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Overheating [again] ?????

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George Zeck

George Zeck

Jedi Warrior
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Just had 2 friends over and did a compression test -- all 170lbs - 180 lbs (quickly). Not Head Gasket. Heater Valve is (& was) open.

2 weeks ago; had radiator recored (outstanding job) and water pump, thermostat, hoses replaced. All up to grade stuff. Lower hose does NOT colapse when revving engine.

Drove it around and after 10 miles it so; oil pressure started dropping, valve train started clattering and engine konked out with 30 lb of pressure shortly afterwards. Letting car cool down and will bring home later.

Central part of cyl head seems much hotter than ends. Lot's of loud "boiling" noises. Have put coolant sys cleaner in radiator, yet to drain. Any Idea's ????

Tx-

Geo
 
Re: Overheating [still] ?????

Same ideras.

pull the head off.

I don't believe that a compression test will tell because compression is a fraction of combustion pressure. Also, you can't inspect the water passages from the outside.

Did you have a shop check for combustion gasses in the coolant as was suggested in the last thread? That is a good idea, but stii won't allow you th check/clean coolant passages.
 
Re: Overheating [still] ?????

Yes, had test done for CO in coolant. All is good (obviously, that's why I walked home).

I just was hoping to get lucky and not have to rip the engine apart. Just brought home from cooling down -- the 2 valve cover bolts were quite lose. Tightened moderately. That will definately help out in the smoking of the engine.

I know enough to be dangerous as previously demonstrated. What you are saying is about the compression test is not to trust it. What should I trust it for and what not? A little confused ??

Tx-

George
 
Re: Overheating [still] ?????

Do you know why this car sat for so long? I.E. Did the P.O. have this problem and leave the car for dead?

Could the cooling passages be so gunked up that H2O isn't flowing through the engine? What did the old H2O pump, thermostat interior and hoses look like, that should help answer that question. If they looked bad, really bad, I think (ulp) it's time to pull the ol' head and examine those passages. You have pretty much addressed the external stuff.

IMHO the compression test and the coolant CO tests tell you that you don't have a blown head gasket, that's good, but if the cooling passages are blocked, you still have troubles...

An "A" series normally looses some oil pressure when the oil warms up. If the oil pressure is above 20 LBS at idle and over ~50 at 3000 RPM it is "safe" to operate. Ideally, you want more pressure, but those numbers are OK.

I think this has been mentioned, but to be sure; A lean tune or really advanced timing could also cause this problem. I would expect the engine to run badly if either of these were the case. If you have checked these, then, I think it's time to pull the head.

Best of luck..

Cheers
 
Re: Overheating [still] ?????

Its really not that hard to remove a cylinder head, and replacing a gasket is ralativly cheap.

Did you buy the radiator cap and the thermostat from a British car parts house or at the local auto supply (Napa, Autozone, ect)? In some cases what they sell you is the wrong part even if it says so in their books. Big Healeys need special thermostats and caps, but I don't remember if that is also an issue with Spridgets.

Also (you may have said this but I missed it) do you know for sure that your thermostat is opening? New ones can malfunction also. You can boil a pot of water, and drop it in to see if it works.

Patton
 
Re: Overheating [still] ?????

Thanks all -- to answer some of the questions:

All parts have been purchased from either Moss or Winner's Circle (aka www.spridget.com) Have confidence in there knowledge & parts.

Assuming Thermo is opening -- mechanic had an infared themometer and it read 180 on the spot. Did not do "boiling water test".

Previous owner, my father-in-law, claims he drove the car regularily int he mid 80's. I think he'd remember / acknowlege a problem if he knew about it. In this case, no reason to "hide" anyting -- it's his daughter who will have to pick me up "roadside".

I agree w/ ThomP about checking the SU's and the timing. I need to solicit help; but feel we should try to eliminate these before tearing the head off -- just paranoid about taking an engine apart. I should probably do it via Haynes book and deal with the aftermath -- I'm going to mess it up and not be able to drive it ?? I'll go slow via the book and I think (hope) I'll be OK.

Thanks all.

George
 
Re: Overheating [still] ?????

Do you have a pressure tester to put pressure on the cooling sytem. When I was in England a buddy of mine had Mini that overheated and boiled and churned like a coffee maker when it was shut off. There was a tiny hole in a hose that would spray out water(steam) under pressure while driving, as the engine hot hotter and was ran hard it would continue to spray until the engine overheated. It was only about the size of a pin and we would not have found it without a pressure tester. Once it overheats and boils and steams you can't tell if was low on water or not. Its an easy test before you tear the motor down.
 
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