Inliners International Forums General Discussion Engines Water Pump/Balancer

I have a 261 and want to bolt on a 216 water pump, harmonic balancer, generator and wide belt. I bought the water pump adapter plate. Now I'm having second thoughts. 1st, will the 216 pump keep the 261 cool? Will it flow properly/adequately? 2nd, will the harmonic balancer work properly on the 261? I don't want to break something after spending a couple thousand rebuilding the engine. The plan is not to have a hot rod, but a reliable truck (carryall). Right now I've got a 254 cam, dual progressive carbs, all machine work is done and all new perts for the rebuild. Do I need to balance the engine, since I'm not using the stock balancer?

Dear Mr. Bancheck;

Yes; The 216 pump will cool it just fine and the ballancer will fit too. No need to ballance anything for a low RPM engine as; The factory did it close enough.

I'm doing one the same, using the wide belt etc. The gen pully fits the 12V generator too.

Good luck.

Dear Walt;

On pre 1949 models the fan that fits the (later) water pump with the 'short shaft' may hit the ballancer and It's to close to the radiator making it hard to change the belt.

Trucks and 49 + are okay.

I'll be running it W/O a fan, using an electric one in front of radiator. The wide (1") belt can be run loose, stay on @ high RPM and still cool & charge okay. They last longer too.

Happy trails.

I installed the water pump adapter on 4 engines,two-235's and two 261's,one of the 261' having typical hot rodding stuff.They all ran cooler at idle and down the road when compared to the usual short water pump.
The stock 216 water pump is driven around 1.4 times faster than the crank,the later low mounted pump spins a little less than crank speed.

Good point Tony; I forgot about that part. The 'later' fan blades have more pitch, posssibly to make up for the speed reduction etc.

The 261 parts don't hit the balancer. They make the fan blade hit the lower radiator hose.

hi my name is mike,
I have a question where do you get the plate?
and do you think it would be a good option for me?
I,m building a 58 235 with hot rod goodies to put in my 54 belaire. I'm in a pretty hot climate and don't want to run into the normal over heating problems

I would be greatful for any help

Mike,the plates are usually available on Ebay,and some old truck vendor's like Jim Carter have them.
From my experience,it's a good option if fan location is important.It's easy to do with the engine on a stand,as you must drill and tap a few holes in the block.It does require a little engineering to get the pulley ratios and belt size correct.
All this only applies to Chevys originally equipped with a 216 or the 54 235-261's.
I used a 60's Falcon 6 water pump pulley on several situations.It did require enlarging the center hole in the Falcon pulley,spacing the pulley to the proper position etc.Some guys just use a smaller 216 damper on 235-261's,but I felt it was best to use the proper sized (weight) damper.
John, I like using an after market paddle blade flex fan,the blade can be easily trimmed for damper clearance cause of the deeper pitch on the blades.And the flex fans are rated for 8000 rpm fan speed,no worries about 50 year old fans flying apart from overspeeding.
But there are some guys using short water pumps who report no cooling problems,I think this all depends on how the engine is tuned and how the vehicle is driven.
Or just use an electric fan if the old school mechanical fan isn't important.

Steve @ Buffalo sells them right here.

The short (shaft) pumg works just fime on the 49-54 series autos. You could use a smaller (216) pulley on the pump to speed it up. The 216 dampner is okay too.

Good luck.

thank guys i would have thought about just useing the pulleys to get a better pump ratio

I meant "wouldn't" have thought of that my apologies it was very early.So you think I can just run 216 pulleys and forget about it thats awsome.

Yeah, just press it on the short shaft pump & use the 216 dampner. Be careful not to push the impeller away from the pumps seal is all.

Patrick's will make you one, if needed.

Good luck.

make me one what? a 216 water pump pulley for my 235? and do still need the adapter plate or is that what you mean?

Jbrancheck,
Your plan will work fine. As noted, the 261 came out in '54 and used that style of pump.
There really isn't any difference in the cooling systems of the 216/235/261 other than the pump and the siamesed block on the 261, which hasn't proved to be an issue from anyone that I've talked with that has used the adapter plate (or runs a '54 261).
The main reason for doing this is to get the fan back into the correct position in relation to the radiator on '54 and earlier vehicles.
I would try to keep the pulley diameters as the factory intended for each type of pump, as changing the speed of the pump too much in either direction can cause overheating due to either not enough flow or cavitation. Just how much you would need to change the diameters to bring this about, I couldn't say for sure. If somebody wants to find out, please keep us all informed of your results. Below a certain rpm (whatever that is??) it wouldn't be as big of an issue.
Changing the balancer shouldn't matter to the balance of a stock engine. However, if you plan on a crusing rpm higher than about 2600, I would strongly urge you to spend the extra $150 (or so) on getting the engine balanced. I've had them both ways, and I will never build another one without getting it done.

Dear Mike;

Yes; If you have a 235 thats 55-62.

When GM (Chevrolet) changed the pump, it added more pitch to the fan blade. This fan won't fit when installing this engine in a 37-54 car as It's to close to the radiator.

The adapter plate does move the fan up, but the orginal fan won't fit the later pulley, so you just swap them by pressing on the early one to use the later pump etc.

Patrick's makes them, "ready to go".

We've been doing this in California (hot summers) for years Bryan, 'so not to worry' about air in the water jacket.

Good luck.

Change the pulley because of the fan?
Try a spacer, or a flex fan, or just trim the blades a little, depending on what you're putting it in...

Thanx Guys ,I'm very grateful for the information.
And jbrancheck dude I'm sorry for jumping in on your thread I apologize if that was uncool I'm still a newbie to the B.B.s

Dear Brian;

When you change the pully everything matches. The wide belt now fits the dampner & generator and the fan is period also. This all looks and cools just fine.

"flex fans" are for extra cooling which the Chevy 6 rarely ever needs. "trimming" a fan can and often does 'throw it' out of ballance creating another problem that's not needed.

This (pully changing) is faster/easyer.

You can have a Machine Shop do it in about the same time it takes just to mail the Postal Money Order to e-bay and sometimes cheaper too.

It's a 'half day' deal & your done. This is long before the USPS gets it (Money Order) to the distribution center.

Happy trails.

As long as everyone else understands what I'm talking about.