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| Looking for someone who can answer a question about the mounting of the throttle linkage at the rear of the LH cylinder head.
I had to replace a rubber bushing in the linkage. Removed the linkage from the firewall. Had to unbolt the bracket from the rear of the LH cylinder head.
Two bolts held it on. Discovered two different length bolts. So it seemed somebody had disassembled this before.
Thought it was dumb that the bracket was bolted up and sealed a water passage at the rear of the head. Lost a few quarts of coolant when I removed the bolts. I also couldn't see if there was a gasket between the head and bracket (working blind back there) but figured there had to be or it would leak.
AFTER reassembly, I discovered a cover plate laying on the back of the block that either fell out when I removed the linkage or had fallen off from a previous throttle linkage removal and was not in place when I took it apart.
I immediately recognized that this cover plate is supposed to go between the head and the throttle linkage bracket and that there must have been a gasket between the plate and the head.
In thinking about it, I thought that there was no way that Plymouth would have designed the cover plate so that it had to be removed when the throttle linkage was removed.
I looked in the Shop Manual but the only mention I could find was in troubleshooting coolant leaks, "other" less common leak points included the cover plates at the rear of each cylinder head.
So my question is, was the throttle linkage bracket AND the cover plate really secured to the head by 2 bolts or should there be 2 studs at the rear of the head so that the cover plate can be nutted down and secured and a 2nd set of nuts used on the studs to secure the throttle linkage bracket?
If the latter is true, using bolts instead would cause the linkage to align differently (the 1st set of nuts would offset the bracket by the thickness of the nuts).
And that misalignment might even explain why the bushing at that end broke apart.
Since I have to disassemble it once again to get the cover plate and new gasket installed, I figure now is the time to make it right.
If they really did just use bolts to hold the bracket to the cover plate and the cover plate to the head, I'll put it back together that way but still believe that is a dumb design.
Thanks for any pictures or explanations that help me put it together correctly. |
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Exner Expert 10K+
Posts: 10136
  
Location: Lower Mainland BC | .
I don't know the answer to your question but to open up the field for potential answers, I am pretty sure that the 1955 Plymouth V8 was actually a Dodge poly engine (with curves at the lower edge of the valve cover) rather than the saw tooth edge of the 56 Plymouth "A" engines.
Therefore, those with 55 or 56 Dodge poly V8s might be able to answer your question.
(My 56 Dodge has a double rocker ("hemi") so I can't directly answer your question.)
Good luck.
Edited by 56D500boy 2023-08-21 2:00 PM
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Expert 5K+
Posts: 9849
 
Location: So. Cal | All early hemi and poly engines that use these plates, attach the linkage with the same bolts - i.e. no studs. I don't have information specifically about the '55 Plymouth application, but this is true for the Dodge & Chrysler cars that I have experience with, so I would expect the same with the '55 Plymouth.
However, there is variation in terms of where the engine sits in the chassis and the condition of your engine mounts etc. So if you are experiencing binding, then by all means, use whatever spacers or shims you need to, to adjust that out of your linkage. |
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| Okay, thanks. No binding that I'm aware of. I'm working on this for my 88 yo f-i-l. He's owned it about 5 years but no longer drives.
My first driving experience, the throttle response was poor. I was certain that little V8 was more powerful than that. On diagnosis, I saw that about 1/2 the pedal travel was just taking up the slop in the linkage caused by the broken rubber bushing that left an empty hole in the linkage support bracket.
The carb will fully open when manually pulling the carb linkage open but the throttle linkage couldn't do it. I molded a urethane bushing (a reasonable looking facsimile of the original) and I believe it will allow the linkage to work properly now.
Luckily, I spotted the missing cover plate before refilling the radiator. I've now made a new gasket and will disassemble/reassemble soon. Just hesitated to reinstall with the existing bolts because it seems like such a dumb design to me.
If my homemade bushing DOES fail, I'll have to disassemble again and waste more coolant. I was really hoping you were going to tell me it should have studs, haha! But if it was always bolts, putting studs on now might result in misalignment and binding so not looking to modify the factory design.
Again, thanks for the responses. |
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Extreme Veteran
Posts: 451
Location: Beaumont TX | Do you need more information on the throttle linkage. I have the original throttle linkage in my 1955 Plymouth Savoy with a V8 and can take some pictures if you still need help.
