Engine to the Machine Shop
January 30th, 2019, 07:42 PM
#2
Hookers under Hood
Join Date: Nov 2013
Location: Ontario, Canada
Posts: 3,543
Looks like you got lucky with the timing gear. Didn't have many more miles left before the oil pump filter would have been sucking up some bits and pieces.
Where is the block headed to be machined ? Whats the plan for the rebuild?
Eric
Where is the block headed to be machined ? Whats the plan for the rebuild?
Eric
January 30th, 2019, 09:10 PM
#3
It is at Automotive Machine Specialty, highly recommended by the gearheads and automotive shops locally. To save my budget, he is doing all the machine work and measuring, but I am the builder. I have built many 350 and 455 engines before. When I know the piston size, I will order them and he'll press them on. Because I had an El Camino with a 3.8 V6, I had the choice of a SBC and getting a transmission or keeping the TH350 and going with BOP engine. My dream car was always a 1970 W-31, so this engine is going to be built to those specs with a lot of advice about how to make it right for an AT., stall, gearing and cam. It will have an Edelbrock intake because my engine was a 2Bbl with low compression. The new pistons will be 10.25:1, When I can afford it the diff will be limited slip. Thia car will be driven and I will take it to shows and swap meets. I will take pride in the Olds 350 being unique and that W Machine sound! Much nicer than every other El Camino! No Cowl Hood for me!
Last edited by Chuck Cole; January 30th, 2019 at 09:16 PM. Reason: wasn't done
January 31st, 2019, 03:37 PM
#4
Yes I was surprised to see the plastic gear still. I thought most had given up long ago. Maybe because this was a low comp 2 Bbl version, it wasn't abused too much. The chain was definitely stretched!
February 1st, 2019, 08:19 AM
#6
Registered User
Join Date: Sep 2011
Location: Plano, TX
Posts: 1,847
Check to see if it'll really be 10.25:1 or if that's just what's on the piston sticker.
Going over 9.5:1 on pump gas with iron heads can be quite dicey. Need precise cam selection and ignition control.
Going over 9.5:1 on pump gas with iron heads can be quite dicey. Need precise cam selection and ignition control.
February 1st, 2019, 09:16 AM
#7
Registered User
Join Date: Nov 2008
Location: Central Fl
Posts: 7,828
And yes do the math yourself. Don’t trust others to tell you what your comp ratio will be.
February 1st, 2019, 10:35 AM
#8
My Olds parts guy sells cast 8:1, 10.25:1 and 10.6:1 (flat top) pistons stock to .060 over. He states the 9:1, which is what I would prefer, are no longer available. I DO NOT NEED FORGED pistons for what I am doing. The Machine Shop guy agrees and states Forged pistons are heavier and harder to balance. At some point you have to trust the guys who do it for a living. Once I get the measurements from the Machine shop I will weigh all the issues. Both have told me with the cam and larger valves, I would not be happy at 8:1 which has a considerable dish. I want to be happy. The 10.25:1 still are dished. If I can find some cast 9:1 pistons, it is what I wanted at the outset. The CR is only a reference point for me, not a hard and fast. My heads did not require shaving, and if the block is also square, I am guessing the compression will be about where it should be. I run premium in a MINI so premium is what I will run in the El Caminolds. I appreciate the tips and I will be sure to get the best things for what I need to make it work right...not overheat, no pinging etc. I-5 Carbs is building me a Qjet carb that will take a lot of these factors in
February 1st, 2019, 10:50 AM
#9
Yep going old school on that, Qjet with jetting for a lively cam and bigger valves. Ebrock RPM, shorty factory headers, and dual exhaust. I am sure there will still be some tinkering. The do have adjustable distributors for a reason, and I am putting on a lightning like ignition and of course new technology in spark plugs too. I think what a lot of people fail to see is the bigger picture, which is to go back to 1968 with this engine, not bring a 1968 engine to 2018 potential performance. I could spend another $2500-$3000 more than I am spending. and get a LS with a computer and fuel injection requiring Cat Converter, but my plan all along was to NOT spend cubic dollars and still have a flashback to the musclecar sound and performance. It does not have to be perfect, just reliable and runnable whenever I want to run it. I know about mixing octane to 105, and I don't want that. I am reading and listening to advice, and appreciate the warnings. I have changed my engine build specs several times based on them.
February 1st, 2019, 12:33 PM
#11
By where it should be, I meant I am hoping for a stock bore. Because the heads were not shaved, the Chamber volume has not changed. The deck cl and the gasket thickness are not changed. The only unknown variable is bore and I won't know that for weeks...long before I buy pistons. Unless there are surprises, this engine will be pretty close to stock, and that is "about where it should be" for CR in that case. Okay?.
Last edited by Chuck Cole; February 1st, 2019 at 01:58 PM. Reason: Add
February 1st, 2019, 05:15 PM
#12
Registered User
Join Date: Nov 2008
Location: Central Fl
Posts: 7,828
Lotsa stuff wrong here.
First of all your machinists’ statement isn’t at all correct. Most forged pistons DO NOT weight more than cast.
Secondly they’re NOT more difficult to balance. True they have less area underneath in which to remove material. However they’re typically closer in weight to each other so it’s a moot point.
I’ll bet you a days pay your block isn’t “square”.
And the 8.0:1, 9.0:1, 10.25:1, 10.5:1 are with what head, what pistons, gasket, deck height, piston height? Too many variables there.
Finally, for that “muscle car” sound you need cylinder pressure. You won’t get it with the wrong cam and piston combination, plain and simple.
I hope you’re not married to that machinist. It might behoove you to find another.
Just my opinion.
First of all your machinists’ statement isn’t at all correct. Most forged pistons DO NOT weight more than cast.
Secondly they’re NOT more difficult to balance. True they have less area underneath in which to remove material. However they’re typically closer in weight to each other so it’s a moot point.
I’ll bet you a days pay your block isn’t “square”.
And the 8.0:1, 9.0:1, 10.25:1, 10.5:1 are with what head, what pistons, gasket, deck height, piston height? Too many variables there.
Finally, for that “muscle car” sound you need cylinder pressure. You won’t get it with the wrong cam and piston combination, plain and simple.
I hope you’re not married to that machinist. It might behoove you to find another.
Just my opinion.
Last edited by cutlassefi; February 1st, 2019 at 05:24 PM.
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