hpfiend Posted September 18, 2011 Report Share Posted September 18, 2011 Hey all- Got this car back in May as a project for my dad and I to work on. Here is what it looked like then: http://i272.photobucket.com/albums/jj162/hpfiend/Gremlin/Gremlin3.jpg http://i272.photobucket.com/albums/jj162/hpfiend/Gremlin/Gremlin2.jpg http://i272.photobucket.com/albums/jj162/hpfiend/Gremlin/IMG00045.jpg Here are some specs the way I bought it and according to the previous owner: 1970 AMC Gremlin 355 SBC 1.94/1.50 fuelie heads with comp cams roller tip rockers edelbrock air gap intake holley 750 double pumper with HP main body K&N 4" tall air filter and Xstream flow top MSD pro billet distributor and 6AL box Holley 130 GPH mech. fuel pump with -8AN/-6AN Lines and a return style regulator Alum. cool can 8 gallon aluminum fuel cell 3/4 length headers with 2 1/2" exhaust and purple hornies glass packs Jegs aluminum radiator and aluminum water pump, mini starter Jegs built TH350 transmission with manual valve body Jegs 10" converter ford 8" rearend Comp. Engineering drag shocks all around Lakewood traction bars driveshaft safety loop Flex-a-lite 210 Dual electric fans with thermostat control, Autometer gauges, 5" tach with shift light, Moroso battery box and trunk mounted battery with kill switch plastic race bucket seats. Car weighs 2730 lbs. with out driver. Quote Link to comment Share on other sites More sharing options...
Buckeye1647545503 Posted September 18, 2011 Report Share Posted September 18, 2011 I have always wanted a gremlin. Quote Link to comment Share on other sites More sharing options...
hpfiend Posted September 18, 2011 Author Report Share Posted September 18, 2011 (edited) After driving it home 3.5 hours we found that in its current state of "tune" 8 gallons of gas doesn't get you very far. We also discovered that it had a starting issue in that it would require several clicking attempts before the starter would turn it over. Apparently the previous owner had put a charger on it before we picked it up. We discovered that the battery relocation had been performed using 4 gauge stereo wire and questionable chassis grounding. Further, the "kill" switch didn't kill the engine. We ran 1 gauge wire all the way to the starter and a dedicated 1 ga ground to the engine block and then redid several chassis grounds. We eliminated the alternator feed-through so that the kill switch is now legitimate. Edited September 18, 2011 by hpfiend Quote Link to comment Share on other sites More sharing options...
zeitgeist57 Posted September 18, 2011 Report Share Posted September 18, 2011 LOVE EEET!!! Quote Link to comment Share on other sites More sharing options...
hpfiend Posted September 18, 2011 Author Report Share Posted September 18, 2011 (edited) We finished the wiring and took it up to Marion to see what it would do. To make a long story short we only got one run (14.0 @ 95)- It has a terrible hesitation at any acceleration beyond 1/3 of the way down. So easing it out of the hole and realizing it has no top end- shifted at 6000 rpm that was that(surpising considering the lope of the cam- maybe its one of those thumprs cams by comp cams- all show and no go. We would have had a second run but I forgot to switch the msd on and cranked and cranked befoe I realized it and the battery died. We pushed it away amid the jeering (#1 its a gremlin- no 2 it wont start) and jumped it with my dads explorer. Well it was about 1AM so we decided to head home. As we drove the headlights gradually got dimmer and the tach was reading funny- just as it started to miss I pulled over and it stalled out. The alternator could not keep up with the fans/msd/headlights/etc apparently- so we flat towed it 35 miles back with a tow strap and no lights in the middle of the night. Edited September 18, 2011 by hpfiend Quote Link to comment Share on other sites More sharing options...
