Urgent, need opinions on my new crate engine

[1972BlueC20]

Originally Posted by FirstOwner69

Dipstick was included, just not installed. Goes on passenger side. Oil filter was included also.

EGR blockoff was included and installed.

I bought it in 2010 from a place on ebay in Kalamazoo, MI, that was a clearing house of sorts for excess GM inventory. They had 8 of them with a couple different part numbers. I talked to someone at performance parts tech support about the differences in the part numbers and was told the number I ended up buying (#19201329) had lighter pistons and one or two other changes. One of which may have been the 670 CFM carb instead of the 650 used on the earlier versions. They also told me they'd only made 8 of that version and recommended it.

I painted it orange, installed aluminum valve covers, an aluminum air cleaner top, and a dark air cleaner element to give it more of a custom look. I also installed the valve covers so the oil fill, PCV, and breather tube were in the original orientation for our trucks. Here's a picture of the installation.

Awesome, thank you for the info!

That is one sharp looking engine bay!

[FirstOwner69]

Originally Posted by mechanicalman

Hey FirstOwner69 I have a question for you on behalf of 1972BlueC20: The threaded hole on the top of the intake manifold on the driver's side-is it 1/2" NPT or 5/8" NPT?

If it's 1/2" NPT then 72Blue could put his coolant sensor there.

I assume you mean the hole my bypass runs to. It is 1/2". I thought about putting the sensor there, but it would have been right under the radiator hose and would have also required a spacer under the thermostat housing. I had also read that the head location gives a more accurate temperature reading. However, it became a moot point when I learned I needed the bypass hose.

[FirstOwner69]

Originally Posted by 1972BlueC20

Awesome, thank you for the info!

That is one sharp looking engine bay!

Thanks.

Be sure to read the edit I added to that post.

Jim

[67 chevelle]

Originally Posted by Lattimer

This engine is "half internally balanced". Thats how GM set them up in the later versions.

So you need a non-weighed balancer and weighted flywheel. Flywheel needs to be for the late 350 with 1 piece rear main.

yep,, crazy how they do this but is factual , the old 2 piece crank were asemetrical and had a unweighted flexplate/flywheel , the one piece cranks are round and use a weighted flexplate/flywheel

[mechanicalman]

Originally Posted by FirstOwner69

I assume you mean the hole my bypass runs to. It is 1/2". I thought about putting the sensor there, but it would have been right under the radiator hose and would have also required a spacer under the thermostat housing. I had also read that the head location gives a more accurate temperature reading. However, it became a moot point when I learned I needed the bypass hose.

On a DIFFERENT manifold, I ran one there and no noticeable difference in temp reading. But, it DID touch the hose and I was always worried it would rub thru.

Fuel injected cars run that temp sensor in that position and not in the cyl head so I think, although maybe slightly different, it actually gives a better sample there for coolant temp last place heading for the thermostat without a spike due to cyl head temp.

[1972BlueC20]

Originally Posted by mechanicalman

On a DIFFERENT manifold, I ran one there and no noticeable difference in temp reading. But, it DID touch the hose and I was always worried it would rub thru.

Fuel injected cars run that temp sensor in that position and not in the cyl head so I think, although maybe slightly different, it actually gives a better sample there for coolant temp last place heading for the thermostat without a spike due to cyl head temp.

yeah my mechanic said we'll just put the temp sensor in the intake manifold...said he's done it many times on engine swaps.

[Brave71]

Is bypass required on 260 hp crate engine?

[FirstOwner69]

Originally Posted by Brave71

Is bypass required on 260 hp crate engine?

I am in no way an expert, but...
The reason GM gave me for needing the bypass hose on the engine we've been discussing which has Vortec heads was that the traditional small block blocks have a coolant passage from the passenger side water pump attachment point that goes up to, and into, the head and intake. This block is the same design with a passage, but the Vortec heads do not have a passageway to allow the coolant to circulate into the intake and prevent the problems mechanicalman listed in one of his posts.

So, to answer your question, since your block and head designs are old school SBC, I'd say you shouldn't need the bypass. That's just my deductive reasoning based on the GM explanation above.

[randy.powell]

So I had the same issue with my temp sending unit for the gauge and did all the different "fixes" that have been suggested on the board and none of them worked to my satisfaction, i.e. - different sensors that were 3/8" NPT, putting a stock sensor in the intake manifold 1/2NPT using the 1" thermostat housing spacer to clear the radiator hose and on and on... None gave me the confidence I wanted.

