Hot Rods XO/PP Bonneville project

XO and XXO.

 

So it’s all X’s and O’s then? Hehe.

 

I have found that with anything more than seven degrees of caster one is likely to encounter death wobble on a decell.

 

It's not a 200 mph vehicle, 6 will be fine.

 

I got the oil pan back from powder coat today, It looks really good.
I also finished up making bushings for the lifter bore holes to install mushroom style lifters with a 1"pad.
And we added a steering shock dampener in hopes to cure the front end problems we have been chasing.

 

Y-Block lifters?

 

Tested the truck again today and the death wobble is no more. Oh yeaah!!

 

Yes.

 

Outstanding work on the oil pan.

 

Thanks

 

Installed all the lifter bore adapters to fit mushroom style lifters from Trend Performance products

 

Next is the crank install with a piston and rod to check piston to valve clearance. Just waiting on the head back from Jimmy's Engine Service.
Once this is done we will deck the block for maximum compression ratio.
Looking for around 15 to 1

 

We are now ready to check valve to piston clearance
I'll pick up the Skinner head from Jimmy's Engine Service on friday

 

Just curious as to how you handeled the line bore. Since you're using billet main bearing caps, i assume you converted the main bearings to all the same diameter.

 

Nope, they're still staggered sizes. Our engine machine guy has an extremely skilled "retired" guy he calls on for "special" projects. He set us up.

EDIT: @jimmy six , this is the block you gave us. Thank you!

 

We need details. Where? How fast?

 

We test on the taxi way at a private airport in West Point. It's probably a little less than a mile long. I took her up to 70 one way and 90 on the return.

 

Was it the caster setting you changed to correct that?

 

We changed a lot of stuff - less caster, new drag link set up that has no play and is parallel with the ground and hairpins, rebuilt steering box, toe-in adjustment, and added a steering stabilizer. We still may swap out the tie rod drop blocks with dropped tie rod ends.

 

Top side photos of the lifter bore bushings to allow the use of mushroom style lifters

 

Is that piston at TDC?

 

I’m guessing yes… there is no chamber with a Skinner, Wayne or Horning 12 port head. You control compression with rod length and pin height when you have your pistons or rods made. If you don’t mind the expense you can have difference thicknesses in copper head gaskets made.
I believe most use 7cc for valve heads above the surface of the head. I still do castings with resin before I order gaskets to get the compression I want. I have never had valve overlap be a concern. Some builders have also made a chamber in the top of the piston but the spark plug location directs its construction. I personally like as flat a piston as possible.
Great work I enjoy following . . . Thanks John.

 

Yes, but the block has not been decked yet. As JD @jimmy six said above the Skinner head doesn't have combustion chambers. We are awaiting additional camshaft profile information before making a decision on how much the block will be decked to put the compression ratio exactly where we want it.

 

Almost ready for valve to piston check just need pushrods. Also taking a look at valve event timing.
Sorry no data on the cam at this time, maybe later.

 

I think you will find ample clearance with any cam on overlap. Once it’s all in test fit it will be great to know your true rocker ratio. All advertised have been BS I’ve found. I’ve always tested with lash caps, made adjustable push rods, and used different keepers on the spring retainers not only for proper pressure but to get the correct geometry on the rocker…. Even though I’ve done that since the 70’s, being retired gives me time to do all that in day light…

 

Quench area?

 

Skinner head has no quinch area

 

So pistons must have a dome of some sort? Can't see in pictures.

 

seb, most are just flat… if you think about it there is no shrouding of a valve this way. There have been pistons designed and used to have a “chamber” cut in and on the opposite side of the spark plug go up to the head but that is shrouding and many engineers have thoughts about it.
Think about the SBC and the different degree heads to achieve high compression with flat top lighter pistons.
Remember these were designed originally right after the war and 2 of the styles did have a chamber. The Horning, round, and the Algon, wedge. There are very few Algons and the Horning’s intake ports were not optimal at best.

 

Flat top pistons