Ultimate pcv question

This post has many measurements so don't get too overwhelmed :grin:

I'm replacing the pcv valve and grommet on a 455. The original one basically shattered and had to be fished out of the intake in rock hard pieces. Now here's where the confusion and thinking comes in. All part numbers are from the Dorman "Help" parts.

The intake hole is 15/16'ths. The pcv valve is 5/8'ths

Grommet 42061 is 1-1/16th wide which means it's too large. It does have the 5/8'ths hole though which is correct for the pcv valve. (This is the valve cover grommet)

Grommet 42056 is the correct 15/16'ths so it will fit the intake. The pcv hole is only 3/8'ths though which is too small.

Grommet 42051 is also the correct 15/16'ths. This grommet has a large hole in the top with a smaller hole in the bottom as a catch for the valve. The top hole measures 3/4" while the bottom hole measures 7/16'ths.

Would it be better to use one of these grommets (42051/42056) with a different size valve or to enlarge the hole on the 42056 grommet from 3/8 to 5/8 to fit the stock size valve?

Originality is not a concern but parts availability is. I really like some of them valves with the plastic L shape to make the hose routing easier, but I'm not sure if they flow well enough.

 

The last PCV grommet I got was a OEM and still available from the dealer. The part # is 1381487.

 

I used 42051 for a bit and decided I didn't like how much the valve could wiggle. I'm holding onto it for later use though as it may work perfectly with an L shaped valve.

In the end I used 42056 and ran a grinding cone on a drill through it to enlarge the hole. It took some time and left the house smelling like a burnout box but it worked perfectly.

I had also picked up a "universal" one that had the 15/16th diameter with a 5/8 hole, but it was made for a thinner intake than the 455 has so it wouldn't seat in right. It would be perfect on a thinner intake. I'm holding onto this one in case the aluminum intake I get in the spring is thinner.

 

Im going through this now. Brought home several from the parts store that the kid at the counter said would work that didnt. The factory one in the mainfold came out in pieces so thats no help. I endedup taking one that was to big and cut a wedge out of it and put some RTV on it and forced it into place. it dont look right or fit the valve right but works. Im goingto try some of these part#'s I found in some other post to see if I get better results.

New question, Will it hurt anything to run a PCV in the manifold and in the valve cover using a T into the base of the carb? I have an open element breather on the L side and a PCV fitting on the R. Im wondering if this might be contributing to my oil leaks.

 

If I understand you correctly, you have two PCV valves teed off one vacuum source, one valve drawing vapors from the stock location and the other from a valve cover?

If so, this won't cause any problems, it's simply redundant and unnecessary; one PCV valve is fine at either of those locations.

Devon

 

Yep, still available, although a little pricey.

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[TD="class: reg"]GM PART # 1381487
CATEGORY: All
PACK QTY: 1
CORE CHARGE: $0.00


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[TD]List Price:[/TD]
[TD]<del>$4.48</del>[/TD]
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[TD]Price:[/TD]
[TD]$2.63[/TD]
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[TD]You Save:[/TD]
[TD] $1.85 (41%) [/TD]
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[TD="align: right"]
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[TR]
[TD="class: reg, colspan: 3"] DESCRIPTION: GROMMET [/TD]
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You've done that too ou: I've done it twice and fortunately the valley pan caught it both times and I was able to fish it out with a coat hanger. Yep, lots of WD-40 and be gentle and patient. I've gotten ones from NAPA and Autozone that have fit properly.

 

Devon, I havent done it yet I was just thinking about that as a solution to my leaks. Really dont think ive got excessive blow by. When I stomp on it I can smell a bit of oil hitting the exhaust and theres always a bit on the inside of the starter cone.I want to cover all the bases before I commit to pulling the engine again.

 

Me three. I now put the grommet and valve in the manifold before applying to the engine.

 

I have a 1969 400 engine, the factory part for the pcv valve grommet for the intake manifold is 1381487, not sure of the original dimensions, but was discontinued. parts store crossed to a dorman part number 42056 which has a hole that is too small for valve to fit and doesn't want to go into the manifold either.. I've tried all different methods and nothing seem to be working

Below is a reference pic, I have the old grommet next to the replacement 42056 and on the left is the 42061 which is a replacent pcv/breather grommet for the valve cover original part number 1231486.

I saw this website for turbo buicks

https://www.kirbanperformance.com/product/460/PCV+VALVE+GROMMET+#7214.html

They have a version part number 7214 they are offering that supposed to be an exact reproduction of the original part. Anyone use this on an older engine

 

Jason your a true blue "Buick-ologist" I will try that method if it comes down to it.

Trying to find a cure for this pain in the you know what problem thru the reproduction parts route first..

 

I tried the 7214 grommet from kirban performance. it went in without any cutting or grinding. I was able to install grommet in the intake first then a new pcv valve went in with a thin coat of grease.

https://www.kirbanperformance.com/product/460/PCV+VALVE+GROMMET+#7214.html

 

Excellent, have to try one from Kirban.. the current grommets available are ridiculous.. have been for years.

If they fit, I will buy them in bulk and add to the tsp inventory list of parts we sell.

Thanks for mentioning it.

JW

 

You're welcome Jim.. I tried every freaking grommet mentioned and nothing fit right.. all the repos from any parts place are the dorman part with the small pcv hole..

the only thing missing from the Kirban grommet is the stamped gm part number..

 

Holy christ...$15.04 shipping to WA. There has to be one closer than PA...and cheaper to ship. UGH.

 

Dang it. I wish I knew about Kirban before I too pushed the grommet into the intake and onto the valley pan.
Cliff

 

Let us know what you find, count me in for one via TSP as soon as you get them.

 

Add one to my order if it works