Sam |
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Posts: 15
| Sam, sorry, I did not see your reply when originally posted. Pictures would be VERY helpful.
As you can tell, this has not been a high priority project for me, still helping my now 89 y.o. f-i-l with his '55.
I finally got around to refilling the radiator. But it seems my homemade gasket did not work.
As I take it apart, I am STILL wondering if the extra plate should be there between the back of the cylinder head and the plate. I installed my gasket, then this plate, and then the throttle linkage engine bracket, secured by the 2 mismatched bolts that were originally holding the bracket in place.
Sam, if you, or anybody with a '55 Plymouth V8 could check, the plate and bracket are visible from the side when installed. The problem is I cannot "see" from the backside as it is up against the firewall. But a side view would help me compare to what mine looks like.
From Powerflite's response, I took to mean the plate I found DOES need to be installed. So no. I am looking to confirm that I have sequenced the parts correctly.
Very possible I need better gasket material. It was not easy for me to make the gasket with the material I had, the plate wouldn't imprint on the material I had very well. Getting good bolt holes was problematic so no surprise if they ripped out when I pushed the bolts thru.
Is a replacement gasket available? I assumed not but if someone knows where to get a ready made gasket, please advise.
I already wasted another half gallon of fresh coolant in the first refill attempt. I'd like to be sure to do it right this go around.
Any and all help is appreciated. |
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Exner Expert 10K+
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Location: Lower Mainland BC | Dick K. - 2024-06-20 6:44 AM
Any and all help is appreciated.
Not sure if this info will help you or not:
 (55PlymouthThrottleLinkageAdjustment_0.jpg)
 (55PlymouthThrottleLinkageAdjustment_1.jpg)
 (55PlymouthThrottleLinkageAdjustment_2.jpg)
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 55PlymouthThrottleLinkageAdjustment_0.jpg (76KB - 38 downloads)
55PlymouthThrottleLinkageAdjustment_1.jpg (237KB - 41 downloads)
55PlymouthThrottleLinkageAdjustment_2.jpg (215KB - 40 downloads)
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| Thanks for posting but the engine bracket on the '56 P29 V8 looks to be very different from the '55 P27 V8.
I have the '55/'56 Service Manual but don't recall anything that shows the detail of the '55 Throttle Linkage engine bracket or if it did, nothing to show how it attached to the cylinder head (to include that pesky plate).
Still hoping somebody is familiar with it and knows something about the gasket. |
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Exner Expert 10K+
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Location: Lower Mainland BC | Dick K. - 2024-06-20 9:43 AM
Thanks for posting but the engine bracket on the '56 P29 V8 looks to be very different from the '55 P27 V8.
Yeh, sorry about that. I was hoping that the P29 linkage diagram would work for you.
So far (just now) I have only found this photo of a 55 Plymouth V8 (which used the 55 Dodge 270/277 Poly V8). I think the strange vertical linkage is related to the dash mounted
Powerflite shifter.
I will keep looking for better photos.
In the meantime, this diagram might be much closer for your 55 Plymouth V8 application:
 (55PlymouthV8EngineBay_1.jpg)
 (55PlymouthV8EngineBay_2.jpg)
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55PlymouthV8EngineBay_1.jpg (116KB - 40 downloads)
55PlymouthV8EngineBay_2.jpg (176KB - 43 downloads)
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Exner Expert 10K+
Posts: 10136
Location: Lower Mainland BC | .
I found PNs for the bracket in question as well as bushings and insulators. No mention of a gasket for the bracket.
 (55PlymouthThrottleLinkage_BracketPNs_1.jpg)
 (55PlymouthThrottleLinkage_BushingAndInsulatorPNs.jpg)
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55PlymouthThrottleLinkage_BracketPNs_1.jpg (181KB - 43 downloads)
55PlymouthThrottleLinkage_BushingAndInsulatorPNs.jpg (129KB - 44 downloads)
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Exner Expert 10K+
Posts: 10136
Location: Lower Mainland BC | .
Regarding the gaskets for the plates, I had to "go back to school" and remember that Chrysler did a good thing, at least back in the mid-50's: They made heads that didn't care whether they were
right bank heads or left bank heads.
As a result both the front and rear of the heads had ports that a) were connected to the water pump manifold at the front of the engine and b) simply blocked off at the rear of the engine.
