RussJagoau

Hi All my 53 Chieftain manifold is showing signs of age and wear in the heat riser butterfly valve shaft / manifold . Recently its had a spray weld repair to fix a longitudinal crack in the directional change area of the hot box that is a common failure over the years. Weld shop did an excellent job of the repair. Ive also refitted the manifold to the block using Belleville spring washers and reduced the torque setting applied to the brass manifold nuts to allow a little more give to allow for heat cycle expansion on the old cast iron to avoid over stressing it again and try to minimise the crack from re-appearing. However when its on clold start and warm-up, there is an annoying exhaust leak from the butterfly valve shaft on the counterweight side. When its reached normalized operating temp and the valve moves to fully open the leak is minimised . Obviously a worn shaft / manifold as was obvious when i measured radial movement jof the shaft just prior to refitment. I needed to move the vehicle to dry storage so it had to be functional to drive it. Now its in dry storage im looking to repair the leak permanently but still retain the functionality of the heat riser valve . Ive seen other classics with the valve removed and the shaft holes plugged off, however the preference is to retain it as standard. Hence my question is to others who may have completed a permanent repair to reduce the leakage. Particulary with material spec details of a bush that may have been fabricated and installed in the cast manifold to minimize the radial clearance to the shaft. Bronze ? Steel ? clearance to the shaft to minimise leakage and binding ? Any previous experiences / guidance would be greatly appreciated. Thanks

Hi Norman. previously i had a similar conundrum whereby i couldnt obtain or locate the correct diameter clutch plate. I did source a somewhat large plate that had a similar thickness and the splined hub was correct in diameter and number of splines. turned it down on a suitable sized lathe takng slow depth cuts as to fit inside the pressure plate. Its been in service 10 years and still going strong ... Looking at the rivet pattern in your pic it may / may not be into the rivets if you get the correct diameter. Some simple measurements will determine that. Borg Warner make replacement plates still in that diameter / pattern as ive sourced numerous other plates for other customers over here in Aus so im sure you would source then a lot easier in the US.

Based on your report and the shipping price to down under I've ordered a set for my 53 Chieftain so looking forward to receiving and fitting them . From the tracking provided they have already winged their way across the pacific and have arrived in country. Purchased from Chevypitstop and the price and the shipping cost to Aus was too good to pass based on your recommendation. Thanks

Good job there. Whatever works to get the successfull outcome is the name of the game. 🛠️

Having tried the Sneaky Pete tool on numerous occassions, just be forewarned that the rope type seals can get really tight in the recess that they sit in - especially over time. So much so that the tool can either part on you or it will just wedge the seal even tighter in the seal recess the harder you pull. So be prepared for a crankshaft removal task at worse or at least the slackening of the main bearing caps to allow a little more access and to relieve the compression on the rope seal itself. When the lower bearing cap is removed, suggest you see how much effort is required to try to remove the lower seal half. You can then ascertain the complexity of the seal removal task for the top half when the cranskaft is still in place...... WIsh you the best of luck......

Hello, your oil leak is most probably from the rear crankshaft oil seal and it usually a dead giveaway if the flywheel cover is missing, so that the oil doesent collect on the components behind the flywheel whether it be torque convertor or clutch. Suggest you first replace the missing bolts on the oil pan rails to confirm its not coming from the pan rail seal,. Then start the engine , when its running its most likely the crankshaft rear oil seal leaking thats the culprit. And unfortunately thats no 5 minute task to repair. It all depends on the leak rate as to whether the "juice is worth the squeeze" to go to the expense of repairing it. Its easier and generally more successful to remove the engine and replace the seal components to ensure a successfull outcome. if you have a Pontiac Workshop manual thats a great source to review to see the size of the task to change the seal. You can do it in the vehicle but its best done on a hoist so that you have good access to change the seal halves.

Once you slacken the generator the belt should slip of the harmonic balancer quite easily. If the belt is slackened and you cant remove it from the crankshaft wheel /hub then the front engine mount may be collapsed or compressed which wil reduce the clearanace of the hub / balancer to the mounting frame / crossmember . That in turn makes it difficult to remove the belt. I have replaced numerous front engine mounts over the years on these vehicles and its due to age and oil exposure generally. it may pay to check it.

