The Stovebolt Site Forums The Shop Area The HiPo Shop Need Your Advice

It's been awhile since I was really active on this board. I've been REALLY disappointed with my TF. Perhaps you can help me get her out of the doghouse.

Here's her story. She's supposed to be a low mileage Air Force truck. Who knows what the truth is. It is pretty solid though. She still had her 235 3 speed when I bought her two years ago. I really struggled with what direction to take her. I landed on 'nostalgia rod'. She's now got an Offy 2 carb intake, Fenton headers, dual exhaust with glasspacks, HEI, alternator and Carter/Weber progressive carbs. She's also got an Offy valve cover. I love the look. She runs like crap.

What's wrong. First, I think I just drove the life out of that engine last fall. She has 3.55 gears and 205 75R15 tires. I drove her a lot at about 70 mph on the highway. She always seem over-carb'd. She ran rich no matter what I did. I'm timing by ear because the timing marks don't work with HEI (right?). My last run last fall was a round trip on the highway with each leg being 60 miles. I drove her at 70 as I said. When I left, I had a full crankcase of oil. When I returned I had nothing on the dipstick. This was the first time she ever really used oil. I never saw anything in my rear view mirror (smoke that is.) Now she smokes out the right side exhaust. (I think that's 1-3 cylinders.)

What have I done? I did a compression check and everything appears solid. The cylinders are up in the 160 range. However, #1 doesn't hold the compression. I pumped 150# of air into that cylinder and it shot out the tailpipe. Exhaust valve? I have taken another head to my favorite machine shop to be rebuilt with hardened seets. I haven't pulled the head off the engine in the truck yet. I guess I'll know when I get the head off if I need to rebuild the block. Any ideas or suggestions here?

What else? Back to the carburetion. I'm still running the stock cam; probably original. The truck is suppose to have 20,000 miles on it. Like I said, who knows the truth. What should I be doing about the carburetion? New cam? What one? Cut back on the carburetion? How? What are your suggestions?

I don't understand your comment about needing to time it by ear. If you are using a timing light the signal doesn't care if its being triggered by points or magnet. If you can't time it with a light, try using a vacuum guage instead.

If it seems to run rich all the time I'd wonder if the carbs are synched right. Have you checked that?

I'm not an expert on these things, but thought I'd share my thoughts in hopes they help.

Just a quick SWAG here. First, the timing marks work the same for points as for HEI. No difference.

Second, if I had to guess, I'd say that the front carb was running lean and the prolonged high speed run caused it to burn the exhaust valve in the #1 cylinder.

I don't know for sure where your oil went...have you looked under the truck to see if there's a gooey mess there? How about the tailgate? Got oil spots on it? These things would indicate a leaking seal or gasket(s) somewhere. Another thing that running lean could do is burn a piston, which would cause the lower compression, smoking, poor performance and the blowby could cause the pressure in the crankcase to force oil out from every possible nook and cranny.

When you get the head off, have your machine shop check the #1 exhaust valve. If it's not leaking, then it might be time to tear it down and replace the burned piston (or possibly all of them) and rings.

How about posting a pic of the head when you get it pulled off?

When you put air to that cyl. are you shure the exhaust valve was closed. It seems like if the comp is good it would not be a burnt valve although a bad seat can show up this way. Pull the valve cover & make shure the valves are all the same heith. If the gap is to close the nolead gas could be wearing down the seat.

I had many of the same problems last year with my 250. It was also a 2 carb setup, had good compression, very high oil consumption but no smoke. It also had a rattle in #5 & #6. Cure: total rebuild, I galled the pistons due to a lean condion on rear carb. After the total rebuild I replaced the two carbs with one 390 cfm Holley 4bbl and a Offy intake. It now starts, idles, and runs great except for a flat spot off-idle which I haven't had time to address.

What did you see that told you that the cylinders were galled?

The only clue was the rattle in #5 #6. Different people who listened to it said it was in the top end, others thought it was in the bottom end. I replaced the valve train (not the valve) in an attempt to fix it and the rattle didn't go away. After that we thought I had a broken piston skirt. Cold weather had come so I went ahead with the total rebuild. It hurt in my backpocket at "*** National" but I not into hotrods/streetrods to save money.

Pardon my ignorance, but what do you mean the pistons were 'galled'? In what way were the pistons damaged by the friction?

Thanks. I'm dropping my engine off at the builders on Saturday. I'm just going to start with a new motor and go from there.

Hi Jerry. Have you checked to make sure you have tight fitting manifolds? It may be that your pulling a vacuum around it and that could perhaps burn a valve. I have the same setup as you and mine is difficult to keep tight so I watch it closely. Also check the gakets under your carbs. Some of them aren't too pretty good and leak. Mine did and it always seemed to run rich too but that helped.

Does your's idle fast?

I haven't driven it since last October so I don't remember the idle. I think it always seemed fast but I was able to get it down enough to be ok.

I have a passenger 57 engine so I'm having it rebuilt. That gets me hydraulic lifters and easier maintenance. I'll make the swap in a few weeks and start again.

Update.

I pulled the head off the old 235 and #1 cylinder walls are marked. I assume that means they are galled. I didn't see any evidence of valve issues.

I've got the new engine mounted and was putting the intake and carbs on last weekend. I RTV'd the heck out of the intake and headers. I also changed the gaskets between the header and exhaust pipes so they are more like a donut instead of a flat gasket.

I think I discovered the problem that started all of this. I decided to grind the ears off the adaptors. The 1bbl side of the Langdon pieces are square and have extra metal toward the front or rear of the engine. When I separated the adaptor from the carb, I noticed that the gaskets had been leaking at the bolts. The gaskets were covered with soot and the soot ran right to the edge in a few places. So; those of you that thought I had a vacuum leak were right. I have made new gaskets and RTV'd the heck out of them. I doubt they'll leak again. Of course, I may never get anything off this engine either.

I should have her running after this weekend unless I run into other issues. Oh; I also lost the glass packs. I'm now running Flowmaster 40's. Thanks for all the advice.

So....

So....

It took longer to get ready to start than I expected. The gas linkage was a pita on this car engine. I did start it tonite but I'm having some sort of ignition problem. I'll start another thread to discuss that.