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Hemi 265 Problem

 
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Elias
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Joined: 13 Feb 2010
Posts: 3

256.96 points



PostPosted: Sat Feb 13, 2010 8:56 am    Post subject: Hemi 265 Problem Reply with quote

HI guys,

My name is Elias, I am from Melbourne Australia and I know what your thinking,,,

"What on earth is a Hemi 265?"

Well it's a Hemi 6 Cylinder motor built in Australia back in the 70's. The RT Charger of Australia ran this motor with tripple weber side draught carbs and ran 14.1 second 1/4 miles. No other locally produced car was able to beat this time until about the late 90's (stock car that is).

I have a problem with one of these hemi's I recently had rebuilt and I'm hoping someone here would be kind enough to offer their opinion on what might be at fault here.

Upon starting the engine the first time (after engine rebuild) we noticed a noise at the timing case, were told that itís probably camshaft float.
Before I had a chance to take the car to the engine guy to fix the cam float the distributor gear broke (due to cam float). I had the gear replaced with a steel one and took the car to get cam float fixed.

Took the car there, had a button put in front of the cam and cam float problem solved.

The car had travelled about 500kms (about 300 miles) at this stage. I soon after noticed the oil light coming on at low revs when the motor was hot.

Took the car back. He checked the oil pressure and found it was 25psi (not sure at what revs), he said it should be between 40 and 70. Upon removing the oil sump he found that part of the distributor gear was lodged in the oil pump pick up and assumed this is what caused the low oil pressure.

Given the low oil pressure he then proceeded to inspect the bearings and found excessive big-end bearing wear and then severe wear on the two centre camshaft bearings. see photos: http://s972.photobucket.com/albums/ae20 ... %20Filure/
All the other bearings (main and outer camshaft) were fine.

When he finished replacing all the bearings and put the motor back together, he had a chat with the mechanic who started the car. The mechanic claimed that he didnít use an oil pressure gauge to check for oil pressure at start up, he did however loosen the oil pressure switch and found there was heaps of pressure (He has been a mechanic for about 35 years and this method has never failed him).The oil light in the dash did come off after a couple of seconds after start up. Upon hearing that the mechanic didnít use a pressure gauge, the engine builder changes his tune from the oil starvation happening from the distributor gear to oil starvation at start up and then went on to charge me for the repairs. In hindsight he also believes that the cam float came about from the worn centre bearings on the camshaft which doesn't really stick with me.

I have paid him for the repairs otherwise I couldnít get my car out of his workshop and I wasnít about to spend more on lawyers than what I paid him, but I donít agree that he could definitively prove that the bearing damage happened at start up in which case I might get hit heard at small claims.

Iím hoping someone out there might be able to work out what might have gone wrong?

In my unprofessional opinion, I belive that either the camshaft was not straight causing the bearings to wear excessively leading then to low oil pressure due to too much clearance between cam and bearing, or that the bearing were too thick causing the wear followed by low oil pressure.

I also believe that if it was in fact at start up, then all the bearings would be damaged and if anything that the big end bearings would have been in far worse condition than the cam bearings.

I am hoping someone here who would have much more experience in engine building might have come accross something similar and may shed some light on this.

Any help would be much appreciated.
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Paul P
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Joined: 15 Aug 2002
Posts: 2449
Location: Townsend, Mass.
83052.36 points


1971 Chevrolet Chevelle

PostPosted: Sat Feb 13, 2010 12:02 pm    Post subject: Reply with quote

Sounds like a bent camshaft to me or the block needs a line boring of the camshaft centerline as things might have shifted slightly over many heat cycles.

When I had my 400 Small Block machined I had both the cam and crank surfaces line honed to make sure they were straight.

I also sprung for the lifters being align bored and bushed for extra insurance that things were straight and in their proper place.

If you can find a machine shop you trust they will surely be able to find this kind of problem and fix it.

Your photobucket link is not complete. Try using the tools for URL tags that are provided above the post window when you are posting. One before you paste the link and one after will do it.

Paul

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2001 Focus 2.0 Zetec
stock cams, bolt-ons and tune
15.63@87 MPH 1/4mi

1971 - Chevelle 408 SBC N/A
6.86@102.5 MPH 1/8mi
10.78@122 MPH 1/4mi
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jeep_406
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Joined: 12 Sep 2002
Posts: 1662
Location: Tewksbury, Mass 01876
53158.50 points


1972 Chevrolet Nova

PostPosted: Sat Feb 13, 2010 12:35 pm    Post subject: Reply with quote

Welcome to SMOKEmUP.com Elias.

Was the engine ever severely overheated? The few times I've run into cam bearings going away it was a problem in the block caused by overheating.
Does you engine come with a cam button and they forgot to install it?
Did the same people install the engine for you. If so they never should have let it out the door making any noises.

Did they reinstall the same camshaft?

Sounds like you did business with the shop from HELL!!

Did a different shop make the distributor gear replacement?

depending on your answers I think I would look into a claim against them.
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Elias
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Joined: 13 Feb 2010
Posts: 3

256.96 points



PostPosted: Sat Feb 13, 2010 7:59 pm    Post subject: Reply with quote

The engine before the rebuild was actually in fair condition. It had the orginal bores. I dont know if it ever overheated before I owned it, I bought it as a long motor to rebuild Since it was rebuilt, it has been running hot sue to undersized radiator, but not overheat as such.

The cam never came with a button, but these motors are renouned for cam float. The engine builder didn't accoutn for it though as he assumed the taper on the cam lobes would keep it in place. He claims that in hindsight it was the worn bearings that caused the cam float.

The camshaft was reground. So in essence it was the same camshaft, but you would imagine during the regrind that they would have made sure it was straight.

The engine was installed by my mechanic. But yes, when I took the car back the first time, they should have made sure no noises, he assumed the noise was because of the lumpy cam.

The engine shop arranged for the rebuilt distributor. When I gave it back they arranged to have the new gear put on, but I re-installed it into the motor.
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Elias
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Joined: 13 Feb 2010
Posts: 3

256.96 points



PostPosted: Sun Feb 14, 2010 5:27 am    Post subject: Reply with quote

Does anyone know what a bearing looks like which has worn due to a bent camshaft or due to too little tollerance between journal and bearing?
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clay
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Joined: 24 Nov 2002
Posts: 3209
Location: South Carolina
318129.23 points


1972 Chevrolet Nova

PostPosted: Mon Feb 15, 2010 1:21 am    Post subject: Reply with quote

Give this a look.
www.engineparts.com/publications/CL77-3-402.pdf
I would think the engine builder should have been able to tell if a camshaft was bent bad enough to cause bearing failure. When I install a cam, I always spin it by hand to make sure it will. Even 25 lbs. of pressure should have been enough to keep things alive without bearing damage. Hope the above pictures help. I don't know about a bent cam - it would have a uniform appearance around the entire bearing I would think. It looks like the bearing was installed in a bore that wasn't round to me. Rod bearing sort of looks like oil starvation though - if the picture color is accurate - it has a blackened appearance of being heated. Welcome to Smokemup. Interesting engine - I like it. Clay

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I have done so much with so little for so long, I can now do anything with nothing.
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10sec.et
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Joined: 29 Mar 2006
Posts: 3483
Location: Houston,Texas
347040.52 points


1969 Oldsmobile Cutlass

PostPosted: Mon Feb 15, 2010 2:24 am    Post subject: Reply with quote

what about the possibility of the cam bearings getting mixed up and not being installed into the correct bores ? maybe the oiling holes not properly lined up with the ones in the block ?
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It seems we can look at our magical Balls and come up with a fix?

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