Consequently, the gaskets that you seek would be PN 1329 336 (or 1329336 when searching the internet).
Not finding anything, you could either make your own using Felpro blue gasket material (comes on a roll) and/or use an Anti-freeze compatible RTV silicone and goop it on where the plate
is going to touch the head. I typically use Permatex Blue *AND* a gasket for my water pump installations (not saying that that is correct, just what I have done).
Some PN chasing, starting with a photo of a 55 era poly Mopar engine showing the block-off plates at the back of the heads.
(I guess somebody figured, "Hey, you know what? We could attach a throttle linkage plate to the engine using those block-off plate bolts. Two birds, etc")
Edited by 56D500boy 2024-06-20 7:48 PM
 (55ChryslerPolyShowingBlockOffPlatesAtBackHeads.jpg)
 (55-56PolyDodgeEngineShowingWaterManifoldAndGasketsAt18and24.jpg)
 (55-56PolyDodgeEngineShowingWaterManifoldAndGasketsAt18and24_PNSection7-44-4.jpg)
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55ChryslerPolyShowingBlockOffPlatesAtBackHeads.jpg (147KB - 40 downloads)
55-56PolyDodgeEngineShowingWaterManifoldAndGasketsAt18and24.jpg (86KB - 38 downloads)
55-56PolyDodgeEngineShowingWaterManifoldAndGasketsAt18and24_PNSection7-44-4.jpg (106KB - 42 downloads)
55-56PolyDodgeEngineShowingWaterManifoldAndGasketsAt18and24_PNSection7-44-4_2.jpg (124KB - 40 downloads)
55-56PolyDodgeEngineShowingWaterManifoldAndGasketsSection7-44-4WithPN1329336.jpg (120KB - 40 downloads)
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Posts: 15
| Okay! Now we are on to something.
The new throttle linkage illustration you found is definitely closer, if not exactly, what is on the car. In particular, the engine bracket with 2 bolt holes seems to be match.
I believe the '55 Plymouth did use a Dodge V8 except that IIRC, the 270 was an optional choice. The '55 I'm working on is a 260 which I understand was a running change (the car here is a late build), the early year base V8 was a 241.
The photos don't help a whole lot since you can't see the engine bracket mounting. But the display engine does at least show the block off plate. And I believe you are right, they decided to mount the engine bracket using the block off plate bolts.
I mentioned earlier in the thread that I see this as a stupid design choice since you have to remove the bolts securing the block off plate to remove the throttle linkage, resulting in coolant loss as the block off plate gets loose. Maybe that was rectified by a redesigned '56 throttle linkage engine bracket. 70 yo spilt milk at this point.
But now I need some clarification.
I assume there is no illustration showing the rear of the block so nothing to identify the block off plates installed at the back of the cylinder head.
And we are assuming that the same gasket used that was used for the water passages to the water pump assembly, ie., items 18, 24. and 41, were also used as the gaskets for the block plates at the back of the head. Fair assumption although I'm curious why they would not have used a full face gasket at the rear, no reason to have the water passage hole I would think.
You have identified the gasket p/n as 1329336 in Group 7-44-4.
I cannot find this gasket for sale. So I have no idea what it might look like. I read the description as Water Pump Body Cover Plate to Engine Block Gasket.
You didn't show the complete Parts List (Plate 9-4) so I'm not sure what the Water Pump Body Cover Plate might be.
However in the same Group, gasket p/n 1328845 is listed. I'm not sure how to interpret the description, but it reads "To Cylinder Block Core Hole Cover, S27".
The core hole cover "block off plate" is mounted to the Cylinder Head, not the Cylinder Block, but I have found a picture of this gasket (NOS), and it appears to be identical to the shape of the gasket I tried to make, including the not quite circular water passage hole itself.
Usage of both listed gaskets is 2 per car. But I see at least 3 gaskets associated with the water pump housing. I'm not familiar with the housing, so perhaps there are actually 4 gaskets associated with it, 2 of each?
I wondering what you think of this 2nd gasket p/n in Group 7-44-4?
Could there be another Group where the rear of cylinder head core hole cover and its associated gasket p/ns can be found?
I really appreciate your help on this.
Edited by Dick K. 2024-06-21 12:25 AM
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Exner Expert 10K+
Posts: 10136
Location: Lower Mainland BC | .