hpfiend Posted September 18, 2011 Author Report Share Posted September 18, 2011 (edited) We were looking for a project ;-) In order to avoid the same disastrous outcome next track outing I got out the Tig welder sourced some steel and got to fabricating... http://i272.photobucket.com/albums/jj162/hpfiend/Gremlin/HitchDonovan015.jpg http://i272.photobucket.com/albums/jj162/hpfiend/Gremlin/HitchDonovan007.jpg http://i272.photobucket.com/albums/jj162/hpfiend/Gremlin/IMG_2463.jpg http://i272.photobucket.com/albums/jj162/hpfiend/Gremlin/IMG_2464.jpg http://i272.photobucket.com/albums/jj162/hpfiend/Gremlin/HitchDonovan011.jpg http://i272.photobucket.com/albums/jj162/hpfiend/Gremlin/HitchDonovan012.jpg Edited September 18, 2011 by hpfiend Quote Link to comment Share on other sites More sharing options...
nurkvinny Posted September 18, 2011 Report Share Posted September 18, 2011 Your 750 DP on that engine is the first issue... Quote Link to comment Share on other sites More sharing options...
hpfiend Posted September 18, 2011 Author Report Share Posted September 18, 2011 We ended up fitting the stock hood on the car as our plans are to make it as surprisingly fast as it is surprisingly ugly- This required a 3" filter and some creative work on the hood with a nibbler... You can also see the hitch receivers installed and painted in this picture... http://i272.photobucket.com/albums/jj162/hpfiend/Gremlin/IMG_2468-1.jpg Quote Link to comment Share on other sites More sharing options...
hpfiend Posted September 18, 2011 Author Report Share Posted September 18, 2011 (edited) Your 750 DP on that engine is the first issue... You aren't kidding- the estimated 8:1 compression doesn't help either- supposedly it has dished pistons!!!- It probably needs a 450 cfm vacuum secondary the way it sits now actually... Right now we think the strong hesitation is likely a result of timing as we discovered the previous owner pulled the vacuum advance off of a venturi vacuum instead of the manifold vacuum source. Also have some bigger shooters to try and need to find out where the overall timing is. The previous owner mentioned something about mix-matching springs in the mechanical advance of the dizzy so we need to look at that as well- and with the way this baby eats gas and smells the jetting has to be way rich as well- Tested the alternator and with the low idle to prevent creep (automatic) it wasn't even working- also it was only putting out about 10 amps just off idle. I got a reman setup from HITE that puts out 30 amps at the low idle speed and 100 amps at its current winding but I can have it rewound for 300 I think he said- the original alternator was chrome and would overheat if rewound according to the guys there and was one wire- figured out the wiring for the excitation circuit (3 wire) and dash wiring for the gremlin warning light just need to finish the custom bracket needed to get it back on... Future plans are to fix some rust issues in the floor, get the bench seat and carpeting back in, get rid of the extra gauges/switches to make it look less like a race car and awkward to operate, put an explorer 31 spline 8.8 lsd setup in, make it a full frame through the floor where the front and rear subframe break, and add some sort of roll bar/cage to stiffen it up this winter. I forgot to mention it came with 10.5" slicks and rims that supposedly fit under stock fenders- hopefully I wont have to do too much work after putting the new rear in-- Edited September 18, 2011 by hpfiend Quote Link to comment Share on other sites More sharing options...
jeffro Posted September 18, 2011 Report Share Posted September 18, 2011 >2011 >carburetor ........................................................wtf. how fast does it go? Quote Link to comment Share on other sites More sharing options...
hpfiend Posted September 18, 2011 Author Report Share Posted September 18, 2011 (edited) >2011 >carburetor ........................................................wtf. lol ask S10 matt about how slow carbs are... right now its one and only pass has been a 14.0 --with a good launch probably mid 13s - Edited September 18, 2011 by hpfiend Quote Link to comment Share on other sites More sharing options...
wagner Posted September 18, 2011 Report Share Posted September 18, 2011 lol ask S10 matt about how slow carbs are... right now its one and only pass has been a 14.0 --with a good launch probably mid 13s - I also read that and laughed out loud as I looked at all the stupid fast cars, at the track, using carbs... Love the choice of this project there is an AMC in drag week this year that was almost running the 7s. Quote Link to comment Share on other sites More sharing options...
nurkvinny Posted September 18, 2011 Report Share Posted September 18, 2011 I ALWAYS giggle when people ask me (more tell me) about carbs being slow. They're just like everything else in life. They're mysterious and hard to work on until you have experience and knowledge. Quote Link to comment Share on other sites More sharing options...
