Change to HV oil pump - your thoughts?

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WARFARE

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Hi Guys, just wanted to know your thoughts on switching to a HV oil pump in my 340.

Original 41,000 miles. While replacing valve seals I discovered a blown head gasket. (Compressed air) While the heads were off I had them hot tanked along with the intake manifold. Cylinder walls look good with very little ridge so am just going to bolt the heads back down. (Plan to do a complete rebuild at some time in the next couple of years) I also changed the timing chain while in there as well.

The engine is super clean inside. Pan is very clean.

My question is, is there any benefit to changing the existing oil pump to a HV type if it is just an occasional driver?

I have not pulled the old pump out yet to see what shape it's in but figured since the pan is off I would change the oil pump as well.

Thanks for your thoughts.

Pat
 
You just threw the heads in the hot tank? The valve seals didn't like that too much.
 
I agree with sticking with a stock pump. The only reason I see for running a HV pump is wide bearing clearances and then you have to also install a larger i.d. pickup on it because the stock pickup is only capable of supplying a stock pump.
 
As long as the heads are off spend the money and get the valves ground and new valve seals put on.

And since you blew a head gasket have the machine shop check the heads for warp and mill if necessary
 
Your a lucky man to have a original 41K 340 :thumleft:. I see no need to replace the pump on a stock engine. If the oil pressure has been fine, just seal her up and enjoy it.

With that said, I'd be more concerned about the head gasket failure. I'm guessing you have a factory high compression 340. Hopefully you had the heads surfaced, but I'd still throw a straight edge on the decks to see how flat they are? If close, a good gasket can probably seal you up, but even then, I'd watch my fuel quality and timing to make sure detonation didn't take them out.
 
I changed the valve seals after hot tanking, removed the valves and oiled them well. The machine shop checked that the heads were square. The heads have been off before, not sure why (single owner/little old lady)but the machinist indicated that the old gaskets were very crappy in there day. No longer sold apparently. I replaced them with Fel-Pro.

I have no specific reason to change to a HV pump. Just wasn't sure if it would be beneficial.

I noticed lower oil pressure on the guage before (not sure the figure)but I think it might be the guage or sender. Seamed to get lots of oil at the top end.

Thought while I have the pan off changing the gasket I would change the pump.
 
WARFARE said:
I changed the valve seals after hot tanking, removed the valves and oiled them well. The machine shop checked that the heads were square. The heads have been off before, not sure why (single owner/little old lady)but the machinist indicated that the old gaskets were very crappy in there day. No longer sold apparently. I replaced them with Fel-Pro.

I have no specific reason to change to a HV pump. Just wasn't sure if it would be beneficial.

I noticed lower oil pressure on the guage before (not sure the figure)but I think it might be the guage or sender. Seamed to get lots of oil at the top end.

Thought while I have the pan off changing the gasket I would change the pump.
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A little bit bigger cam with a modern grind, combined with some time spent gasket matching the intake and exhaust along with smoothing the bowls and a high quality valve job would be money and time will-spent, block the heat crossover and toss a set of Summit headers. If there is a ridge in the cylinder, bore it and have it honed to the next size. More money, but how many times are you gong to rebuild this? A fully rebuilt motor may cost a bit more initially, but its a lot cheaper than a new car payment for 5 to 7 years.
 
a NEW stock pump. dont use the old one if you have a chance to replace it with a fresh pump (i.e. you have the oil pan off)

HV would be if...
lots of bumper to bumper traffic and you sit there a lot stuck in traffic
or custom valve train that intentionally passes lots of oil (harland sharp, etc)
or real loose clearances

what has your oil pressure been like while driving around ?
 
