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Old 04-25-2019, 12:57 AM   #1
03Fozzyboost
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Default Ej251 6psi wastegate

Hey all, been on the forum for a while now building a low buck boosted car. Have an ej251 6psi wastegate running peak at 10psi.

Custom tmic, boost ref fuel pressure regulator at 40 psi vacuum, 50-55 psi on boost, walbro 255 pump, 1 step colder plugs, and 5.1v diode mod.

Built to hopefully last but the head gasket failed pretty good today. I was wondering if a MLS head gasket alone will hopefully help it last a little while, maybe gap the rings while I'm in there?

Trying to see what other people, if any, have done lately to make a half reliable boosted 251. I've used search of course but nothing on what other peoples working setups have been. Would love to see what I could change or do while the engines out to have a few extra ponies on the low.
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Old 04-26-2019, 08:47 AM   #2
pcampbell
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If I were doing the HG I personally would replace rods and pistons and bearings for the effort of removing the motor, checking the heads, etc. Of course it spirals out of control from there!!! MLS head gasket is what one would want to use regardless though - once you have an MLS in there, boost is not really an issue until much higher boost levels. 6-10psi is not that big of a deal for stock 251.
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Old 04-27-2019, 02:38 PM   #3
03Fozzyboost
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Thanks for the reply! Yeah I definitly want to go upgraded internals at some point but being me it would definitly spiral and fast lol.

Did compression test, cylinder 1,2,3 are at 165 psi exact and 4 is at 80. Definitly a hg issue. I'm going to be putting it on within the week hopefully and see how it lasts in the future.

Do you know of any cheap rebuild kits available? If possible would love to rebuild the block but as of now I have nitride rings to go in and just gonna make sure the heads and block aren't warped
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Old 04-30-2019, 06:41 AM   #4
pcampbell
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DNJ has cheap rebuild kits but I am not sure how good they are. I’m thinking of trying their pistons if I ever do a stock rebuild.
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Old 05-02-2019, 01:08 PM   #5
PA-Outback2000
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i would stay around 7psi.

as far as internals/upgrading in general, i would look into a used turbo block instead of using the N/A block. internals of the 351 are less of an issue than the block itself.

OEM STI MLS HG is the way to go.
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Old 05-18-2019, 12:46 AM   #6
03Fozzyboost
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On the rebuild now! Pulled all pistons and #4 has baaaad ring and failure lol. Gapped top ring to 0.018 and second to 0.023 for the new build. Spec is 0.014 and 0.021 max so went a little over. Pulled the numbers 1/2 outta my ass with a bit of research. Should hopefully be back together with new MLS head gaskets by Monday and see how it bangs. PCV valve was the culprit of spaying crank case pressure out of the valve covers. Baffle blew from the 12psi max it hit. Will post later to see how she runs! Hope to crank boost to hit 12 all day every day!
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