points gap/dwell

[responding]

I have ordered a manual for my 88 5.0 Chevy - OMC and am waiting for it to be delivered. In the meantime, since I have the day off, I'm trying to get it running today. Is there anyone willing to look up the points gap and dwell for me? I particularly need the gap, since I don't have a dwell meter here today. I would sincerely appreciate the help!

 

[Lou C]

Re: points gap/dwell

From my 88 OMC shop manual--gap.018 in, dwell 30 plus or minus 2, timing 8*BTDC with high octane gas, 5*BTDC with regular, idle speed 500-600 rpm in foward gear in the water. Plug gap is .035, plugs should be AC MR44T

 

[CHEVYV8]

Re: points gap/dwell

i'm new to all this, what is points, and dwell. i know the timing and plug gap. not sure on the others though
probably a stupid question so take it easy on me

 

[skynyrdcat]

Re: points gap/dwell

i'm new to all this, what is points, and dwell. i know the timing and plug gap. not sure on the others though
probably a stupid question so take it easy on me

This article has some good info...

http://www.jetav8r.com/Vision/Ignition/CDI.html

 

[responding]

Re: points gap/dwell

From my 88 OMC shop manual--gap.018 in, dwell 30 plus or minus 2, timing 8*BTDC with high octane gas, 5*BTDC with regular, idle speed 500-600 rpm in foward gear in the water. Plug gap is .035, plugs should be AC MR44T

Thanks! Looks like I got the wrong plugs based on what I was told by the local boat store, so thatnks for the additional information!

 

[Silvertip]

Re: points gap/dwell

ChevyV8 -- I can't help but poke a little fun at you but not knowing what points and dwell are means you are definitely in the 40-year old range since you never owned a car with them. Distributors on car and boat engines in the "good old days" relied on ignition points (electrical contacts) to open and close the circuit to the ignition coil. By the mid 1970's most manufacturers had made the switch to electronic ignition, although marine power plant vendors continued to use point style distributors for some time. Lobes on the distributor shaft cam which ran at 1/2 engine speed (four cycle engine remember) opened and closed the points. The amount of time the points were open was determined by the gap between the contacts at the high point on the distributor cam lobe. A feeler gauge was used to set the gap (although a matchbook cover worked nearly as well). When the dwell meter was developed this was an electrical method of setting point gap. It expressed the gap as degrees of distributor shaft rotation. The two terms result in the same adjustment. It's just that using a dwell meter is a little more accurate and can also indicate distributor shaft bushing wear. You should now have an idea how old I am. Along with point style distributors, there were 6 and even 8 volt electrical systems but we won't go there.

 

[bruceb58]

Re: points gap/dwell

And just to add to Silvertips description. The dwell angle is the number of degrees the points are closed. To increase the dwell, you reduce the gap.