Newbie budget build 350
#1
Newbie budget build 350
First things first, I’m just a hobby gearhead that set a wildly unrealistic goal of building an entire car in 6 months (already over a month in), and the engine is just one piece of that puzzle. This is my first time working on Oldsmobile engines and im already starting to become fond of them.
i currently have in my possession:
1) 1977 Olds 350 from the project car in question. It looks greasy and high mile but it ran like a clock when i pulled it. Maintained steady temp, oil pressure on the factory gauge showed between 10-35psi at temp, and it had impressively snappy throttle response. It didn’t seem to be an oil burner, maybe just the slightest haze. It is however a windowed main, 3A head, dog dish piston smogger deluxe and the timing set is one of the most stretched ive seen. I only ran it in my garage/driveway since the car was not driveable.
2) 1972 Olds 350 complete parts engine for which i have to give the block back to its original owner (numbers matching block to his car & slightly spun bearings). It has some really good parts on it that i got for a great price. 7A heads, comp 210/216 hydraulic roller cam & 1.6 pro mags, performer rpm intake, nice valve covers and hooker competition headers. When the engine was built the pushrods were measured wrong and the intake gasket failed immediately resulting in P-T-V contact and cylinder 8 hydrolocking on coolant. but despite all that happening the top end seems good. I also have a melling oil pump with standard and high pressure springs to choose from.
my plan is to swap the top end of the 72 onto the 77. Question is, what considerations do i need to make to make a good street engine that can see a lot of miles. It won’t be raced. just want it to sound healthy, be fun to drive and have enough power to not feel pathetic.., something like 300hp with good usable torque. I plan on using a performer intake instead of the performer rpm for use case reasons and hood clearance.
Questions:
1)i know compression is an issue. How far can i mill 7A heads to get the most out of my setup? Is there a specific head gasket that would work best?
2) I’ve never done a DIY bottom end rebuild, but this might be the time i take the leap. Does a re-ring and bearings make sense or am i better off leaving well enough alone and just running it? What kind of things should i check to help decide?
3) strength wise, am i going to have any issues with the 77 bottom end for what I'm doing?
... or anything else i might be overlooking. Thank you!
i currently have in my possession:
1) 1977 Olds 350 from the project car in question. It looks greasy and high mile but it ran like a clock when i pulled it. Maintained steady temp, oil pressure on the factory gauge showed between 10-35psi at temp, and it had impressively snappy throttle response. It didn’t seem to be an oil burner, maybe just the slightest haze. It is however a windowed main, 3A head, dog dish piston smogger deluxe and the timing set is one of the most stretched ive seen. I only ran it in my garage/driveway since the car was not driveable.
2) 1972 Olds 350 complete parts engine for which i have to give the block back to its original owner (numbers matching block to his car & slightly spun bearings). It has some really good parts on it that i got for a great price. 7A heads, comp 210/216 hydraulic roller cam & 1.6 pro mags, performer rpm intake, nice valve covers and hooker competition headers. When the engine was built the pushrods were measured wrong and the intake gasket failed immediately resulting in P-T-V contact and cylinder 8 hydrolocking on coolant. but despite all that happening the top end seems good. I also have a melling oil pump with standard and high pressure springs to choose from.
my plan is to swap the top end of the 72 onto the 77. Question is, what considerations do i need to make to make a good street engine that can see a lot of miles. It won’t be raced. just want it to sound healthy, be fun to drive and have enough power to not feel pathetic.., something like 300hp with good usable torque. I plan on using a performer intake instead of the performer rpm for use case reasons and hood clearance.
Questions:
1)i know compression is an issue. How far can i mill 7A heads to get the most out of my setup? Is there a specific head gasket that would work best?
2) I’ve never done a DIY bottom end rebuild, but this might be the time i take the leap. Does a re-ring and bearings make sense or am i better off leaving well enough alone and just running it? What kind of things should i check to help decide?
3) strength wise, am i going to have any issues with the 77 bottom end for what I'm doing?
... or anything else i might be overlooking. Thank you!
Last edited by ck__joel; December 15th, 2022 at 08:37 PM.
