Builds My 40 build (1 Viewer)

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

Thought about this a little more.
  1. Your compression numbers are actually a little low for a freshly rebuilt motor.
  2. Low compression is often the source of poor vacuum.
  3. Running rich will not help the rings to finish seating.
  4. I have seen more than one engine ruined (rings never fully seat) while people were sorting out fuel and ignition problems.
  5. Break in is NOT the time to be dealing with multiple unknown quantities.
  6. I have suggested before in this forum that for start up/ break in, it would be REALLY useful if the OP could borrow a carb and dizzy in known working order for break in, regardless of whether they ultimately intend to run fool infection on their rig.

How many minutes/hours of run time do you have on the engine?


Mark,

Yes low vacuum/running rich has created lots of problems.

Probably has 3 hours run time and I am guessing the rings are about gone. Been thinking about installing new ones.

If the engine was rebuilt correctly it should of produced enough vacuum when it was first started.

Nobody is close to me to borrow a carb and dist.

Have thought about a different engine altogether. The question is, when do you stop pouring money in the current engine?
 
I don’t know the answer to that one.

I built a beautiful 2F for @Downey about 20 years ago that the rings got washed out on while they were trying to dial in their fool infection system. After I balled Jim out about the critical nature of the break in (and I wasn’t nearly as patient then as I am now!) he put a Holley carb and standard dizzy in. But it was too late for that motor. Jim ended up pulling it for a v8 conversion and sold it to me cheap.

I bought a new set of rings for it and resold it with full disclosure to someone with the time to tear it back down. Never heard back from them about how it turned out.

And of course the YMMV comes into play.
 
Last edited:
Looked in the cylinders. All look about the same.
 
Last edited:
I would do a leak down test since you have it all prepped for it.
 
I have not found a tester unless I buy a new one. Called a local parts house that loans tools. They said they had one but it was a compression tester. Then the guy wanted to argue that it's the same as a leak down tester. Still undecided on what to do. Had a couple inquiries about engines but nothing has worked out.
 
After calling a couple places this morning my wife asked, what are you doing? I said, getting prices to haul the 40 off. Her reply, you will regret doing that.

Cheapest tow company, $35 plus $1.65 a mile. About $135.

Uhaul trailer $60 but I don't have anything that I can tow with. Will need to borrow a truck.
 
After calling a couple places this morning my wife asked, what are you doing? I said, getting prices to haul the 40 off. Her reply, you will regret doing that.

Cheapest tow company, $35 plus $1.65 a mile. About $135.

Uhaul trailer $60 but I don't have anything that I can tow with. Will need to borrow a truck.

You shouldn’t let this one beat you. However if you do throw in the towel, I’ll give you $135 to tow it away.
 
You would of been the new owner if you had been here this morning.

Wife has used a lot of psychology on me since then and I guess I will continue to work on it.

These things seem to fight being brought out of retirement. Doesn’t help parts are expensive and getting hard to find. I’ll get going full speed only to be brought to a screeching halt over a missing or worn part. I am in the land of the big 3 so parts arnt just laying around.
 
I have not found a tester unless I buy a new one. Called a local parts house that loans tools. They said they had one but it was a compression tester. Then the guy wanted to argue that it's the same as a leak down tester. Still undecided on what to do. Had a couple inquiries about engines but nothing has worked out.
I found this article many years ago and built a leak down tester. I've never used it but I'll let you borrow it if you want to try it out. Let me know.

 
What he said ^^^^^
 
Done a leak down test. Engine was cold, nothing was put in cylinders. After about 50 lbs of air the engine rotated and the piston ended up on the bottom of the cylinder.


Amount of leakage at 100 psi.

1-10%
2-6%
3-6%
4-4%
5-6%
6-13%
 
Last edited:
Interesting that 1 & 6 are the outliers. Maybe one of the engine gurus will chime in on the results.
 
Don`t seem to bad for new engine. Could you tell were the air was escaping from exhaust valve or intake or from the crank case? My guess would be the bottom end crank case.
JP
 

Users who are viewing this thread

Back
Top Bottom