jag1886

Took the old #8 heads in for there rebuild, the shop fully ported them, relieved the valves in the combustion chambers, 5 angle valve job, double springs, positive valve seals, cut the heads .030. I think they look pretty good. The shop did all the porting for free, sold me all the parts for cost and discounted the rest of the machine work because he screwed my engine up so bad to begin with. Compression worked out to 8.8.

oldcutlass

Can't wait to see if this corrects your issue. What will your compression be now?

jag1886

8.8. I also found out the engine shop lied about my compression on the current set up was suppose to 10-1 at most and it's actually 10.2-1.

cutlassefi

You probably wouldn't ever feel the .2 difference.

Just curious, why not the larger intake valves while you were at it?

Thanks

jag1886

The .2 sure didn't help with the pinging problem I have. I have an all bottom end engine with a small RV type cam so I didn't think bigger valves would make much difference in my application.

jag1886

Been driving the car that last few days, the pinging problem appears to be gone and I can honestly say I don't think I gave up anything dropping a point in compression.
Glad I had the guys do all that porting and I think adding the adjustable valve train also helped.
Can't believe what a PITA this engine build has been, I've had more problem with this engine that the last 6 put together. Wish there was a data base like Angie's List you could contact and find good engine shops.

RetroRanger

glad you got it sorted sounds like th ewhole thing has been a PITA at least the shop helped out in the end tho

Olds442redberet

Nice! I hope this clears everything up for you. I ran into a simular issue with my rebuild on the 69 Cutlass S.

DoubleV

Nice to see there are at least some places who step up when they make a mistake instead of running away and refusing to fix their mess like certain people. Glad everything worked out.

jag1886

Well they didn't exactly step up I still had to cough up $700 and I had to install them. The shop went on and on about "giving" me the port work but when I removed the #5 heads, I found they hadn't ported those heads and I had paid them to do it.

So anyone living in the Boise ID area, Meridian Automotive doesn't know at Oldsmobile engine from the Easter Bunny and will take advantage of you any change they get.

oldcutlass

So now it's all said and done, what are your timing settings?

jag1886

I have the initial set at 10, I pulled 4 degrees out of the vacuum advance so it should be a 12 and I installed one light and one medium spring in the advance to slow it down a little.
I wish I had one of those fancy dial back timing lights but I don't. I also use manifold vacuum for the distributor, I have tried it both ways and the car just runs way better using manifold vacuum.
Is a dial back light worth it? I have read some people cuss them and some people love them.
What should I be shooting for timing on this thing? This engine makes all it's power down low, cam runs out at 5000, 2000 stall, 2004R transmission, 3:90 gear 27" tires.

oldcutlass

I love my old 35 year old Craftsman dial back timing light. The rule of thumb on timing has always been around 36* total timing without vacuum advance, all in where the engine likes it. Usually somewhere from 2000-3000 rpm. With vacuum connected generally no more than 50* max. Every engine is different so there will be some variation. Some can max out at 32* and some have gone as high as 38 without detonation. With vacuum same thing. Timing variations depend on cam, compression, altitude, and how good your fuel octane level is.

pmathews

As a point of reference, I'm running 8 degrees initial, 28 total, with 10 degrees on my vacuum. We overshot the compression on the build, so I'm running 10.4 to 1 with a CompCams 265DEH (211/221 duration) 110 lobe separation. If I run 32 total, it pings on me a little, so 28 is where I'm running with 93 octane.

At this point, I'm seriously considering a thicker head gasket (lol).

CyberCholo

Nothing makes me more miserable than trying to chase down an issue I can't solve, makes me want to scrap the car and never own one again, haha. Glad you got it sorted out!

HWYSTR455

Keep in mind cam selection plays a key part in resistance to detonation, sure cutlessefi can comment more on that. Intake valve closing and off seat time to be exact.

pmathews - Your example isn't relevant since the static CR is not comparable. But, looking at your cam choice, with an intake closing at 58, your DCR is like 8.66, and 8.5 is roughly the upper limit on pump gas these days. A simple cam swap to something with a later closing event, like in the 70 range, and you would have any det issues well under control, as well as pick up considerable power. Basically, the cam you have is too small. A thicker head gasket would probably make your issues worse, since it would impact quench.

Plug your numbers in here, to see what your basic DCR is:

http://www.wallaceracing.com/dynamic-cr.php

jag1886 - Sorry to hear you had issues, know how frustrating that can be. And true, .2 in static isn't a deal breaker, if you're that close to your target static CR, the machine shop did their' job. What was the cam used in that original build? (I didn't read the other thread) And what cam do you have now? Key ingredients to determine timing and a curve.

