The Ford Barn

Mikeinnj · 02-19-2018, 08:53 PM

Quote:

Originally Posted by midgetracer

After reading this thread, I panicked and checked the adjustable tappets that I had purchased a few years ago to build a spare engine for my Model As. I checked them and sure as hell, they are about 1/8 inch smaller in base diameter than stock ones. I am not even sure where I purchased them, so return is not an option. They are exactly the width of the cam lobes. Will these cause problems for my cam? Should I just junk them and buy good ones? Being car poor, I have waited to assemble this engine and another $100 seems like a lot right now, but early failure of this engine would be even more expensive. What do you think.... A. give up beer?

...B. put the junk tappets on Ebay and pass along the problem?

..C. Wait for my ship to come in?

D. use the tappets and go to church a bit more often?

No option seems right. Seriously would I have much of a chance of getting by with these tappets ?

What is the actual base diameter of the tappets that you bought ?
When you mention the "stock ones" are they the non adjustable type ?
What type of cam are you using; original;reground,new Stype performance cam ?

Tom Wesenberg · 02-20-2018, 03:40 AM

It depends on the opening and closing ramps for the cam lobes. You could put a thin coat of blueing on the tappet base, then roll the cam around and check to see if the blueing got scraped off the edge of the tappets.

I bought a set of adjjustable tappets several years ago, and they are still in the blister pack, but I have a feeling they are also the small diameter ones.

midgetracer · 02-21-2018, 01:14 AM

Quote:

Originally Posted by Mikeinnj

What is the actual base diameter of the tappets that you bought ?
When you mention the "stock ones" are they the non adjustable type ?
What type of cam are you using; original;reground,new Stype performance cam ?

Actual base diameter of the purchased tappets is just shy of 1 inch. Cam is stock Model A not reground 5 bearing style. The stock ones are the non adjustable type originally used in the Model A.

Tom, I will try the bluing test tomorrow and post results.

PC/SR · 02-21-2018, 12:09 PM

The stock lifter is 1.110--1.125. That is a lot of tolerance. As I recall, the so called double lock lifters are .998, and the single lock friction fit are 1.118.

Jim Brierley · 02-21-2018, 12:16 PM

They should be OK with a stock cam, but going to church wouldn't be a bad idea.

02-20-2018, 03:40 AM	#22
Tom Wesenberg Senior Member Join Date: May 2010 Location: Mpls, MN Posts: 27,582	Re: Tappets? It depends on the opening and closing ramps for the cam lobes. You could put a thin coat of blueing on the tappet base, then roll the cam around and check to see if the blueing got scraped off the edge of the tappets. I bought a set of adjjustable tappets several years ago, and they are still in the blister pack, but I have a feeling they are also the small diameter ones.

02-21-2018, 12:09 PM	#24
PC/SR Senior Member Join Date: May 2010 Location: Santa Rosa, CA Posts: 1,278	Re: Tappets? The stock lifter is 1.110--1.125. That is a lot of tolerance. As I recall, the so called double lock lifters are .998, and the single lock friction fit are 1.118.

02-21-2018, 12:16 PM	#25
Jim Brierley Senior Member Join Date: Jun 2010 Location: Temecula, CA Posts: 4,085	Re: Tappets? They should be OK with a stock cam, but going to church wouldn't be a bad idea.