• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    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

i guess i am still not clear.

is the dial wheel supposed to be on the camshaft gear and taking angle measurements there?
with the specs of open @ 18 BTDC & close @ 58 ABDC, is that the angle on the camshaft or crankshaft?

then to set the crankshaft timed to the camshaft, where will the crankshaft be at?
 
recordsj said:
i guess i am still not clear.

is the dial wheel supposed to be on the camshaft gear and taking angle measurements there?
with the specs of open @ 18 BTDC & close @ 58 ABDC, is that the angle on the camshaft or crankshaft?

then to set the crankshaft timed to the camshaft, where will the crankshaft be at?
Click to expand...


The degree wheel mounts to the crankshaft. specs are in crankshaft degrees. all measurements are made with the chain on the sprockets.

TDC must be determined to zero the pointer on the degree wheel. a piston stop is recommended to determine this. Or some real good dead reckoning.

set valve lash at .05

with a dial indicator on the valve, find the max lift of the valve, zero the dial indicator rotate the engine thru, read you number. It is best to read the number on the degree wheel at .02 from the zero on the dial indicator and then again at .02 after the zero on the dial indicator, add them together and divide the sum by 2. this will be your opening (or closing angle) adjust as needed by removing cam sprocket and aligning a different set of holes, or flipping the cam sprocket and trying another set of holes, or if needed jump a tooth on the chain. Do not move the crank during this adjustment.



It may take some patience and a dry run or two to get the hang of it. Always turn in the direction of normal engine rotation.

your car is running so it cant be very far off. This means you most likely aren't going to make any large drastic changes, may be one tooth or so. if anything it should be a little advanced a degree or three for more umph in the low end.

to advance turn the cam in the direction of engine rotation relative to the crank.



this site has a picture of a wheel mounted to the crank. For a pointer i usually make one from a coat hanger and bolt it somewhere solid on the block

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

when all done recheck ignition timing with a light.

FYI it took me better than two weeks to finally say "I believe i have this right" before i would seal up my engine.


hope this helps.



mark
 
sorry for all my questions, and thank you for your help.

I believe the spark plug thread is a M14x1.25 (if I am correct?), I haven't been able to find any bolt or anything with that type of thread to use as a deadstop to find TDC of the piston, any other ideas?

what must the valve lash be set to .05 when this is done?

when you say "add them together and divide the sum by 2. this will be your opening (or closing angle)", I assume you are talking about the 15BTDC for opening and 58ABDC for closing on the intake valve?
 
Take an old spark plug and grind the the upper rolled section of metal off and the ground electrode. Now you can punch out the ceramic body and tap the spark plug body. Grind a piece of all thread to a ball shape and secure this to the spark plug body with a nut. Only turn the engine gently by hand.
 
Be careful with the dead stop. I think you can make one that is too long and the valve will hit it way before the piston gets to the top. Takes a little experimenting before you find the right length. Start shallow... Someone here might have a good length on how much the stop should protrude past the end of the plug.
JC
 
When you have a dead stop installed, and the degree wheel mounted on the crankshaft. Slowly and gently turn the motor by hand in the direction of rotation until you contact the dead stop. At this point zero your degree wheel pointer. Rotate the engine in the opposite direction until you are against the stop again. read the degree wheel. Halfway between zero and the indicated reading will be TDC. Example: your reading is 35°, 35°+ 0= 35°, 35° divided by 2 = 17.5°. Now set the degree wheel so that on either end of the piston travel (from stop to stop) is at +17.5° and -17.5°. In other words equal on either side of the zero. When you remove the dead stop and now rotate the crank to zero on the degree wheel you will be at TDC.


use the same method when you degree the valve. The dial indicator should be zeroed on the full lift of the valve. As the engine is rotated the indicator will come to zero and then travel back down. On the way to zero stop at some number before the zero, (.03) take a reading from the degree wheel. continue rotating to the dial indicator zero and then back to the same number you took your reading at on the way up. take a reading from the degree wheel. Add the two readings together and divide by 2 (taking the average) this is the angle the valve is at. Example at .03 before the lobe center your wheel is at 62°. at .03 after the lobe center you reading is 54°. 62°+54°= 116°, 116°/2=58°. the average.

This is done because there is an area at the top of the lobe (and the piston travel) where the crank is still rotating and the lobe (or piston) is not traveling. A dead spot so to speak. you need to find the center of these dead spots to do the job accurately.

.05 is used to help remove residual motion and make the job a little easier. It is also a standard for cam manufactures.





mark
 
good, i am glad i have been able to help. Dont hesitate to ask if you have any more questions.


mark
 
First off, I normally degree the cam in a engine when I'm rebuilding with the head off, but it possibly to do it with the head on, just harder. Secondly if you're coming up at 110 on center line you are correct, if you jump a tooth on the sprocket with a link of the timing chain that's like 18 degree change on the center line, so at 110 you would be correct. Now all performance cams or even stock cams can benefit for 2-3 degrees of advance timing, you can achieve this with either offset keyways or a adjustable timing gear set, I'm a big fan of the vernier timing gear sets, but you talking $200+, with 1500 maybe a little less money, you can order just the TR6 Kent adjustable cam pulley for Vicky Brit, TR6, Spite/Midget 1500 cam gear are the same part.
 
Back
Top