Old Olds Fan

I am trying to accurately time my engine, also check for accurate fire on the cylinders other than #1. I want to use a timing tape, they come in different lengths for different diameter dampers. I'm not with my car but would like to order the tape. Does anyone know what the diameter of a stock 1966 'E' 400 harmonic balancer is ???

Fun71

I can go measure one in the garage, but I can also tell you that the timing tapes you see are likely not the correct length for an Olds balancer, plus the one I used back in the 80s flew off after some 5000 RPM pulls, even though I had sprayed over it with clear paint to hold it on.

Here's a thought: measure the circumference of your balancer with a piece of string, divide that length by 360, and you will have the number of inches per degree. Then measure and mark your balancer with a white paint pen. I made a line every 10 degrees at 10, 20, 30, and then every 2 degrees from 30 to 40. It's 100% permanent and can't fly off like that tape did.

Edit: My '67 balancer measured 22.5" circumference. That would make the diameter 7.1619". I don't know if there is a difference between the 66 and 67.

I noted that the ring was very narrow and had two fairly large scallops 180* from each other that may be large enough to be an issue with tape adhesion.

Ozzie

I'm a bit puzzled. I looked in the 1966 Oldsmobile parts book. Under group number 0.659, it shows a part number of 386351 for the balancer for the 442, but makes no distinction of early or late. The same number was used on the 1965 442. I pulled a spare part with this number. It appears to be approximately 7 inches diameter. The photo may suffer a bit from parallax. If the parts book is wrong, and there is a difference between early and late, wouldn't it be safer to measure the one that you want to install the tape on before ordering?

Octania

I got 7.009" with hyper-accurate digital calipers.

Would have a photo but MS hotmail is pulling shyt again and wants to send security code to my home phone and to no other phone. The trouble with that is that we no longer have that technology, and there appears to be no other MS option.

Say, is that there 425 balancer available?
I have a low mileage Toro 425 to resurrect that could use that

Dammit I hate MS / hotmail
30 minutes to iron out what should not be a problem

Ozzie

Unfortunately, it appears that it is the only one I have. I probably should save it for use on the car while I try to rebuild the failed one.

Fun71

I think he is referring to the early '65-'67 400 vs. the late '68-'69 G block 400.

Ozzie

If so, then it is clarified. Thanks.

Old Olds Fan

Thank you guys, yes, I was referring to (early) 65- 67, I know the 68 and up were different bore and stroke, perhaps balance? The pictures sent are great, answers my question. Thanks again.