Thread: What do you engine guys see here?

Tweet

Don

If all the oil was coming from the manifold surface there would be a trail around the valve stem/guide area---that looks like the oil came directly out the guide

Before I would go to all the work of a different block, I would see what/how much size it takes to clean up that area----sometimes a little detonation will knock off the ring land of the piston and they scrape like that--you can probably see pass the top edge and get an idea of what happened--rock the piston over a little with a screwdriver blade for a better look

Don I enjoy screwing my own engines together after the parts come back from the machine shop, and even though I trust the machine shop(s) I use I still check everything. It adds at least a couple of hours to the build but that's a lot less than pulling the engine back out and re-doing it. I doesn't happen everytime, but it's not unusual for me to find at least 1 ring in a set that is a little tight.

What is nice about rubbing elbows with guys like some of you who know how to really put an engine together is that shadetree guys like me can learn a lot. I'm probably like most car guys, I just take the parts out of the box and assume they are within specs.........you guys check every piece and make corrections and allowances to make them fit properly. I think that is what happened with this engine, the end gaps were too tight and butted up and caused the rings to fail.

As far as maybe overboring the engine another 20 thousandths, it looks like the scoring might be deeper than that in some spots, but won't know until a machinist looks at the block. If boring it over is possible that would be great, and save us having to use a new block. But it will probably be smart to buy the block we found locally anyway as Olds 455 blocks don't come available very often around here.


Thanks for all the help, we will post what we find when the engine comes apart.


Don

Don

don't bore that hole---take it to someone with a Sunnen CK10 and have them hone it til it cleans up and then measure it--I'd bet a 6 pack of cold ones that .010-.012 will clean it up

well yes and no i had better size on cheap cast pistons . then the race stuff for size to size in a set now they put coating on the skrit and you cant mic it for real size you bore it for the size whey want and hope for the best if i know its going to live a hard life i throw another .0005 or .001 on the bore .

Tonight when he gets home from work Dan and I are going to meet with the guy who has the bare 455 block and if it looks good we are going to buy it "just in case" the old one can't be saved, or at least saved reasonably. They don't show up every day, so we don't want to pass it up and then need it later.

Don

Originally Posted by Itoldyouso

Tonight when he gets home from work Dan and I are going to meet with the guy who has the bare 455 block and if it looks good we are going to buy it "just in case" the old one can't be saved, or at least saved reasonably. They don't show up every day, so we don't want to pass it up and then need it later.

Don

that one can be fixed EZ one sleeve put in bored and honed to size + sleeve $100.

Originally Posted by pat mccarthy

that one can be fixed EZ one sleeve put in bored and honed to size + sleeve $100.

I was going to sugest that. I have run a lot of engines with sleves. Also I think I'd get the block just to have it you never know what will let go later.

Originally Posted by pat mccarthy

that one can be fixed EZ one sleeve put in bored and honed to size + sleeve $100.

That's what i was thinking , sleeve that bore and get another life out of that block and buy the other block , oil it up ,and store it for later ,

So what is this coating they put on the piston skirt and why? Does it really make a difference in wear? Does it somehow keep the skirt from collapsing? Is this coating optional?

Damn, things have changed alot since I used to do this.

coating help with dry start ups aids to lower the friction under hard loading .takes up space most all harley davidsons pistons have it air cooled .i have built or machined about 20+ engine with coating s my feelings are mixed no its not going to stop collapsing of skrits

We picked up the spare block tonight, it looks pretty good and has never been bored. There is a machine shop about 100 miles from here that has a pretty good reputation among the Mustang racing crowd and seem to put together a pretty good motor. I think we are going to use them to machine this new block. If it were my engine I would sleeve or see if it could be honed oversized, but he is afraid of doing that and still having issues.

Since it is Dan's money I have to go along with what he feels most comfortable doing, and he has pretty much had it with the block and heads that were giving us trouble. I can understand how he feels, he has 4-5 years in building the car and more money than either of us care to think about, and the only problem so far has been the engine. He just wants to make sure this one is done right, so it looks like I will be hauling it up I75 for him and dropping it off.

Is it best to take the pistons we are using along with the block so each cylinder can be honed to fit each piston? Or don't they need them to do that?

Don

well if they do not ask for your pistons keep hauling it north on i 75