Hot Rods More Problems With My Crate Engine ?

This dam GM 290 HP crate engine is kicking my butt. First it had heating problems with the Zips pump riser which we solved by going back to a conventional pump and Cooling Components fan. Motor now runs about 185 on the road and goes up to 205 in heavy traffic. Temp sender is in rear of the right head which is a known hot spot. Now today went on a short trip and noticed on my way home about 40 miles from the shop what I consider a significant drop in oil pressure from 45 down to 25 at 2000 rpm. When I got home checked the oil and it took 2 1/2 quarts to get it back to full on the dip stick. It doesn't smoke, it doesn't leak, I"m baffled? PVC hose is dry. Changed the oil first after a 200 mile break in period. Put in 20/40 QS with a Zinc additive, just like the first time. Drove it 1000 miles and discovered it's low on oil. I've had ZZZ, ZZ3 and ZZ4 crate motors and never had any problems. Maybe I'm just jinxed with this motor. Chevy dealer will not help. By the way this motor is in my new deuce 5 window.

 

I would pull a few plugs on both sides and see if they are oil covered. And maybe do a compression test on the cylinders, is were I would start. 20/40 seems a little heavy for a pretty stock motor like you have. 10w-30 would be more appropiate.

 

Oil doesn't evaporate so you're either leaking it or burning it (or your neighbor is playing a really nasty trick on you). Since you're not seeing leaks, I'd start with PCV (easier, external) and then move to rings.

Have your sneaky neighbor put on a white track suit and stand behind the tailpipes on morning startup. Evaluate the soot.

 

Gary, could be the intake gasket is leaking in the valley and pulling oil in.

 

My preference is 15W40 HD Diesel engine oil. The viscosity is great, and they have a much more robust additive package. Screw the zinc additive, use an oil with a good level of high performance zinc to start with. Just make sure that if it is a CK-4 product, that it is not also rated SL, that will be limited to 800 ppm of zinc. CK-4 alone will have around 1200 ppm, just fine for a flat tappet engine.

Technically oil does evaporate, it's what's referred to as "volatility". In order to get the viscosity just right blender use what is known as a "dumbell" blend, a mixture of light and heavy hydrocarbons. Especially the lower priced brands really rely on this rather than using a more expensive select cut from the feed stock. The light ends will volatize (evaporate) at high temps leaving just the heavy ends behind, so viscosity goes up, and oil level goes down. It's a known problem the industry has dealt with by putting volatility limits in place.

 

Get one of those cheap Chinese bore scopes you hook up to your Iphone. Pull the carb and put the camera down each intake runner and look to see which intake port shows signs of oil beyond the intake gasket. For $20 you really can't beat 'em.

 

I KNEW I should have added an asterisk to that comment... because someone would call me on it. So... * in the context of a largely closed system such as an engine, with only a few hundred miles on it (minimal heat cycles), in the time frame of days/weeks/months, not year/decades/centuries... approximately no evaporation.

Also, +1 on the diesel grade 15/40. Costco Chevron Delo is stock-up cheap a couple of times per year.

 

Auto tranny?

 

I run 20W-50 high ZDDP Kendall in my new-ish 355 and it stays inside the engine. I agree, look at the plugs and have someone drive behind you at a variety of speeds to watch the exhaust.

 

Is compression okay? Maybe rings never broke in, oil is getting by and burning off. Had 2 used engines in years past, where oil was getting by and burning, but you couldn't see smoke.

 

Yes a engine with good compression can burn oil and not smoke. Ive seen diesels that never smoked and diesel fuel is oil. When your engine was overheating? Possibly you got it hot enough to take the tension out of the piston rings or glaze the cyls. I would change brands of oil first. Back in the day the engines that used Quaker state or Pennsoil never leaked oil. That black oil would coat the insides with a layer of soft sludge that prevented leakage. In most engines Valvoline would find a place to leak out. Myself I use 15w 40 shell diesel oil in everything. It has enough zinc and anti foam and detergents ect.

 

205F is fine.

 

Fram filter ?

 

Had a buddy buy a new car and it drank oil and dealer said it was normal . They even had it listed in the warranty one quart per 5k miles if I remember. He never found what was eating the oil But believe it was going out the tail pipe

 

A guy I knew bought a new pickup that used oil. He was told it was normal as long as it didn't run out of oil between fuel fill ups.

 

I remember seeing a similar problem with a Corvette sb on the TV show Fantom Works. IIRC, the intake and/or gasket was the issue, as Allmotor stated.

