Boost Valve Float
Boost Valve Float
1987 300D Sturmmachine
1991 300D Nearly Perfect
1985 300D Weekend/Camping/Dog car
1974 L508D Motoroam Monarch "NightMare"
OBK #42
Forced, IIRC was told by someone that the valve springs would have to be replaced for running higher than 20psi. I hereby challenge somebody here to pressurize their intake system with the engine off and see what these springs (in average wear and condition) can really hold up to. Checking for valve float from RPM is probably impossible to check but boost should be easily enough, especially on the 617 as the rockers are easily removed without removing the cam.
1987 300D Sturmmachine
1991 300D Nearly Perfect
1985 300D Weekend/Camping/Dog car
1974 L508D Motoroam Monarch "NightMare"
OBK #42
Static opening pressure doesn't mean much. When the engine is running there is always positive pressure in the cylinder working against the intake valve head (Compression, power, exhaust backpressure).
The exhaust side is what I'd be much more worried about. Its got a 1:1 to 3:1 (VNT) ratio over boost and during the intake stroke there can be vacuum on the valve head from the 617's low VE.
The figure in the FSM for the OM602/3 is no more than 30psi backpressure. Now remember thats the spec for the stock turbo and fueling, not a safety limit.
ForcedInduction
08-17-2010, 05:02 AM
#2
When I eventually swap the GT23v on the 300D I'll see about making a test plug for #5.
Static opening pressure doesn't mean much. When the engine is running there is always positive pressure in the cylinder working against the intake valve head (Compression, power, exhaust backpressure).
The exhaust side is what I'd be much more worried about. Its got a 1:1 to 3:1 (VNT) ratio over boost and during the intake stroke there can be vacuum on the valve head from the 617's low VE.
The figure in the FSM for the OM602/3 is no more than 30psi backpressure. Now remember thats the spec for the stock turbo and fueling, not a safety limit.
1987 300D Sturmmachine
1991 300D Nearly Perfect
1985 300D Weekend/Camping/Dog car
1974 L508D Motoroam Monarch "NightMare"
OBK #42
Very interesting items. On the 617 its easy enough to replace the springs. I think on the om60x the cam has to be removed along with the tappet buckets.
1987 300D Sturmmachine
1991 300D Nearly Perfect
1985 300D Weekend/Camping/Dog car
1974 L508D Motoroam Monarch "NightMare"
OBK #42
1987 300D Sturmmachine
1991 300D Nearly Perfect
1985 300D Weekend/Camping/Dog car
1974 L508D Motoroam Monarch "NightMare"
OBK #42
Some good vids : http://www.youtube.com/results?search_qu...float&aq=f
1987 300D Sturmmachine
1991 300D Nearly Perfect
1985 300D Weekend/Camping/Dog car
1974 L508D Motoroam Monarch "NightMare"
OBK #42
I have a few heads in the garage I'll make a plate and pressurize it till it leaks out.
Lol the 6th video down the 242 Volvo one is a friend.
-Jesse
80 300sd hy35, front mount intercooler, w115 intake, rack limiter removed, Alda removed, full load turned up, boost, ebp, trans, pyro, egr delete, 3.5" exhaust, e-fan, 16x8 rims with, 245/50 tires, lowered, bilstien 5100's, 12" front brakes, 2.65:1 diff.
97 f250 psd 4x4, crawler
70 f250 390
83 Volvo 242, lots of mods
66 Volvo amazon
10 mistsubishi fuso service truck.
I ran 30-35+ for a few months with no problems. brabus has a friend in the 40+ zone. I bet he has stiffer springs on that one.
I have a few heads in the garage I'll make a plate and pressurize it till it leaks out.
Lol the 6th video down the 242 Volvo one is a friend.
-Jesse
80 300sd hy35, front mount intercooler, w115 intake, rack limiter removed, Alda removed, full load turned up, boost, ebp, trans, pyro, egr delete, 3.5" exhaust, e-fan, 16x8 rims with, 245/50 tires, lowered, bilstien 5100's, 12" front brakes, 2.65:1 diff.
97 f250 psd 4x4, crawler
70 f250 390
83 Volvo 242, lots of mods
66 Volvo amazon
10 mistsubishi fuso service truck.
Mb 1984 w201 om603 swap.
Mb 1986 w201 190E 2.3-16v
Mb 2004 w203 C230k
George3soccer
03-09-2011, 07:28 PM #6Yea I think its no problem, but if you run it for awhile it could cause severe problems I suppose.
Mb 1984 w201 om603 swap.
Mb 1986 w201 190E 2.3-16v
Mb 2004 w203 C230k
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