#3
The oil pressure is a bit on the lower side, it will need new bearings at minimum. A compression test is another good tool. You can mill the heads a good amount but the intake will also need cut to fit. Even a cleanup mill would require the thin intake gaskets. Welcome.
#4
A compression test, better yet a leak down test would be a great starting point to know the ring condition. A complete bearing inspection on a 45 year old motor that is being upped in HP is absolutely necessary.
Good luck!!!
Good luck!!!
#7
Those pistons and some early head should give you useable compression if you mill the heads. I build a budget 350 with a low compression bottom end and 7A heads maybe at best we had 8.2 to 1 compression I used a 260h comp cam , built a th350 for the guy with a 2200 stall converter 3.42 gear full weight street trim car ran 14.8's which was impressive imo. You'd be amazed at how well the olds rev. My current 355 which is a budget build for a " race " engine I wind up to 7k rpm on stock rods and crank , car runs 11.50's but it's more strip / street car lol. The comp 260h is my go to choice . I ran 13's with a near stock 350 9 to 1 compression performer intake , stock valve train , headers , 600 cfm carb th400 2200 stall and 3.73 gears in my 72 cutlass. The pistons from 73 and up where 14cc with bigger chambers in the heads. So the later pistons would be the better choice.
#8
You will be close to 8.5 to 1 with stock 7A heads on a stock 77 block with .042" compressed Felpro head gaskets. The regular. 040" Mahle 3533 is slightly thinner. CC those 7A combustion chambers, which may have been cut at some point and be closer to the factory 64cc blueprint spec. Usually uncut, they are larger. See where you are at to start and plan from there.
#9
The oil pressure is a bit on the lower side, it will need new bearings at minimum. A compression test is another good tool. You can mill the heads a good amount but the intake will also need cut to fit. Even a cleanup mill would require the thin intake gaskets. Welcome.
thank you!
I know, unfortunately I can't use the 72 block. I got it from friend and its numbers matching to his car so he wants it back. I might be able to rob the crank out of it though, I think i read the earlier cranks were stronger. Not sure if it would be worth while since the bearings were starting to spin on it.
Those pistons and some early head should give you useable compression if you mill the heads. I build a budget 350 with a low compression bottom end and 7A heads maybe at best we had 8.2 to 1 compression I used a 260h comp cam , built a th350 for the guy with a 2200 stall converter 3.42 gear full weight street trim car ran 14.8's which was impressive imo. You'd be amazed at how well the olds rev. My current 355 which is a budget build for a " race " engine I wind up to 7k rpm on stock rods and crank , car runs 11.50's but it's more strip / street car lol. The comp 260h is my go to choice . I ran 13's with a near stock 350 9 to 1 compression performer intake , stock valve train , headers , 600 cfm carb th400 2200 stall and 3.73 gears in my 72 cutlass. The pistons from 73 and up where 14cc with bigger chambers in the heads. So the later pistons would be the better choice.
You will be close to 8.5 to 1 with stock 7A heads on a stock 77 block with .042" compressed Felpro head gaskets. The regular. 040" Mahle 3533 is slightly thinner. CC those 7A combustion chambers, which may have been cut at some point and be closer to the factory 64cc blueprint spec. Usually uncut, they are larger. See where you are at to start and plan from there.
Thanks everyone for the information. I will do a leakdown test and CC these heads and go from there.
#10
Why not put 1968-70 high compression pistons in it, a cam and lifters and be done with it ? You don't need to mill anything, or get different push rods. With the thicker head gaskets available, you'll lose compression ratio anyway. How far in the hole are the pistons now ?
#12
The 1971-1972 engines have huge 24cc dishes.
The 73-later engines had 14 cc dishes.
The 68-70 2bbl engines had 12(?)cc pistons.
the 68-70 4bbl engines had 6 cc pistons.
The 73-later engines had 14 cc dishes.
The 68-70 2bbl engines had 12(?)cc pistons.
the 68-70 4bbl engines had 6 cc pistons.
Last edited by Fun71; December 18th, 2022 at 06:22 PM.
