Flathead cam timing marks??

R

Roland cad 500

Junior Member
Im not familiar with these engines. Although i have built a few other types chevy, caddy and a number of 4 cylinder engines. It just doesnt seem to do what i would expect when i turn it over. I am aware they have a different firing order and piston positioning to some. Just need a picture with the timing wheels and cam position.

Thanks in advance.

Roland
 
Which Year engine are you working on?
Firing order(15486372) and cylinder layout are the same(pass bank 1,2,3,4 and drivers side 5,6,7,8)
But the early dist goes counter clockwise and the later clockwise, uses different cut gears. I'll see if I can round up a pic.
 
Roland cad 500 said:
Im not familiar with these engines. Although i have built a few other types chevy, caddy and a number of 4 cylinder engines. It just doesnt seem to do what i would expect when i turn it over. I am aware they have a different firing order and piston positioning to some. Just need a picture with the timing wheels and cam position.

Thanks in advance.

Roland
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Hi Roland, here's a pair of photos showing the 59A and the 8BA side-by-side, hope this is what you're looking for??

Shows the timing marks aligned.

Thanks, Gary in N.Y.

P.S. Wishing all here a very Happy New Year!
 

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  • Flathead T-Set Alum-59A.JPG
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Thanks for taking the time to reply. Its a later engine. The dizzy goes clockwise. i will try and load a photo. i am concerned with where the cam bolts onto the 4 bolt area. as it doesnt seem to be in the right orientation.

Thanks for Pics.

Happy new year to you guys too.
 
This is how i got it. I was just checking some bits on the engine. Checked the firing order. It just didnt seem right.

Any input welcome.

Thanks Gents

Roland
 
I don't see anything wrong with it. What is wrong with the firing order?

Is that a 3-groove pulley? What is the application?
 
Ro, Hi and welcome (back) to the barn. As long as the line between the teeth on the ally gear aligns with the 0 on the crank gear then all should be well. It looks like it does in your pics, but the 0 isn't particularly clear. If that is the 0 then all should be well.

If I remember right, the gear can only be fitted to the cam in one position (odd spaced holes) so you can't get that wrong.

40cpe, The big 3 groove pulley is stock French Flathead.

Mart,
 
Just to make sure, you can visualy check the split overlap on any engine. That should at least be close. Had an engine that had an adj cam gear installed wrong. Engine actually ran, but kept blowing through the carb.
 
Hi guys. Was just checking and cleaning i really. But noticed as i rotated the assembly the piston was on the way back up before the inlet valve closed. Just didnt seem right to me. Maybe ive got it wrong. Im happy to be told it will be fine. But i would like it confirmed. Before its all bolted back together.

Hi Mart. Need to get it built for pendine 2017.

Thanks Roland
 
Roland cad 500 said:
But noticed as i rotated the assembly the piston was on the way back up before the inlet valve closed.
Thanks Roland
Click to expand...

That is correct. The piston will be on the way up before the intake closes. This allows more time to get the air/fuel mixture into the cylinder. Air flows through the intake at relatively high velocity so will keep flowing into the cylinder for a time even as the compression stroke is starting. The higher the engine speed, the longer you can keep the intake valve open for better cylinder filling, thus more power. This is the premise behind race cams.
 
Ro, "Early" gears are right for a French motor. Thrusts the cam towards the block.

Mart.
 
Roland cad 500 said:
Been up the garage for another look. Took a better photo. Looks to me like i have early gears on a late engine.



Is that correct?
Click to expand...
R.H. early gears may have been used on late '48 pickup (late) engines.
R.H. early gears were in fact (according to parts book) used on early '49 Mercury and were replaced by L.H. late gears thru '53.
 
I did not know the French blocks had early style heard in them. But I have never seen a French block other than in a book or magazine.
 
The early gears may have been a problem with the later type distributor gear mesh. I imagine it wouldn't have taken them too long to notice a problem like that at FoMoCo. What I don't know is whether a 8BA family cam can run well with early gears and an 8BA type distributor. Most folks use the early gears in an 8BA to be able to change to the crab type distibutor & early pumps will also change the cam to get the drive for it. The crab needs thrust forward and load-o-matic needs thrust aft or visa-v.
 
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The crab has the thrust towards the block. The Load-o-matic in the 8BA has the thrust taken up by the front cover.
 
Just check the amount of thrust between the end of the cam and the timing cover - use a dial indicator on the BACK of the cam and make sure you have the correct thickness timing cover gasket (not the one that Speedway ships). It should have about .006 or so of thrust clearance (don't have the spec in front of me).

On the cam to valve relationship, what you're seeing is also very noticeable when the exhaust valve is closing (getting toward TDC) - the intake opens EARLY (before TDC) and the exhaust closes LATE (after TDC). The number of degrees that they are both open is known as 'overlap'. In the early years of gasoline engines, they didn't use overlap -- they later found out in performance testing and racing that opening the intake early (before TDC) and closing it LATE (after BDC) improved performance. (similar with the exhaust). On our race flatheads, we have a LOT of overlap - due to extreme duration of the grinds we use (at least the ones I use!).
 
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Overlap allows for better incoming mixture flow and better exhaust scavenging. It makes the engine operation much more efficient.
 
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