The Ford Barn

skeazle · 09-22-2021, 02:43 PM

I would like to do a compression test on my '30 Model A. I didn't buy the gauge yet but I also know i will need an adapter to thread in to the spark plug holes. Can anyone tell me what size and where can I find it? Jim

Rob Doe · 09-22-2021, 03:06 PM

The vendors have them. 7/8-18 thread.

nkaminar · 09-22-2021, 03:07 PM

Vendors sell 14mm spark pug adapters. At Snyders the part number is A-12405-ADP and the price is $6.75.

Patrick L. · 09-22-2021, 04:29 PM

They still sell the handhelds which have a tapered rubber cone. Just hold it in the hole, crank away and watch the needle. They work just fine for our old easy to get at monsters.

alexiskai · 09-22-2021, 05:06 PM

AutoZone will lend you a compression tester at no charge under their loan-a-tool program, so you only need to buy the adapter. Remember to set the throttle fully open.

Neshkoro · 09-23-2021, 08:05 AM

Sponsored Links (Register now to hide all advertisements)

I bought a tester from Harbor Freight and the adapter from Snyders. The tester was the screw-in type. It's easier than using the rubber tipped compression gauge if you're doing it alone because you need to sit in the car to press the starter switch with your foot.

Patrick L. · 09-23-2021, 08:09 AM

Quote:

Originally Posted by Neshkoro

I bought a tester from Harbor Freight and the adapter from Snyders. The tester was the screw-in type. It's easier than using the rubber tipped compression gauge if you're doing it alone because you need to sit in the car to press the starter switch with your foot.

I just push the starter rod with my hand.

09-22-2021, 02:43 PM	#1
skeazle Senior Member Join Date: Dec 2013 Location: Hershey, Pa. Posts: 102	compression test I would like to do a compression test on my '30 Model A. I didn't buy the gauge yet but I also know i will need an adapter to thread in to the spark plug holes. Can anyone tell me what size and where can I find it? Jim

09-22-2021, 03:06 PM	#2
Rob Doe Senior Member Join Date: Apr 2021 Location: Central Illinois Posts: 490	Re: compression test The vendors have them. 7/8-18 thread. __________________ "It ain't what you know for certain that gets ya in trouble. It's what ya know for certain that just ain't so!"

09-22-2021, 03:07 PM	#3
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 3,898	Re: compression test Vendors sell 14mm spark pug adapters. At Snyders the part number is A-12405-ADP and the price is $6.75. __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past.

09-22-2021, 04:29 PM	#4
Patrick L. Senior Member Join Date: May 2010 Location: Largo Florida Posts: 7,225	Re: compression test They still sell the handhelds which have a tapered rubber cone. Just hold it in the hole, crank away and watch the needle. They work just fine for our old easy to get at monsters.

09-22-2021, 05:06 PM	#5
alexiskai Senior Member Join Date: Apr 2018 Location: Mebane NC Posts: 2,350	Re: compression test AutoZone will lend you a compression tester at no charge under their loan-a-tool program, so you only need to buy the adapter. Remember to set the throttle fully open.

09-23-2021, 08:05 AM	#6
Neshkoro Senior Member Join Date: Dec 2020 Location: Central Wisconsin Posts: 105	Re: compression test Sponsored Links (Register now to hide all advertisements) I bought a tester from Harbor Freight and the adapter from Snyders. The tester was the screw-in type. It's easier than using the rubber tipped compression gauge if you're doing it alone because you need to sit in the car to press the starter switch with your foot.