Do a compression test before jumping to any conclusions, if the comp numbers are low you can do a leak down test to see if it’s a valve issue. Would be a great time for studs too.
Strange issues, tried basically everything
- Thread starter pelky350
- Start date
IDIBRONCO
IDIBRONCO
You'll have to go a little bit deeper yet to replace the cam. If you're going to install a bigger cam, then it may also be a good time to install new lifters as well. I'm just assuming that you'll have some Comp 910 valve springs put on when you have the heads redone.
pelky350
Full Access Member
Yes when doing cam I plan on all the proper stuff and replacing whatever I can for the most part while inside there lifters being one of the items, really any item that is considered a wear item so long as funds allow. Hopefully studs happen as well but with everything I’ve built so far on the motor I think 20psi max is gonna be the goal with only a 90cc and stage 1’s that’s about all that’s gonna be happening. And the 1 r and d cam is supposed to lower cylinder pressure a little bit along with my timing is gonna be at 7 hopefully tomorrow since I got to borrow the timing meter a couple days longer now. I’m gonna keep on running truck for a while and potentially buy a back up motor to build up and drop in hopefully by end summer since rebuilt idi’s come up fairly often for around 500-1000 dollars
im running a bull moose. and while we have different equipment, I can tell you going from 4-5 to 7-8 psi on the incoming fuel pressure makes a big difference.
while your fuel pressure is adequate in stock situations, I like to have as much fuel delivery as possible.
if its not needed, then you simply don't use it.
I don't like having my truck down for long, so if im doing any kinda engine work, id rather build one on the side, and simply transplant it when the time comes.
while your fuel pressure is adequate in stock situations, I like to have as much fuel delivery as possible.
if its not needed, then you simply don't use it.
I don't like having my truck down for long, so if im doing any kinda engine work, id rather build one on the side, and simply transplant it when the time comes.
Finn
Registered User
Running 20 psi boost on an engine with 21.1:1 compression ratio will eventually pound out the ring groves and break the compression rings, if it doesn’t crack the piston through the pin boss or bust the crankcase through the main Journal webs first.
Have fun, but keep your pocketbook handy.
Have fun, but keep your pocketbook handy.
This isn’t true at all.
pelky350
Full Access Member
@IDIoit i though it was more about volume than pressure? I’ve got a constant 5 psi never really drops with high fuel demand the carter has a high fuel volume. Guess I could buy a higher psi carter and see if it helps any? I was also planning on a second motor and just run till this one dies which I’m sure it never will totally fail on me probably just make more noises and leak more oil lol
@Finn lots of people run 20psi in these motors all day with no issues, and stock is 21.5-1 for 7.3 and most 6.9 besides the really early ones
@Finn lots of people run 20psi in these motors all day with no issues, and stock is 21.5-1 for 7.3 and most 6.9 besides the really early ones
IMO, both are equally important.
it made a huge improvement. and I didn't over fuel until I added more psi.
if you have already tried everything else, what do ya have to loose? lol
it made a huge improvement. and I didn't over fuel until I added more psi.
if you have already tried everything else, what do ya have to loose? lol
That’s odd, what do you have it timed at Brian? I’ve run up to 40 psi inlet pressure on the stand and it doesn’t affect fuel delivery only your advance, maybe you only got smoke after the pressure increase because the timing was advanced?
Edit, maybe your gauge was reading 5 psi low and at 7-8 it’s actually 2-3?
timed at 8.5* increasing my fuel pressure did bump my timing almost a half a point, I checked it, but was under 9, so I left it.
this was a new mechanical lift pump. lets call it 3-5, I never saw 2
with the holley blue, it runs 7-8 psi
this was a new mechanical lift pump. lets call it 3-5, I never saw 2
with the holley blue, it runs 7-8 psi
Gotcha, that’s strange but glad you got the fuel delivery issue worked out
pelky350
Full Access Member
I’m thinking is a injector issue, and I think the injector is making the motor fight itself in the higher rpms range if that’s a possibility? Used to run super smooth but not I’m getting occasional slight miss and I can hear it out the exhaust other times the only thing I’m noticing is the single mass flywheel rattling back and forth caused by the rougher idle and running. It’s not super rough but defiantly not as smooth as when I first installed everything and the random missing is just making me think an injector is hanging up now and again from something? Maybe even though I was careful installing and removing things a foreign material or small item is something ended up in injector? It’s been a long time since I’ve had any of the lines off though.
How many miles do you have on the injectors? Mine lasted about 40k before I needed to rematch them, but seems Justin is using a different supplier since then.
Op
for grins, load it down and haul some hills to get it HOT AND SWEATY...
usually helps in small ways to "clear the pipes" as it were.
Thanx wes for the tech input.
for grins, load it down and haul some hills to get it HOT AND SWEATY...
usually helps in small ways to "clear the pipes" as it were.
Thanx wes for the tech input.
pelky350
Full Access Member
Well changed the other valve cover today that I hadn’t been into yet, absolutely 0 sludge and even the valve spring retainers where shiny which seems kinda odd for a 190xxx mile motor maybe? I’ve had it for the last 75xxx miles. No crusty looking valve springs and nothing was loose. Only thing I remember from driver side was one valve spring looked maybe a little dirty but nothing like the picture I’ve seen with people having bad valve guides
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