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pmathews

Thanks HWSTR455, that's good advice, I wasn't thinking about swapping the cam, that sounds like a better plan.

jag1886

jag1886 - Sorry to hear you had issues, know how frustrating that can be. And true, .2 in static isn't a deal breaker, if you're that close to your target static CR, the machine shop did their' job. What was the cam used in that original build? (I didn't read the other thread) And what cam do you have now? Key ingredients to determine timing and a curve.

It is a small RV type cam that specifically said don't use if compression is above 9.5-1, it has the same specs as Edelbrock Performer cam, cutlassefi told me it wouldn't work, I went and talked to the engine builder 3 times about this I even took in cam specs for several other cams that would work and he wouldn't give me the time of day (he had 1/2 my money by this time) he swore up and down the cam he picked would work because we live at elevation, man was he wrong. I was only trying to get 300HP out of this engine and I'm pretty sure I hit that, it does run real good now.

HWYSTR455

What kind of gears do you have? And stall? Those play a big part in what your cam selection will be too. If you have 342s and like around 2500 stall, you can run that same Crower that I had in a previous build, the 56263 (220/226), and be around 7.76 DCR, which can easily support 91 octane, even 89 depending on your timing. I really liked the manors of that one, great idle, good vacuum, and decent performance. More gear and more stall really wakes it up too.

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HWYSTR455

I tried to initially get away with an XE262, because I got such a deal on a kit, and the fact I was targeting a lower static CR. That was my mistake, and I knew I had to swap it out. Was not happy about that. Surprised the machine shop made the same mistake, they should have flat known better. Engine building 101.

Remember, you can't judge a build by how much total timing it takes. Technically, less timing indicates a better burn, and is more desirable. 32 total is acceptable (not including vacuum). Anything below 30 though is probably not optimum, but I'm still learning Olds. Rear gears and stall play a part in what your timing is too, load is a factor.

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olds 307 and 403

Just curious pmathews, what is your cranking compression? I know with my future 9.6 to 1 with the Edelbrock cam will be pushing the limits on the street.

HWYSTR455

The DCR calculator on the Wallace site also provides cranking compression. In general, 150-170 is street friendly, and with some dancing with tune, you can make up to 200 work. But I don't advise it.

To calc intake closing from advertised numbers, use this formula:

Take the advertised intake duration and divide by 2.
Then you add the LSA to this number.
Then you subtract out the ground in advance.
Then you subtract 180

From another post, if you want to calculate.

Some cams are specifically made for low static CR engines, and build pressure. This is to improve low end hp & tq. It works against you if you don't have low static CR.

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pmathews

For cranking compression, I'm getting 190 psi on a warm engine, so it's pretty high. I can run 93 octane without pinging, but that's with my total timing at 28 degrees. Also, if I get bad gas it may ping a little, so I keep some octane boost in my trunk for those situations.

I'd follow HWYSTR455's recommendation and calc the dynamic compression, that will help with cam selection, cam timing events, etc...

olds 307 and 403

My calculated cranking pressure will be 183 psi with the head swap. The Wallace Racing calculator was bang on for my current 7.9 to 1 350. It said 142 psi and my engine was 140 to 142 psi.

HWYSTR455

See? Math can be fun!

183 psi is going to be borderline, may want to consider a cam swap at the same time.

I know guys that make 220 psi work on pump gas, but that's with aluminum heads. You really gotta know what your doing when you go above 190 psi, especially with iron heads.

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olds 307 and 403

I can get Shell 91 octane for sure. If can even run the full 36 total without pinging, I will be happy. I will be pulling at least 20 degrees of vacuum advance out and running super cold NGK 5670-8 spark plugs.

HWYSTR455

Do you ever take your car on trips? Is there 91 octane available the route you would take and back? Quality gas? Point is, you may not always be able to get 91.

Again, ever combo is different, and the amount of total mechanical timing is variable. What makes you believe that 36 is the magic number? Because that's what the factory spec is? Is the engine all factory?

If compression is raised, it take less spark lead (advance) to burn the fuel. Period. A fast burn is desirable, it's more efficient. So the more efficient it is (head chamber design plus other factors), the less total timing it will need. Efficiency = power.

To determine the advance curve, initial, total mechanical, and vacuum advance a combo can handle is outside the scope of this thread, but it's a fairly simple process. Many combos prefer more initial than what's listed 'in the books', as an example. So right away, you have to limit total mechanical.

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olds 307 and 403

All my Olds ran best at 36 total in 1/8 mile. These were 8 to 1 350's and 403's, makes sense it won't be the same. None ran fast or without issues at the track. I should have specified where the timing makes the most power. I also need to figure out where the Qjet needs it's primary jetting with 43K rods. The 73 primary jetting, stock for a 403 is a hair rich with this 7.9 to 1 350.