Finally got to the root cause of popping/stuttering at WOT. Did compression test on all cylinders, 3,4,5,6 all test over 135, 1,2 test at 75 to 80psi. Pressurized 1 & 2 and had air coming out of the throttle plate. All new springs on both heads, so it can't be seat pressure, beehive 90lbs. Is there anyway to remove carbon build up on the valves without taking the heads off? Is there something else that could be causing this?
Leaking Intake Valves
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Berryman's
Berryman's is O2, and Cat safe, I personally use it in my vehicles. Really though, I think that you will need to pull the heads and get to the root of the problems with those 2 cylinders.
Are you sure it's just carbon buildup on the intake valves causing the problem, or could it be a valve that has cracked? The reason I say this is because I just went thru this. All cylinders were good except #5, could only get 65psi max on a compression check and bleed down almost immediatly. I did a leak down and heard air coming out the exhaust, so I knew I had a problem. Once I pulled the head, it was real easy to figure out, exhaust valve had a hole in it. The amazing thing was the engine ran basically on 5 cylinders. Hopefully the rest of my parts come in this week and I can get her fired up this weekend. See ifyou can spot the problem...LOL
I'm not trying to discourage you in trying it, B12 is good stuff, I just don't want you to be disappointed if it doesn't work.
As I was typing a bulb went off in my head....you mentioned new injectors, could it be possible the injector o-ring is leaking/tore/not seated causing this problem?
Steve
Berryman's is O2, and Cat safe, I personally use it in my vehicles. Really though, I think that you will need to pull the heads and get to the root of the problems with those 2 cylinders.
Are you sure it's just carbon buildup on the intake valves causing the problem, or could it be a valve that has cracked? The reason I say this is because I just went thru this. All cylinders were good except #5, could only get 65psi max on a compression check and bleed down almost immediatly. I did a leak down and heard air coming out the exhaust, so I knew I had a problem. Once I pulled the head, it was real easy to figure out, exhaust valve had a hole in it. The amazing thing was the engine ran basically on 5 cylinders. Hopefully the rest of my parts come in this week and I can get her fired up this weekend. See ifyou can spot the problem...LOL
I'm not trying to discourage you in trying it, B12 is good stuff, I just don't want you to be disappointed if it doesn't work.
As I was typing a bulb went off in my head....you mentioned new injectors, could it be possible the injector o-ring is leaking/tore/not seated causing this problem?
Steve
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Carb cleaner
3x's a year I get some O2 sensor safe carb cleaner and spray some in a cup actually put a 1/2 a can in. Start car pull the vacuum line off AFR and dip it into the cup of cc and the vacuum. line sucks it up into TB. The car will try and stall so don't give it real big drinks of cleaner. Give it enough rpm so it doesn't stall out... Reason I use vac line off AFR is I have easy access to throttle if I'm doing it solo. If you can have someone help with throttle it's easier. Have had my son help me because it's a 3 hand job. It cleans the top end pretty good IMO. The exhaust is black you'll think it was an old deisel. The last couple times I've taken the O2 sensor off because a lot of carbon is freed up and even though it's O2 sensor safe I just take the precaution to not foul it up alot of soot. Not sure this will help your immeadiate problem as I just do this as maintnance.. Good Luck
3x's a year I get some O2 sensor safe carb cleaner and spray some in a cup actually put a 1/2 a can in. Start car pull the vacuum line off AFR and dip it into the cup of cc and the vacuum. line sucks it up into TB. The car will try and stall so don't give it real big drinks of cleaner. Give it enough rpm so it doesn't stall out... Reason I use vac line off AFR is I have easy access to throttle if I'm doing it solo. If you can have someone help with throttle it's easier. Have had my son help me because it's a 3 hand job. It cleans the top end pretty good IMO. The exhaust is black you'll think it was an old deisel. The last couple times I've taken the O2 sensor off because a lot of carbon is freed up and even though it's O2 sensor safe I just take the precaution to not foul it up alot of soot. Not sure this will help your immeadiate problem as I just do this as maintnance.. Good Luck
bmackinnon
Active Member
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That's what I thinking.....
burnt or cracked valve(s).... injectors are above the valves... won't cause a 'compression' leak....turbofabricator
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I'd also like to know how you got 90lbs. of seat pressure with Comp Beehives (conical springs)? Even with a +.050" keepers, they measure usually around 135-140 lbs. of seat pressure.
If your valves are leaking, no way to fix them w/o doing a valve job. No way. Just pull them and install a ported set. Contact one of the vendors for a good set of ported heads. If you want to tackle the port work yourself, I can give you some pointers and tool reccomendations.
