Flex plate clearance issue - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**ClassicIron** · 08-16-2023, 12:28 AM

Hi everyone, I tried to do my due diligence to find if others have had this issue but came up empty. I have a 383 Stroker with a 168 tooth flexplate and new PowerMaster starter. When I installed the starter I discovered the starter gear was already contacting the flex plate even before engaging/receiving power. Taking a closer look the flex plate is also extremely close to contacting a rear main seal stud on the back of the block. It also measures much closer to the rear of the block than all my other small block 350s, leading me to believe this is a flexplate issue, not a starter issue. I confirmed with my engine builder the flex plate was correct (Pioneer FRA-159) and oriented appropriately (raised pads facing converter). So what could have caused this? I’m looking at a flex plate spacer as a possible solution but I’m resistant because this shouldn’t be an issue to begin with, maybe I’m overlooking something... Any help is greatly appreciated!

**HO455** · 08-16-2023, 01:39 AM

I don't know about the model of Powermaster starter you have but the NAPA late model starter I put on my Burban's 350 had a similar issue that I cured with shim washer that came with the starter. See post 462 in the link.

http://67-72chevytrucks.com/vboard/s...698377&page=19

72c20customcamper · 08-16-2023, 09:11 AM

The starter should have come with a few shims a couple for between the starter and engine to increase the gear engagement gap and a couple of round shims like big washers to move the bendix gear back and away from the flex plate .

https://duckduckgo.com/?q=shimming+a...%3DQaJ-67YGfg4

**kwmech** · 08-16-2023, 10:22 AM

How did you acquire this engine? built it or bought it?

**ClassicIron** · 08-16-2023, 10:54 AM

Quote:

Originally Posted by 72c20customcamper

The starter should have come with a few shims a couple for between the starter and engine to increase the gear engagement gap and a couple of round shims like big washers to move the bendix gear back and away from the flex plate .

https://duckduckgo.com/?q=shimming+a...%3DQaJ-67YGfg4

I started down the route of shimming the starter towards the front of the engine using the round shims. But it’s so far off that by the time I have enough shims installed, the starter no longer seats in the mounting block flange to center the bendix gear.

**ClassicIron** · 08-16-2023, 10:57 AM

Quote:

Originally Posted by kwmech

How did you acquire this engine? built it or bought it?

Built by a local engine builder. I called and spoke with one of their techs but he was unsure of what could have caused this. I’ll post a couple more pics once I pull the trans off

**Rust_never_sleeps** · 08-16-2023, 12:09 PM

72c is right, it's a two-part process, you may need the "other" shims, or some of both.

This one's pretty clear and helpful: https://www.youtube.com/watch?v=QaJ-67YGfg4

08-16-2023, 12:28 AM	#1
ClassicIron Junior Member Join Date: Jul 2021 Location: Sandy, Oregon Posts: 37	Flex plate clearance issue Hi everyone, I tried to do my due diligence to find if others have had this issue but came up empty. I have a 383 Stroker with a 168 tooth flexplate and new PowerMaster starter. When I installed the starter I discovered the starter gear was already contacting the flex plate even before engaging/receiving power. Taking a closer look the flex plate is also extremely close to contacting a rear main seal stud on the back of the block. It also measures much closer to the rear of the block than all my other small block 350s, leading me to believe this is a flexplate issue, not a starter issue. I confirmed with my engine builder the flex plate was correct (Pioneer FRA-159) and oriented appropriately (raised pads facing converter). So what could have caused this? I’m looking at a flex plate spacer as a possible solution but I’m resistant because this shouldn’t be an issue to begin with, maybe I’m overlooking something... Any help is greatly appreciated! Attached Images

08-16-2023, 01:39 AM	#2
HO455 Post Whore Join Date: Feb 2016 Location: Portland Oregon Posts: 11,393	Re: Flex plate clearance issue I don't know about the model of Powermaster starter you have but the NAPA late model starter I put on my Burban's 350 had a similar issue that I cured with shim washer that came with the starter. See post 462 in the link. http://67-72chevytrucks.com/vboard/s...698377&page=19 __________________ Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377

08-16-2023, 09:11 AM	#3
72c20customcamper Registered User Join Date: Jul 2018 Location: Catskill Mountains,NY Posts: 8,737	Re: Flex plate clearance issue The starter should have come with a few shims a couple for between the starter and engine to increase the gear engagement gap and a couple of round shims like big washers to move the bendix gear back and away from the flex plate . https://duckduckgo.com/?q=shimming+a...%3DQaJ-67YGfg4 __________________ Mark 72 c20 custom camper Husky edition, 66 SS396 Chevelle 1964 Hawk, 63 Avanti,62 lark 1969 AMX , 1968 c20 stepside ,85 K20 1977 Suburban sold 68 anniversary.

08-16-2023, 10:22 AM	#4
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,649	Re: Flex plate clearance issue How did you acquire this engine? built it or bought it?

08-16-2023, 12:09 PM	#7
Rust_never_sleeps Senior Member Join Date: Jun 2022 Location: San Ramon,CA Posts: 608	Re: Flex plate clearance issue 72c is right, it's a two-part process, you may need the "other" shims, or some of both. This one's pretty clear and helpful: https://www.youtube.com/watch?v=QaJ-67YGfg4



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