a bit small - so I took out my 1" - 2" mic . . . yep, .010 undersize. I check everything - regardless of where it came from or what I want to believe . . .

Many folks/shops would not even have checked it . . . then wondered why the oil pressure was very low with STD cam bearings!

Tis the nature of the beast . . .

Dale great example of why when someone wants a Flathead built they really need to go to the experts who know what to do. Not just the local machine shop that on occasion will build a Flathead in between a Chevy, Toyota or Honda builds especially when its a modified Flathead. Heck decades ago i ran into an Isky cam new out of the box with .010 under cam bearing journals of course discovered after the crank assembly was already installed! Ford dimension 1.7955 is etched into my memory for just this reason. Lesson learned measure cam before installing cam bearings. This talk about cam end play is interesting my solution is simple check end play without cover gasket prior to assembly most of my builds do not have cover gaskets to help on this movement issue just something I always do.
Ronnieroadster

 

[RalphM]

P.S. Went to install a Speedway/Offenhauser "custom" timing cover on a "blown" unit here and discovered there is no way it's going on w/o some very major "surgery", I can't even get it started to go!

I had one of those covers several years ago tried to put it on and never could get the damn thing to fit right.

 

[Ol' Ron]

I find that cam backlash is pretty bad on the 8BA cams, I've found as much as .022", The 59 covers , if not worn to bad can hold closer tolerance. I never use the cover gasket. On the 8ba cam you have to put a shim behind the dist drive gear. I always use the early timing gears, this puts the thrust against the block under all engine operations. I didn;t realize this untill we switched to an 8ba cam in the stock car..
Learn sumpin every day.

 

[GOSFAST]

When you're ready to begin the actual (final) assembling of the build the very first item to begin with is the installation of the camshaft. If it's not going to go in and turn correctly you want to know this way before any other pieces are installed.

When we do cam brg installations here on any builds we check every one with a an older cam blank with the lobes taped up so as not to mark up the new brgs. we don't want any calls AFTER the fact!

Below here is a few shots of the cam end-play being checked and addressed, you can see the dial indicator (not really able to read it) showing the EXACT amount of movement, on this build it has .005" clearance, "dead-on".

If you look closely you can see the "nylon" cam button in the photos below fitted to the cover to keep it all in place.

Thanks, Gary in N.Y.

P.S. The first 2 shots show the dial indicator, the second 2 show the button separate from the cover and then installed sitting in place! This was all checked with the timing cover gasket in place and all 5 cover bolts tightened!

 

[Ronnieroadster]

I find that cam backlash is pretty bad on the 8BA cams, I've found as much as .022", The 59 covers , if not worn to bad can hold closer tolerance. I never use the cover gasket. On the 8ba cam you have to put a shim behind the dist drive gear. I always use the early timing gears, this puts the thrust against the block under all engine operations. I didn;t realize this untill we switched to an 8ba cam in the stock car..
Learn sumpin every day.

Ron the idea the early cam/crank gears thrust towards the block being a good idea is not what it seems. Without anything else in the assembly thats exactly what happens thrust is rearward into the block. However when add in the oil pump idler gear and the oil pump you will find the cam is now trusting forward. Testing this was a surprise to me again I learned something new but that was a very long time ago now.
Ronnieroadster

 

[Ol' Ron]

Ron & Gray
Like I say learn sumpin every day. I like the method you use for the cam thrunt and never considered the oil pump drive. It's amazing how much there still is to learn about these engines. I wonder if my new port will work?

 

[Bored&Stroked]

Given my expeience with the Cloyes adjustable SBC timing cover, I think if/when I built another 8BA I will make an adustable "button" with a bearing in it - that way I can get exactly the end-play/backlash that I want and with the engine running (or on the dyno), I can actually adjust it if needed. I was VERY happy to have that timing cover on the SBC - it saved me from having to screw around with a cover that only allows pre-adjustment/setup of the backlash - not after it has actually ran a bit.

 

[V8COOPMAN]

…... or the cam is incorrectly ground. Now I have the question, have any of you ever gone through every lobe in the cam checking for specs? Amazing seeing how much some of these are off.

It can be EXTREMELY amazing! I bought a brand new "151" 350 HP Chevy cam across the local Chevy dealer's counter about 1968. I threw it in a little 283 I rebuilt for a friend's '61 Vette. Had hell trying to initially set some of the rocker arms. That thing wouldn't crank for nothin'. We even tried pulling it...notta! After much butt-scratching, I pulled the cam back out and laid it beside the stock cam. NINE lobes out of sixteen were ground nowhere near where they were supposed to be on that stick. Only after finally convincing the guys at the Chevy house to lay another cam beside this one did they believe that this cam came from the manufacturer ground this way. DD

 

[GOSFAST]

Given my expeience with the Cloyes adjustable SBC timing cover, I think if/when I built another 8BA I will make an adustable "button" with a bearing in it - that way I can get exactly the end-play/backlash that I want and with the engine running (or on the dyno), I can actually adjust it if needed. I was VERY happy to have that timing cover on the SBC - it saved me from having to screw around with a cover that only allows pre-adjustment/setup of the backlash - not after it has actually ran a bit.

Hi Dale, do yourself a great favor and get away from using cam buttons at all, all-in-all they are a "headache" to setup (time-consuming) and just more "moving" parts in the unit (this is assuming you use the roller buttons like we use to)!

