dath

EDIT: Fixed typos...

After many months of waiting, I finally have my AR 383 up and running. I'm still waiting on the final specs from Mark, so I cannot give any cam details yet. . . Basic engine is a 383 with forged pistons, iron eagle heads, roller rockers... Mark said it dynoed at 427 HP, a bit weak, but after so much waiting, I don't care anymore... (Some of you probably recall my posts from a year back or more...)

First off, the engine is running way rich with the Holley 750 DP. I've put in a 5.5 power valve (8 inHG at idle in gear) and set the idle screws about where I thought they should be... Seemed to take care of the black exhaust at idle... Still seems rich under throttle based on the clouds of smoke that follow my car when under heavy throttle. Currently the main metering system has 71H jets, probably need to drop back a ways... Here are where a few of my questions come in... I have hooked up my old 2 1/4" exhaust with dynomax super turbos just to quiet it down a bit from the open header sound that is way wicked, but a bit extreme Should I even bother tuning with this exhaust system, or should I just wait until I have my final system in place? I'm considering running 3" pipe to glass packs as I don't have much money for mufflers at this point... I will be running nitrous oxide (probably 100-200HP total, not sure yet) on this engine once I have everything else tuned in and ready... Is 3" pipe too big or excessive?

Next question . . . I have Dynomax ceramic coated headers that I have *NEVER* been able to get sealed on *ANY* engine with any gasket I've tried. Sure enough, they seem to leak on this engine as well. . . I even got the graphite impregnated custom cut gaskets this time around and cut them to match the header tubes, but still the middle seems to leak on the passenger side (unless something even worse is wrong, lets hope not). What should I do? I've been thinking of dumping these in the trash heap and getting some Hooker headers, but I'm pretty much out of buget at this point...

Last question . . . Strangely enough, I cannot seem to get the distributor locked into place tightly enough. . . Seems that if I womp the throttle the timing inevitably gets way out of wack (went from about 12BTDC at idle yesterday up to around 34+BTDC and I almost couldn't make it home). I don't get it, I cannot turn the thing by hand or even come close, but yet it slips? Is there something I may be overlooking here? I'm worried something else is wrong that I'm not thinking of? The timing was definitely off as I had knocking under anything more than light acceleration, so I know it wasn't just the damper slipping (though it is possible it moved as well, no?)...

Regards,
-dath

comp

cam break-in ???? did you run it 20 min. ????

dath

Mark broke it in before dynoing it. I did another short (~10 minute) breakin, but it had definitely been done.

comp

now you can't wash-down the rings by runing rich to long.... it doesn't sound like you have....

dath

No, I have less than 50 miles on it. Trying to get it dialed in before changing the oil so I don't end up needing to do it 20 times

I really just don't get the timing slipping on me, I've never seen a distributor do this before...

dath

TTT - Anyone else out there have any input? I'm particularly concerned about the distributor slipping . . . Here are a couple of my thoughts on the subject as I've had more time to ponder what may be important. . .

1 - I'm a moron and forgot that last night my vacuum advance was still hooked up when I checked the timing, so my numbers may have been skewed quite a bit and that would probably explain why it wouldn't start this morning, I'll have to check that tomorrow. . . It was definitely off though as it was pinging after it died on the quick throttle burst that caused it to happen.

2 - I left the oil filter bypass blockoff mount in that Mark supplied on his recommendation. Perhaps having the oil filter bypass blocked off is not a good idea (the more I think about it, the worse the idea seems). I have one with the spring loaded deal intact from my old engine, I think I'll change the oil and filter and bolt that bad-boy in.

3 - Maybe I should install an oil pressure sender on the top of the engine as well as the one that is just above the filter? Could it be the top end isn't oiling well enough even though I have high pressure (needle stays either pegged or just below 80 once it warms up with 10w30). . . Would this cause the distributor to have undue friction? Still doesn't explain the extra advance, unless of course my stupidity with the vacuum advance caused me to misread it as being advanced when it was really retarted? Hmmm, seems fishy to me.

Regards,
-dath

dath

In fact, I also forgot to mention that I hooked up the vacuum advance to the manifold vacuum instead of that port on the front right side of the 750. . . I think that was a boo-boo, no? Didn't occur to me until just now. . . Doh!

71coupe

Make sure the dist is actually seating on the intake. Some have an adjustable collar for tall blocks - if yours has make sure it's in the right position.

1970-Bronze

On the headers, have you tried copper gaskets? SCS makes some fairly thick ones. I've never had an issue when I've used the copper gaskets.