Mattsv8 Posted September 18, 2011 Report Share Posted September 18, 2011 carbs are easy to work on but you dont get the labtop out to tune, u just get the wrenches. mine isint perfect but think i found my main issue now so hopefully i can lean the sucker down and get best of both worlds 8s and perfect street maners. well as perfect as a 88mm and uncomfortable truck can b. Quote Link to comment Share on other sites More sharing options...
hpfiend Posted October 11, 2011 Author Report Share Posted October 11, 2011 (edited) Thanks for all of the comments everyone! Well managed to weld up the hitch adapters and snap a few pictures- still need to throw some paint at them. I also finished fabricating the new alternator bracket but no pictures of that yet. It should charge itself now and be more easily brought home should it break down again. http://i272.photobucket.com/albums/jj162/hpfiend/Gremlin/Receivers001.jpg http://i272.photobucket.com/albums/jj162/hpfiend/Gremlin/Receivers002.jpg Also mounted an insulated distribution block to run the accessories off of with a larger source off the starter and wrapped some wires with convoluted tubing for protection. We checked the timing and it appears the base timing has been set at max advance according to the pointer. The problem as mentioned before was that the vacuum advance for the distributor was pulled off of a venturi vacuum source instead of manifold vacuum. We teed it in to the proper source off of the carb and it was a completely different animal. Low speed torque was increased immensely. It can smoke the tire (no lsd yet) in third now. No signs of detonation on 93 octane. We also installed the 40 accelerator pump shooters to replace the 31s that were in there- this resolved about 95% of the major throttle induced hesitation. Off to the track. Edited October 11, 2011 by hpfiend Quote Link to comment Share on other sites More sharing options...
hpfiend Posted October 11, 2011 Author Report Share Posted October 11, 2011 (edited) We headed to MCIR on Friday night after work- happened to run into Rob Lasota and his dad which was a nice surprise! Shifting at about 5500 in first and crossing the lights just after the shift light indicates 5500 in second it ran a best of 13.20 @ 95? the slip says 101 mph but it ran 95 all night long and ran a 13.22 @95 the run before. The 60' on the 13.20 run was a 1.82 but I don't think about a tenth in the 60' would equal 6 more mph and only 2 hundreths faster. We put the 10.5" cheater slicks on and found there to be two sets of spacers behind the street rims. We put the welds on without any spacers and there is about another 3/4" to an inch on each side to the fenders now if bigger tires are needed. There is no stall in this car (contrary to the PO) or its not working if thats possible as we could not hold it back beyond 1500 rpm as my dad redlighted twice trying to launch it harder. With this moderate launch and warming the tires a bit it dead hooks on one sticky tire. It is amazing what a little vacuum advance and carb tuning will do. We think if shifted at 5900 (rev limiter pill at 6000 now) in first and pushed the timing to detonation and then a touch back (on a hot day- it has dished pistons in it) we may break into the 12s as it sits. We still need to mess with the shooters and it will still randomly not want to start unless you turn the key about 10 times.. the solenoid is probably on the way out as it is soo close to the headers... we need to pull the carb off and see whats in it as when we called holley they suggest blocking the rear powervalve so we will play around with that next. Edited October 11, 2011 by hpfiend Quote Link to comment Share on other sites More sharing options...
