Took some measurements - any clues?
- max71
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Took some measurements - any clues?
I spoke to Dave Anton and he wanted me to find TDC and then measure I thought the lift. I got one of those TDC tools and turns out my degree mark on the crank pulley is spot on. Exactly.
I then put the dial gauge on #2 rocker of #1 cylinder. I had to reverse the engine and the rocker came up (front of rocker which pushes the valve) 70º exactly on my dial gauge.
I checked all the valves and they were spot on. Spot on.
Does that tell us anything as to where the cam is timed?
Oh and a note to Jimmy. Please say something constructive or just pass on this topic. I'd appreciate it.
I then put the dial gauge on #2 rocker of #1 cylinder. I had to reverse the engine and the rocker came up (front of rocker which pushes the valve) 70º exactly on my dial gauge.
I checked all the valves and they were spot on. Spot on.
Does that tell us anything as to where the cam is timed?
Oh and a note to Jimmy. Please say something constructive or just pass on this topic. I'd appreciate it.
- Jimmy
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Re: Took some measurements - any clues?
In my opinion (if allowed), no.max71 wrote:Does that tell us anything as to where the cam is timed?
In baseball, running into someone is apparently a "collision".
But doing the same thing in a car somehow makes it an "accident".
But doing the same thing in a car somehow makes it an "accident".
- max71
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Re: Took some measurements - any clues?
Dave Anton said he has some math that should determine it. I'll keep my fingers crossed. Remember it has a 2º key in there.
- malcolmr18zoy
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Re: Took some measurements - any clues?
Hi Gary,
So are you saying that the exhaust valve reaches it's center of lift at 70 degrees before TDC? Did you measure the center of lift with a dial indicator? Without knowing the cam profile , that doesn't say much, except it doesn't seem right.
Malcolm
So are you saying that the exhaust valve reaches it's center of lift at 70 degrees before TDC? Did you measure the center of lift with a dial indicator? Without knowing the cam profile , that doesn't say much, except it doesn't seem right.
Malcolm
- max71
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Re: Took some measurements - any clues?
I measured with a dial indicator. Again on the front of the rocker not the back. I think I mislead something as the front of the rocker went UP not down so that wouldn't be lift. Maybe I need to do it again but it was impossible to get the dial gauge on the back of the rocker/push rod.
APT is not the best at supplying specs with their cams. This is from their website.
APT is not the best at supplying specs with their cams. This is from their website.
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Re: Took some measurements - any clues?
max71,
Have you look at a restricted exhaust system. Just a though as I know that will also cause the same issue especially at higher RPM's.
Just a thought.
Have you look at a restricted exhaust system. Just a though as I know that will also cause the same issue especially at higher RPM's.
Just a thought.
Martin Keller
Ventura, Ca.
Ventura, Ca.
- max71
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Re: Took some measurements - any clues?
Thanks for the post Martin!
Yes, both resonators were replaced for different reasons since the engine has been put in.
Yes, both resonators were replaced for different reasons since the engine has been put in.
- max71
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Re: Took some measurements - any clues?
Followup: Just got off the phone. Dave doesn't want to deal with the rocker ratio. He want the rocker train removed and have me measure the push rod at Center oppose the lobe (hope I just wrote that right I forgot the term) and then rotate until I measure maximum lift.
I was just curious where the cam was timed. If I do all this I might as well have the engine ready to be timed correctly. Something I don't trust myself to do. I guess it will be a mystery until I get the budget to do that.
Thanks everyone for all your help.
I was just curious where the cam was timed. If I do all this I might as well have the engine ready to be timed correctly. Something I don't trust myself to do. I guess it will be a mystery until I get the budget to do that.
Thanks everyone for all your help.
- malcolmr18zoy
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Re: Took some measurements - any clues?
Hi Gary,
If you want to measure the position of full lift on your exhaust cam, you will have to rotate the engine until maximum lift is shown on your dial indicator, and keep rotating until the reading starts to reduce. Then rotate the engine back the other way until the reading reduces to the same amount at the other side. Then take a mean of the degree disc readings, and that should give you the position of full lift of the exhaust cam. I still don't quite get the 70 degrees BTDC that you mentioned before.
Malcolm
If you want to measure the position of full lift on your exhaust cam, you will have to rotate the engine until maximum lift is shown on your dial indicator, and keep rotating until the reading starts to reduce. Then rotate the engine back the other way until the reading reduces to the same amount at the other side. Then take a mean of the degree disc readings, and that should give you the position of full lift of the exhaust cam. I still don't quite get the 70 degrees BTDC that you mentioned before.
Malcolm
- max71
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Re: Took some measurements - any clues?
Thanks Malcolm.
I made an error when I said 70º. Since I haven't used the dial gauge in years I forgot the measurements. It was 70 on the dial which Dave said means 70 thou. But it moved quite a bit so I don't know how that could be 70 thou.
I made an error when I said 70º. Since I haven't used the dial gauge in years I forgot the measurements. It was 70 on the dial which Dave said means 70 thou. But it moved quite a bit so I don't know how that could be 70 thou.
- malcolmr18zoy
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Re: Took some measurements - any clues?
No Gary, that doesn't sound right. I would have thought that you need to measure lift and timing.
Malcolm
Malcolm
- max71
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Re: Took some measurements - any clues?
What are the graduations on a dial gauge then? Sorry to be so basic.
Right now the method as you described it is to find lift and look and see how that corresponds to where the timing mark is since I have verified that mark is TDC. The I get can a 'rough' estimate of how far off it is. Just for education not for actually timing.
Right now the method as you described it is to find lift and look and see how that corresponds to where the timing mark is since I have verified that mark is TDC. The I get can a 'rough' estimate of how far off it is. Just for education not for actually timing.