Teddy Exhaust valve guides have a counterbore inside the valve guide to allow for expansion. This is near the top of the guide and if you have access to a workshop manual the dimensions of the counterbores is stated as its different for 6 cyl vs 8 cylinder engines. This may well be what you are seeing as the eroded section you refer to, in the 6 cylinder engine application, the counterbore is approx 0.750" depth according to the Pontiac workshop manual The guides are driven out downwards and the new guide is installed the same way, ie from the top of the block downwards. Before installation, i place them in the freezer overnight to minimise the OD of the guide insert before its driven into the block. Never had any issues with this method in the engines i have done. Prior to removal - suggest you measure the heights of the guides protrusion in the block under the valve head before you drive them out, and then replace to an identical height . They dont have to be within 0.010" of one another as some of the Pontiacs I have dis-assembled had significant assembled height variations for years and were running well, as the engine simply wore out over time. Depending on the manufacturer of the replacement guide, and the dimensions of the valve stems, some guides will require precision reaming to obtain the correct radial clearances, whereas others dont. So its a condition based approach based on the measurements of the guide ID vs Stem OD. To do this you will need a good small hole bore gauge and a micrometer to accurately measure the dimensions . Some of the old guides can be difficult to remove given the time they have been installed. A good soaking with release fluid sometimes helps as does some local heat application using a paint stripper hot air gun. If you try to rush the job, then generally something wil invariably end up damaged, generally its the operator applying the removal techniques. Good luck

My Motor Book specifies 95 ft/lbs for the front caps and 120 ft/lbs for the rear. It doesent specify fastener sizes however . Hope thats helpfull

The oil filters are by-pass or side stream filters as fitted are optional or after market, so as Kornkurt says ensure you dont allow too much oil flow through the side stream filter for obvious reasons. The side stream filters I have fitted run 5/16th OD or 1/4 " ID lines to the filter inlet from the oil pressure gallery tapping point near the oil pump. This size tubing is a natural choke / restriction of flow that will still allow the standard oil pump to deliver / maintain good pressure at idle when at Normal Operating temp but allows a reasonable flow through the side stream filter. You should also consider placing Rare earth magnets on the exterior of the filter housing as you wlll be surprised at the material it captures on the inside of the housing over time- this material normally passes through the filters given its small micron rating but the magnet will capture it on the inside of the filter housing. I've run these magnets for years on all my vehicles and motorcycles both old and modern and swear by their ability to capture very small ferritic particles from within the oil stream. its an extremely efficient way of fine micron filtration without impediment to flow.

Hi Paul, Good looking car for a project. I have 2 Pontiac Chieftains , 1951 and a 53 version both built in Aus. I have acquired a few spare engines and gearboxes, gasket sets valves etc. Gates TR 24403 fan belt is the correct fan drive belt for my models as it has the 3/4" cross section and i confident that will fit your model as well. Anyhow if i can be of any help pls just message me. Rgds Russ

Nice Car John, and one that you can be proud of from your efforts. The 53 is the pick of the shapes i think from that era and they do drive well. Great job !

No probs - if you get the time when you get the new guide and fabricate the drift - pls post a few pics as would be interested to see what it looks like and how it performed. Ive tried numerous combinations over the years and some work better in some applications than others. In cast blocks like you have there, removal is generally straightforward. In alloy heads where steel / bronze guides are fitted, when the guide is being taken out, it can damage the head and make the counterbore loose even when the head is heated in the oven to assist with the removal and installation process. Good luck !

I have replaced guides in these engines numerous times. One method i successfuly used ( without knowing which tools / drifts you have looked at) is to measure the Guide ID and OD and have a tool made on a lathe that has a step shoulder on the tool. I have done this for numerous guides that were an interference fit in various heads or blocks that Ive restored over the years. Just ensure the tool ID is long enough to be the length of the guide so it acts a a good pilot whilst you are removing the guides. Any machine shop should be able to make this for you at a reasonable cost. I have used standard Grade 8 engine bolts with the nut screwed on to sometimes start the removal of the guides if they were tight as I didnt want to damage the shouldered tools that I manufactured. Some of the guides removed took a lot of pounding to start the removal process so only use hi-grade bolts that will withstand the impacts. If the protruding section of the guide is broken - i would suggest you square that off before commencing the removal process to have a uniform surface area to act upon when you are removing the guide. If not you can skew the guide sideways somewhat as well making life more difficult than it needs to be. For what its worth many manufacturers make guide removal tools for British motorcycles - to which i have a BSA engine guide tool that comes very close to the original dimensions of Pontiac guides. However its a selective fit that you can only try at the time before you purchase or manufacture the tool. Hope this helps

Ok so we are on the same page then regards the octane selector tab . Are you familiar with checking the static ignition timing with the engine stopped and using a test light ? Thats as good a starting point as any for ignition timing checking. And i found both methods accurate when compared to one another ie static vs dynamic checking. The beauty of using a strobe timing light is that you can verify not only ignition timing at idle but more importantly the amount of total advance. In my opinion total advance is more critical for engine performance and economy than initial timing at idle hence i tend to tune engines on the total advance number rather than at idle. Not so much with these old girls with low compression ratios but later model engines running greater than 8.5:1 Compression ratios then are prone to detonation with resultant damage incurred if there is too much advance dialed in. On the Pontiacs I have, i found to have total advance of 34 deg BTDC required initial timing of approx 7deg BTDC whereas the manual for memory quotes 3 deg ? obviously there may well be some cam drive / distributor drive slack in there that may account for this as well.

