McIntosh

Guy's
I've just completed my build and have about 100 miles on my new 455. It's bored .030 over and has 9.8:1 compression and a Comp Cams XE230/236 cam. I put on a set of Dougs headers. I have the Holley 600 CFM carb with vacuum secondaries from my 350 on it now and I know I need to upgrade soon but it's what I have on hand for now. I've been concerned about being lean because of the small carb but plugs look good. Keep in mind I'm still breaking it in so I'm not revving it up very high. It seems to have a ton of power. I have experienced some spark knocking if I jump on the skinny pedal while already going 60ish MPH. I'm not sure if it's trying to open the secondaries at that point or not. So I wonder if it's carburation or timing? I have set the dwell angle at 30 degrees( I'm using the stock 350's points style dist) and the initial timing at 8 degrees BTDC. It turns over well hot or cold.
Anyone have an opinion of how much total advance is good? Should my initial timing be something other than 8 BTDC? Is it going lean when the secondaries open? Thoughts?

Vintage Chief

Did you disconnect the vacuum hose at distributor & plug the hose (vacuum advance) prior to establishing timing? If the air cleaner is removed you need to plug the vacuum hose fitting, also.

(1) After disconnecting vacuum advance and plugging air cleaner hose, establish the timing. I think your timing should be ~10° (BTDC @ 1100 RPM).
(2) Reconnect the vacuum advance and set the A/F mixture to the highest vacuum possible. The best method is to use a vacuum gauge. Without a vacuum gauge, dial in each A/F mixture screw until the engine reaches its highest RPM @ slow idle. If the RPM increases while adjusting the A/F mixture screws, just dial back the slow idle screw so engine idles ~600 RPM in drive.

McIntosh

I did disconnect the vacuum advance and plugged the hose. Air cleaner was removed but I don't have a vacuum hose running to it to plug.I set timing to 8 at an idle of about 600-700 rpm. I have not messed with the air adjustments on carb. I'll check if timing changes from 650 rpm to 1100.

Thanks

Vintage Chief

It's important to establish the appropriate A/F mixture at the prescribed timing & RPM only after you have established dwell & timing.

(1) Establish Dwell;
(2) Establish timing;
(3) Establish A/F mixture.

dc2x4drvr

McIntosh, your engine build sounds like a copy of my engine, which has been running strong for several Power Tours.
I just took off a highly modified 800 Q-Jet, so keep that in mind..
Throw the stock timing #’s out, I would look for 34-36* at 3000 rpm’s, the cam likes 18-22* initial at around 800-900 rpm’s, try this, and check your initial, you may have to try different springs in your distributor to achieve the #’s.. You’ll need to get a degree tape for the balancer to check timing out..
Rocket on!

dragline

A 100 cubic inch increase may call for a carb rejetting. I'd contact Holley's tech line and ask for recommendations.

McIntosh

Thanks for all the great advice. Yesterday I was checking the timing and my mini starter failed. So with family obligations over the long weekend I won’t get back to it until mid next week. Hope my stock started fits with the headers. I was able to confirm that I might have been advanced a bit much if I understand Norm correctly. I had set base timing at 8/9 BTDC at 650/700RPM. At 1100 RPM this would have been advance much more. Didn't get to see how much more, but I did see that the mechanical advance is in play by 1100. I didn't know that base timing was set while advance was in play. I thought that was the point of disconnecting the vac advance and setting it a idle. Everyone in agreement of around 36 total?

dc2x4drvr

Yup, 34-36* at 3000 rpm, and that cam likes 18-22* initial.

svnt442

From what you're posting about your total advance vs initial, I'd guess that you have an HEI. His points distributor and MUCH more mechanical advance built into it, so 18 - 22° initial would get him closer to 44°-48° all in.

dc2x4drvr

Yes, I suggested 34-36 all in, then check initial timing.

android 211

I wondered why my 8.5:1 455 that had the Engle 18/20 cam pinged when I got on it even with only 93 in the tank. It was my vacuum advance can. It gave like 20 degrees advance. When you mash it the advance stays there for a moment before the lack of vacuum retards the timing.

cutlassefi

Got a pic of the plugs? If you're idling it for any period of time it'll color the plugs accordingly and make them hard to read accurately beyond that. I'll bet it's lean as hell.

70W-32

What grade of gas are you using?

McIntosh

So I got back to the Cutlass a bit over the last two days. Much better after timing it to 10 degrees BTDC at 1100 RPM. No spark knock anymore. Now I'm dealing with hot start issues. I know I earlier said it would start hot or cold but now I'm not sure that was true. I'm not sure I tried it hot before. I already did the Ford style solenoid hot start set up and it doesn't seem to help. I'm going to work on a heat shield and see if that helps. Any suggestions?

Fun71

What exactly do you mean by hot start issues? The Ford solenoid cures the starter not engaging when hot, so is that still an issue or is it something else?

don71

The ford solenoid addition is only a band aid. A heat shield will do nothing but waste your time.I believe your problem is the cables and their connections/terminals, ground side included like the fresh paint on a new engine on the neg cable. The battery could be part of the problem as well. A diagnosis of resistance in the system when attempting to start would be proof. Hope you find the gremlin.

