Old GM TBI reliability, questions, concerns

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kens
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Old GM TBI reliability, questions, concerns

Post by kens »

I finally got this donor boat engine in my possession. It is a 1998 PCM 350 5.7L, TBI
Its got all the goodies on it, remote oil, FWC, top mount starter, velvetdrive
It got good compression, rocker arms look like new, but everything on the outside is rough rusty, all the TBI items included.
TBI fuel pump(s) FCC cell is rusted internally, no fuel pumps work
Computer controlled distributor is rusty
I am debating myself to just strip off all the TBI parts and go with brand new Edelbrock carburetor & new distributor
New TBI fuel pumps by themselves cost = new Edelbrock carb
Not to mention any other sensors
Computerized distributor needs replacing due to corrosion = cost of new conventional dist
Thus far I have unbolted the TBI unit and put on a automotive Edelbrock carb, it starts, runs, and idles like a swiss watch.

Who has experience with this 1998 vintage GM TBI marine engines?
Parts availability?
Reliability?
Cost to maintain?
Used one from their own donor?

I'm open to opinions on ditching all the TBI/computer, and just install brand new carb & brand new distrubutor.
This would leave me with a 350 5.7L with great compression, roller cam, vortec (906) heads, remote oil, FWC, top starter
Oak..........the juice ain't worth the squeeze :D :shock: :o :)
Hercdrvr
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Re: Old GM TBI reliability, questions, concerns

Post by Hercdrvr »

Easy answer for me, carb with a mechanical pump. Anything with a computer quits and we have to pack up and go home.
Matt B
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Rich Coey
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Re: Old GM TBI reliability, questions, concerns

Post by Rich Coey »

Yes, ditch TBI/computer, and install brand new carb & brand new distrubutor.
This would leave you with a 350 5.7L with great compression, roller cam, vortec (906) heads, remote oil, FWC, top starter
Great reliable setup.

Rich
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kens
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Re: Old GM TBI reliability, questions, concerns

Post by kens »

I got it to fire up with a clanky old auto carb, PVC plastic sewer pipe for exhaust. TBI distributor runs but obviously dont see the throttle body.
Compression test came up even higher, and the velvetdrive works.
No water leaks in the block.
I'm about 99% convinced I'll go on with the carb conversion.

Anybody wanna bet how much weight I shed by doing this?
Oak..........the juice ain't worth the squeeze :D :shock: :o :)
hoodman
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Re: Old GM TBI reliability, questions, concerns

Post by hoodman »

Are you putting this in the DE?
Matt

Building a Geronimo......!
viewtopic.php?f=2&t=25139
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kens
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Re: Old GM TBI reliability, questions, concerns

Post by kens »

I don't know yet.
I got 4 different transmissions, and cant get any one of them to look like a good fit.
But I got a chevy inline-six that will nearly drop in the DE
Oak..........the juice ain't worth the squeeze :D :shock: :o :)
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kens
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Re: Old GM TBI reliability, questions, concerns

Post by kens »

20220129_163354.jpg
?
Oak..........the juice ain't worth the squeeze :D :shock: :o :)
hoodman
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Re: Old GM TBI reliability, questions, concerns

Post by hoodman »

You got a new project there, Ken?
Matt

Building a Geronimo......!
viewtopic.php?f=2&t=25139
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kens
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Re: Old GM TBI reliability, questions, concerns

Post by kens »

i put a new Pertronix distributor on this, purrs like a kitten.
After tracking down the camshaft part number, it is also used in some GM performance crate engines
I was somewhat afraid of the TBI engine/cam used with old-school distributor and carb.
Now I see GM offers same cam in crate engine with carb
Oak..........the juice ain't worth the squeeze :D :shock: :o :)
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steveh41
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Re: Old GM TBI reliability, questions, concerns

Post by steveh41 »

Ken,

That Gar Wood design is a real beauty... it would be a great build to follow!

Steve
The longest journey begins with a single step… then repeat as necessary!
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kens
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Re: Old GM TBI reliability, questions, concerns

Post by kens »

Yeah, I know.
But, that design was of the old flat-head sixes of the era.
There is a few reproductions with flat-tappet V-6's, and they seem fine.
But, I have a roller-cam V8, I dunno if that little hull will take it.
I am in fact a big fan of the narrow beam, long water line design.
Waiting on Neel's build at this point.

Notwithstanding the hull itself, the TBI conversion-to-carb looks like a success.
I have as yet to find any dynomometer results that tell me fuel injection alone and by itself makes more HP than a carb.
And then the next argument for fuel injection is ease of starting. Well judging by this thing sitting on a skid in my garage, that is total BS.
This thing starts immediately !! and, with authority!
Oak..........the juice ain't worth the squeeze :D :shock: :o :)
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Mr Hot Rod
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Re: Old GM TBI reliability, questions, concerns

Post by Mr Hot Rod »

I'll put up this link to keep your bench racing alive ...
Many of the older, lower RPM engines and gear were quite a bit heavier than the more modern v6's and V8's.

If you want to make it bullet proof, you can always increase the rib scantlings or laminate the ribs with plywood to prevent splitting.

____________________

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Click Image to see video.

Paul Kane
Kane Custom Boats Ltd.
Chelsea, Quebec

Building the Glen-L Hot Rod : http://www.kanecustomboats.com
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kens
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Re: Old GM TBI reliability, questions, concerns

Post by kens »

yep, bench racing. I need to get a for real carb now.
This old crusty auto carb can't stay. Nobody has a Edelbrock 600cfm marine in stock.
Not available.
But, I can find the 750cfm version.
Holley's are easily in stock but I'm leaning towards Edelbrock.
Oak..........the juice ain't worth the squeeze :D :shock: :o :)
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