#14
Why not put 1968-70 high compression pistons in it, a cam and lifters and be done with it ? You don't need to mill anything, or get different push rods. With the thicker head gaskets available, you'll lose compression ratio anyway. How far in the hole are the pistons now ?
Ok thanks. I plan on using the hydraulic roller that came in my parts engine. 210/216 so similar size.
Last edited by ck__joel; December 18th, 2022 at 08:07 PM.
#15
I started digging in to this a bit today and while it is blatantly obvious to me that the pushrods are too long as i had mentioned before. That being said, I have no experience with Oldsmobiles and my wisdom for other engines is such that the rocker should be perpendicular around mid throw. On this engine, the rockers are starting perpendicular at the base circle. The pushrods measure 8.250" and I read on another post that pushrods with hydraulic lifters should be somewhere in the 7 range, problem is when I do that, the rocker doesn't have enough adjustment to even reach the pushrod. It seems the mounting stud is way too tall, and the guideplates are contributing to that problem. Any thoughts on this situation and how it would be resolved? I'll put some pictures in the next reply.
#18
I didn't spec this out, bought the engine this way for parts and am diagnosing their mistakes. It had obvious issues and should have never been ran in the first place because the valves hit the pistons. I would not have assumed there was a problem with combining roller rockers and roller lifters, but sounds like there is in this case? The engine I plan on transferring parts to is still completely stock, so i have those rockers as well.
Last edited by ck__joel; April 15th, 2023 at 06:20 PM.
#19
The SBO will have at minimum an 8.250 pushrod. My current set up with ford rocker arms is 8.650 with a solid flat tappet cam. Obviously with roller lifters the length will be different due to height this is where the checker will be your friend and understanding proper geometry. Contrary to popular belief a sweep isn't bad and your contact pattern on the valve stem does not have to be dead center.
#20
#21
The SBO will have at minimum an 8.250 pushrod. My current set up with ford rocker arms is 8.650 with a solid flat tappet cam. Obviously with roller lifters the length will be different due to height this is where the checker will be your friend and understanding proper geometry. Contrary to popular belief a sweep isn't bad and your contact pattern on the valve stem does not have to be dead center.
#23
comp k42-413-9
Xtreme Energy Retro-Fit XR262HR Hydraulic Roller Camshaft Small Kit
Lift: .505''/.505''
Duration: 262°/268°
Lobe Separation Angle: 110°
RPM Range: 1000-5000
#26
I don’t know what the truth is. Thought about putting playdough in there or something because my borescope doesn’t get me a good look at it.
#29
#33
this engine is hurt it wont be running anytime soon. I was just trying to understand what the issues were before using the heads and cam in another engine. Sounds like you solved the mystery though, i appreciate it. I need to find the documentation on this timing set.
#34
Those timing marks are correct, as shown in the Olds factory service manual. I would actually degree it, could be many degrees off, due to a possible inaccurate timing set or improper cam grinding. Also are those rocker studs the conversion studs with a 5/16" base? Not a good idea with the increased spring pressure of a roller cam. Maybe the orginal timing chain failed badly and the pistons kissed the valves at that point?
#35
Those timing marks are correct, as shown in the Olds factory service manual. I would actually degree it, could be many degrees off, due to a possible inaccurate timing set or improper cam grinding. Also are those rocker studs the conversion studs with a 5/16" base? Not a good idea with the increased spring pressure of a roller cam. Maybe the orginal timing chain failed badly and the pistons kissed the valves at that point?
interesting question on the studs i havent pulled one off yet but ill check.
#36
this chain set is not lined up correctly. It’s supposed to line up dot to dot, not cam gear dot to crank keyway… the way it is set in this picture is your problem. Look for the dot on the crank gear closer to the teeth. this dot the cam gear should be lined up to.
#37
Agreed. That is set way off. The 0 near the tooth is the one to line up to the cam 0.
#38
#40
And by the way, there is zero confusion here. Once again, if the marks are aligned at 12 - 12, turn the crank one full turn and they will also be aligned at 12 - 6. The piston is at TDC both times. The issue is compression vs exhaust, and that only matters once the distributor is installed.