McIntosh

It engages but crankes very slowly if at all. It may be as simple as I need to buy another starter. I'm using the starter from my old 350. It was purchased a year or so ago for the 350 from a local parts store. Maybe I can find on at a local parts store for a high compression 455.

Vintage Chief

It cranks very slowly (if at all) when it is hot or cold...is that correct? And, you have confirmed you have a fully charged battery? You (obviously) have to have full CCA and a fully charged battery and as don71 suggested, evaluate (in particular) all ground side terminals at every point where they make contact. I don't believe I'd rush out to purchase a starter until you've evaluated your terminals, connections and battery state of charge. You could be experiencing a massive amount of resistance on the ground side and a massive draw down when attempting to start.

OLDSter Ralph

What year car ? I think there might be a more powerful starter for the high compression 455.

McIntosh

Thanks for all the input guys. This forum is such a valuable resource. Its fantastic.
The issues are all when trying to start it hot. It starts well cold. I have a new battery and the cables are new or in great condition. I have to admit I have cheep bolt on repair terminals at the battery. I used a "cookie" on a right angle die grinder to clean the paint from the block where the ground strap lands. I have seen the voltage at the battery hit 8ish volts while trying to crank hot. Certainly a massive draw down.

Vintage Chief

I could be incorrect about this, but you shouldn't see more than 0.5V draw-down while cranking. Dragging down to 8.0V is a large draw-down. Check each battery cable and its point of contact and each cable at the starter/solenoid.

EDIT: I think 0.5V - 3.0V (9.0V-10.0V) draw-down while cranking is w/in range.

Vintage Chief

I'll just toss this out. If it's starting fine when it's cold I'm assuming cold means after it's sat overnight or a day or so - e.g. the engine and all components are 'cold'. When you say 'hot', I'm assuming you mean the engine was recently turned off and you ran into the store, came back, or the engine was only left for maybe 15' - 30' and it's still warm (hot). Double-check your choke settings - maybe the choke is closed? Do you have an electric or manual choke?

dc2x4drvr

Check your grounds again..is the starter new, or a rebuild?

oldcutlass

How many amp battery did you buy? The 350 starter may not be up to the task of your 455. How did you wire the aux starter solenoid?

McIntosh

I've been away for the weekend so nothing has been done in a while. I'll answer some of the questions.

My new battery is sadly only 700 cca. If I anticipated these issues I would have sprung for something bigger. Think its enough?

Starter is an off the shelf rebuilt unit from local parts store for the 350. I see that 455 especially high compression 455 use a torqueier starter.

Ford solenoid is mounted to inner fender. Primary wire from battery positive to solenoid. Then from other primary term of Ford solenoid to GM starter solenoid. Primary + wire landing on starter primary terminal where GM originally intended. On the secondary side of things the cars start and ignition resistor bypass wires land on the Ford solenoid. On the GM soleniod there is a 10 gauge jumper from the primary to the "S" seconday terminal. After wiring it like this and not getting the results I was looking for I tried a jumper across the primarys on the GM solenoid leaving the jumper to the "s" terminal as well. Was disapointed to find that the drive no longer engages wired this way. I think it tries, but can't because the starter motor starts turning before the drive extends and the gears are meshed. So I have removed that jumper. I don't understand how the Ford solenoid helps if the GM solenoid stays in play. I guess it only helps the seconday side of things.
I plan to look at all connections and test voltage drop accross them in the comming days. The bolt on repair battery terminals are suspect. And I'll confirm I cleaned the ground location on the block as I think I did.
Thanks again for all the input

dc2x4drvr

A Powermaster starter would solve your slow starting woes..

Fun71

When using the Ford starter relay, the 4 gauge or larger large battery cable is shorted to the S terminal on the solenoid and takes the place of the 10 gauge wire that runs from the battery, through the ignition switch, then down to the solenoid. So when you turn the key, the solenoid is powered through the large gauge battery cable and jumper instead of through the long smaller gauge wiring. This bypasses the voltage drops in the smaller gauge wiring system and ensures (nearly) full battery voltage and maximum current to the solenoid.

Yes, you need to check those as they are very often a problem point. Loose connections and corrosion are opportunities for error with those that you don't have with good quality pre-made cables.

It is still entirely possible that your starter is not up to the task of turning a high compression engine, either because it is failing or is a low torque model. The high torque starters are easily identified by the 1" spacer between the field winding terminal and the solenoid.

https://www.chevyhardcore.com/news/c...all-situation/

oldcutlass

I wired mine this way

Fun71

I did the same, but instead of a jumper wire I made a bridge out of a metal plate to short the battery cable lug to the S terminal.

McIntosh

Guy's
Just checking in to let you all know I whats happened in the past weeks. I replaced the battery cables with 2 gauge cables and proper battery terminals. It didn't help the hot start issuess. I fabricated a heat shield for the starter and solenoid, also didn't help. Then I purchased a new rebuilt starter from Rock Auto for something like $60 delivered to my door including core charge. It was labeled " AC Delco" brand and designed for a high compression 455. In the specs it was listed as a 1.5KW electric motor. Car now starts hot or cold with no issues.

Thanks for all the input.

oldcutlass

Glad you got it fixed.

Orlando 1

It's crazy how those GM engineers came up with this stuff. Is the Ford wiring really necessary if you have the right starter to begin with?