Mid- Engine Modified Sports

[manta22]

Thanks for the advice, guys. I'll re-lash my valves to the cold values you suggest. After warm-up I'll re-lash them to Crower's recommended values.

When I was thinking about the relative expansion of the aluminum block vs a steel pushrod, I reasoned that aluminum expands more than steel so that the clearance closes up. I didn't consider that the rocker arm reverses that!

Somehow I overlooked the fact that there was no cam thrust button installed in my initial engine build. I remember seeing it somewhere back then, a steel needle bearing button, but it didn't get installed! I'm sure that accounted for the cam gear rubbing on the inside of the timing cover. It was not too serious but it may have been one source of some aluminum debris in by bearings. Needless to say, this afternoon I'll order a cam button if I can't find my original one.

If the cam moved forward, it must have also fouled up my ignition timing. Hmmm.

Regards, Neil  Tucson, AZ

[manta22]

I found that blasted cam button! It was still in the other gear drive that I had as a spare. Black on black- it was lucky that I found it. Maybe I grabbed the wrong one when I bolted it on. Anyway... It looks like it would be usable if it had all its original shims installed but someone (?) has removed most of them so it's now too short. I've ordered another roller bearing button and a Nylon one just in case I might need it.

It's really hard to get useful information on car parts. It seems like nobody knows much of anything about what they're selling. I tried to find dimensional info on cam buttons and some (Jegs) only showed the dimensions of the box it was packaged in! Really useful. Even manufacturers don't provide much of anything, the prevailing philosophy seems to be "order it and see if it works". Arrrggghhhh.

[manta22]

Here is the elusive cam button.

Regards, Neil  Tucson, AZ

[handyguy]

That is quite a piee to be somewhere else !!

[Dynoroom]

Here is the elusive cam button.

Regards, Neil  Tucson, AZ

Sorry to keep raining on your parade Neil, it's not intentional.
If you are going to install the thrust button now you need to do a few other things first. This type of thrust button requires some thrust (no less then .010 but ideally no more than .020 IMO) but this means you need to check it. The correct way to do this is when you start the assembly of the engine before the cam plug is in place. But you are beyond that point. So now I would remove all the pushrods so there is no load on the cam, install the bearing & front cover then reach through a lifter bore (after you remove a pair) & using a screw driver on a lobe load the cam forward & back to make sure I have a reasonable amount of movement, not too much, not too little. Especially not too little! At this point it will be your best guess.
Really sorry to keep being the guy who brings a dark cloud. 

[fordboy628]

Here is the elusive cam button.

Regards, Neil  Tucson, AZ

Sorry to keep raining on your parade Neil, it's not intentional.
If you are going to install the thrust button now you need to do a few other things first. This type of thrust button requires some thrust (no less then .010 but ideally no more than .020 IMO) but this means you need to check it. The correct way to do this is when you start the assembly of the engine before the cam plug is in place. But you are beyond that point. So now I would remove all the pushrods so there is no load on the cam, install the bearing & front cover then reach through a lifter bore (after you remove a pair) & using a screw driver on a lobe load the cam forward & back to make sure I have a reasonable amount of movement, not too much, not too little. Especially not too little! At this point it will be your best guess.
Really sorry to keep being the guy who brings a dark cloud. 

Neil,

I also am sorry to keep offering possible solutions, "after the fact" . . . . . .

My suggestion is that you take some time and make a list somehow, (I use an Excel spreadsheet), of "check list items", in the order of engine assembly.    Do this now while the memory of how things should be done, is fresh in your mind.   It does not have to be "the perfect list", just a starting point incorporating what you know now, items can always be added or revised.    The great thing about an Excel spreadsheet is that it can easily be "revised" as you go forward.     I suggest you break it down for every operation, no matter how small or seemingly "unimportant".

I think there are several of these available online.    Might require a bit of searching though.    Then just modify it to make it yours.

If you use it as intended, then when you come back to assembling after some "hiatus", you don't have to try to remember where the heck you were and what is done for sure.

It's intended to prevent all those "arrrggghhh" moments . . . . . .

Diligence about records DOES add time to the assembly process.    But I find it helps to provide a better finished project.    And can add "piece of mind" . . . . .

 
Mark

[Peter Jack]

There's a book out there by Waddell Wilson who built really successful NASCAR engines back in the day. It's called "Racing Engine Preparation" and it's still available but the pricing looks absolutely ridiculous to those of us who bought it when it first came out. Whatever it costs you it's worth it if you follow all the instructions on preparation and assembly. The part numbers were long ago obsolete.

Good luck with the reassembly Neil.

Pete

[manta22]

Thank you for all of your suggestions and comments, they are truly helpful and I welcome your inputs. After all, that's part of the learning process. Disregarding constructive criticism from knowledgeable and experienced people would be foolish.

DynoRoom:

Measuring the cam button clearance will not be difficult as my timing gear drive cover has a removable flat round plate that covers the cam gear. I'll install the button, push the cam gear to the rear so it seats on its rear thrust bearing, and place a straight edge across the access cover where the cover plate seats and then measure the clearance with a feeler gauge. No need to remove the rear cam plug or lifters thanks to the removable cover plate.

[manta22]

My engine is almost finished but I'll post a picture of it before the intake manifold and valve covers were installed. It is an aluminum block Donovan 383 CID. This particular block was originally sold to Dan Gurney for his "stock block" class Indy car in '82 or '83. He entered it as a "Chevrolet".

[robfrey]

Wow! This block has some history!


Rob Freyvogel
#496
AA/BFS

[manta22]

Yes, it has. I did not know about it until I called Donovan last year to ask about its cylinder liner thickness. They checked the serial number and told me that Dan Gurney's "All- American Racers" had been its original purchaser.

Regards, Neil  Tucson, AZ

[WOODY@DDLLC]

Wow! This block has some history!


Rob Freyvogel
#496
AA/BFS

So do the members, Rob! 

[floydjer]

Neil...Different ratio rockers or are those color coded?  Red hot/blue cold. I can see that simplifying lash setting time.

[gray63]

Neil,  It is really cool seeing this engine in actual use rather than someone having it on their shelf or used
as a coffee table in their mancave.
I am looking forward to your future success.

Dave Gray
3611 BGMS Corvette

[manta22]

Neil...Different ratio rockers or are those color coded?  Red hot/blue cold. I can see that simplifying lash setting time.

You guessed it- blue for intake, red for exhaust.

Regards, Neil  Tucson, AZ