Hi. I'm in process of building reliable yet interesting setup for my 1981 98 olds and I will be very pleased if anybody can answer some of my questions.
I want an engine with high low-end torque spec. I won't go racing and etc. It's all just about daily driving, cruising and going out to late night meetings.
Before so-called "restoration" I had:
403 1978 block
4A heads
RV cam
Edelbrock performer intake
1905 Edelbrock carb
Stock manifolds
Pertronix flamethrower HEI

During the rebuilding process I had to buy new pistons and bought KB .024. I believe this will rise CR to about 9 with stock heads
So, my questions are:
1. Is it ok to use 4A heads with this setup? I cant get any "good" factory heads because of the rarity of oldsmobiles where I live. Also, buying Edelbrock heads seems to be a financial nightmare (shipping will cost 20-25$/kg). Are there any possible upgrades to 4A heads? Maybe it is a good idea to use stainless steel valves (they are a bit bigger)
2. Cam. I feel like RV cam is winner in low-end perfomance. Are there any other good options of cams with similar curve idea that will be rather interesting in my setup?
3. Intake. I read a lot about it and I think I will swap to performer RPM later if there won't be any issues with hood clearance.
4. Long tube headers. They will be made from scratch
5. Girdle. I can make one but I think that it is too much

Seems like final setup will be like this:
403 1978 block
KB pistons
4A stock heads/ 4A stock heads with stainless valves
RV cam / 212/218 (?)
Performer intake that will be changed to RPM later
1905 carb
Long tube headers
Progression ignition distributor

Is it a rather balanced setup or should I consider a different?

As for the driveline. Now it is TH350 with 7.5 axle and 2.41 final. I will swap it to 200-4R with 8.5 axle and 2.73 final.

 

With a 2004R, go 3.23 minimum. With a stock height tire, a 3.42 or 3.73 would even be better. A stock stall, around 1900 will work Ok but the 2004R will need strength upgrades. That cam should work fine with your low 9 to 1 compression. You can replace the 2" intake with a 2.07" intake but the shitty exhaust port and 1.5" exhaust valve really need to be replaced with a 1.625" valve and port work. Pretty sure A body headers fit. Sounds like a fun cruiser.

 

Of course, 2004R will get all updgrades, that's why it is now laying around and waiting.
Ok, thank you for the info about valves. I 'll try to get big stainless ones and make some work in machine shop (by the way, all machinig is rather cheap there).
As for the cam, I'm not sure, maybe 212/218 will be better instead of 204/214. Rather good question to discuss

 

With the extra cubic inches and better than the stock sub 8 to 1 compression, the 212/218 will be better than the 204/214 cam, which is mild. For figuring out gearing, the 2004R drops about 1000 rpm on the highway with the converter locked up. This is a very accurate calculator.
http://tech.oldsgmail.com/ch_axle.php

 

I think 3.23 with a 200r4 is the sweet spot. I had 4.11's, then 3.73's, finally 3.23's. But that's living in a busy urban area where we cruise on the highways at 80mph or sit in traffic.

Agreed on going another few steps on the cam. You can go to the 224 duration area without much trouble. I would aim for a torque stall from 2000 to 2500. Something in the 214 range will still be very mild and will idle nicely. 224 range starts to get a little rumbly and needs some attention to get a good idle, especially with A/C.

The 200r4 won't really need a whole lot at this level, especially if you have street tires. Slicks on a drag strip break parts. A billet forward drum is probably the only modified hard part, otherwise the basic modifications from any good kit.

The 4A heads can perform well, but need a lot of time on the bench with someone that really understands how to port iron heads. There was a guy, Jim of J&S, that really loved the 403 and spent the time to figure out the 4A heads but he retired several years ago. He could get them to flow similar to a C head, but required more than twice the amount of work. At the level you're working at there doesn't need to be a lot of work. Bigger valves, a good valve job, and some basic porting should get you a good setup. Jim also did one of the early halo girdles, specifically for the 403. I don't think you'll really need a girdle at this level. It can be a pain to correctly install a girdle if your machinist isn't used to doing them.

 

Thank you!
Unfortunately I can't find where to buy in stock 212/218 in the US, all of them are on back order (end of March) therefore I will use my RV cam this season and will order 212/218 in summer.

As for the valves.
Am I right that I can buy 1.625 valves from BBO and place them in my heads? I noticed that they are a bit taller https://www.rockauto.com/en/moreinfo...=5328&jsn=3444
Do I need to use replacement valve seats? https://www.rockauto.com/en/moreinfo...=5784&jsn=1838
Is it worth to use stainless valves in my engine or just Melling BBO will be ok (if they fit)?