Which intake are you running? Did you get the Cam specs?

Did Mark use a high pressure high volume oil pump?

Is the acutal Dist housing moving? Have you pulled the dist and checked to make sure everything looks normal and the shaft moves freely?

tshort

Dath, not sure about the distributor. I know they have aftermarket billet clamping collars that are supposed to hold the distributor much better than a stock one. I'm sure Summit or Jeg's carries them.

Now, onto your smoking. I had the same smoking and it was due to the rings not sealing. The smoking didn't stop until I installed a crankcase evacuation tube and did some hard acceleration runs with it. I'll bet you'll continue to see the smoke until you are done with the break-in and then can really get on it and seat those piston rings.

Good luck with the engine and good luck getting those specs from Mark. He is a good guy but can take an excruciatingly long time getting stuff like that to you. It took me many months to get my engine specs and there are still a few things that I don't know about the engine. Overall though I'm happy. This thing makes a TON of torque! Approx 515lb-ft at crank!

tshort

Also, I disagree about the oil filter bypass block. I like having it in there. Maybe a discussion on this from the more wise would be appropriate.

dath

71coupe: It looks like it is all the way down against the intake as far as I can tell. I'll double check that just to make sure before I pull it out for inspection. The collar is not adjustable on this one, it is a HEI stock style Proform POS. . . I'm a bit annoyed about GM selling these things as stock replacement, but that's another story/rant...

1970-Bronze: Yeah, I tried copper gaskets, the problem is that I couldn't find a gasket that matched the header tube properly, so they leaked. The Dynomax headers have a kind of oval shape on the flange, but most gaskets I find are either round or square. . . That's why I went with the custom cut deals that are super thick themselves... They are really nice gaskets, in fact, I will most likely stick with them no matter what (though I shouldn't need the custom cut (U-cut) inserts for most headers, I could just get premade ones to match). . . I'd take some pictures of what I mean, but my digital camera bought the farm recently

Travis: I may look for a better collar if nothing else seems wrong. . . Just seems strange that I've never had this kind of issue before, but perhaps this engine just revs so much more quickly or something . . . Crank case evacuation tube you say? So that is different than a PCV then? I do have a PCV installed. Yeah, I'm a bit annoyed about the specs, not to mention that he still owes me a fuel pump, but always changes the subject. . . It would be really nice to not be using my stock fuel pump at this point... About the bypass, starting a new thread is a good idea. I am curious to know what others think. I'm just worried that if the filter were to plug up for some reason serious damage could occur. . . I'll start a new thread for that...

dath

Oops, sorry 1970-Bronze, just realized I didn't answer all of your questions. . . The intake is a Performer RPM. I don't have the cam specs, still waiting on the paperwork (several months and counting). I haven't pulled the distributor yet, but that is the next step. I will also put a mark on the distributor base and on the intake so I can make absolutely sure it is the whole housing that is slipping, but I am about 90% sure it is at this point.

EDIT: Oh yeah, it is a high volume oil pump as well. My gauge stays pegged most of the time. . . That's a bit annoying.

lowvette

It sounds like you're new at performance engine tuning and enjoy the learning process. If you have time, I'd recommend you read more about tuning Holleys and ignition systems and take this as an oppotunity to practice new skills. Once the final system is in place you'll have most of your questions answered and will be all the better at getting things adjusted.

Scooter70

Dath,
Good luck at getting everything sorted out. I was about to pull the trigger on an AR motor when all the questions started coming up about them last year. So instead I found an LS1 and 6-speed and put that in instead. My tuning is now done on a laptop. There's still much that I have to learn but hearing your struggles, it kinda makes me glad I went the way that I did. (No offense to you though.) Good luck and I hope you get it sorted out and drivable soon. Tat first ride around the block is nerve-racking but once you're sure it's ok, it's great to know that you did it.

SanDiegoPaul

Sounds like your block is decked enough to cause the dist to not seat fully. Did they use RTV at front and rear of manifold or gaskets? If they used RTV then you probably won't have to worry about the thing leaking but if they used gaskets on a decked block, it will leak.

Now as for the distributor walking. Pull it and make sure the gear is assembled properly on the bottom. Has the roll pin come out of the gear? Is the gear in place?

If so then the problem is bigger. Possibly the oil pump drive to the dist is mismatched or you need a hardened gear for the dist.

