16 replies to this topic

[LC-GTR-1969]

Gday,

 

I am trying to accurately determine top dead centre on my red 202...

 

I appear to have a red 202 timing cover, although I appear to have an unknown brand/ aftermarket harmonic balancer. 

 

My balancer has no degree indications however it does have one sharp line scored at what I presume is TDC indicator. However, I am not sure which mark to use on the red timing cover. I understand the standard balancer uses the FAT line on the cover as the 5/6 degree line, but my engine does not appear to follow this protocol.

 

I have used the old screwdriver method as well as a torch in the plug hole to determine where TDC is relative to the balancer mark, and it appears as though my balancer indicates TDC at the FAT line, with about 2-3 degrees of dwell (the piston appears to dwell at the FAT line as well as the small line next to it on the right of the cover).  I would, however,  like a second opinion...

 

Here is a pic to help describe...

 

 

Here is another pic that shows a little more of the balancer...

 

[S pack]

Your timing cover is not from a red 202/173 rather it is from a 138, 149, 161, 179, 186 engine. (4 deg Advance and 8 deg Retard markings)

173/202 timing covers are marked with 8 deg Advance and 4 deg Retard.

 

The longest (thickest) mark on any Holden 6 cyl timing cover is TDC.

[warrenm]

Looks like it may be a Pro-Race, it doesn't appear to be a romac. 

Use the method Bluejinx202 mentioned, bust the insulator out of an old plug, run a 3/8" or 10mm tap through, then use some threaded rod to suit your thread, you now have a piston stop.   

Edited by warrenm, 25 January 2015 - 06:13 AM.

[LC-GTR-1969]

Thanks for the help everyone- some good ideas... I will make a piston stop and re-check...

 

I am curious though regarding the long fat line on my cover- it seems as though there is a range of conflicting information regarding these covers- do some of the red 6s use the thick line as TDC and others as 5 degrees?

 

Here is a comment from holdenpeadia regarding the red timing cover. I don't really know what is what with these covers TBH, just seems to be conflicting info from various knowledgable sources... Did they change mid production or something?

[S pack]

^^^ The longest mark is 0 deg, ie TDC. The two marks to the left hand side of the 0 deg mark are 2 and 4 deg Advanced and the four marks on the right hand side of the 0 deg mark are 2,4,6 & 8 deg Retarded.

[Dr Terry]

^^^ The longest mark is 0 deg, ie TDC. The two marks to the left hand side of the 0 deg mark are 2 and 4 deg Advanced and the four marks on the right hand side of the 0 deg mark are 2,4,6 & 8 deg Retarded.

This is NOT correct !!

 

The timing cover shown is from 149/161/179/186 engines & the long mark is 5 degrees before TDC.

 

They cleared things up when they released the 173/202 engines where the long mark is zero.

 

Dr Terry

[LC-GTR-1969]

This is NOT correct !!

 

The timing cover shown is from 149/161/179/186 engines & the long mark is 5 degrees before TDC.

 

They cleared things up when they released the 173/202 engines where the long mark is zero.

 

Dr Terry

Hi, thanks so much for your input, but can you pls clarify whether the cover shown in my first post is from the 149-186 or from the 179/202? Sorry mate but am not sure if you are referring to the image pinched from holdenpedia or my original image in the first post.

 

Kind regards and many thanks!

[S pack]

This is NOT correct !!

 

The timing cover shown is from 149/161/179/186 engines & the long mark is 5 degrees before TDC.

 

They cleared things up when they released the 173/202 engines where the long mark is zero.

 

Dr Terry

Well there ya go. I've spent the last 40 years believing the longest mark on the 149/161/179/186 timing cover was 0 deg/TDC. Seems a bit stupid to have the longest mark at 5 deg BTDC and not have it clearly identified as such.

 

Thanks Dr Terry

 

Cheers

Dave.

[Dr Terry]

Hi, thanks so much for your input, but can you pls clarify whether the cover shown in my first post is from the 149-186 or from the 179/202? Sorry mate but am not sure if you are referring to the image pinched from holdenpedia or my original image in the first post.

 

Kind regards and many thanks!

All 3 pics above depict the early 5 degree tag. This is used on all pre-1971 6-cyl red motors i.e. 149, 161, 179, 186 & early 138 (Red).

 

I'm not sure if it was a typo or not, but you've said the late tag was fitted to 179/202, did you mean 173/202 ?

 

Dr Terry

[Dr Terry]

Well there ya go. I've spent the last 40 years believing the longest mark on the 149/161/179/186 timing cover was 0 deg/TDC. Seems a bit stupid to have the longest mark at 5 deg BTDC and not have it clearly identified as such.

 

Thanks Dr Terry

 

Cheers

Dave.

This was common practice by most manufacturers on older style engines. Have a look at Grey motors. They have a ball bearing pressed into the flywheel at the desired ignition timing mark, which is different for different model series. Once again there is no mark for zero.

 

This becomes a problem if you fit say an EJ flywheel to an FJ. From memory one is 5 degrees & the other 10. That would drastically effect performance.

 

Dr Terry

[LC-GTR-1969]

I'm not sure if it was a typo or not, but you've said the late tag was fitted to 179/202, did you mean 173/202 ?

 

Thanks again for the info!

 

I'm not quite sure what you mean here, but are you asking me whether the timing cover shown in my first post is fitted to a 202? If so, YES, the timing cover illustrated by the pics in my first post, is fitted to a HQ sourced 202... Not sure why they have done this, but it may be what they had lying around...

[LC-GTR-1969]

Your balancer looks like an old B&M, however mine has graduated degree marks and a TDC mark. None of my marks are acurate.

Checked with the good old positive stop method.

Regards

I used the stop method- works a treat...

 

I found TDC was exactly where I believed it was with my screwdriver/ torch method, but at least I am confident about exactly where tdc is now (I was seriously questioning myself before lol)

[LC-GTR-1969]

The problem with the screwdriver method is that the piston stops at TDC for a couple of degrees before it goes back down the cylinder, not very accurate.

Regards

Yep, your right, this was why I wanted to find a more accurate method... I noticed about 2 or 3 degrees of dwell at TDC which meant that I kind of took the middle of the dwell- still not accurate enough to trust, but as it turns out I was extremely close...

 

I have set it at 32 degrees and feels strong, but I need to get the car on the rollers to really find out what lead it wants