mytblue

Afternoon all, I have a concern I’d like to get some guidance on.
Engines at #1 TDC with new timing belt installed & taught all the way around. I turned the engine over w/ the starter for about 5 sec & then a several
times by hand to TDC & I get some funkiness with the 1-4 gear alignment.

Cam gear 5-8 notch aligns with back plate V nicely as in photo
Cam gear 1-4 notch is off of back plate V a bit as in photo
. New belt
. New PK tensioner
. New cam gears

Where can the miss be? I could slacken the belt a tooth on 1-4 gear, but that would create sack only between the two cam gears & that seems like a lot of slack at the water pump.

Thanks for any help.
David



5-8 cam gear


1-4 cam gear

mytblue

cars an 86.5

ammonman

Did you spin the engine with the spacer and rings for the PK32VR installed? If so, your cam gears have likely slipped position on the cams. Reset the timing of the gears, then remove the timing tools before spinning the engine. Be sure the cam bolt threads are degreased and dry. Be sure the threads in the cam snout are degreased and dry before torquing the cam gear retaining bolts.

mytblue

Thanks for reply
I did not spin the engine with the spacer installed. I noticed the offset while installing the timing plate.
Regardless, the 2 cam gears & crank gear are locked together by the timing belt. If the crank gear & 5-8 cam gear are aligned, how could 1-4 gear be off?

ammonman

Your photo shows the spacer installed under the 5-8 cam bolt. When you set the cam timing how far did you have to rotate the 1-4 cam gear to set the timing? Could you have strung the belt so that the 1-4 cam is off by 1 tooth and have adjusted most of the error out with the timing adjustment? Where are the holes in the spider for the 1-4 rotor relative to the slots in the 1-4 cam gear? They should be somewhere close to center. If the spider bolt holes are all the way to one side of the slots in the cam gear you need to remove the belt from that gear, adjust the cam gear so that the bolt holes in the spider are roughly centered, then re-install the belt with the notch in the cam gear aligned to the index notch on the timing cover. Spin the engine and make sure the marks come back to alignment with #1 at TDC. Finally, proceed with cam timing per the PK32VR procedure.

FredR

It is a common error to end up one tooth out. Mike has covered what you need to know/check in post No 5.

When you restring the belt, make sure the crank is locked at 45 BTDC, the de-tensioning pin is re-inserted in the PKT and the cam position on 5/8 is retained. When you get the belt over the 5/8 sprocket maintain tension with a wrench over the large hex washer - better if you have a spare pair of hands to help with this. Then with the 1/4 sprocket bolted up with the slots in the centre , re-thread the belt onto the 1/4 sprocket. At this point the timing should be within a few degrees either way.

Note that 1 tooth on the cam sprocket represents 15 crank degrees and the adjustment range is about 10 degrees either direction so there is a little overlap range between teeth as would be expected.

mytblue

you are correct. i had installed it under 5-8 to start setting timing, then while looking things over noticed 1-4 cam gear offset. Did not proceed with timing & took spacer out.
Did not spin the engine with spacer installed.
Photos show:
. orientation of spider gear bolt holes in relation of cam gear slots of 1-4. not a bad setting
. current 1-4 timing of 1 deg of retard
. full view showing TDC on balance & good alignment of 5-8

As you recommend, my next step will be to remove belt & reset rt cam gear to back plate, then start over. However i just don't see 1 tooth's worth of adjustment,
thanks

mytblue

Thanks Fred, that's my plan for tomorrow.

FredR

Not sure what is going on here but the photos in your post 7 suggest you are pretty much there- the sprocket in the photo is around mid range and the 32VR is where is where it should be [more or less]. I would not change anything based on what you have just posted - I cannot explain the position of the notch on the 1/4 sprocket- remember they are a visual cue but not the final arbiter of cam timing.

Let's see what input others in the brains trust might have before changing anything.

mytblue

morning,
Fred, that's my concern. I could take everything back apart, rotate 1-4 cam gear 1 tooth & be farther from an ideal starting point for timing.
Agreed on the visual cue aspect, If both cams are properly timed, is it imperative that the notches line up? My progress is well documented. However, if this offset in 1-4 gear can be remedied, I'd start over to make it right. Stretching of the belt will make the offset greater.
We'll see what others have to contribute.
thanks

SteveG

To answer your question re how 1/4 got off in the first place: at TDC, the pressure from valve springs can cause the cam to move, unpredictable and perhaps when you were not present. This is why the recommendation to set the cams at 45 for the job. And once belt is in place to rotate by hand several times and check notches before buttoning up. Also note, the belt is likely to stretch somewhat after use and the stip to check timing again after 1200 to 1500 miles on a new belt. Usually you will need another 1/4 turn on the tensioner bolt at that time, though YMMV,

FredR

The initial belt stretch is irrelevant at the moment- that is worth about 2 degrees on 1/4 bank thus why Ken recommends setting the timing at 0 on both banks on a new belt as a "pre-stretch" calibration.

One assumes the sprocket photo you posted showing the bolt holes relative to the slots is that of the 1/4 bank as it currently stands- correct?.

FredR

[QUOTE=SteveG;14828574
Usually you will need another 1/4 turn on the tensioner bolt at that time, though YMMV,[/QUOTE]

There is a pretty good chance his model may vary as the OP has just fitted a PKT

Wisconsin Joe

That's not "off", that's the vagaries of installing a belt. You are as close as you are going to get. Moving the belt on the 1/4 gear is going to put it further off, not closer.

It is not an absolute measure. You simply get it as close as it can be. Which it appears to be.

From there, you use the adjustment slots in the gears to get the cams 'perfect'.

mytblue

please pardon my quotations, i'm new to posting & don't know how to get quotes in blue rectangles.

Steve G- "To answer your question re how 1/4 got off in the first place: at TDC, the pressure from valve springs can cause the cam to move, unpredictable and perhaps when you were not present. This is why the recommendation to set the cams at 45 for the job. And once belt is in place to rotate by hand several times and check notches before buttoning up"
. In 2nd photo of post 7, the cam timing is only 1 deg retard, thus the cam has not rotated unexpectedly (I have rad about this occurrence in many threads)
. The flywheel was locked at 45 deg BTDC for the belt change. then after the balancer & pulleys were torqued into place I rotated the engine per PKT S instructions

Fred- "One assumes the sprocket photo you posted showing the bolt holes relative to the slots is that of the 1/4 bank as it currently stands- correct?."
. Yes, photos are as everything currently stands

Fred- "There is a pretty good chance his model may vary as the OP has just fitted a PKT "
. Yep, no adjustment bolt on PK tensioner

I did think that the new tensioner could be pulling too much on the 1-4 cam gear creating the CC rotation. But I dont believe the belt has that much stretch between the 2 cam gears.
New Gates racing timing belt from Roger