Save yourself time and money and just do this - "If you want to run an original temperature sensor in the original location in the head (most folks have had problems getting one that reads properly), forum member brian mac machines the originals to 3/8" NPT. Here's a link with some discussion on this topic and his contact info http://67-72chevytrucks.com/vboard/s...d.php?t=627880"

Best $30 (including the sensor" I ever spent! Even though I think I read in some of the earlier posts you said you only had lights vs. gauges, I'm sure he could machine one of those down for you also.
B/R,
RP

[1972BlueC20]

that link to brian mac doesn't work.

Can someone help me get into contact with him?

I need to see if he can help me out and make me a few sensors before next week.

[1972BlueC20]

Originally Posted by 1972BlueC20

that link to brian mac doesn't work.

Can someone help me get into contact with him?

I need to see if he can help me out and make me a few sensors before next week.

Nevermind, I found Mr Mac.

PM sent!

[mechanicalman]

Originally Posted by randy.powell

So I had the same issue with my temp sending unit for the gauge and did all the different "fixes" that have been suggested on the board and none of them worked to my satisfaction, i.e. - different sensors that were 3/8" NPT, putting a stock sensor in the intake manifold 1/2NPT using the 1" thermostat housing spacer to clear the radiator hose and on and on... None gave me the confidence I wanted.

Save yourself time and money and just do this - "If you want to run an original temperature sensor in the original location in the head (most folks have had problems getting one that reads properly), forum member brian mac machines the originals to 3/8" NPT. Here's a link with some discussion on this topic and his contact info http://67-72chevytrucks.com/vboard/s...d.php?t=627880"

Best $30 (including the sensor" I ever spent! Even though I think I read in some of the earlier posts you said you only had lights vs. gauges, I'm sure he could machine one of those down for you also.
B/R,
RP

The intake location is the best, accuracy wise. That's why when more accuracy was needed for fuel injection, the factory started putting them there as close to the thermostat as possible.

Also, there is no issue with the 5/8" sending units for the "idiot" lights. They do not operate on resistance, they are a simple switch and they all turn on at a reasonable temp to indicate overheat.

You sound like an advertisement for machined down sensors.

[1972BlueC20]

Originally Posted by mechanicalman

The intake location is the best, accuracy wise. That's why when more accuracy was needed for fuel injection, the factory started putting them there as close to the thermostat as possible.

Also, there is no issue with the 5/8" sending units for the "idiot" lights. They do not operate on resistance, they are a simple switch and they all turn on at a reasonable temp to indicate overheat.

You sound like an advertisement for machined down sensors.

yeah if brian mac doesn't get back to me, then will just go with the intake mount idea....im sure it will be fine...

[mechanicalman]

Originally Posted by FirstOwner69

I am in no way an expert, but...
The reason GM gave me for needing the bypass hose on the engine we've been discussing which has Vortec heads was that the traditional small block blocks have a coolant passage from the passenger side water pump attachment point that goes up to, and into, the head and intake. This block is the same design with a passage, but the Vortec heads do not have a passageway to allow the coolant to circulate into the intake and prevent the problems mechanicalman listed in one of his posts.

So, to answer your question, since your block and head designs are old school SBC, I'd say you shouldn't need the bypass. That's just my deductive reasoning based on the GM explanation above.

Are you aware that his crate engine has vortec heads? Instructions for that engine state that:

"Any small block engine, regardless of year, that uses Vortec heads, will require an external coolant bypass line from the intake
manifold to the 5/8" hose nipple on the water pump (passenger’s side). Suggested routing is from the 3/8 NPSF boss on intake
manifold to the water pump".
http://www.chevrolet.com/content/dam...t-19210009.pdf

I had assumed that engine blocks destined for vortec heads only would not have the coolant bypass passage machined but I was wrong. Can't say they all have it, can't say they don't. GM though as a result of CNC and the ease of programming saves a lot of money on production runs by deleting machining operations that are not necessary to the application. For instance, it's hard to find a late model block with a machined fuel pump provision and lots of the flat tappet engines from 87-95 do not have the holes threaded for the lifter spider and the cam thrust.

I have 2 production vortec 350 blocks in my garage, and they are both machined for the coolant passage that goes up to the head deck. I have 2 sets of vortec heads, and they do NOT have the hole.

