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Valve guides on intake side


etzmolch

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I had my engine at a machine shop for complete overhaul. The mistake they made was, that they installed all valve guides in one direction despite the note from me to install them with counterbore down for intake valves. Now all are installed with counterbore up as stated in the manual for exhaust valves only. My question is how important is it for the intake valves? I am a little afraid if they now try to change them and install them in correct direction once again. What is the reason to install them with the tapered side up for intake valve? Gas flow?

Thanks,

Andre

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The bore upward on the exhaust allows more oil to run down to help cool the exhaust valve stem. This will cause more oil to get burned up over time. The intake does not require the extra oil cooling therefore counter bore is installed downward. Saves making two different valve guides.

 

I do not know if removing the intakes valve guides and reinstalling them the correct way if the press fit tightness will still be enough to keep them tight in their bore.??

 

Best,

 

DJ

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Actually the counter bore on the exhaust guide faces up to shield the exhaust valve stem from excessive heat. The valve also has a 1" long narrowed stem in this upper guide area and has a sharp edge to scrape carbon out of the guide so it will not build possibly causing a sticking valve.

 

The intake guide is the same as the exhaust guide but the counter bore faces downward to shield the valve stem from excessive oil. The intake valve also has been narrowed near the lower end by the valve keepers and has a sharp edge as on the exhaust valve but is designed to scrape down oil on the valve stem to help prevent excess oil consumption.

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Thank you both for the explanation.

The shop told me they see no problem to leave the intake guides in wrong direction. After I requested a letter guarantee me that nothing will happen in the future with the wrong installed guides. They want to change the intake guides once again. I see also the problem to get the guides out with no damage and second to get them tide installed again. For this I asked, whether it is really necessary to change them.

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Insist it be redone with new guides on the intake side. You told them how it needed to be done, you paid the to do a correct job. They need to make it right regardless of any extra cost that they may face to do so.

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Do it right.

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while it is not any shock the shop  installed them wrong....it always seems to be a slap in the face when you point this out prior in writing even and they failed to heed any prudent advice and continued with their own 'wrong' method..be sure they cover all cost of this mistake as it is entirely that of their own doing...and as advised by dodgebe4ya, please do it right and get the peace of mind you were asking about..

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They picked the engine up today and will install the intake guides the right way. Hopefully no other surprises.... It was expensive enough to let the engine overhaul here in Germany.

Thanks guys. I will keep you updated.

Andre

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  • 1 year later...

Car is running great. First 1200mls are on the odo. Just came back from a 300mls trip this weekend. No issues except with gasoline.  Looks like the gas pump can't deliver enough but is new. A deeper investigation is necessary. I asume the extra electrical pump is the problem because is directly in line with the mechanical one.  

Oil consumption is normal. Everything else working perfect.

Thanks for asking.

Andre

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I have run into problems  (thankfully on other people's cars)  where the electric pump ( when not activated)  impedes the mechanical pump's ability to deliver fuel.

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  • 2 months later...

Watch out for dirt and debris in the fuel line if you have not cleaned the tank or replaced rusty lines. Also on 1948 Dodges there is a heat shield between fuel pump and exhaust manifold. 48's will stall sometime if they get hot. See how close the fuel line is to the exhaust. 

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