With 41K on it - I'd just disassemble adn clean the original pump, lube it a little with some white grease so it primes quick, and stick it back in.
Back when these cars were on the road it was common to pull heads and clean the lead off the valves and chambers as part of a major tune up. They'd wire brush the chambers and valves, sand blast the plugs, file the points, and stick it all back together. Many engines have had some kind of internal work like that whether or not the current owner knows it. Make sure the head bolt holes are tapped clean and the bolts themselves have cleaned threads. torque from the center out, I lube the bolts with a few drops of 30wt oil, and torque in 3 steps.
 
Stock pump is fine , put in a new one though 41 k and 40 years old best put a new pump .
 
WARFARE said:
... I have no specific reason to change to a HV pump. Just wasn't sure if it would be beneficial.

I noticed lower oil pressure on the guage before (not sure the figure)but I think it might be the guage or sender. Seamed to get lots of oil at the top end.

Thought while I have the pan off changing the gasket I would change the pump.
Click to expand...

What do you mean by lower pressure? At what RPM? What kind of oil? If you do not use a HV pump, there is no reason to replace a HP, 65 psi, pump with a newer one. If you do change it out use the HP spring.
 
Oh for Christ's sake. Lets stick an air gap, MSD and a HP Holley on too. What is it with some of you? He's got a PERFECTLY good 340 and some of yall just gotta tell him to screw it up. A "modern" cam? All else the same, there's not a much better cam he can have. It was a good package 40 years ago and it's still a good package today. And gasket matching? A numbers matching 340? You've lost your everlovin mind. Oh wait, you gotta have one first.


jbc426 said:
A little bit bigger cam with a modern grind, combined with some time spent gasket matching the intake and exhaust along with smoothing the bowls and a high quality valve job would be money and time will-spent, block the heat crossover and toss a set of Summit headers. If there is a ridge in the cylinder, bore it and have it honed to the next size. More money, but how many times are you gong to rebuild this? A fully rebuilt motor may cost a bit more initially, but its a lot cheaper than a new car payment for 5 to 7 years.
Click to expand...
 
I just keep hearing "41K miles" in my head... If the car is original I'd leave it as is. Just my opinion but you only have original once and in this case it's low milage original. If it's not broke don't fix it.
 
RustyRatRod said:
Oh for Christ's sake. Lets stick an air gap, MSD and a HP Holley on too. What is it with some of you? He's got a PERFECTLY good 340 and some of yall just gotta tell him to screw it up. A "modern" cam? All else the same, there's not a much better cam he can have. It was a good package 40 years ago and it's still a good package today. And gasket matching? A numbers matching 340? You've lost your everlovin mind. Oh wait, you gotta have one first.
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moper said:
I just keep hearing "41K miles" in my head... If the car is original I'd leave it as is. Just my opinion but you only have original once and in this case it's low milage original. If it's not broke don't fix it.
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Xs - 10
 
Ya, I hear you guys. That was the idea, no mods, keep it stock but just fix the head gasket and valve seals and put her back together. Not going to go wild right now. I just want to get some driving out of it.

Other than lots of oil leakage from the valve covers the engine ran and sounded great. Even with the cracked head gasket. LOL Quite clean inside other than bits of valve seal. Some bits in the pickup screen.

I am a bit OCD and just want the "peace of mind" of knowing what's in there. Atleast some of it. While I have it apart I thought I would change the straight forward stuff like timing chain, water pump, head/intake gaskets etc. Also doing the brakes front to back, had the Carb redone to new (thing of beauty) and replacing the fuel tank and lines.

Now I will just change the oil pump to a new one. (peace of mind thing - better safe than sorry)

Thanks for the help and advice. I appreciate it.
 
The only thing I WOULD recommend like others have said is get the heads done. Complete valve job. Don't skimp on that. It does not sound like you had that done. While they are off, it would be foolish not to . NOW'S the time. lol
 
Use the FelPro 1008 head gaskets. The "replacement" FelPro gaskets are .054" thick which will drop compression significantly. Actual real world compression for the '68-'70 340 was around 9.5:1 not the factory listed 10.5:1 so you don't want the mega thick "replacement" head gaskets on there....
 
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