chev 186 double hump heads

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riverracer
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Re: chev 186 double hump heads

Post by riverracer »

history,
original motor wiped cam lobe oct 2013,
march 2014 REBUILT ENGINE SPECS.
4.020" 4 valve relief flat top pistons
CHEV FUELIE 186 HEADS - 64cc - 1.94 X 1.50 valves - screw in studs/guide plates and machined for positive stem seals
mild cleanup and gasket matched to EDELBROCK PERFORMER 2101 MANIFOLD, center divider wall machined down 1/2”
pcv and all breathers installed correct for a 1972 engine.
HOWARDS RETRO FIT HYD ROLLER CAM – CL111145-12 - RPM Range: 1500 to 5600
Duration Exhaust: 278 Intake: 272 Duration @ 050 Exhaust: 225 Intake: 219
Intake Centerline: 108 Lobe Separation: 112 Valve Lift Exhaust: .525 Intake: .510
Stock GM cast exhaust manifolds into twin system with “H” crossover pipe behind cross member.
Unfortunately I do not know the compression ratio, my engine builder passed away earlier this year.
It won't be a high comp build, I run std 91-95 octane (Australian spec).
oil used is ULX110 - 20w50
engine was started and rings bedded in by builder.
ProPower engines wrote:Where is the PCV connected??
on the front base plate of the quadrajet carb
ProPower engines wrote:You never mentioned how much vacuum it pulls while running. If it has good vacuum it may be a ring issue more then a guide issue with that much build up on the plugs in that short of time.
at about 800rpm in neutral it pulls 16.5 vac and 12ish when driving along.
ProPower engines wrote:Where they new pistons??
yes
Dan Timberlake wrote: Just for the record, what ring manufacturer, and part number?
What were ring gaps? Got pictures of the cylinders during the re-ring job?
unknown now as my engine builder passed away earlier this year.
20160213_103245 (Copy).jpg
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pdq67
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Re: chev 186 double hump heads

Post by pdq67 »

Point of clarification is all here.

Fwiw, "real", fuelie heads are the -461 heads that have 2.02"/1.60" valves in them.

I have a pair of big-valve -461's out in my garage.

pdq67
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Re: chev 186 double hump heads

Post by Carnut1 »

pdq67 wrote:Point of clarification is all here.

Fwiw, "real", fuelie heads are the -461 heads that have 2.02"/1.60" valves in them.

I have a pair of big-valve -461's out in my garage.

pdq67
186, 041's are real fuelies as well but have bolt holes. 041's have a triangle casting mark. Ports and chambers are very similar except they did away with the double quench near the plug for better flow.
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Carnut1
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Re: chev 186 double hump heads

Post by Carnut1 »

For this build with the mild cam and small valves I would rather see a EPS manifold or even a l79 intake than the milled out divider performer intake. The milled divider just takes low end on this mild combo. Jmo.
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riverracer
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Re: chev 186 double hump heads

Post by riverracer »

Carnut1 wrote:For this build with the mild cam and small valves I would rather see a EPS manifold or even a l79 intake than the milled out divider performer intake. The milled divider just takes low end on this mild combo. Jmo.
unfortunately i'm on classic rego here in australia, and in my state, a left hand drive car has to be stock.
a higher manifold also wouldn't fit under the hood of a 72 vette.

engine was only built for cruising and cross country drives, no racing or track work etc.
Belgian1979
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Re: chev 186 double hump heads

Post by Belgian1979 »

riverracer wrote:
Carnut1 wrote:For this build with the mild cam and small valves I would rather see a EPS manifold or even a l79 intake than the milled out divider performer intake. The milled divider just takes low end on this mild combo. Jmo.
unfortunately i'm on classic rego here in australia, and in my state, a left hand drive car has to be stock.
a higher manifold also wouldn't fit under the hood of a 72 vette.

engine was only built for cruising and cross country drives, no racing or track work etc.
I bet they wouldn't know the difference between an original manifold and an aftermarket one.
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Re: chev 186 double hump heads

Post by Newold1 »

Do a quick compression test on the engine WARM, then squirt a little oil in each cylinder and retest each cylinder. I notice some funny marks in the cylinder for cylinder #5 but it might just be a reflection of light on the bore. If the block was bored to accept +.020" pistons, why are there still top ridges showing in all the bores and the finish on the bores looks extremely polished if this picture was taken before piston and ring installation.
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