 

I have a Buddy that purchased a real nice Street Rod with a new crate engine, used oil, you could not see smoke, you could smell it when close behind in traffic. This went on for 2 summers, (car not driven much) I never heard of this, but someone suggested to stop running synthetic oil, (previous owner told him use Mobil 1 synthetic 10W30.) He changed oil, used Shell Rotella oil and after some miles it improved greatly. Just a suggestion that is cheap to try. Something to do with rings seating is my guess. With my last crate engine, I used Joe Gibbs break in oil, recommended by Jegs where I purchased engine, maybe consider using this for 500 mile instruction on bottle, my engine is great.

 

There was some problems with the valve seals on that and the engine that a lot of sellers call the 260 h.p. version (even though GM NEVER rated it as that, it was previously referred to as Targetmaster). Personally I dealt with a few of them with problems, not many in relation to how many I sold.

From a TAC case I opened in 2013 with GM Performance Parts (retired GM parts counterman of 47 years, I used to sell performance parts) the fix was 8 intake valve seals P/N 10212810, 8 exhaust seals P/N 12564852, 1 Valve spring kit P/N 19154761, contents of that kit was 16 of P/N 10212811 and 16 valve spring caps, P/N 10241744. There was a design change in the seals that mandated the different springs and valve caps. These part numbers may or may not be valid today but you get the gist of the fix.

 

How about some pics of the engine in place in the car, specifically showing the PCV and crankcase venting and breather parts. Are you using stock valve covers and the correct oil fill cap? Are the valve covers baffled?

Also like shovelheadrider's idea of checking the valve seals, springs and caps for interference.

 

Are you sure about that (5k means 5000 miles) !! After a working life career in auto dealerships (4 decades), my experience was the manufacturers considered 750 miles per quart "acceptable" consumption. Most customers would not be quick to accept that, but several years ago 1000 to 1500 per quart was common and not particularly objectionable to most people.

My experience these days with my own late model OT DD cars is more like 3000 miles per quart, if that.

Ray

 

Thanks for all your comments. On the last several cars I've built using a GM crate motor we have put the PCV in the intake between the carb and distributor using a baffled grommet for the valve to plug into. We have no problems to date. I do this so I can run the early style Corvette valve covers and an early intake with the oil fill tube. It's a personal ascetics thing with me. That was my first thought that the PCV was sucking oil but the hose appears to be dry? My second thought is as suggested the rings got cooked and possibly the cylinders glazed preventing sealing and oil is getting by the rings. 2.5 quarts is a lot in a 1000 miles and when I start the car in my small shop you would think there would be a hint of smoke? I suspect an engine rebuild of the upper end may be in order? The GM dealer is not wanting to help. This car really works good and it needs to be driven. After building over 30 deuces I'm to old to have these problems. I'll follow up on your suggestions and report back.

 

Wow, Ray that’s crazy and you wouldn’t need to change the oil

 

My wife's 2017 Whocares is rarely more than a pint low between oil changes... every 15k. Either that or she's picked up a man on the side who's, um... "topping off her oil."

 

No sign of leaks at the intake manifold end gaskets? Not that they would foul, but the spark plug color may guide.

 

Forgot after refilling the engine I took it for a drive and cold the oil pressure was 55-60, warm at 2000 rpm is was steady at 45 and at idle around 20. I don't think the bottom end is damaged but it might need rings?

 

I would say those oil pressures are similar to my 290hp with 45k miles.


Phil

 

FYI, with CK-4 Chevron made Delo 400 a "universal" oil, which means they lowered the zinc level to 800 ppm max. I'd look at a different brand if I were you.

 

When I worked at a heavy equipment dealership, some of our equipment used Cummins engines. Sometimes you'd get a brand new engine under warranty that would use a lot of oil. When a customer would complain about it, we had to have them complete a log of the hours used, the fuel consumed, and the oil consumed. Depending on the duty cycle (the more fuel consumed per hour, the heavier the duty cycle) Cummin's considered a surprisingly high amount of oil to be normal and acceptable and would not cover a warranty ticket for repairs. We had some customers that were pretty pissed off about it, but there was nothing we could do. Yes you're right, a surprisingly high level of consumption is considered normal.

 

Enough oil talk. Changing oil is probably not going to FIX the problem.

Gary, assuming the bottom end is good, then we have to determine which cylinders have a problem. I would do a compression check first. Then the next step would be to determine whether the weak cylinders have ring or valve seal problems. Just an absolute guess, but I feel a bad valve seal is the culprit.
Maybe other mechanics will help out.


Phil

 

My guess would be valve seals.