Dave1647545494 Posted March 19, 2012 Report Share Posted March 19, 2012 get a mini starter and or put a heat shield on it looks like a fun car! Quote Link to comment Share on other sites More sharing options...
hpfiend Posted September 30, 2012 Author Report Share Posted September 30, 2012 (edited) It's got a mini starter and we replaced the ignition switch which has helped a lot... A heat shield and or a ford remote solenoid are next- it happens more rarely now but still present- thanks! We pulled the hp 750 carb off and went through it to see what was in it... As the vacuum at idle in gear was about 9 we put a 4.5 power valve in the front- the back had no power valve but did have jet extensions and a plastic notched float. It's got 72s in the front and 84s in the back, we took all the slack out of the accel pump linkages (there wasn't much to begin with) and discovered that the hp main body upgrade has no provisions for the timed spark port (which would explain why it showed no vacuum). We put it back on and tried it out.... No change... Edited September 30, 2012 by hpfiend Quote Link to comment Share on other sites More sharing options...
hpfiend Posted September 30, 2012 Author Report Share Posted September 30, 2012 Next we tried to fix the deadspot with timing. We took the msd dizzy apart and replaced the blue bushing with the black one and put the two light springs in instead of one light and one heavy. This should bring in 18 degrees by 1600 rpm. We then upped the base timing to about 16. The car seemed to pull a little harder but the dead spot was the same... Btw does anyone know why the timing pointer is in the center at about 12 o clock behind the water pump as opposed to the 2 o'clock as is customary? A different balancer? We even bought a pointer from jegs for an 8" balancer and it didn't work (duh- not sure what we were thinking perhaps blinded by optimism). We then tried position 2 on the pink accelerator cam in the front and one in the back. I think this helped at little with the deadspot but it's definitely still there... Quote Link to comment Share on other sites More sharing options...
hpfiend Posted September 30, 2012 Author Report Share Posted September 30, 2012 Okay after talking with MSD and Holley tech support again they now both think the cam is the problem. I had comp cams recommend a cam for this engine with a turbocharger in it and they came up with a reverse pattern cam of 230/228 @ 0.050 and .525/.525 lift. The problem was I needed roller lifters and bigger springs. As the numbers of the block indicated 1980-85 and I shot an email to the previous owner and he didn't think the rollers had been updated- that made the cam swap very expensive. Double hump heads don't have spring seats big enough for that cam, link bar roller lifters were 400, and the custom grind was 300 I had some decisions to make. I contemplated putting an ls truck engine in with engine mount adapter plates but was afraid of the hassle of tuning/wiring fuel injection mega squirt and an msd multi-spark, fuel pump, injectors etc and with a carb manifold and the plates we may not be able to fit the stock hood anymore.. Sooo... Quote Link to comment Share on other sites More sharing options...
hpfiend Posted September 30, 2012 Author Report Share Posted September 30, 2012 (edited) I did some research and apparently the cam from the L46 corvette which had a 350 hp/350 is still available and they used the same cam in the low compression L82 350ci corvette. Federal mogul calls it the CS1095R and a lot of old corvette guys are using it... The best part is it has specs similar to the custom grind but with lift I can get away with on these heads... 224/224 at 0.050 .450/.460 114 LSA I figure if I can't boost up to low 10s then I can add some aluminum heads and higher ratio rockers to get the flow there... Well, I put it in with new lifters, pushrods, sparkplug wires, and those short accel spark plugs (burned up #6 plug boot apparently) spent all day Friday trying to figure out this terrible sound on startup (readjusted valves twice, pulled electric fans, adjusted timing (thinking it was detonation) which apparently was the flex plate hitting the dust cover as I must have bumped it when I removed that @&$@ filter when I changed the oil...broke the cam in, test ran it, looked for leaks, and changed the oil again... Got to the event at 4:45 as most of you were leaving- as tired as I was I didn't want to change tires to slicks- stayed for the trails event and it got a 14.6/14.7 at 98.x mph. The dead spot is not gone but it seems to pull a lot harder and shows about 3mph faster than we got at marion. 60fts were 2.6 to 2.9 as it falls on its face and then spins when it takes off after you pump the gas a few times to get through the dead spot. So even though it ran slower I am not concerned as it was mainly from running on street tires. Going to try to find a 650 dp to try to see if that helps with the dead spot... Edited October 1, 2012 by hpfiend Quote Link to comment Share on other sites More sharing options...