If your valves are leaking, no way to fix them w/o doing a valve job. No way. Just pull them and install a ported set. Contact one of the vendors for a good set of ported heads. If you want to tackle the port work yourself, I can give you some pointers and tool reccomendations.
TexasT
Texas, Where are you from
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- Sep 10, 2002
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If you want to tackle the port work yourself, I can give you some pointers and tool reccomendations.
I'd love to see some pointers and tool recommendations. PLEASE!
Brutusturbov6
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Dont forget to check the cam lift on those 2 lobes, you could also have a cam that is going flat or has gone flat due to new spring being installed and inproper break in or not enough lubrication at startup..
, a flat cam would cause exactly the symptoms that you are describing above, I know this because it happened to me so im talking from experience, I am surprised nobody above mentioned to check the cam. I am suspicious of only those 2 valves leaking due to carbon build up, carbon builds up evenly on all cylinders not just that one..turbofabricator
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Keep the short side radius as wide as possible. Knife edge (sort of) the the intake guide on the upstream side, and put a generous radius on the back side of the intake guide. Radius the back side on the biased side of the port. The factory puts a little radius there already, but, it really needs to be much bigger. I like the Makita electric hand grinder. It is small enough to hold all day (because you WILL be grinding all day
) and you will also need a good assortment of 6" carbide burrs. I like to use fast cut burrs, that have been chipped when grinding aluminum heads/intakes and use them to rough in the ports. It goes MUCH faster, but they will send shrapnel into the back of your hands.
The double cut carbide burrs are intended for cast iron, but they take for ever to get enough material removal. I do the rough cutting with aluminum (priviously chipped) burrs, then finish the base grinding with a double cut burr. Then use extended shank stones to perform preliminary finish work, then cartridge rolls for the real finish work. I could spend hours typing about head porting, but there is good info on other web sites, such as speedtalk.com. Read and read before you ever attempt to grind on a cylinder head. A turbocharger will cover up alot of mistakes, though:smile: . Intake volume is key to making power on a turbocharged engine. BUT......if you kill low lift flow, you will have a hard time initiating the power curve. A good three angle valve job will help the heads alot. 70% of flow gains are in the first 1.5"-2" under the valve seat, and the actual valve seat. 8445 head castings are pretty cheap, so go for it and keep trying. After your first set of heads, you will understand why a good set of heads are well worth the money. It is NOT easy, and is VERY dirty, and VERY, VERY time consuming. Be SURE to wear a face shield and a respirator, and hearing protection. Not just a dust mask. Use a shop vac to suck all the debris/dust while you work. Your hands will buzz for days after your first 8 hours of grinding (just on one head). If you want to learn how to port heads, then do so. If you are trying to save money...............Look elsewhere. It will cost you over $500 in equipment to get a basic tool selection to port heads. I have been grinding on heads for over 25 years, and really feel that I am just learning what I am doing. The more I do, and the more research I do.......the dumber I feel. Good luck.
I am running stock heads, the beehive springs are part #26981-12. They are rated at 95# - 105#. at installed height 1.700". I've decided to pull the motor out and go through the whole top half.
As far as the cam goes, it will get replaced when the motor gets yanked. When I leak tested the cylinders I had the rockers and push rods out, so I don't think the cam had an effect on the valves seating.
Any suggestions on a mild cam?
As far as the cam goes, it will get replaced when the motor gets yanked. When I leak tested the cylinders I had the rockers and push rods out, so I don't think the cam had an effect on the valves seating.
Any suggestions on a mild cam?
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Could be..
Injector problems.
Inj harness problems.
Intake leak at ft of manifold.
While you have the heads off, put them face down on some newspaper, and squirt some WD in each int port.
Look for a leak pattern on the paper.
Change the paper, and do the exh ports.
FWIW, as long as I've been doing leakdowns, I 've always had at least 1 valve w/ abnormal leak. When that happens, I rap the top of the valve w/ a plastic hammer. The escaping cyl pressure will make a "barking sound", and the leak % will go waaay down..Minute carbon particles, and in some cases rust particles, will hold a valve open just enuf to mess up a leak down....Works for me..
Injector problems.
Inj harness problems.
Intake leak at ft of manifold.
While you have the heads off, put them face down on some newspaper, and squirt some WD in each int port.
Look for a leak pattern on the paper.
Change the paper, and do the exh ports.
FWIW, as long as I've been doing leakdowns, I 've always had at least 1 valve w/ abnormal leak. When that happens, I rap the top of the valve w/ a plastic hammer. The escaping cyl pressure will make a "barking sound", and the leak % will go waaay down..Minute carbon particles, and in some cases rust particles, will hold a valve open just enuf to mess up a leak down....Works for me..