When you pull the dist out, you should be able to see the wear pattern in the gear. If it is not worn in the middle, something needs to be done right away. RIGHT AWAY ... contact the builder.

dath

Iowvette: Yeah, I am fairly new to "performance" engine tuning, but I have read quite a lot on the subject. As for Holley tuning in specfic, I have read Lars's paper and have also read the SA Design book "Super Tuning and Modifying Holley Carburetors". . . I liked Lars's paper better Definitely is a learning experience and I wouldn't have it any other way. Plus as with most people, I don't have money to waste, so I do all of my own work on all of my cars and pretty much always have. . .

Scooter70: I am one of the people who started bringing up some of those issues with AR in the first place. I had troubles with my first engine build, so it went back and this is now my second engine. If this one has any issues, I'm about ready to just give up. I have sacrificed a lot of time to this (and don't get me wrong, I enjoy it), but I can't see spending so much time for nothing... It is way premature to say that any of the issues I'm having now has anything at all to do with the engine build this time around. I've done more than drive it around the block, but will not be doing much more than that from now until I figure out these last few issues (or at least my distributor slipping issue)...

Paul: From my memory, it seems that RTV was used all the way around the intake along was a gasket set as well. Mark believes in RTV, the stuff is oozing out of all kinds of places Sounds like pulling the distributor is the logical next step no matter what. . . It is a new distributor, but like I mentioned before, it is a Proform deal... It seems the whole body is moving on the distributor, could these problems cause that to happen? I'll mark it when I reinstall it (assuming there are no issues) and then see if I can get it to slip again and check the marks this time around. Would the wear pattern by the deciding factor on weather or not the distributor is seating properly against the oil pump and gear as well? Otherwise, is there an easy way to check for proper (full) oil pump engagement? Maybe packing grease around the oil pump bit and then dropping it in fully and pulling it back out to see how much is displaced? I do *NOT* want to have to deal with AR on this again. I will be eating it and taking it to someone else if there are problems this time around. It took 6 months or better to resolve the first issue and I was told that would take 2 weeks . . . Arrrrgh!

1979toy

Header gaskets - I used the Earl's pressure seals and loved them. They did need to be checked for tightness after every run until it all seats together.

Exhaust - Yes you will need to retune the engine some when you change exhaust. It will not be so much that you have to start over again at tuning. 3 inch sounds fine, unless you can get bigger True 2 1/2 inch duals with a crossover are not going to hurt you if you want to make your installation easier.

Distributer - Is the dist. sitting all the way down on the manifold when you set it in place? It should be setting on the flange. If it is not you can shim it up with a couple of gaskets at the flange.

Tuning - Good luck. I had 69 mains in my Holley 3310 when I removed it. The idle screws were 1 1/4 turn out and I think that I had a 6.5 power valve. I have forgotten what squirter I had but that is one of the last things to tune anyway. You may want to open the rear throttle blades a bit to lean out the mid range, or drill the throttle blades.

dath

1979toy: I think the gaskets I have now are the Earl's... It was quite a while ago when I bought them (for the last engine, but never used them there). . . They are the aluminum gasket housing deal with some kind of graphite material inserts that you cut (they have precut ones available, but I cut my own as I couldn't find anything that matched Dynomax headers). . . So I bolted the headers against them before cutting them to make marks where to cut, then cut around the inner edge of where the header tube rests... I'm thinking my headers may not be completely flat across the flange and this may be causing the leaks. Maybe I should just reef the bolts down super tight and see what happens?

I was thinking of 2 1/2, but couldn't decide what would be best for my application. I'm planning to fab it up myself. I also am having fits trying to choose a muffler that will flow enough. . . I'm trying to get a perfect tune once and not have to redo it for the track (say if I had cutouts and more restrictive mufflers). . . I know glass packs will flow enough (basically no restriction other than pipe size), but I'm worried it will be untollerably loud...

Yeah, the distributor seems to be sitting all the way down. My dad had one more idea when I talked to him on the phone a few minutes ago (we wrench together most of the time) . . . What if the mechanical advance weights were sticking out? That would explain why it is getting advanced instead of retard and would also explain why it happened from a dead standstill, but not while already moving along down the road at speed. I'm going to mark the housing and intake together so I know what is going on (and so I can put it back together again without resetting back to TDC) and inspect everything the best I can.

lowvette

Dath,

It seems that many of my co-workers even pay someone else to change their oil. I just don't have confidence enough in the general service industry to know that it would be done correctly each time and w/o damaging other components in the process.

I actually get satisfaction out of fixing things myself - automotive and around the house. The money saved is better spent on developing my side business and having fun with the Corvette.

It sometimes feels like those of us who choose to do our own work are a dying breed.

Lars has some of the best how-to and how-come posts I've seen on the web. Sounds like you're on track!