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Slipper
11-28-2010, 03:18 PM
Hi Ladies and Gents,

Does anybody know which Connecting Rods to use in the 1725 from the Chevy 4 cyl?

Thanks

T

jumpinjan
11-28-2010, 03:37 PM
Which ones? I don't understand that?
Jan

Barry
11-28-2010, 03:39 PM
Maybe this will help:

http://www.google.com/search?q=chevy+connecting+rod+site%3Asunbeamalpine .org%2Fforum&hl=en&num=10&lr=&ft=i&cr=&safe=images

http://www.google.com/search?q=chevy+rod+site%3Asunbeamalpine.org%2Fforu m&hl=en&num=10&lr=&ft=i&cr=&safe=images

sunbeam74
11-28-2010, 05:01 PM
Most likely you are thinking of the 6 cylinder Chevy rods that most are using. The Chevy engine is the 250 CID in-line six.

There are a number of previous postings and I think there may be an article in the old feature article newsletter section.

Steve

RootesRacer
11-28-2010, 05:03 PM
Its the ones that fit the chevy II.

Since thats a very dead engine these days, the same rods are used on 250 and 292 OHV straight 6 chevy engines.

jumpinjan
11-28-2010, 05:10 PM
same rods are used on 250 and 292 OHV straight 6 chevy engines.
Oh please, the 292 used the 6.0 rod....NOT THE SAME (but I think you used them, right?)

RootesRacer
11-28-2010, 06:41 PM
Oh please, the 292 used the 6.0 rod....NOT THE SAME (but I think you used them, right?)

No, they used a 5.7 rod.
I bought 6 inch from crower, but that is not stock for a 292.
Crower sells 5.7 and 6 inch performance rods (sportsman).

Touchy much?

Slipper
11-29-2010, 11:15 AM
Sorry for the initial confusion chaps but my knowledge of your engines is a little vague, and I am sure I read that the rods used were from the 4Cyl (issue 7). Anyways.......... is this what I should be looking for?

http://cgi.ebay.com/ebaymotors/4-1L-250-CHEVY-66-84-6-CYL-GM-CONNECTING-ROD-CR178-/370351724121?pt=Motors_Car_Truck_Parts_Accessories&hash=item563aaed659

Regards

Tony

RootesRacer
11-29-2010, 12:02 PM
Sorry for the initial confusion chaps but my knowledge of your engines is a little vague, and I am sure I read that the rods used were from the 4Cyl (issue 7). Anyways.......... is this what I should be looking for?

http://cgi.ebay.com/ebaymotors/4-1L-250-CHEVY-66-84-6-CYL-GM-CONNECTING-ROD-CR178-/370351724121?pt=Motors_Car_Truck_Parts_Accessories&hash=item563aaed659

Regards

Tony


Yes, thats the one however, those rods will need to be changed from press fit to bushing style, they need narrowed (or the crank journal widened) and since those rods take 2.000 journal shells, you will need to have your crank ground (a lot) to take that bearing.
You MUST go with custom pistons as these rods are .050 longer than stock rods and use a different pin diam.

Also it may be worth mentioning that new crower sportsman rods dont cost much more, have the bushings lready to go and I had crower narrow mine for no added charge.

I hope you understand what you are getting into, this is not a drop in mod.

HTH

RootesRacer
11-29-2010, 12:25 PM
Here are a few more less expensive set of rods from ebay.

http://cgi.ebay.com/ebaymotors/CHEVROLET-6-CYL-194-230-250-CONNECTING-RODS-ARP-BOLTS-/250724451089?pt=Vintage_Car_Truck_Parts_Accessorie s&hash=item3a60578311

http://cgi.ebay.com/ebaymotors/Chevrolet-6-Cyl-Reconditioned-O-E-M-Rod-194-230-250-/290292918410?pt=Motors_Car_Truck_Parts_Accessories&hash=item4396ce688a


BTW the difference between 250 and 292 rods appears to the the journal size which is 2.000 for the smaller 6s and 2.125 for the 292.
The 2.125 is closer to what would be needed for the rootes crank journals, but the rods big end is also larger and may not fit down the bores without a lot of grinding and large cyl overbore.

HTH

todd reid
11-29-2010, 02:25 PM
Just a historical note. The original Chevy II was a available with a 153 ci 4 cylinder engine that was essentially 2/3 of a Chevy 230 ci 6 cylinder engine. Presumably if one could locate the rods from one of these "classics", they would work. It is my understanding that most of these engines have been converted to boat anchors! I think the automotive industry has learned a lot about balancing "big" 4 cylinder engines since the early 1960s.

jumpinjan
11-29-2010, 06:45 PM
Thats true. Also look at the Mercruiser engines, they are same Chevy engines too.
Jan

RootesRacer
11-29-2010, 06:49 PM
The chevy II, is also considered half a 305 V8.

Barry
11-29-2010, 08:02 PM
The chevy II, is also considered half a 305 V8.

Not even remotely correct.

The 153 cubic inch "Chevy II" engine was a 4-cylinder version of the 3rd generation Chevy 230 cubic inch 6-cylinder engine (3.875" bore and 3.250" stroke).

The Chevy 305 V8 had a weird 3.736" bore (small) and 3.480" stroke (long) in an attempt to reduce emissions. It is generally regarded as the worst SBC engine of all time.

The 151 cubic inch GM "Iron Duke" (aka 2500, 151, Pontiac 2.5, Cross Flow, and Tech IV) 4-cylinder was made by Pontiac from '77 to '93 using small block Chevy V8 tooling and had a 4.000" bore and 3.000" stroke. Most Iron Duke engines were VERY low performance, but there were "Super Duty" parts available that made serious power.

Kansas Racing Products still makes blocks based on the Iron Duke design. They can use modern aftermarket SBC (or SBF) heads, offer bores up to 4.125" and strokes up to 4.000". With some imagination and a large checkbook, you could build a very interesting 4-banger.

RootesRacer
11-29-2010, 08:28 PM
Not even remotely correct.

The 153 cubic inch "Chevy II" engine was a 4-cylinder version of the 3rd generation Chevy 230 cubic inch 6-cylinder engine (3.875" bore and 3.250" stroke).

The Chevy 305 V8 had a weird 3.736" bore (small) and 3.480" stroke (long) in an attempt to reduce emissions. It is generally regarded as the worst SBC engine of all time.

The 151 cubic inch GM "Iron Duke" (aka 2500, 151, Pontiac 2.5, Cross Flow, and Tech IV) 4-cylinder was made by Pontiac from '77 to '93 using small block Chevy V8 tooling and had a 4.000" bore and 3.000" stroke. Most Iron Duke engines were VERY low performance, but there were "Super Duty" parts available that made serious power.

Kansas Racing Products still makes blocks based on the Iron Duke design. They can use modern aftermarket SBC (or SBF) heads, offer bores up to 4.125" and strokes up to 4.000". With some imagination and a large checkbook, you could build a very interesting 4-banger.

I stand corrected, I had the 153 confused with the 151.

Barry
11-30-2010, 11:06 AM
I stand corrected, I had the 153 confused with the 151.

Welcome to the club; it currently has about a gillion members!