• Hi Guest!
    If you appreciate British Car Forum and our 25 years of supporting British car enthusiasts with technical and anicdotal information, collected from our thousands of great members, please support us with a low-cost subscription. You can become a supporting member for less than the dues of most car clubs.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

1500 midget camshaft about 180 out of timed?

Share this page

R

recordsj

Jedi Warrior
Offline
I am replacing the timing gears and chain on my 1500 midget that I have recently purchased. I think that the camshaft gear is 180 degrees out of timed, the car is drivable, should this be possible? Also by the way, ot actually get it to run I have to set the distributor at around 22 deg BTDC to get some good power. Speaking of the distributor, it is new one with electronic ignition.

any thoughts?
 
If you cam was out 180° your engine would most likely not run at all. But that all depends on where the number one plug wire is located on the cap. 1-3-4-2(ccw)is the firing order.
As to timing being set at 22° BTDC you don't say at what rpm you are checking it at. Is it a stock cam? Do you still have the smog equipment on it? What carb do you have? Is it pinging under load? if so retard it a little and check again.

mark
 
timing was checked @ idle

I assume it is a stock cam, but don't know (is there a way to check?)?

smo equipment removed

weber dvg carb
 
From my experience with a weber carb, the timing liked to be advanced a bit to get it to run ...sounds like your ok. if it pings under load back it off some until it stops. drive it and enjoy it.

mark
 
one thing that made me question that it is 180deg out was from the haynes manual and from another posting (see the picture of the timing sprockets
https://www.britishcarforum.com/bcforum/ubbthreads.php/ubb/showflat/Number/294811/fpart/2

In the haynes manual and in the posting (which I PM the person who posted to confirm, no answer back), it shows in the camshaft sprocket, a slot in the camshaft through the upper lefthand hole in the camshaft sprocket. Mine is not in that position, but 180 deg off.

do you have a 1500 midget also?
 
Yes i do have a 1500. I started with a weber and now have it set up with twin SU's. the weber was a decent carb for me. And ran it for about 2 years. In fact i just set it up on a friends rebuilt 1500.

I have read the above referenced thread, and i do believe that it was mentioned in there about getting a degree wheel and checking it if you have any doubts.

if you were careful when you changed the sprockets and did not move the cam or crank, then it is likely to be pretty close.

you mention that you changed the distributor as well this can be out as well, the dizzy mount is keyed offset and not likely to go in wrong. Did you disturb the dizzy drive gear in relation to the cam?


Where is the number one wire on the cap? should be at about a 10 o"clock position

mark
 
recordsj said:
it shows in the camshaft sprocket, a slot in the camshaft through the upper lefthand hole in the camshaft sprocket. Mine is not in that position, but 180 deg off.
Click to expand...

and you are positive that you have number one on tdc compression stroke?

mark
 
yes. I have taken out the #1 spark plug (the closest to the front of the engine) to view the piston to make sure it is at the TDC.
 
and the valves on number one were closing and number four valves were rocking?

it is possible that you were on the TDC Exhaust stroke..


mark
 
I think you are right, it is just on the exhaust stroke. How do I know if a valve is open or closed? I have the valve cover off, is the valve closed when the rocker is lifting off of it and stops (valve moving up out of block)?
 
The valve is closed when the valve rockers are "rocking" meaning you can grab the rocker and wiggle it a bit. If the valve is open, the rocker is pushing down on the spring and it will not wiggle.

From the symptoms you described, it sounds like your cam timing is just off a bit. There are 4 positions that the cam sprocket can be attached to the cam, and if the sprocket was attached in the incorrect position it could cause the cam to be off by just enough to cause your car to run funky.
 
I found the lobe center on the #1 valve (is the #1 valve the intake valve?) Where do I go from here to get the crankshaft sprocket and camshaft sprocket in the correct timing position together?
 
110 deg ATDC. It appears that I have a stock cam for the 1500.

By the way are the odd number valves intakes while the even number vales exhaust valves? With the #1 valve at the front of the engine.

In other words I am wondering where should the camshaft be setat when the crankshaft is set at TDC on the compression stroke?
 
https://www.teglerizer.com/triumphstuff/spitcamspecs.htm

this could be of help with the specs on your 79 1500, it is the same as a Spit engine.


the number valve (at the front of the engine is an exhaust valve. Please check out this pic. the square holes are exhaust, and the round ones intakes. Note one valve to one hole. 2,3 are intakes, 4,5 exhaust, 6,7 intakes, and number 8 is exhaust.

the cam should be set so that the valve events happen at the specified degrees read off your degree wheel

roughly 18° and 58° for intake and 58° and 18° for exhaust. You also have a low compression engine 7.5 to 1, that is if it is stock and has not been changed or modified...

your stock cam is detuned to help meet emissions, and i have read that some folks believe that even with smog removal, you are not going to gain much in the performance.



mark
 
i have a 75 1500 midget, does that make any difference?
are you sure that valves #1,4,5,8 are exhaust, and 2,3,6,7 are intakes? I haven't been able to find any reference info in manauls to confirm this.

so if I understand this correctly, after I find the centerline, which then I can timing the camshaft gear to 18BTDC for the intake valve opening spec and then set the crankshaft gear to 0TDC on the compression stroke which then will have the camshaft and crankshaft timed correctly?
 
oops sorry, a 75 may be a hi comp motor...maybe. other than that no difference.

if you look at the picture i posted you can see that the valves aren't odd and even. the front of the head in the picture is on the right.

Basically you are setting the lobe center separation (the distance between the intake and exhaust lobes) to the TDC position of the crank. or setting max lift on the intake to a position on the wheel...hard for me to explain...



check out this page, it may make it more clear to you than i can. https://www.cranecams.com/pdf/803.pdf

https://www.starracing.com/Cam Lobe Center Explained.htm

https://www.enginelogics.com/camdegree.html

https://www.ridgenet.net/~biesiade/camdegree.htm


mark
 
I mean even and odd as you count the valve number as you go from front to back of the engine. I don't have the engine head removed so I can not see what you show in the picture.
 
recordsj said:
....
are you sure that valves #1,4,5,8 are exhaust, and 2,3,6,7 are intakes? ...
Click to expand...



Yes i am.

the number two valve, is the number one pistons intake valve

mark
 
Back
Top