- malcolmr18zoy
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1949 MG TC
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1985 BMW 528i
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1995 Landrover Discovery
2003 BMW 325i wagon.(wife's car) - Location: Big Bear City, CA
Re: Took some measurements - any clues?
Hi Gary,
From the responses that you are giving me, I think it would be if you let me, or somebody else who is familiar wth the proceedure, carry out the checking for you. no disrespect intended.
Malcolm
From the responses that you are giving me, I think it would be if you let me, or somebody else who is familiar wth the proceedure, carry out the checking for you. no disrespect intended.
Malcolm
- max71
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Re: Took some measurements - any clues?
its fine. i keep saying i'm not qualified. I'm going to give it one more go.
- max71
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Re: Took some measurements - any clues?
Just got the proper cam specs from APT. Their card was wrong and I was waiting on the corrections.
In/Ex duration 224 deg @ 0.050"
Lobe lift 0.280"
Lobe center angle 106 deg.
Timing specs:
Time to full lift on #1 intake @ 103 deg. ATDC (3 degrees advanced)
Lift @ TDC #1 intake 0.073" (This gives exactly the same timing set up as the method above, but is probably more accruate as long as your TDC point is very precise.
Lash with stock rockers In/Ex. 0.016"/0.018" and if using higher ratio rockers increase this a couple of thou. These are minimum figures.
The rockers should be removed from the engine to get the dial indicator onto #1 intake push rod. Set indicator to zero when lifter is on base circle of cam.
In/Ex duration 224 deg @ 0.050"
Lobe lift 0.280"
Lobe center angle 106 deg.
Timing specs:
Time to full lift on #1 intake @ 103 deg. ATDC (3 degrees advanced)
Lift @ TDC #1 intake 0.073" (This gives exactly the same timing set up as the method above, but is probably more accruate as long as your TDC point is very precise.
Lash with stock rockers In/Ex. 0.016"/0.018" and if using higher ratio rockers increase this a couple of thou. These are minimum figures.
The rockers should be removed from the engine to get the dial indicator onto #1 intake push rod. Set indicator to zero when lifter is on base circle of cam.
- Jimmy
- Don't take him seriously!
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'79 MG Midget (parts car)
'63 LBC
Plus, a Turbo S (with a damn roof) in the household.
And three Mercedes on 20" wheels. - Location: NM
Re: Took some measurements - any clues?
I see no reason to bother with removing the rocker arm, unless you want to be awfully precise. Which isn't easy with a push rod flopping around in a hole, anyway.max71 wrote:Just got the proper cam specs from APT. Their card was wrong and I was waiting on the corrections.
The rockers should be removed from the engine to get the dial indicator onto #1 intake push rod. Set indicator to zero when lifter is on base circle of cam.
In baseball, running into someone is apparently a "collision".
But doing the same thing in a car somehow makes it an "accident".
But doing the same thing in a car somehow makes it an "accident".
- max71
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- Joined: Sat Jun 02, 2007 9:36 am
Re: Took some measurements - any clues?
Its hard for me to get the Dial gauge onto the push rod with the rocker. Good point though.
- Jimmy
- Don't take him seriously!
- Posts: 1434
- Joined: Tue May 26, 2009 7:25 pm
- Vehicles Owned: '74-1/2 MGB
'76 MGB (parts car)
'52 TD
'71 MGB staqtion wagon
'69 MGB (parts car)
'60 Sprite
'79 MG Midget (parts car)
'63 LBC
Plus, a Turbo S (with a damn roof) in the household.
And three Mercedes on 20" wheels. - Location: NM
Re: Took some measurements - any clues?
I suppose that means that you don't have one of those $20-at-the-most adjustable magnetic stands for your dial indicator?
In baseball, running into someone is apparently a "collision".
But doing the same thing in a car somehow makes it an "accident".
But doing the same thing in a car somehow makes it an "accident".
- max71
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- Posts: 422
- Joined: Sat Jun 02, 2007 9:36 am
Re: Took some measurements - any clues?
I have a magnetic base its just too large to easily place without it being precarious and moving.
- malcolmr18zoy
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1990 Jaguar XJS V12 convertible
1995 Landrover Discovery
2003 BMW 325i wagon.(wife's car) - Location: Big Bear City, CA
Re: Took some measurements - any clues?
Hi Gary,
Just a stupid question here. When you installed the offset woodruff key, did you install it to advance the camshaft, or advance the timing sprocket?
Malcolm
Just a stupid question here. When you installed the offset woodruff key, did you install it to advance the camshaft, or advance the timing sprocket?
Malcolm
- max71
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Re: Took some measurements - any clues?
I don't remember but I do recall we had a discussion about that and I posted before we buttoned up to confirm with mechanics on the MGBE we were doing it right. Since we did the measurements afterwards with two different sized keys and finally got the proper reading of 103º with the 2º key I was confident that it was correct.
Still kicking myself for not opening the timing chain cover when it was on Steve's floor and having this discussion then. People have gone over this with me enough that it seems so easy. Without someone trained looking over my shoulder I really think its possible to just do it wrong again.
I still haven't had the time/incentive to measure #1 inlet. I will probably try it this weekend.
Its not a stupid question. It was just stupid people who set it up wrong if its off.
Still kicking myself for not opening the timing chain cover when it was on Steve's floor and having this discussion then. People have gone over this with me enough that it seems so easy. Without someone trained looking over my shoulder I really think its possible to just do it wrong again.
I still haven't had the time/incentive to measure #1 inlet. I will probably try it this weekend.
Its not a stupid question. It was just stupid people who set it up wrong if its off.