Inliners International Forums General Discussion Hi Performance stalls when put in gear

I need help!!!!
Here is what I have
65 chevy 2-- 250
crane rv cam
offy 4 barrel intake
holley 390 4 barrel
split exhaust manifold
hei ignition
Circle track head (big valves-ported-siameese ports cut out with recessed head bolts- guide plates and planed
Stock power glide trans
THE PROBLEM
starts and run with a shake below 1100 rpm
Idle set at 700 in park
put it in drive and it pull the rpms down to about 400 and it stalls
set the idle a 500/550 in drive and it races to 1000/1100 in park "to high to pull back in gear"
Doesn't seem to be any vac leaks as it has 17 inchs of vac no fluttering. The only thing I can think of is that the converter is locking up to quickly but I have know idea how it can be checked other than replacing it. Any suggestions will be appreciated as I have just about had it. Thanks

what are the spects on the cam. but if it is a rv style. The stock convertor should work. How many miles are on the Tranny??? And when did this problem start? }[oooooo]

I don't have the specs on the cam anylonger, I just remember that I ordered a rv cam. I have know idea how many miles are on the tranny, because it was in the car when we bought it. We had no problems with it when we had the original 230 in it. I guess I should have left well enought alone The problems started after we installed the new modified 250.
Thanks for your response

well i have ran cranes rv cam On my stock power glide and didn't have any problems if you have the cam Number i can look it up if that will help u }[oooooo] and maybe we can go from there .

I think your problem is the big valve circle track head, and the fact that your runner velocity is so slow that fuel is falling out of suspension at slow air speeds, causing roughness and poor fuel distribution. Try a head that is not cut up, with standard sized valves, blended bowls, polished chambers, and a three angle valve job blended into the throats.

You wont hurt that powerglide by engaging it at 1100 RPM. If changing the head seems counterproductive then sleep well knowing your trans will live and live with the "problem".

If the cam has under a 215 duration @ .050" I would also agree that a stock convertor should work. Putting the convertor question aside for a moment something else came to mind and is similar to one I had with my 250 only I'm running a 4 speed. Trying to get a steady and controllable idle was a pain until I noticed a little sentence in an Edelbrock carb tuning book that said some engine / cam/ carb / ignition combinations do not like to run with ported vacuum advance and the solution was to run the vac advance directly, meaning from the nipple at the base of the carb.
Deciding that anything was worth a shot I moved the vac line to fully ported and everything fell into place. It sounds contrary to what we know but it works fine. Idle is great and the carb sets up nicely. I haven't had to so much as adjust the idle speed in almost 2 years. Part of what may make this work is my HEI I built using a 20 inch vacuum diaphragm that also has the lightest spring in it, so it responds instantly to the slightest drop in manifold pressure as the throttle plates begin to open.

Back to the convertor - a 12 inch convertor is pretty tight and just might be too tight for what you have. Stall is related to engine torque and vehicle weight as well as rpm. What worked on the stock 230 now will work differently on the
hi-po 250 you have. If you can check out either a listing for those PG convertors or can see one from something like a 300hp 327 you might find out there was more than one that went with the PG depending on which engine it was behind. Whatever you do about changing it don't get a replacement convertor with some silly hi rpm stall speed. You'll hate it for everyday driving.

I personally would swap to a nice street built TH350 if you get to the point you want to yank the 'glide. You'll be amazed what that one extra gear will do to wake up the 250. Summit, Jegs, and all sorts of other speed suppliers have them for around $600 to $700, complete with the right convertor.

Ok going with Cranes Powermax Cams These are the Low lift 1 is a 1600-2200 cruise rpm Basic rpm range is 1000-4000 rpm with a 192/204 @50 duration with a lift of 467/498 2)is a off road towing economy cam.2200-2600 cruise rpm Basic rpm is 1500-4500 rpm 204/216 duration@50 with a lift of 498/530 Both these cams will work with the stock convertor. I may agree a little with French
But before buying another head. Try bring the Idle rpms up to about 900 and see what that does for you. It has been awhile since I ran the crane Rv cam But I think My Idle was around 900 rpms But I also had a stock head Yet on the motor. So this is why I may have to agree with French. But if your not worried about the MPGs I think it would far cheaper to step the cam up.You should also think about installing a set of bolt in lumps To pick the air flow Back up. Because I think you have a flow issue with the bigger valves On that small cam(again agreeing with French) hope this helps }[oooooo]

Thanks for the replies.
Mike: I have had the distributor hooked up to both ported and manifold vac and it still runs the same. I was hoping to swap out the PG to a beefed up 200r4, but would like to solve the problem before I do the swap and cause more problems. It would be nice to have the thing running good before I start changing it again.

French: I had a feeling that the head was to much for the PG, but didn't want to go there because the head cost me a lot, and I didn't want to get rid of it. The problem shifting into drive at 1000 rpm is that the car jumps and bang badly.