Thank you for your answers again. We don't have anybody in my country that has any information on Olds engines. Also I've just got book by Bill Trovato, very useful thing, I guess

 

Number 8 350 heads from 73 to 76 also use a 1.625" exhaust valve. Hardened seats or replacement seats aren't necessary. You do want proper factory valve installed height, if using stock, non adjustable rocker arms.

 

Standard valves are fine. Seats only need to be replaced if they're unusable. Using unleaded gas isn't a real problem unless you're daily driving.
Any good machine shop can inspect and repair the heads. There's nothing unique to the olds in that respect. Standard practices are fine. They just need the specifications from either Bill's book or the Mondello tech reference book.

The Olds unique stuff is more about the oil galley plugs (all 4 are different), extra freeze plugs, how to get a good rear main seal, remembering that the rods go "backwards" compared to a Chevy, stuff like that. Getting a good intake seal can also be a challenge depending on how much machine work has been done.

 

The difference in height between SBO 403 and BBO valves is 0.17 mm, Will this affect anything? Also, I can shorten them by 0.17 and get a stock height, I think

 

All std SBO and BBO valves are about the same length. Not sure where you’re getting the difference from.

 

I got the dimensions from RockAuto. The first is for 403 1978, the second is for BBO
If they are the same in real, I'll get BBO valves and will not worry about it

 

No, that difference doesn't matter, and it's probably not even correct. Catalog data on Olds parts tends to have errors.

 

When it comes to ex valves, the amount of margin left on the seat area will affect installed height. So the overall length can vary a bit anyway.

 

When it comes to ex valves especially(they typically have a larger margin), that amount of margin left on the seat area will affect installed height. So the overall length can vary a bit anyway.

 

Ok, I’ll get them, thank you

also, is it a good idea to buy adjustable rocker arm kit like this one? https://www.summitracing.com/parts/c...ake/oldsmobile

 

You do realize the difference between the valves is seat angle and head size ?

 

Yup, that's a very commonly used kit. I started with that same kit in the 90's. The pinch nuts are really annoying, so upgrading to short poly locks is a nice idea. The pushrods are extremely soft, so I had a problem with bending pushrods. It's still cheaper to start with that kit and buy better pushrods and poly locks than buying everything separately. "High Energy" is Comp's bottom of the line series for pushrods. Just remember the guide plates have a 5/16" slot, so need to stick with 5/16" pushrods. There's a pretty good chance that you would need a different length anyway. Always check the rocker geometry!
The Comp Magnum pushrods are much better than the High Energy. I'd recommend checking with the ones that come with the kit before buying replacement pushrods. You can always use the ones that come in the kit, just don't be surprised if they bend.
Poly locks extend past the top of the stud and can hit the valve cover. The easiest solution is to get an aluminum 3/8" valve cover spacer and silicone it to the valve cover. This also gives you a much better seal between the valve cover and the head! Several different vendors sell spacers now. I don't know what the accessory brackets look like on your car, but my stock valve covers still fit under the stock A/C valve cover with these spacers.

Good point. Some are 30 degrees, some are 45 degrees. It also depends on what machine work you have done to the head. Changing to larger valves requires a machinist to re-cut the seats, so they will cut the seats to match your valves. They might have to replace the seats if they are damaged or aren't large enough to accommodate the new valves. That's very common work for a machinist that does valve jobs on any overhead valve engine, and they probably have suitable valve seats on the self in their shop.

 

The installed height is the same or set the same for both int and ex. on a factory set up.

the extra length on ex is the thicker face on the valve because of the heat it see’s, which is on the combustion chamber side. It does not change the tip installed height

 

Another question has arrived. Am I right that I can use KB pistons with stock connecting rods? I'll just throw away their spiral locks and do a press-fit mount instead of float

 

No the rods will need honed for the full floating pins. Even my Molnar direct replacement connecting rods needed to be honed for the Mahle Powerpak pistons with floating pins.

 

Maybe I didn't express myself clearly. I'm going to press pins into rods just like factory ones. I found out that they supposed to work both ways according to uempistons website (https://uempistons.com/product/2473/...05.024?sflag=2)
I'm just checking if somebody did it and I'm right.