hpfiend Posted November 26, 2012 Author Report Share Posted November 26, 2012 (edited) I ended up purchasing a "650" double pumper from craigslist. Upon closer inspection, the carb is impossible to identify as the identifying list number was on the milled choke horn. The number listed on the metering block identifies it as a 700 double pumper... I tried measuring the venturis from the top but the boosters are in the way for an accurate measurement. The venturis are not equal sized front to back so it is not a 750, but other than that I am at a loss. In the meantime I disabled the secondaries on the installed/converted hp750 and tried to tune the primary using shooters and different accelerator pump cams. After much trial and error and pump cam curve analysis I came up with the blue cam in position 2 with a 31 shooter and then after connecting the secondary linkage a green in position one in the back with a 40 shooter. The dead spot was pretty much eliminated from a standstill. (Knock on Wood). I then read that the hp main body is setup for a 4 corner idle adjustable carb and I only have 2 adjustments in the front. Apparently it was discovered by this fellow that by switching the high speed secondary air bleed for one the size of a non-hp 750 he had much better idle and throttle response... so I put a set of 28s in place of the 75s as he did and tried it out. It did seem to idle better and have a little better off idle response... In order to try and band-aid this oversized carb situation further I bought a linkage to be able to adjust the secondaries for idle from the top rather than pulling the carb every time. I cracked open the back and reduced the front opening to prime the rear transfer slots and it seems to run pretty well now. I did have a situation where the dead-spot was back once from a mid throttle cruise with a stiff punch but I am wondering if that was at the point of the primary to secondary transition on this little engine and the transfer slots couldn't make up for the load of the high rear gears... who knows. It does pop now in the tailpipes which I believe is indicative of an over-rich condition??? But I feel I can now make a clean run from a standstill... Edited November 26, 2012 by hpfiend Quote Link to comment Share on other sites More sharing options...
hpfiend Posted November 26, 2012 Author Report Share Posted November 26, 2012 I dropped the Explorer 8.8 off with Gary Horn at Babbitt Bearing to be narrowed, axle tubes welded, and 9" ends welded on. He is working on it as I type this and last week before the turkey festivities I rebuilt the 31 spline track-lok carrier with a set of the cobra carbon fiber clutches. Going to try the 3.73s that I bought it with as they look to be in good shape and I have no idea what ratio will be ideal at this point.. anything will be an improvement over the 2.56s in there... Once I get it in I will probably have to go back into the carb as it's now more ideal for a double pumper.. (light car, high stall, lower rear gear). More pictures are needed for sure- I apologize for that for anyone reading this.... I have a few from the cam swap I can upload and I guess I could scan a few timeslips.. I Quote Link to comment Share on other sites More sharing options...
10phone2 Posted November 29, 2012 Report Share Posted November 29, 2012 I curious, how much did you get charged for the 8.8 narrowing? Quote Link to comment Share on other sites More sharing options...
hpfiend Posted April 22, 2013 Author Report Share Posted April 22, 2013 Got the 8.8 back and installed! http://i272.photobucket.com/albums/jj162/hpfiend/image_zps9328c24f.jpg http://i272.photobucket.com/albums/jj162/hpfiend/image_zps0041445c.jpg http://i272.photobucket.com/albums/jj162/hpfiend/image_zps1f9e0dae.jpg http://i272.photobucket.com/albums/jj162/hpfiend/image_zpsc9566184.jpg http://i272.photobucket.com/albums/jj162/hpfiend/image_zpse72825e7.jpg http://i272.photobucket.com/albums/jj162/hpfiend/image_zps265cc718.jpg http://i272.photobucket.com/albums/jj162/hpfiend/image_zps71c1b149.jpg http://i272.photobucket.com/albums/jj162/hpfiend/image_zps164a9ec6.jpg http://i272.photobucket.com/albums/jj162/hpfiend/image_zps44751635.jpg http://i272.photobucket.com/albums/jj162/hpfiend/image_zps579c0a45.jpg Quote Link to comment Share on other sites More sharing options...
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