Originally Posted by
xbrxlunch
I am in the process of doing a turbo build on my M50TU, and to kick things off I opted to use the Cometic MLS .140 head gasket. The install seems to have gone as planned for the most part, however I am having an issue in the lower RPM range now.
Just a little bit on insight into what I did:
- Head was sent off to the machine shop to be resurfaced. I also had the valve seats grinded, valves restemmed, and valve seals replaced
- MLS .140 HG w/ copper spray
- ARP head studs (did a torque sequence of 25/25/50/50/75/75)
- Battery disconnected for 3+ weeks
- Replaced oil with 0w-40 Mobil1
The engine builder that did the machining on my head said that since the valve stems were raised 5/1000ths, I would need to adjust valve lash.. which the engine should do on it's own because it has hydraulic lifters.
Now to get to the point. Ever since I reassembled the engine and fired it up, it has been having trouble in the low RPM range. The low end power is non existent, and if I lightly press the throttle, the engine will hesitate and die out. When I drive the car, I have to keep pressing the gas peddle semi-rapidly to get the RPMs up so I can take off. I can smell fuel inside the cabin, but I've inspected the engine around the fuel components and do not see any leakage. Once the engine hits around ~3500-4000 RPM it runs flawlessly, and achieves a nice healthy hard pull. I don't daily the car, but I just wanted to be able to drive it before I get the rest of the turbo parts installed. I have driven the car roughly 15 miles since reassembly, just in case the ECU needs to relearn or something of the likes.
Am I missing something? Perhaps I forgot to install something? Has anybody else driven their M50TU on a lowered compression without boost? Will this have to be corrected with a tune?
Thanks in advance
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