Re[2]: {Chrysler 300} H vs. J distributor
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re[2]: {Chrysler 300} H vs. J distributor
- From: "Carl Bilter" <cbilter@xxxxxxxxx>
- Date: Tue, 18 Feb 2025 16:25:28 +0000
Ok mate, yes, I doubled the distributor degrees to reflect degrees measured at the crank, but didn't on the rpm, sorry. Point noted. Still, the H distributor advances farther than the J distributor by 9 degrees at the crank. So, while in normal driving perhaps there isn't much difference, but at full throttle there would be some, correct? J was designed for greater initial timing, at first it was 15 degrees BTDC (later revised to 12.5 due to customer complaints of detonation), less advance on distributor, so maybe 28 total at the crank. H had initial timing of 10 BTDC; total of maybe 32 at the crank. Vac. advance disconnected, of course.
So total advance spec on ram cars (initial + mechanical) seems to be in the 27- 28 degree range for F/G/J/RamK, whereas inline dual quad (H) and single quad (Sport and non ram K) seem to max around 32. The muscle car guys with the later 440s always say to set 34 to 36 degrees total when tuning for "maximum performance,", wonder why ram cars are less? Yes, I know they aren't race cars, midrange torque and high speed cruising was the emphasis. You try too much timing on ram cars they will "ping" even on high octane non-ethanol, devastating to engine, they don't like it, and don't perform as well. Factory had a reason for these specs.
Carl B.
------ Original Message ------
Date 2/18/2025 8:36:56 AM
Subject RE: {Chrysler 300} H vs. J distributor
Centrifugal advance in the chart is at distributor rpm which is half engine rpm. So, not “all in” just above idle. Must always check this as it can be shown in different manuals as distributor rpm ( for testing in a distributor machine) or engine rpm on the car.
Henry
From: chrysler-300-club-international@xxxxxxxxxxxxxxxx <chrysler-300-club-international@xxxxxxxxxxxxxxxx> On Behalf Of Carl Bilter
Sent: Tuesday, 18 February 2025 1:37 AM
To: Kurt Brueske <kurt.brueske@xxxxxxxxx>; chrysler-300-club-international@xxxxxxxxxxxxxxxx
Subject: {Chrysler 300} H vs. J distributor
Here is the response I had sent to Kurt. Others have more knowledge on this than I do and are welcome to add or correct as necessary:
The distributor differences are in the internal mechanical (also called centrifugal) advance curve. The vacuum advance is about the same on both, assuming the vacuum advance was working correctly on the J distributor. The reason for the mechanical advance difference is because the H cam profile/in-line intake is different from the J cam profile/short ram setup. The J also has a more advanced initial timing setting (12.5 to 15 degrees BTDC) than the H (10 degrees BTDC). The J advance curve curve tops out at 13 degrees (plus initial of 15 for a total of 28 degrees) at only 910 rpm, and so it is "all in" just above idle (J idle is 750-800 rpm). The H advance curve is fast at low speed (13 degrees at only 640 rpm, plus initial 10 degrees for 23 degrees total just above idle) but then has additional ramp up to 22 degrees (plus initial 10 degrees for a total of 32 degrees) by 2400 rpm, where it is "all in" (no further advance with increase in rpm).
So, what this means, is that the J distributor, assuming everything was set and working properly, was probably limiting your high speed/full throttle performance as it was only advancing to 13 degrees (+ 10 initial) for a total of 23 degrees. Whereas, your proper H distributor will advance 22 degrees (+10 initial) for a total of 32 degrees. At heavy or full throttle, vacuum advance goes to zero. Vacuum advance gives you better fuel economy at light throttle/cruising. You should experience livelier acceleration now.
One risk with more advance is that you may hearing detonation (pinging), and so you'll want to check for that in the spring. Fuel and spark plugs can affect that as well.
------ Original Message ------
Date 2/16/2025 10:19:40 AM
Subject Re: {Chrysler 300} Rick DeBruhl 1963 Chrysler 300 Video
Thank you Bob. Carl Bilter kindly replied but I see it went to me only, I’ll ask Carl to post for other members.
On Sunday, February 16, 2025 at 5:25:33 AM UTC-6 Bob Merritt wrote:
On 2/15/2025 9:25 AM, Kurt Brueske wrote:
Interesting video:
Starting to get cabin fever here in Omaha although it allows garage time for winter projects. Just finished installing a freshly restored and correct distributor in our 300H…very happy with work that Joe White performed (check out his Facebook page). For some reason, my 300H had a 300J distributor…pretty similar minus differences in the part number, or so I suspect. Are there any other differences? Should i expect improved performance and what would this be? I appreciate feedback on this.
--
For archives go to http://www.forwardlook.net/300-archive/search.htm#querylang
---
You received this message because you are subscribed to the Google Groups "Chrysler 300 Club International" group.
To unsubscribe from this group and stop receiving emails from it, send an email to chrysler-300-club-international+unsubscribe@xxxxxxxxxxxxxxxx.
To view this discussion visit https://groups.google.com/d/msgid/chrysler-300-club-international/69bae5ab-7095-4c18-8078-4fef483ace68n%40googlegroups.com.
--
For archives go to http://www.forwardlook.net/300-archive/search.htm#querylang
---
You received this message because you are subscribed to the Google Groups "Chrysler 300 Club International" group.
To unsubscribe from this group and stop receiving emails from it, send an email to chrysler-300-club-international+unsubscribe@xxxxxxxxxxxxxxxx.
To view this discussion visit https://groups.google.com/d/msgid/chrysler-300-club-international/em36c7e1bb-ce99-457d-8d86-8f4689b42425%40158eef86.com.
For archives go to http://www.forwardlook.net/300-archive/search.htm#querylang
---
You received this message because you are subscribed to the Google Groups "Chrysler 300 Club International" group.
To unsubscribe from this group and stop receiving emails from it, send an email to chrysler-300-club-international+unsubscribe@xxxxxxxxxxxxxxxx.
To view this discussion visit https://groups.google.com/d/msgid/chrysler-300-club-international/00cc01db8212%248fe7b1b0%24afb71510%24%40optusnet.com.au.
--
For archives go to http://www.forwardlook.net/300-archive/search.htm#querylang
---
You received this message because you are subscribed to the Google Groups "Chrysler 300 Club International" group.
To unsubscribe from this group and stop receiving emails from it, send an email to chrysler-300-club-international+unsubscribe@xxxxxxxxxxxxxxxx.
To view this discussion visit https://groups.google.com/d/msgid/chrysler-300-club-international/em15b3a8af-d9b8-471d-9848-9db2c750045c%404baeca75.com.
Back to the Home of the Forward Look Network
Archive Sitemap