Dick: I think that you are overthinking the gaskets for the block-off plates. I don't think they were a replacement part because there was not need to ever remove the plate (not withstanding your throttle bracket issue).
The water manifold connects the heads and the block to the water pump at the front of the engine:
The water manifold gaskets (that you could use as the templates for your block-off plate gasket if you don't want to go the RTV route,
are available in Felpro's full engine gasket kit, like this one, FS 7790 PT-2.
https://www.drivparts.com/part-details.html?brand_code=BCWV&part_num...
Or in their timing cover gasket set (if it is still available)
Or just make them |
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| Overthinking is my character flaw, haha!
So both the engine overhaul gasket set and the timing cover gasket set include 2 each of the 2 different gaskets listed in Group 7-44-4., one of which can be used for the block off plate at the rear.
I have to disagree that the block off plate gasket would not need to be serviced. Surely the block off plate would be removed to do an engine overhaul, perhaps even a valve job if you were going to tank the heads.
I also noticed the timing cover gasket set includes a 5th gasket different from the other 2 and not apparently included in the overhaul kit. I don't need to know but I wonder what that gasket is for and why is it omitted from the overhaul kit, and looks like there may be a couple other items omitted also. No matter for my purpose, just curious.
I found a guy claiming to have the 1328845 gasket. They look to be what I could use. For all I know, he has misidentified the p/n so I will ask him to give me measurements so that I can match them up to the block off plate. If they match, I'll buy.
I thought about RTV but I've never used the stuff, so my skill level is immediately suspect. More importantly, it is not easy to get everything together, very limited access. I can picture myself getting RTV all over everything except where it needs to be.
If the gasket I found doesn't match, I'll go to NAPA to see what they can obtain from Fel-Pro for me.
I owe you a big thanks. The parts illustrations and p/ns you posted have been a tremendous help to me. Thank you!
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Exner Expert 10K+
Posts: 10136
Location: Lower Mainland BC | .
Glad to be of assistance. Hope it works out.
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Extreme Veteran
Posts: 451
Location: Beaumont TX | Hello Dick,
I've been away for a while and I apologize for being late with this reply. Have you solved your problem yet? I can take pictures of the throttle linkage for you and I have spare gaskets for the water pump mounting manifold that I made when I had the heads off my engine recently. I can send them to you. Very easy to make. It is better on the blind cover plate on the back of the heads to make a gasket that doesn't have the big hole in the middle so that the metal on the cover plate does not see the coolant. Just lest opportunity for rust.
I'll watch closely for a while and see if you reply or you can PM me.
Sam
Do you need |
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Extreme Veteran
Posts: 451
Location: Beaumont TX | Hello Dick,
Here are three pictures of my throttle linkage. I have a 259 V8 in a 1955 Plymouth Savoy and it is a late 1954 build.
There is no connection of the throttle linkage to the back of the driver side head, at least on my car, and I'm sure my car is as original. There are water jacket cover plates on the back of both heads that show clearly on Dave's engine picture above.. Both heads are exactly the same and totally interchangeable but the passenger side head is rotated 180 degrees, front to back, as compared to the driver side head. That's why both heads have a small cover plate that covers the water jacket opening on the back side of the head. These cover plates cover the holes in the water jacket that would be connected to the water pump mount on the front of the engine if the head was rotated 180 degrees. My cover plates are shaped a little differently than the ones in Dave's engine picture. These cover plates don't have anything at all connected to them. The two bolts hold the cover plate on and nothing else. So if your car is like mine, disconnecting the throttle linkage would not open the water jacket in any way. I hope you can see this in the pictures.
It is very easy to make a gasket for these cover plates with Garlock gasket material that you can get from any auto parts store. Just use the cover plate as a pattern and don't cut a big hole in the middle of the gasket because there is no need for the hole in the gasket on the cover plate.
Here are the pictures.
Edited by samstrader 2024-09-05 10:31 PM
 (At Carb.jpg)
 (At Distributor.jpg)
 (At Firewall.jpg)
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At Carb.jpg (231KB - 2 downloads)
At Distributor.jpg (205KB - 5 downloads)
At Firewall.jpg (242KB - 3 downloads)
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'55 Plymouth Throttle Linkage Mounting
