Clutch pedal push rod

[Ken Harants]

Can anyone tell me the difference between the clutch pedal push rod on a 327 an 427 engine. If it is the length, I would like to know the length of the 327 engine clutch push rod. (The rod that goes through the fire wall)

[Ken Harants]

Re: 1966 Clutch pedal push rod

Sorry, forgot the year 1966

[Michael H.]

Re: Clutch pedal push rod

Ken,

I don't know the length of the rod but the same part was used for both 327 and 427. There was a difference in the attachment at the clutch pedal and also a different part number for both the cross shaft and the short rod that connected to the release lever.

The replacement 3888213 that was serviced for many years is, I believe, longer than the original.

The 3888213 went into production on 13 July 65 and continued to be the number used throughout the 66 run. I think I have a new one and can measure if you need the dim.

[Ken Harants]

Re: Clutch pedal push rod

Michael, I just replaced the clutch pedal and bracket. The bracket was a little different with the stud for attaching the rod was lower on the bracket. Now my rod is hitting the inner fender. I could cut the rod since there is plenty of thread. I just want to be sure I have the right rod and then maybe something else is wrong. Please send me the length and any info you can.

Thanks

Ken

[Michael H.]

Re: Clutch pedal push rod

There were two different brackets that bolted to the clutch pedal. One for small block and one for big block. The difference was the location of the stud that you mentioned. If it's different than your original, it's then likely you have the wrong one.

Did you find an NOS bracket or a used one. The 3819152(?) bracket used from 63 to 65 had only one hole and pin. The later bracket used in 66 had two holes and the stud location in either of these holes was the difference between small and big block. Which engine do you have?

The clutch rod that I have would not be the original dim as it was purchased in the 70's or 80's and the incorrect length was supplied by that time.

[John H.]

Re: Clutch pedal push rod

I have two '67 rods here, and both are 19-1/4" from the center of the pin hole to the end of the threads.

[Michael H.]

Re: Clutch pedal push rod

John,

Are the two that you have old originals or new service replacements. I have one new and it also measures 19.25. The 64-67 clutch issue can be very confusing. Seems like anything that is replaced in the clutch/release brng results in a clutch that can not be properly adjusted. I have at least part of the problem figured out.

BTW, I haven't forgotten your blueprint. I have to redraw several areas. Coming soon.

[Wayne M.]

Many clutch linkage component variations

In the C2 era there were 3 different Z-bars (bellcranks), 3 clutch fork rods (counting the unique '63 pin design), 3 pedal push rods, and 2 pedal brackets.

Of the 3 pedal push rods, my original # 3819154 (for the '63-'65 small block) measures 17-9/16" from threaded end to centerline of hole. I see in Noland's Vol 2 pg 329 there's a GM dwg of the # 3888213 ('66-67 all motors), and it measures 19.1" (end to hole c/l). 396 engines had a unique rod, #3872961, and mine measures 18-7/8" (end to c/l hole); 19-5/16 overall; this agrees closely with a GM sketch of the L78 rod in RESTORER racing mod's article.

But probably the single most likely culprit, in your case, is the clutch fork rod, as these have vastly different lengths. GM dwgs for both in Noland's book.

[Michael H.]

Re: Many clutch linkage component variations

Add to that the different length throwout lever pivot studs and the several different length T/O bearings and it's a wonder anyone ever gets the combination correct. I think engineering was even confused by the end of the 60's.

I'm pretty sure Ken's problem is the clutch pedal bracket tho. All was working properly until the pedal and bracket were changed. He wound up switching between B and Sb.

[Michael H.]

Scan of Clutch SB/BB Brackets

Different pin location for SB and BB.

[John H.]

Re: Clutch pedal push rod

Michael -

One is original (with the pin hole worn to a slot) and one is a service replacement; both are identical except for the wear on the original.

[Joe L.]

Re: Clutch pedal push rod

Ken------

The GM #3888213 was the pedal push rod used for most 1966 Corvette applications. However, early 1966 small blocks used the 63-65 small block pushrod, GM #3819154. I don't know when the changeover occurred but I expect it was within the first few months of production.

Likewise, early 1966 big blocks likely used the 1965 L-78 pushrod, GM #3872961. Later cars got the 3888213 pushrod which was then used for both big blocks and small blocks through 1967.

The clutch pedal bracket for early 1966 Corvettes equipped with the GM #3819154 pushrod was GM #3819152. Later cars equipped with the 3888213 pushrod used the GM #3872963 bracket for BOTH big blocks and small blocks.

Regardless of what some parts information sources may say, including some GM sources, if the early design pushrod and bracket are used on a 1966 small block, then the GM #3844209 clutch FORK push rod MUST be also used. This pushrod is 10-9/16" overall length. If the 3888213 pedal pushrod is used, then the GM #3872960 clutch FORK pushrod MUST also be used. This pushrod is 8-37/64" in overall length. To "muddy the waters" even further, the GM #3819154 pushrod was discontinued from SERVICE in November, 1966 and replaced by the GM #3888213, even though there is a significant difference in their lengths. No instruction was provided to replace the clutch FORK PUSHROD if the 3888213 was used for an application originally using the 3819154 rod even though that change is absolutely critical if the 3888213 is used for the earlier applications. For example, how many of you know that? By the way, the 1965 L-78 (and early 1966 big block) pedal pushrod, GM #3872961 was discontinued without supercession in October, 1971. The 3888213 will work for 1965 L-78 and early 1966 big block, though.

1963-66 small blocks use clutch cross shaft GM #3832857. 65-66 big blocks use cross shaft GM #3872962. The difference between these 2 pieces is a VERY slight difference in the angularity relationship between the end levers. Unfortunately, these cross shafts were never originally stamped with a part number so there is no easy way to tell them apart.

As others have mentioned, there are a great many different components of the clutch actuation system used over the 63-67 period. Considering all of the possible combination of these components, some combinations used in PRODUCTION and some not so-used, there are a HUGE number of possibilities and chances for error when working on one of these systems, especially if some "klutz" has been there before. The proper combination of components MUST be used if one is to have the slightest chance of having it work right. The Corvette clutch actuation system, in ALL of its ORIGINAL configurations, is as "delicately balanced as the hair trigger on Palladin's long-barrel Colt 45".

[Richard S.]

Re: Clutch pedal push rod

Ken,
The 427 rod is longer than the 327 rod....look in the Long Island catalog.....I had the shorter rod in my 66 427 and had to change to the longer rod for proper adjustment.