Engine rebuild woes |
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Engine rebuild woes |
william1764 |
Mar 14 2022, 11:25 AM
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#1
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Member Group: Members Posts: 252 Joined: 11-May 10 From: maryland Member No.: 11,717 Region Association: MidAtlantic Region |
Just had completed a full engine rebuild of my stock 2.0L (with Webers) to a 2.3L by a small Porsche indy in Maryland (2.256 big bore, 10:2:1 compression, mild cam). Carbs were also rebuilt to accommodate new build. Unfortunately, engine runs like crap with incessant backfire out of exhaust and carbs (during both acceleration and deceleration). Hard to even really tell yet how the increase in displacement feels due to the bucking and backfiring. However, I do know that power seems to peak at mid 4K range. Planned to have dyno'd but until this is resolved no point. Their estimated build time of 2 months took 14 months and still not drivable so I'm a bit frustrated. Indy acknowledges that he doesn't know what the issue is. Said he suspects its carbs but not certain. Wants me to invest in a new set. To be clear, the carbs have worked perfectly for the last 10 years up to the day i dropped off to their shop. Indy acknowledges no issue with carbs when he received. Frankly, I've lost all confidence and contemplating having another shop look at this issue and resolve. In all fairness, this is not a hack shop...very reputable. I don't want to bash/mention names. Requesting recommendation of an indy, ideally in Maryland, that is capable of assessing and hopefully fixing the issue.
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VaccaRabite |
Mar 15 2022, 08:00 AM
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#2
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En Garde! Group: Admin Posts: 13,554 Joined: 15-December 03 From: Dallastown, PA Member No.: 1,435 Region Association: MidAtlantic Region |
Your mechanic set the idle and maybe never drove the car. I'm sure it's fine under no load.
I very much doubt that this is a mechanical problem. That said. 1) did the builder do a cam break in? 2) did the builder do a ring break in? (this may be something that you are expected to do.) Now its your turn: 1) check the basics. Do valves. Do compression. 2) you need to note your carbs. Find out the size of your: Mains, Idle, Vents at least. 3) get a balancing snail and check balance between carbs at hot idle and at 3K rpm. 4) Do all the stuff mentioned in the previous posts about checking timing. PS: my Vegas bet is that the builder set the timing and balance with the engine and carbs ice cold. Like overnight, below freezing cold. Its been a cold winter in the MidA. As soon as they warm up it all goes to shit and you have an unhappy engine. Once set while warm, the engine starts behaving much nicer. Zach |
william1764 |
Mar 15 2022, 01:46 PM
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#3
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Member Group: Members Posts: 252 Joined: 11-May 10 From: maryland Member No.: 11,717 Region Association: MidAtlantic Region |
Your mechanic set the idle and maybe never drove the car. I'm sure it's fine under no load. I very much doubt that this is a mechanical problem. That said. 1) did the builder do a cam break in? 2) did the builder do a ring break in? (this may be something that you are expected to do.) Now its your turn: 1) check the basics. Do valves. Do compression. 2) you need to note your carbs. Find out the size of your: Mains, Idle, Vents at least. 3) get a balancing snail and check balance between carbs at hot idle and at 3K rpm. 4) Do all the stuff mentioned in the previous posts about checking timing. PS: my Vegas bet is that the builder set the timing and balance with the engine and carbs ice cold. Like overnight, below freezing cold. Its been a cold winter in the MidA. As soon as they warm up it all goes to shit and you have an unhappy engine. Once set while warm, the engine starts behaving much nicer. Zach Hi Zach - What shop would you recommend? Maryland...possibly PA? You know my limitations;-) |
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