Valve timing question

[hayesbd]

I would like to ask a question regarding valve timing. I just got this 1973 (1592) 124 spider and since I have no idea how many miles were on the timing belt, I installed a new one tonight. With the old belt, the car was running okay with decent power, but not idling too well. I discovered that the timing marks on both cams were off by one tooth each. In other words, when I rotated the engine to align the cam marks, they were on the spot, but number 4 was definitely not at top dead center. When I put a wire indicator into the number 4 spark plug hole and rotated the crank to achieve top dead center, the cam marks were very clearly off by one tooth. Egad!

I installed the new belt correctly with the marks right on the pointers (including the auxiliary shaft lining up with the tensioner bolt) with number 4 at top dead center - everything lined up perfectly. I rotated the engine through several revolutions to ensure that nothing hit and all was well.

However, the car now runs like crap and is very clattery. No spark timing adjustment can get it running properly. Has anyone run into this situation before? Any help is greatly appreciated.

Thanks,
Brian

[vandor]

Clattery does not sound good! It could be that there is slight piston-to-valve or valve-to-valve interference.

I would double check everything (including auxiliary shaft) and also make sure you have the right camgears on there.

Sometimes the exhaust has an 'S' and the intake an 'A', but you can also check by the relationship of the camdowel holes to the timing mark holes. Someones posted a pic once of how it's supposed to look but I can't find it now.

[hayesbd]

Vandor,

Thanks for the feedback. I found references for determining the differences between the intake and exhaust sprockets so I will check those. Assuming that the PO did indeed swap the intake and cam sprockets, will there definitely be damage that requires me to pull the head? Turning the engine by hand after belt installation did not produce any noises - it just clatters a bit when running.

Thanks,
Brian

[So Cal Mark]

Be sure to check the aux shaft timing, it could be the cause of your noise. If you had the spark plugs out, some debris may have fallen into a cylinder

[hayesbd]

Mark,

The auxiliary shaft was lined up correctly, so it should not have interfered. The clattery sound is definitely from the top of the engine, but it's running so poorly that it may simply be excessive lash that wasn't very loud with a smoother running engine.

After looking further into posts on this forum, I am beginning to wonder if the two cam sprockets are mounted backwards. If it's possible for them to have been misinstalled this way, this would account for the original "incorrect" timing belt installation actually working. It's clear that if they were simply swapped left-to-right and if the cam timing marks matched okay relative to each other (which they did), the engine would run very poorly indeed (which it didn't).

Anyway, I'll take a more detailed look at things this evening and should be able to sort out the correct orientation of all the parts (the PO definitely had the cam sprockets off at one time since there are no bendable washers in place ).

My biggest concern is whether or not I have dinged the valves. It's not clear from searching posts whether running this engine "one tooth off" will cause interference (it's a 1592). Any thoughts?

Thanks for all your advice.
Brian

[majicwrench]

THe old "wire down the plug hole" is NOT a good way to find TDC. Do you not have a crank pointer??
Compression test will tell you if you have bent a valve.
"excess lash that wasn't very loud.." not likely.
Keep us posted
Keith

[hayesbd]

Keith,

I do plan on checking the TDC with the marks on the crank pulley against the timing shroud, but I am not quite sure why that will be more precise than the wire down the plug hole. I find it much easier to view and orient the crank with that method than the problems with parallax trying to sight along the sloppy fitting fiberglass shroud.

I will also run a compression check tonight; thanks for the suggestion.

Regards,
Brian

[vandor]

>the PO definitely had the cam sprockets off at one time since there are no bendable washers in place

I don't think those were used by 1973. IIRC they were only on the 1438 and 1608 engines.

[hayesbd]

Well, here's an update...

I found that the sprocket timing marks, when lined up with the cam housing casting marks, actually are off compared to the pointers on the front. I put everything back using the cam housing marks and ran a compression check. Unfortunately, my compression tester has a faulty check valve, so it does not have a chance to pump up to a good measurement. Nevertheless, I got 120/120/120/100 by just watching the needle jump, so I think the valves are probably okay.

However, my starter is now no longer willing to turn the engine over, so I have to see to that nightmare before I can get it started and checked out.

Thanks for all the suggestions.

Brian

[divace73]

However, my starter is now no longer willing to turn the engine over, so I have to see to that nightmare before I can get it started and checked out.

Thanks for all the suggestions.

Brian

if you have to replace your starter it is worth considering the hi torque light weight unit as a replacement

[hayesbd]

It was just filth and worn brushes. I have had good luck in the past with just cleaning and renewing the brushes, so that's the route I will go with for now. Someday, if I opt for a new starter I'll do the reduction starter, but I don't really want to spend that much for now.

Thanks,
Brian

[divace73]

It was just filth and worn brushes. I have had good luck in the past with just cleaning and renewing the brushes, so that's the route I will go with for now. Someday, if I opt for a new starter I'll do the reduction starter, but I don't really want to spend that much for now.

Thanks,
Brian

While you are there is is worth investiating the brown wire fix and possibly clean up all the ground point and ignition switch as well...

[hayesbd]

Yes, indeed - the brown wire fix is already in the works! I have the 10ga wire and terminals, now I just need to find where I put my !@!#!@# crimping tool!

Thanks,
Brian

[hayesbd]

An update...

I finally got the starter brushes, but I had to take care of another car first (subframe removal and weld repair, yuk!). Anyway, I got the starter all sorted out and all is well with the "Arachnis Deathicus". Now on to the endless list of minor items to fix/upgrade, but I'll at least be driving it regularly now and hope to complete a rolling restoration gradually.

Regards,
Brian

[RRoller123]

"Arachnis Deathicus", love it!