They also claim that the crate engine comes with a bypass hose kit. It will be interesting to see if his comes with that.

His particular truck has an un-restricted heater flow circuit that will function as a by-pass hose, so he needs one and he has one.

[CUSTOM/10]

So I'm going to have this same issue with my truck, ( Glad I'm learning about it now ). What would be the correct routing of the heater hoses with A/C ?

Gary

[mechanicalman]

Originally Posted by FirstOwner69

I am in no way an expert, but...
The reason GM gave me for needing the bypass hose on the engine we've been discussing which has Vortec heads was that the traditional small block blocks have a coolant passage from the passenger side water pump attachment point that goes up to, and into, the head and intake. This block is the same design with a passage, but the Vortec heads do not have a passageway to allow the coolant to circulate into the intake and prevent the problems mechanicalman listed in one of his posts.

So, to answer your question, since your block and head designs are old school SBC, I'd say you shouldn't need the bypass. That's just my deductive reasoning based on the GM explanation above.

I believe you are right that the block design has a passage but he has vortec heads without the passage.

I have a set of vortec heads that I'm considering putting on my truck. I'm also considering drilling out the heads for the by-pass due to the fact I have a nice aluminum water pump without a return, but I'm going to research it first. I may drill out the water pump instead seeings how a bypass works best the higher up it is to capture air bubbles closest to the thermostat.

[mechanicalman]

Originally Posted by CUSTOM/10

So I'm going to have this same issue with my truck, ( Glad I'm learning about it now ). What would be the correct routing of the heater hoses with A/C ?

Gary

Intake manifold 5/8" hose to heater core, 3/4" heater core to either suction side water pump (9 o'clock fitting) or cold side radiator. If you don't run a heater flow valve, you will need a "restricted" nipple on the intake manifold. If you run a heater control valve, the restriction is built into the valve when it's open.

Not sure what year your truck is, I assume it needs a heater flow shut-off valve for the A/C. Look at your control head and if it has a vacuum valve with 2 nipples then run manifold vacuum to it then from it to the heater valve on the passenger side fenderwell.

IF you have Vortec heads, you NEED a by-pass hose IF you have a heater valve. IF you use your heater circuit for your only bypass hose (Vortec heads no heater valve), keep a 5/8" to 3/4" hose adaptor handy if you blow a leak in your heater core or hoses to keep the circuit alive between the intake and the water pump to avoid engine damage.

[mechanicalman]

Originally Posted by firstowner69

here are 4 pictures that show the bypass, a/c intake bracket and 2 braces. The intake bracket is based on the original older style that was used on my 69. The front brace is similar to those used on the mid-60s cars. Doing the bypass in this fashion required a spacer under the thermostat housing.

nice, very nice.

[CUSTOM/10]

mechanicalman

I have a 1990 or so vortect headed 383 roller motor, with an aftermarket aluminum water pump. It only has the one port on the top of the pump, nothing at the 9 0'clock position. So should I put a T off the water pump ?

I'm keeping this in this thread for now so other people following this can learn from it.

Gary

[FirstOwner69]

Originally Posted by mechanicalman

Are you aware that his crate engine has vortec heads?

I am very much aware that the original poster's engine has Vortec heads and since he does not have A/C and the heater shutoff valve his heater core should allow water to circulate such that no bypass is required. However, my response that you are commenting on was to Brave71's post #107 asking if his 260 HP engine needed a bypass. I'm 95% sure that engine has Vortec heads. So, my belief is that no bypass is required, A/C or no A/C, since it should have the water passages just as our original 350 had.

Do you agree that Brave71 should be OK without a bypass? I don't want to mislead him.

Incidentally, my engine like the OPs did not come with a bypass kit, nor did the instructions say to add a bypass. I only found that out during a discussion with the tech support folks. In fact, their first suggestion was to merely add a bypass around the heater shutoff valve! I asked them if that was the fix, why would I want to leave the valve installed. Dumb...

Thanks for the compliment about the pics I posted showing my A/C bracket and braces!

Jim

[mechanicalman]

Originally Posted by FirstOwner69

I am very much aware that the original poster's engine has Vortec heads and since he does not have A/C and the heater shutoff valve his heater core should allow water to circulate such that no bypass is required. However, my response that you are commenting on was to Brave71's post #107 asking if his 260 HP engine needed a bypass. I'm 95% sure that engine has Vortec heads. So, my belief is that no bypass is required, A/C or no A/C, since it should have the water passages just as our original 350 had.