Does your distributor have the Octane selector tab fitted as per this picture - ( the tab thats shown sitting up against the block and is held in place by the distributor base ?) Be interested to see what you refer to as the tab at the distributor cap as Im assuming we are talking about the same part ??

Howdy - do you have a timing light where you can check the current ignition timing after you cranked it clockwise ? Or even if you do a static check with a test light to see where the ignition is occurring related to BTDC. It would be interesting to see where its currently timed at as compared to before when the engine was suffering the hiccup before. Some of the old engines that have a significant of timing chain wear require more advance due to the lag in the valve timing as the chain stretches and of course then retards the ignition. 1/8th of a turn is a significant amount to rotate the distributor in relation to static ignition timing and then of course total advance. Even though these engines are low compression, too much advance is not good. By the sounds of it, it may have been running with the spark timing well retarded before High HT Plug lead resistance can also cause a hiccup off idle as well as the spark will be extinguished as the load comes on the engine to move off from standstill. Be interested in what you find as to the current / previous settings. More importantly its good that you have cured the hiccup

The Internal seals on the Hardy Spicer u joint cups are the modern elastomer type . I have fitted them to both my 51 and the 53 that my Dad had and so far its all good. Not that they do a lot of miles nowadays but every time i put the grease gun to it they dont take a lot of grease to refill the cup, and there is no evidence of grease fling out around the transmission tunnel or diff floor pan area. So far so good, they should outlast this current owner

Dave - So the front u-joint is different on my '51 as it has 4 round cups that are more typical of later model U-joints as compared to the flat face mounted cup type in the rear. Looking at Ebay here it seems that both front and rear for a '37 are the same. I had to go with Hardy Spicer here as that was the only supplier available locally that could supply that style of flat faced cup joint. To import from your part of the world is worth more than the component is nowadays...

Nice job ! Straight 8 - the rear uni joint with the grease nipple that will fit is Hardy Spicer 114-2111 - it has the correct flat flanged cups for mounting on the Pontiac pinion flange. Hope that helps.

So I have used a 12V oil suction pump that has a small diameter suction line that will easily enter the housing fill plug. I've used these to empty crankcases in boats and transmissions that the drain plug when opened will only create a huge mess to clean up. These pumps are cheap and available on Ebay and will pull the heavy weight oil out in short order. Also - If you are changing the pinion seal then jack the vehicle up at the rear and support under the rear axle then remove the rear uni joint base as you call it and the pinon seal, , a lot of the oil will then drain through the pinion shaft bearings and you wont have to pump much out if utilising the vacuum pump method. Thats how i changed my final drive oils in my old Chieftains......

Its going to be tough to get 1000 rpm when you are cranking on the 6V starter so those compression figures are somewhat optimistic.!! It depends on the C.R of the engine but if its standard Compression ratio with a standard camshaft grind you should see approx 105 to 120 psig at operating temp with all the plugs removed and the throttle held wide open.... Its not so much the ultimate pressure but the variance between the cylinders to give you good cylinder balance and a smooth running engine.

Some of the other Classics I have been involved with that suffered from vapor lock due to heat transfer from the exhaust manifolds, the owners actually extended the heat shield in both directions so that the radiant heat along the entire manifold length was deflected away from the fuel system. The extensions were rivetted to the original heat shield and supported at either end by a small stay. It made a significant difference also just having the deflector in place for the length of the exhaust manifold. These vehicles when running at parade speeds and idling in summer were prone to vapor lock once the temps started to rise in the warmer monthes with the lower flash point fuels that are sold today. Years ago it never seemed to be the issue, maybe the lower flash point fuels that are sold today ? I know if i dont start the vehicle for approx 10 days then i have to utilise the 6V electric primer pump to fill the carb bowl again. Cheers

Not that Im aware of re the Material Specification for the brass manifold nuts . They are thicker in section / width than normal steel nuts. Both of my Chieftains have them fitted. UNF threads and were purchased through Ebay years ago. Originals still in place and been removed numerous times over the years. Also used on the exhaust flange gasket outlet at the manifold.

You could try using whats known as a Dowty Seal as used on hydraulic system banjo fittings, these have a Nitrile insert on the ID of the washer and are perfect for this application. I use them numerous times on the By-pass filter on my 50's Pontiacs and classic bikes for sealing external oil lines at connections. The Nitrile insert is slightly thicker than the base OD washer and they can be re-used many times. And they are not expensive in the smaller sizes....