Twisted: If I step the cam up, will this not make the motor run rougher at an idle and therefore cause more problems for the tranny going into gear? I thought going with a small cam would not cause problems, but I do have problems. If lumps were installed do you think that it may smooth it out and idle around 500-600? I have never installed them so I know little about them, are the hard to install, can it be done with the head on the motor, motor in the car? I seen somewhere a tin plate was installed between the intake and head, and that was suppose to help, do you know anything about it?
Again, thanks to you all for the suggestions.

Johnson
The head it self is not the problem for the tranny. But more of a motor issue Because of what ever cam you have.?? and Not knowing the spects on it is the problem for the tranny.Because You may need more stall speed over the stock. Now 2) The head may very well be a issue Again Because of cam. This meaning to Small for how the Head was built. Again Not knowing what your Cam is. The cams that I listed will work with the stock convertor (if it's up to again not knowing anything about it Miles wise) But those cam have a fairly smooth idle. another words Not lumpy.

The tin plate that your are talking about Should be your Gasket(intake/exhasut)That needs to be there. Now as for installing the Lump NO it can Not be done with the head on the motor It HAs to come off. And as for the average Back yard mechanic. I would have to say No. Because of the added Work that yet needs to be done to the Head. It has to be drilled from the Underside and counter sunk, for the bolt that holds the lump in place.Then Comes the work That is Needed to the Lumps themselfs. The flashing that is still on
PES cast lumps need to be cleaned up The Center Main Head Bolt hole needs to be Opened Up at Least On Every set i have bought from them.(Don't take it wrong they are nice Just they need some work) Then You have to tapper/Blend the intake side to the port floor to the intake itself. OR Make a peice to go into the intake. And Then That too would need to be blended to the floor So for the most part it is better to just work the Lump itself with out adding More work to the whole process. They would GREATLY Improve air flow.
But again the cam may very well be a issue Because of the size Of the valves.sorry and again Not knowing the specks.
and not to beat a offen touched topic But when You Build a motor You have to look at the Whole Picture. What you plain on doing with the motor/Car,truck what ever. But Cam, Head,Intake system, Headers Tranny ,Convertor. All has to work together. Or in some cases you end up with some problems Like your running into right Now Or even in the worse case You end Up brakeing alot of parts.

At this point right now with the lack of info about the cam and Tranny/conertor miles.What I would try and do is find a REALY cheap stock head Just clean it up check the spring to make sure non are broke Iwouldn't worry about if it smokes on start up because of maybe worn guides or anything Just make sure the spring are not broke Stick it on the motor If it still won't idle Then I would have to go with the Fact That You have a Problem with the convertor. If it Does run and idle with no Issues. Then I would just take the springs off the other Head ,clean up the test head
do just a good valve job on it clean up the ports. And if your going to have the Boss removed stay with the smaller stock valves. just to give you a idea on how the lump imporves flow. But Not knowing the reall flow numbers on you head the way it is or whos work it is. Ruffly what you maybe flowing with out the lumps could be around 190 cfm give or take like i said. Now with the lump it can flow over 240 cfm

The only other opption I see is to Get a new stall convertor something with a little more then the stock stall speed.(1000-1500(2000?) stall)

PS have you thought about trying to get with the folks that either built your motor Or the Head and see if they may have the card Or to what lift they built the head for (meaning the spring).
sorry a long post but i hope this helps }[oooooo]

Twisted
The tin plate that I mean looks like the intake gasket except that the port opening is punched cut on the left, right and top, like a upside down U. The bottom is left connected. The purpose of the piece that is left attached gets bent back into the port, to deflect the flow upwards and closes in the lower part of the port. It has to be bent back and fitted into the port opening, as tightly as possible. I have seen it installed on a ford 351 to increase flow speed, and it appears to work. I guess it may have been the original form for lump ports. I spoke to the converter people and they suggested that since I am going to a 200r4 in the future, I may as well do it before I start playing with the converter. In the mean time I will pick up and old head and try that. Would you suggest a 250 or 194 head?
Thanks for the help.

You can use Either head. What psitons are you running? The 194 head will Boost the compression. with a flat top pistion it can be up around the
10-1 compression Give Or take a little. With the dished pistion it can be around the 9.5-1.
Hum interesting and the gasket. I have Never seen one for a chevy. If you can I'd like a picture of this gasket and maybe a Part number. But Something you could try??? if you wanted to is cut that Off.If you find you another gasket like that If cutting it Off doesn't Help.

The 194 head has a smaller combustion chamber That is why the compression will go up.This head can be made to flow some fairly good cfms But maybe Not like the 230-250 heads can.But if you want more of a low buck boost for some hp the added compression will help. If your running a flat top with the 4 valve relef like a 307 piston will net a little less compression Then a TRUE Flat top pistion.with the dished pision I see no reason why you couldn't still be able to run the cheaper 87 gas.As to the higher 91 that maybe needed if your running a flat top( closer to the 10-1 compression)
hope this helps }[oooooo]

Twisted
The part I am refering to is call a "port plate"
Ford used them on their 351 to increase the flow. Look at "mpg heads" and then click port plates. I couldn't find then for a chevy, but it may be of interest. Let me know what you think.
Thanks