f134 TDC

zeke57 · Post by **zeke57** » Sat Mar 30, 2019 12:17 pm

Starting to put things back together and am at the point of installing the distributor, carb and fuel pump. I read a post on here from back in 2014 by Wes explaining the procedure to find TDC and it is pretty clear as to how to do it. I just had a question about when inserting a pencil into the spark plug hole to observe piston travel when looking into the hole what I actually believe I see is one of the valves and not actually the piston. If I am correct which of the valves would I be seeing, exhaust or intake?

Post by **wesk** » Sat Mar 30, 2019 12:58 pm

Hello Zeke, On the F134 I do not recall mentioning placing a pencil in the spark plug hole. Must have been another commenter on that post. You need an offset device to track the piston movement because the spark plug hole is not above the piston. All F134's have the four intake valves in the head. You should not be able to see the intake valve looking in the spark plug hole. The exhaust valves are still in the block. If you are re-assembling your engine this is the best time to accurately determine TDC with a dial indicator before the head gets installed. This should be done on any engine to insure the remote located marks for ignition and valve timing are accurate and correct. On the L134's it is usually the marks on the flywheel and on the F134's it is usually the tab on the front timing gear cover.

zeke57 · Post by **zeke57** » Sat Mar 30, 2019 1:14 pm

Hey Wes if you get a chance do a search for "f134 tdc". You have a posting there that I was referring to and I thought it pertained to the f134. Also my head was not removed everything still intact and I have the number one plug removed and when I look into the hole I do see the top of the intake valve. Thanks.

Post by **wesk** » Sat Mar 30, 2019 2:19 pm

Sorry about the mis-understanding.

I think I grasp your real question now.

Maybe this illustration will answer it.

You should be able to see the exhaust valve thru the plug hole but you should not be able to see the intake valve until it opens and extends further down where you can see it thru the plug hole.

When checking TDC on #1 using a visual view thru #1 plug hole both valves should be completely closed since we are locating TDC Top Dead Center on compression stroke. The other TDC occurs at the top of the exhaust stroke and at that instant the exhaust valve will be open.

This illustration is perhaps a more accurate showing of what you can see thru the spark plug hole:

zeke57 · Post by **zeke57** » Sat Mar 30, 2019 3:17 pm

Good illustrations Wes it was definitely the exhaust valve I am seeing. So what would be the best method to determine tdc on this engine?

Post by **wesk** » Sun Mar 31, 2019 1:52 am

As I said with the head off is my choice.

This is what we are trying to measure and the easiest and most accurate way to do it.

There are several type TDC finders for use thru the spark plug hole. I try to avoid the threaded piston stop type and stay with free to slide in and out units I can link to a dial indicator.

Then there are dial type direct connect gauges:

or you can just take an old 18mm spark plug and saw off all but the threaded base. Then drill it for a rod and voila you have your home made TDC finding tool.

zeke57 · Post by **zeke57** » Sun Mar 31, 2019 8:00 am

For me I think the last option would be the best. Where would I locate the adaptor to hold the dial indicator? I have been searching but have not found one like the one in your photo? Thanks again Wes.

Post by **wesk** » Sun Mar 31, 2019 2:21 pm

The last option is written below the last photo and is unlike the last photo.

That last photo has the correct 18mm adaptor with the dial indicator and is on Ebay:
https://www.ebay.com/itm/Top-Dead-Cente ... ctupt=true

Just search ebay and google for "Piston Top Dead Center Finder"