I bought a tired 65 Wildcat with the purpose of turning it into a drag racer using mostly stock parts. I would like to be running 13's with it. I got the engine running nice and smooth and got the switch pitch working, but still doesn't have near the punch my street Wildcat does. I want to take the car down the track to get a baseline but not at the expense taking out my valves if it is a stretched or skipped chain. I checked the intake valve action and it opens well after TDC (with the rocker still hooked up). What is the valve timing spec for the 401, and will a new chain kill top end power which has been my experience in many engines.
That looks like a good old car..... ck. out my list of cheap tricks.... I have done all those things and they work.... reduce the weight as much as possible.... and put some lower gears in the diff....and a posi if it dont have one.....
I'm a low buck racer from way back, but what need to know is what does the nailhead like. If I put a new chain on it will it poop out at 4000 RPM. I did a compression check and it was all between 115 and 125 nice and even but it seems too low. That's why I was suspecting a stretched or skipped chain. My street Wildcat just cooks the tires, this one is lacking.
Yep,,, higher figures would be better..... 95# is absolute minimum to run.... I am betting that if you put a new chain and gears in, it will run better but not that much better....if you rebuild now it wont cost as much to do, as it will later....
For the late 401/425 cam with 114 degree lobe spacing: At 0.002" lobe lift: Intake opens 34.5 deg BTDC, closes 95 deg ABDT (309 deg duration) Exhaust opens 75 deg BBDC, closes at 42.5 deg ATDC (298 deg duration) At 0.050" llobe lift: Intake opens at 7 deg ATDC, closes at 36 deg ABDT (209 deg duration) Exhaust opens at 40 deg BBDC, closes at 12 deg BTDC (208 deg duration) You will have to pull the intake and valley cover to check the cam timing. You would also be able to determine if there is a lot of slack in the chain by watching the cam for movement as you turn the crank forwards/backwards.
If you put a socket and breaker bar on the harmonic balancer to crankshaft bolt and move the crankshaft back and forth, you will be able to feel when the chain starts to move the camshaft. The amount of pressure required to move the crank will drastically increase. If you align the timing mark and pointer, you can read how many degrees of crankshaft rotation occur before the slack in the chain is taken up. More then 4 degrees = new chain and gears. This procedure will work for any pushrod engine with a timing chain.
7-8 degrees slack. I just checked my driver Wildcat and it has 2-3 deg and compression of 125 -140 but mostly 140's. I guess that will make a difference.
I've decided I'm going to replace the timing chain in the "race" Wildcat before I take it for some time trials. I've never done a chain on a Nailhead before. Anything to look out for, or is it pretty straight forward? Where would you recommend I buy the chain and gaskets from?
I just went through this procedure a few weeks ago on my 65 GS nailhead engine. Pretty straightforward, just don't expect the local parts stores to carry what you need. Believe me, I tried a few, but not all of them. Here's what I remember; Disassembly is rather easy, after getting the peripherals out of the way. You might not need to remove the rad, I didn't on mine. The harmonic balancer is torqued to 225-250 ft/lbs, but you can loosen it by using a long bar braced to the ground, and touching the ignition key (remove coil wire first:laugh: ) Retorquing back to spec is must, according to the nailhead gurus. The water pump has about 12 bolts of various sizes and lengths, four or five of which go through the timing cover into the block. There are two bolts holding the bottom of the timing cover to the oil pan, which aren't that difficult to deal with. The rest of the timing cover bolts are also different sizes and lengths. Once the timing chain and gear are revealed, it's a simple matter to R & R them, if you done this before. The cam gear is pretty tough, but I replaced mine, just in case. Reassembly is also straight forward, just be sure to properly align the timing marks. It's important to use reassembly lube on all bolts as well as some type of silicon on the gaskets. My car runs great with the new timing chain. Oh yes, there is a water manifold connecting the heads, which has an O-ring beneath the thermostat, which seals it to the water pump. The correct size is very hard to get up here, I've tried. Maybe at a plumbing supply house.o No: I simply got everything I needed from Tom Telesco, aka telriv here.
Thanks Tom. Some real good points there. How loose was your chain and did you notice a change in the power curve?
I never measured it, but since it appeared to be original, it had some slop, thus I out the new one on. As for performance, it's always been "seat of the pants" for me.:laugh: There does seem to be an improvement in throttle response. Since my tires are iffy, I have not run it above 70 mph yet. Tires are next on my to do list, after I get my lawn back in shape,that is.ou: BTW, I saved my old O ring, in case I can match it up somewhere.
Thanks for the offer John. If I end up needing one I'll know where to go. The reason I was asking about the power shift is that you can get some real beneficial effects from the late timing you get with a loose chain. So much so that a couple of time I regretted changing it. My Dad's 80 Olds 88 with an Olds sb 307 would get routinely get 28-30 MPG. The car had 180.000 miles on it so I did the crank shaft test on it and you could tell the chain was real loose. so I decided to change it . When I had it all apart, I could see the chain was not in danger of slipping but I was in there already so I changed it. After I put it together, The car had way better throttle response and could now squeel the tires but now the hwy mileage was 22. I have more stories like this.
If you want to advance/retard your cam a few degrees, the MOPAR offset cam keys will fit the Nailhead. Melling still offered replacement timing chain and gears last time I checked. Might have to call them to find a distributor in your area. Autozone did carry them a few years ago.
I'm not finding any deals on Melling chains or crank/timing gears. Prices vary from $102 to $115 for the set. TA Performance 2009 catalog lists stock sets for $100 and a 7-keyway adjustable for $130. Tom Telesco, Carmen Faso, and Russ Martin are Nailhead gurus that can supply you with parts as well.:TU:
