Thread: Certainly not what I expected.

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if that other engine needs a bore. i go back to the older 350 pistons on the vtech engines rings are much less $$ like 40.00 for hasting molys and the new vtec oil rings get plug up fast on the M.M pistons with the small oil ring pack

Good tip Pat. I did a little digging on the pistons, they are GM 10172839 and use the metric rings. Is that what you mean by the "small rings?"

Don

yep i use the older pistons like older dish 4 valve relief that have the 5/64 5/64 3/16 ring pack that are about 50.00to 80.00 a set and moly rings $40.00 yours are 1.5mm 1.5mm 4.0mm ring pack and $70.00+ just for the rings i think the pistons are abit more then $70.00

Pat, I also noticed something else odd. Usually you know how you have to finger force the connecting rod bearing halves back into the connecting rod and cap? Well, the ones on this connecting rod kinda just lay in there, somewhat loosely. When you put the cap and nuts on it does tighten them up a little, but I've never seen ones that you didn't have to push down into place and that were held in place by tension. I sure don't remember them being like that when I put the engine together 3 years ago.

Don

Originally Posted by Itoldyouso

Pat, I also noticed something else odd. Usually you know how you have to finger force the connecting rod bearing halves back into the connecting rod and cap? Well, the ones on this connecting rod kinda just lay in there, somewhat loosely. When you put the cap and nuts on it does tighten them up a little, but I've never seen ones that you didn't have to push down into place and that were held in place by tension. I sure don't remember them being like that when I put the engine together 3 years ago.

Don

could be abit big on housing bore size i just did a 350 like that.i rebuilt them for the smaller side of spec. they give you a small size to .over 0006 on rod housing bores that on the small block chevys. i keep them at -0001 to +0001 on the small end of spec for hi bearing crush . bigger bore less crush thats why they say its ok for.0015 to .003 on rods for a chevy with every thing in spec you can be at 003.2 oil clearance this has some bearing on who made then size from make like mich. king . acl. fed. etc can be +or- 0005 on just the bearing . well i do not care for that i like to keep the oil clearance on the rods on the small side on a stock to mild build with stock oil pump.that starts with the rods on the small side of spec .if the crank is in spec then and oil clearance is better the 002.5 + .i will use a 001 bearing or grind the crank for size .for race still small bore for hi crush but a abit looser

It concerned me because it was almost like the bearings had spun in the rod, but there is no evidence of that. The backside of the bearing halves are unscored. I'm just used to having to take two thumbs and push the bearing halves into place in the rod. I guess when it is torqued down it will be a tight fit? It's evidently been that way for two years now. They are Federal Mogul bearings.

Don

Originally Posted by Itoldyouso

It concerned me because it was almost like the bearings had spun in the rod, but there is no evidence of that. The backside of the bearing halves are unscored. I'm just used to having to take two thumbs and push the bearing halves into place in the rod. I guess when it is torqued down it will be a tight fit? It's evidently been that way for two years now. They are Federal Mogul bearings.

Don

well yes that there the crush comes in to play the small bits of the bearing that hangs out of when you put them together inturns push the bearings in the bores. check the bore size on the rod . you got them out not hard for your machine shop to check. the bearings can get like that if they get hammer very hard too but i know you do not run it hard should see a good cross hach on the back of bearing .if you see a dark lines or small fret marks then the bearing is loose in the bore .and moving metal from bearing back to rod you can see this on very hi HP engine to .i am sure jerry has seen this

Good idea Pat. I have 8 more piston and rod combos from the exact same engine I have stored. I can pull one of them out and check the bearing fit in one of them. I can also have my machine shop guy mike them. The crank journal is perfect and so it the wear pattern on the bearing, no scoring or goofy stuff. It just seemed odd that the bearing halves don't click down into place like every other engine I've done, with sort of an interference fit.

Don

well i like to see that but its is the crush that hold them the bearing is abit bigger and get push in to the rod bores . the 4.3 rods were like that very loose out of the box but it is the crush that holds it in not so much as a snap fit . that helps hold the bearing in place some when building . the tangs hold s the shells in place on the rod

Makes sense, and since it worked for 2 years and had great oil pressure, I guess it was ok.

Don

I 'm not trying to be funny guys, I am just trying to understand how it was blowing into the crank case. If like you said it had carbon build up on the valves the wouldn't cause that. I guess a ring must have been the problem then. In any case good luck and I hope it works out for you. Kurt

Kurt, I think the pressure in the pan was coming from the rings, but not just on that one cylinder. All the cylinders look pretty glazed and when I ran the hone down number 7 I got a lot of black carbon on the hone. So I think with each cylinder wall being carboned up a little each cylinder was contributing a little more pressure to the pan. But you are right, if it was only the valves the pressure would either be going out the intake or exhaust, not into the pan.

The other smoking gun was the amount of black sludge in the bottom of the pan. It looks like gas has been washing past the rings for some time now.

This little episode has me rethinking if I will put the 2 x 4 manifold I have on the new 331 stroker I'm building. I have way too much money invested in that one to have it running rich, so I am considering putting an Edelbrock RPM AirGap intake on it with a single Holley 650. I usually use Edelbrocks, but IMO they look kind of lost on top of a single 4 barrel setup........too compact. At least the Holley with it's large bowls fills out the top of the engine out a little better. I really like multiple carbs for the hot rod look they give, but I really don't want this happening to an engine I have so much money and time in. And in all honesty, a good single 4 barrel will run better anyway.

Don

Pat, I learned a whole lot more about my cylinder problem today and something you mentioned above ended up being exactly true.

I got off work early and spent the day making the rounds of auto parts stores getting the parts I need to reassemble my 350. First of all, what I thought were 10 thousandths oversized bearings were actually 1 thousandths oversize. I always have trouble with those decimals. After I found out what they were I remembered a conversation with my machinist when he polished the crank and supplied the original bearings 3 years ago. He said a lot of engines are now coming off the assembly line with odd sized crank journals because the factories are not tossing slightly defective cranks these days, but they turn them down just enough to make them work........so a brand new engine may not be "standard" sized, you have to mike the journals to be sure.

Finding a .001 bearing was tough, but a local engine builder had as set on the shelf. Now, for the part where you were right on the money Pat. You mentioned bearing "crush." I took my connecting rod and the loose fitting bearings that came out of it to my machinist and he said exactly what you said..........once the bearings are installed the crush is gone and the bearings shouldn't be reused. I bought a new set and they snap in the way I remember all previous bearings have fit. So you nailed that one Pat.

I also learned that Vortec parts are a lot more expensive than regular Chevy parts.........also something you said Pat. Even with my price being cost the gaskets, rings, etc were a lot more than most regular Chevy stuff.

Finally, my machinist told me why my compression was gone in that one cylinder. Carbon builds up on the valve stem and finally keeps the stem from going all the way into the valve guide, holding the valve open a little. That is exactly what I saw when I pulled the valves out of the head, carbon was very heavy on about two inches of the stem.

Besides the wire wheel cleaning and honing I bought two products our techs at work suggested. One is Power Tune, a product you shoot down the air intake as the engine is running at a fast idle. The motor will eventually stall, and you leave it sit for a while.........15 minutes is good, overnight is better. Then when you start it all this crud blows out the tail pipe because the Power Tune dissolves the carbon. The second product I bought is one you put in your gas tank. It is a Mercury Marine product called Quick Kleen, and it does the same thing but over a longer period of time for more complete carbon removal.

Tomorrow I am putting the engine back together and will do a compression test before the intake goes back on, just in case I haven't fixed the problem.

Don

Dan and I worked on my T all day Saturday getting it put back together. Dan worked on the fuel pressure regulator and also helped me put the engine back together. Today we picked up a couple of last minute parts and some fresh gas and finished it up. Before I tried starting it I took another compression check of the cylinder that had zero compression, and now it reads about 195.

We got it running and put a heavy dose of the Quick Kleen in the tank and also sprayed the whole can of Power Tune down the carb throat, and shut it off to let it soak some of the carbon loose. When we started it again you should have seen the crud coming out of the headers. Some guy walked by and said "boy, you sure are burning a lot of oil" The motor runs much better and sounds crisp now. I also changed the plugs, cap and rotor while I was at it.

Then the starter crapped out. I have a Power Master 9000 on it and it has never been right since day one. We had to actually build a shim way back when we first got it running because the starter wouldn't engage the flexplate right, it either was catching just the edge of the teeth or went in so deep it wouldn't disengage when the motor started. We finally got it to work fairly well two years ago, but today it took a dump. So I called Summit and ordered a plain old Chevy type starter because I am tired of these gear reduction after market ones. All my life I have simply gone to the auto parts store, bought a regular starter, and they work as they were designed. I hope by going back to one of those types I won't have to fiddle around with it any more.

Dan and I are planning on taking the T to the Billetproof Drags this next Sunday, so I hope we get all the little bugs worked out before then. We are trying to talk Don into going but it isn't looking good..........he wants to work on his boat instead. BTW, the weather was FANTASTIC this weekend, I actually had to have my car heater on coming home tonight......what a great change.

Don

stock starters work fine .i like them if you have the room for one i used one that had a caddy field and a iron nose. HD drive new not re built .that starter would crank my two 548cid with 14.8 CR.the other 10to1 i still have the same starter on a 548 blower car they work great guys just buy the gear starters thinking thats going to fix it when you need to do more work to them to get them to work then if they just take the time to check the gear to fly wheel air gap and the right starter bolts and front strap