 

It would be better to hone the rods so the pins can float - an engine machinist should be able to do that easily.
I don't know about using them as pressed. If the diameter is the same as the stock piston pin diameter, then it should work.
If you plan on doing it yourself, note that the pins aren't actually pressed into place. The small end of the rod is heated so the pin can slip though, then the rod shrinks onto the pin. Machinists use a special heater to do this, and that's why newly installed pistons and rods have blue ends on the small end of the rod. It can be done at home, but I don't know how precise the temperature must be. The pins are removed using a press. Pushing the pin through the rod via a press galls and scratches the surface of the pin, destroying it, so can't do that to install it.

 

you’re right. don’t listen to the bad advice on here.

when the Piston manufacturer says they can be floated or pressed..that’s what they mean. the pin is extra thick in those for that reason.

if it said floating only, it would have a thinner lightweight pin , which would distort in a press fit app.

 

Thank you, everyone. I've successfully built and installed the engine. 9.2:1 CR and 204/214 Melling cam
But there is an issue that I can't solve. Very low vac at idle (I achieved max 16-17 inHg) and thus it runs very rich at idle and rough. Any tuning with timing and carb doesn't help at all
As far as I diagnose everything I am really very concerned with the following. I've built this type of engine first time and didn't degree the cam, that's my mistake. So, it is installed at 0 mark, as it was stock one. The manufacturer says it has 112 LSA and 106 intake centerline. Should I advance It 6 deg? I also intalled Cloyes timing set with 9-keyway spocket

 

I would say 17 inches is about right for that cam.The carb probably needs different jets, rods or springs swapped to run properly. What is the timing set at? The front cover needs to come off and a degree wheel is needed to figure out if your cam is accurate as is.

 

whats the cranking compression?

 

I’m curious about the base timing as well. My 350 with the 217 / 221 cam had bouncy 15-ish idle vacuum with 10* initial timing, and increasing that to 18* and connecting the vacuum advance to manifold vacuum smoothed the idle and increased the vacuum to a steady 17”.

 

I don't think that it is related with carb (Edelbrock 1905) or initial timing. Floats are set right, it reacts on idle screws kind of weirdly but acceptable, It is not dripping any fuel while idling, and It also doesn't have any misfires. It acts like it can't burn all the fuel, like it condensates or valves are open not in proper time.
I think this is mostly like stock cam and it should produce 19-20 vac. I run 16 initial timing. I tried 13 to 18, It doesn't matter. Connecting vac advance to intake manifold also doesn't make it happy. The curve is not perfect, I know. It has mechanical advance as following:
RPM Advance
500 0
1000 8
2000 12
3000 16
4000 19
This is out-of-the box springs and weights for pertronix. They have kit with lighter springs. Maybe I need to try them.

I know that I need to degree my cam with wheel and all that stuff but I'm also curious about others experience. As in my opinion, you can predict how to intsall your cam (how to degree it from baseline). And moreover I have to wait for 1 or 2 month (then it will be winter and I will have to wait for spring) to get all this stuff to make it right. That's why I'm asking how to try it the easy way.

 

Compression test

 

Yep, I'll perform it shortly. It'll show if valves open not at right time

 

not really.

those Melling cams come with the advance ground into them. So if you used a quality timing chain set, which you did, and you installed it straight up in the no adv/retard position, the cam won’t be too far off the 106 intake centre line.

another thing…you say you have 19 deg max advance at 4000, how are you figuring that out? is it what pertronix says the weights will give you?

 

Yes, they stated it in papers and also I used digital timing light to check it

 

Degreeing a cam is not strictly required. Cheap timing sets can have problems, but quality sets less so. I've degreed 10+ cam installs and only moved a cam once. But that's using Cloyes 9-keyway kits. 106 ICL is pretty far advanced already, probably wouldn't want any more advanced than that for a driver. Cam timing is unlikely to be a problem.

General advice is to get all the mechanical advance in by 3k rpm, but also want to ensure timing isn't bouncing around at idle. That can be a tough combo to hit.

Keep working on the carb. The AVS2 has a lot of tuning features and it won't be set up correctly for this engine. This engine probably has more vacuum than the carb was set up for - most performance builds will have less vacuum - 12" or less - so putting an out-of-box performance carb on a high vacuum build will pull more fuel than it really needs.

Tuning a good idle is, in my opinion, the hardest thing to tune. Well, the most time consuming. I've spent many many hours tweaking idle settings on carbs and distributors, sometimes with great results, sometimes with almost no change. Other things, like tweaking a qjet power spring, may require a complex setup but tend to be straight forward.

Did you end up using a Progression distributor or something else?