The Jalopy Journal
Discussion in 'The Hokey Ass Message Board' started by Devmar07, Feb 28, 2018.
If you know how to properly adjust the valves I would do all of them first.
Even with no pressure on the exhaust valve it was leaking pretty bad.
Every cylinder has either an exhaust valve or intake valve leak
So plan on at least re adjusting them.
First back off the adjustment to be absolutely sure you have full spring pressure on the seat. Repeat your test. If you get the same results your heads will be coming off for a valve job.
Ok.... If you have leaky valves, had to clean out a pushrods and rocker to get oil to the top and you are pumping oil out the exhaust.... I think your rebuilt engine was done with Krylon. I have a feeling you got took when you bought it.
Sent from my Moto G Play using The H.A.M.B. mobile app
I have had a bore scope in the engine trust me it' all brand new.
Why would I get acceptable compression numbers with valves leaking that bad
You may have the valves lashed too tight.
I would back them off and reset. Just did a cold leak down test on a used sbc engine that I just bought.
The worst 2 cylinders were at 12 % so going to put a new cam in and run it.
A compression tester gauge holds the compression that built within the gauge itself not within the combustion chamber. Think about how long in fractional seconds the valves are actually closed and sealed in a running engine and how long they are required to hold FULL pressure. On the compression stroke About 2/3 Of the way up and about 1/3 the way down on power stroke.
Again, back off the adjustment so the rockers are loose and test it. That will eliminate adjustment error causing a leak.
Everything may look brand new, and the only thing you can do easily from the outside of the engine is valve adjustment. This "everything is new" statement just means that nothing has proven itself to be worthy yet. Also this "everything is new" depends greatly on good parts, good machining, proper fitment and proper installation.
I can't tell you what's wrong exactly, but if it's not running perfectly and without very even cranking compression numbers and blowing oil out of the exhaust something is beyond all reasonable certainty not right.
Should I put it though some heat cycles then retest or should I just pull the heads and take them to be repaired.
How long did you run the engine before it got hot? And how hot did it get?
4 or 5min total on the motor and I got up to 220
If your valves are leaking that bad they may have kissed the pistons and are bent.
Did you adjust EVERY valve on the engine? Did you back the valves off to do the leak down? I would back the rockers all the way off, remove the rockers, hit the top of each valve stem a couple times with a dead blow hammer to make sure there's no crud hanging in there then do the leak down and see what you get. It has to be done right to matter.
220 aint bad
vettes run that hot all day long
I don' think there is any damage do to heat. I' just wondering if I will do more harm than good by run this again. I don' have a ton more money to dump into this restomod so I'm trying to find the cheapest way out. If I should just pull the heads to get them looked at I will but if actually break in the engine might help everything seal than I would prefer that method. Just let me know if that is even feasible
It wasn't shipped filled to the cam with oil was it? May have too much oil in it .Maybe a broken ring. If a ring is broke, it will score the hell out of the cylinder . If all the cylinders have oil in them the intake may be leaking in the valley area. I build all my engines by dunking the piston assemblies in a bucket of oil and never had one burn excess oil. A little puff at first startup ,then no burning. I have built many engines at Chrysler Corp. engine lab for thirty years.
If the valves leak without any tension on them there is something wrong. When a valve job is done properly they shouldn't leak at all. I suspect the heads weren't rebuilt properly which may include loose guides that can allow oil to leak through them. It leads me to have doubts about the competence of the builder. If it sat around for a while, it could have developed some rust on the valves which could cause leakage and they might seat in by running the engine.
So what's to loose by running it and see what happens?
220 in 4 mins is a pretty fast heat up if the cooling system is operational and full without restrictions.
I had a car come in here, 62 Chevy with a brand new high stepping 355. It got hot in about 4 mins too. Car builder blamed engine builder. Engine builder blamed car builder, car was pushed into the corner for almost 1 yr.
I found a cap on the water pump inlet with the hose clamped over it. Car builder bla,Ed his help, but nobody thought it thru or did 5 mins of thinking and trouble shooting.
It was basically a wet block with no radiator. Great for a start up, burn out, stage, and 10 second blast.
When I 1st read this is I thought piston rings. I don't think valve guide seals that would typically clear up once the engine is warmed up.
Maybe ask the engine builder what rock he used for honing and what rings do you have?
The reason I keep saying everything is new is because some people don' read everything and they go right to it' a tired engine that has been prettied up with spray paint. Someone spent a ot of money building this that' not saying they knew what they were doing and that' why I'm here, I would kind of like to know what I'm doing and what I'm talking about so I ask questions from you guys who know a ton more than me, so I'm just trying to learn all of this.
The leaking is a red flag as to the quality of the rebuild. The SBC is one of the most straight forward engines out there as far as tear down. Anyone who has done several SBC tear down inspections could have done so in the time that it took to write 3 pages of "what's wrong". Smiley face.....................................
I didn' want to tear it down especially if this was all just user error which 3 pages worth of what' wrong have proved otherwise
Hey Buddy, I think its time to pull it apart.
^^^^ this-pull the heads.
The speed shop quoted me 200 to 350 for rebuilding the heads does that sound like it' in the right ballpark.
Maybe I can get a thicker head gasket to pull some compression out of it while I'm at it.
Yes, depending on parts needed.
My machine shop charges 200 for a 8cy valve job.
Guides are extra and so is everything else.
When was the first reply that said a tear down would be in order?
I've been at this game for a while. Very sad but in today"s world "new" does not mean good anymore. The sooner you wrap your head around this sad state of affairs the further along you'll be. "New" just means the part has not proven it self yet. Not proven good or not proven bad. "New" means potential problems, it's not "known to be good"
Plus for every one guy who knows what he's doing, there are 25 assholes watching him thinking awe hell I can do that. To much TV.
I agree with everything you just said. I' a general contractor and the materials that are available are junk so I'm sure that Carries over into the automotive world. I have a friend that watches house flipping shows and now he can do what I do.
Separate names with a comma.