Do you agree that Brave71 should be OK without a bypass? I don't want to mislead him.

Incidentally, my engine like the OPs did not come with a bypass kit, nor did the instructions say to add a bypass. I only found that out during a discussion with the tech support folks. In fact, their first suggestion was to merely add a bypass around the heater shutoff valve! I asked them if that was the fix, why would I want to leave the valve installed. Dumb...

Thanks for the compliment about the pics I posted showing my A/C bracket and braces!

Jim

Hi Jim-
Stock 260HP engines with the original heads do not need a bypass hose. So, if he has not installed Vortec heads then I agree he don't need it.

"Any small block engine, regardless of year, that uses Vortec heads, will require an external coolant bypass line from the intake manifold to the 5/8" hose nipple on the water pump (passenger’s side). Suggested routing is from the 3/8 NPSF boss on intake manifold to the water pump".
http://www.chevrolet.com/content/dam...t-19210009.pdf

The bypass passage that comes off the water pump and goes to the deck does not do anything with Vortec heads because the Vortec heads do not have the passage drilled that lines up with the passage on the block from the water pump so the coolant does not circulate. Production Gen 1 Vortec 305's and 350's have a bypass hose from the factory.

On earlier heads that are drilled, only one hole actually circulates and that's on the passenger side head on the front only. The hole on the other head ends up in the back of the engine and does nothing. The coolant crossover that runs under the thermostat brings the coolant from the driver's side and it all goes to that little hole on the passenger side of the water pump.

The roof of the cylinder heads (arguably the hottest part of the engine) have coolant right on top of them and are what can create the steam pockets like a boiler on a steam engine so they have to have coolant circulating to prevent steam and so the thermostat can feel the hot coolant; if there is a steam pocket under the thermostat it will not open until the engine is very overheated.

Here is some VERY MIS-LEADING information put out by Edelbrock.

"�� SPECIAL NOTE: This intake manifold is primarily intended for use with Vortec heads on pre-Vortec blocks. Standard engine blocks route thermostat bypass water from the block directly to the water pump through the passenger side water pump mounting flange. If the manifold is used on a 1996 and later Vortec engine that does not have the in-block bypass passage, you must route a thermostat bypass hose from the water bypass port on the front of the manifold to the 5/8” hose nipple on the passenger side of the Vortec water pump. Use a 3/8” pipe to 5/8” hose nipple fitting, and a 7” length of 5/8” hose to accomplish this. If your engine block has the thermostat bypass passage, use the 3/8” NPT plug supplied in the kit to plug the bypass port in the front of the intake manifold".
http://www.edelbrock.com/automotive/...7000/71116.pdf

If you are running production Vortec heads, regardless of what block you have you need a bypass. These instructions from Edelbrock, if applied to production iron Vortec heads, are wrong.

MAYBE they are applying it to the Edelbrock aluminum Vortec style heads, I don't know, and I don't know if Edelbrock aluminum Vortec style heads have a bypass passage to align with the bypass passage in the block.

Here is a picture of a SBC that does NOT have the coolant bypass drilled in the block. It should be on the front of the deck above the hole that's above the dowel pin and next to the head bolt hole above it.

[mechanicalman]

Originally Posted by CUSTOM/10

mechanicalman

I have a 1990 or so vortect headed 383 roller motor, with an aftermarket aluminum water pump. It only has the one port on the top of the pump, nothing at the 9 0'clock position. So should I put a T off the water pump ?

I'm keeping this in this thread for now so other people following this can learn from it.

Gary

Do you have a 3/4" nipple on the passenger side radiator tank?

[mechanicalman]

Originally Posted by Brave71

Is bypass required on 260 hp crate engine?

No.

It's only needed on Vortec heads and some odd blocks that don't have a bypass drilled into the block.

Yours is OK as long as you have not added Vortec heads.

[CUSTOM/10]

Originally Posted by mechanicalman

Do you have a 3/4" nipple on the passenger side radiator tank?

No, I believe it's 1/2" and I am using it for my electric fan control .

[1972BlueC20]

Hey guys where is the oil pressure sensor located on this new engine?

http://www.summitracing.com/parts/nal-19210008

Is it the same place as my old original 350?

I couldn't see the hole for it in the pictures of the version with no intake.