P.S. If you have time here's a method we actually devised over here to eliminate the buttons in the early SBC's, we set them up like the later OEM roller units with the stepped-nose cams and the thrust plates. We've actually sold dozens of the installation kits so far, containing ALL the necessary tooling/components to set up the early blocks with the stepped-nose cams, mostly to other machine shops. No more "adjusting/measuring/shimming", put the cam in, bolt on the thrust plate, throw on the timing chain, and you've got your .003"/.004" end play! If you have time follow this link here, the entire story is over on the Chevelle site! Makes no difference anymore which timing cover you use!! We've built "dozens" already with our method.

https://www.chevelles.com/forums/18-engine/?daysprune=-1&order=asc&sort=postusername (It's the second "sticky" down)

 

[Pete]

It can be EXTREMELY amazing! I bought a brand new "151" 350 HP Chevy cam across the local Chevy dealer's counter about 1968. I threw it in a little 283 I rebuilt for a friend's '61 Vette. Had hell trying to initially set some of the rocker arms. That thing wouldn't crank for nothin'. We even tried pulling it...notta! After much butt-scratching, I pulled the cam back out and laid it beside the stock cam. NINE lobes out of sixteen were ground nowhere near where they were supposed to be on that stick. Only after finally convincing the guys at the Chevy house to lay another cam beside this one did they believe that this cam came from the manufacturer ground this way. DD

You might have had a cam for a left hand marine engine. Some were gear drive, some were chain drive. In either case the lobes were in different locations from a standard right hand automotive one.

 

[V8COOPMAN]

You might have had a cam for a left hand marine engine. Some were gear drive, some were chain drive. In either case the lobes were in different locations from a standard right hand automotive one.

Purchased from Knapp Chevrolet, Washington Ave., Houston.....they don't sell boat parts. Plus, it had the correct "3863151" part number on the tube. DD

 

[JSeery]

V8, the supplier/manufacture could have mixed them up?

 

[Pete]

Purchased from Knapp Chevrolet, Washington Ave., Houston.....they don't sell boat parts. Plus, it had the correct "3863151" part number on the tube. DD

My local Chev dealer sold a cam to my customer once. The box had been opened at some point and a new gear drive marine cam exchanged for the original one in the box. Who knows why but guess how I can relate to part of your story.

 

[Ol' Ron]

Monday morning cam

 

[Bored&Stroked]

Hi Dale, do yourself a great favor and get away from using cam buttons at all, all-in-all they are a "headache" to setup (time-consuming) and just more "moving" parts in the unit (this is assuming you use the roller buttons like we use to)!

Hey Gary - good idea! I used a similar technique on the FlatCad engine for Bonneville - using a Timken thrust bearing and my own thrust plate - then I put a BBC Chevy nose on the cam and ran a Donovan gear drive. I much prefer a thrust setup like this - over anything that uses the timing cover.

I'll checkout your link - seems like a good way to go on any SBC/BBC type engine. Thanks!

 

[Desoto291Hemi]

Gary I am glad to hear this now.
I have degreed every cam I have ever used,,,,but I have never owned a Flathead before.
I just assumed they were doweled already to the cam gear.

Didn’t Isky do this already?
I can’t believe no one has ever done a kit with a cam gear already drilled for a dowel to set the cam timing advance.
Man,,,I am glad I came here,,,already learned a few things,,,no longer than I have been here.

Tommy

 

[GOSFAST]

Gary I am glad to hear this now.
I have degreed every cam I have ever used,,,,but I have never owned a Flathead before.
I just assumed they were doweled already to the cam gear.

Didn’t Isky do this already?
I can’t believe no one has ever done a kit with a cam gear already drilled for a dowel to set the cam timing advance.
Man,,,I am glad I came here,,,already learned a few things,,,no longer than I have been here.

Tommy

Hi Tom, many of the procedures we do no one else in the country is doing to the best of my knowledge anyway??

Here's a few:

We pin the heads/gaskets to the blocks, same as a SBC (we do this with the block plate that we use to finish-hone every block we build). This keeps the heads from "moving around"?

We set up the cam up with a "pin and (sometimes) a pill", also the same as the SBC, makes moving (degreeing) the cam a simple task.

We install bronze-lined guides/stainless valves in EVERY build we do here along with some "Viton" valve stem seals on the intakes!!

We use "Teflon" coated cam brgs (when needed to tighten up cam brg clearances some).

We do the oiling modification to the blocks to run a "real" remote oil filter. This is done by others.

More recently (in the last couple months) we began modifying the dipstick mounting brkts on the pans to be 100% removable from the outside without "dropping" the pan! I can all but guarantee the original gasket is about disintegrated? This is something you'll never know unless you remove the OEM rivets!

An oversea's member here just ordered a kit to modify his!

There's probably more but that's about all I can think of tonight!

Thanks, Gary in N.Y.

P.S. On a side note here I see you're into the early "Hemi's", just did a 341"/345 HP (I believe) from a '57 Desoto? Have also been talking to my friend at "Topline" (the original Johnson adj tappet mfr) about doing a hyd-lifter Flattie, not sure it will ever happen, but I've been kicking it around! We could pull it off here, I know it, I'm just running low on time!! I have another member's build here now with so many issues with some of the aftermarket parts (alum timing cover/Mallory distributor), these were supplied by customer, I'm not certain tonight we can even use them? These are for his "blown" unit.

 

[Desoto291Hemi]

I will be communicating with you soon.

Sorry,,,I don’t mean anything by this,,,,but your in Long Island,,,,,what n the world is a Flathead shop doing in Long Island,,,,Lol?
Man,,,I can’t believe it.
I remember reading some stories years ago about a lot of Mopar guys in New York and Jersey,,,and having a lot of Hemi stuff,,,they were really cool guys too!
But,,,Flatheads,,,,,man I am blown away,,,,Lol
You seem to really know your stuff too,,,,no BS artist.

I will definitely contact you for some help soon.

Tommy