PDA

View Full Version : Pros and Cons of a Crossover Kit....



fogducker III
10-07-2010, 10:14 AM
Procharged BBC 454 Mag MPI Bravo, fresh rebuild, open cooling, EMI exhausts.....is a crossover kit with bypass the way to go....:confused:

Currently has stock water pump with seperate in-line oil and power steering fluid coolers.

Will the water be circulated with enough pressure just from the raw water pump....:confused:


Good points or bad points.....:confused:

http://www.hardin-marine.com/p-13357-big-block-chevy-water-inlet-crossover-kit-with-bypass.aspx

VetteLT193
10-07-2010, 12:03 PM
Procharged BBC 454 Mag MPI Bravo, fresh rebuild, open cooling, EMI exhausts.....is a crossover kit with bypass the way to go....:confused:

Currently has stock water pump with seperate in-line oil and power steering fluid coolers.

Will the water be circulated with enough pressure just from the raw water pump....:confused:


Good points or bad points.....:confused:

http://www.hardin-marine.com/p-13357-big-block-chevy-water-inlet-crossover-kit-with-bypass.aspx

Plenty of pressure. sometimes too much pressure is a reason people don't run them, the water pump helps regulate the pressure down some. It is rare to have a problem overall to the number of people running them.

Be sure to get a crossover that will allow for a T-stat. Stainless Marine sells a different T-stat that has holes drilled in it... they will flat out tell you to just drill the holes yourself on your own T-stat but will be happy to sell you theirs modified if it is too much (LOL)

Benefit is one less moving thing to break. couple of HP to be found. Cleaner engine with less crap on it.

I ran one and my brother always ran one with no problems. I would run them on my new engines if it wasn't a serpentine system.

mrfixxall
10-07-2010, 12:30 PM
leave the wp on the engine,the rear cylinders take all the heat and their will be no where for the hot water to go if its not circulated in the engine. on my x18 with the cam driven water pump i run the rear of the block will get as high as 220* on a good run but when i back off it it will go down to 160*..

fogducker III
10-07-2010, 12:41 PM
leave the wp on the engine,the rear cylinders take all the heat and their will be no where for the hot water to go if its not circulated in the engine. on my x18 with the cam driven water pump i run the rear of the block will get as high as 220* on a good run but when i back off it it will go down to 160*..

So with the current water pump it `slows` water flow down and recirculates before expelling the warmer water.....:confused:

If I run a cooler thermostat won`t it open and let the water through the bypass and back into the engine....

cutwater
10-07-2010, 01:01 PM
leave the wp on the engine,the rear cylinders take all the heat and their will be no where for the hot water to go if its not circulated in the engine. on my x18 with the cam driven water pump i run the rear of the block will get as high as 220* on a good run but when i back off it it will go down to 160*..

Fixx - can you explain this one in more detail? I don't understand why a crossover w/bypass wouldn't circulate water in the block. As far as I can tell, the only real difference is that you're using the impeller in the outdrive (or raw water pump) to supply the block pressure rather than the circ pump.

VetteLT193
10-07-2010, 02:54 PM
when the stat is closed the water sits in the block on the crossover setup. I haven't ever owned a boat that doesn't have the stat opened basically from the time the engine warms up from there on though.

I can't figure why the rear would be any hotter than the front though :confused:

The holes in the t-stat help get some circulation in there too, although they are really there to purge the air in the block more so than water.

mrfixxall
10-07-2010, 03:26 PM
Fixx - can you explain this one in more detail? I don't understand why a crossover w/bypass wouldn't circulate water in the block. As far as I can tell, the only real difference is that you're using the impeller in the outdrive (or raw water pump) to supply the block pressure rather than the circ pump.


when you run a cross over theirs one main water inlet which forces water into both ports on the front of the block..when water is being forced in the front of the block by the sea pump,by the time the water reaches the back of the block the water has to pass 6 other hot cylinders and the 2 rear cylinders 7 & 8 gets the hot water which cant escape that fast through the small pin holes which are in the head gaskets plus the rear 2 ports in the back of the intake manifold are plugged off which will create more heat in the back of the block...

the circulation pump on the front of the block circulated the water in the block which keep the engine at a steady tempture,,then when the thermostat opens it will dump the water out through the thermostat..

so basicly the water goen in through the front of the block,get trapped in the back then theouth the little holes in thehead gaskets then back through the hot ctlindr heads then out the thermostat..oh and i for got to mention that you get less head gasket life with a cross over because of the water pressure that the seapump puts out..

axelkloehn
10-07-2010, 03:33 PM
would be interesting to install 2 temp gauges- one in the front and the other in the rear to really figure out what the difference is.
I installed a crossover some years ago and my engine ran a bit cooler compared to the circ pump setup... haven't noticed much power gain at that time

cutwater
10-07-2010, 03:33 PM
Got it. Thanks :wink:

So in order for this to be true, the circ pump has to put a positive pressure on one inlet, and a negative pressure on the other, correct? Else, the water in the block wouldn't circulate with the T-Stat closed... Otherwise it would appear the exact same as a crossover, right?

MOP
10-08-2010, 06:44 AM
No matter how you feed water to the block the back cylinders do run a bit hotter a bypass makes -0- diffrence, I have friends with race engine that have drilled and tapped the heads for by pass lines to help with circulation. With any high speed application water pressure must be controlled with a relief valve, this has been pointed out on every hot boat board. The is critical on raw cooled engines, very few head gaskets will survive the pressures generated at speed. Griz stated very clearly that he saw 70-80 lbs. @ WOT! Being an old marine mechanic I will tell you this, over pressured head gaskets will leak at the outer perimeters. Any of us that have done this for a living have seen the rust drool down the side of a block. Well happy campers if they droll down the outside they also droll into the lifter valley, anyone who does not realize this should do their homework before they help their mills along to an early death. Go and find every post on on as many high perf boards as you can find, you will find guys with blower motors running as low as 20psi relief valves. Relief valves reduce the amount of water in the exhaust which in turn reduces back pressure giving a boost in power. The valves should be installed after the oil cooler or heat exchanger to give the added flow to give good cooling at higher speeds.

Phil

LKSD
10-08-2010, 08:44 AM
JMO, I do like crossovers on some applications. However I do not like the ones with t stats. I have seen them be more aggravating than the ones with out. I have also seen them cause issues or wildly fluctuating temps in comparison to the stock merc set ups. Not that you cant do things to help regulate it better, but it starts to be a bit of a pain and not worth the effort or risk IMO...

If you are going to run a crossover I would run just a basic one with no tstat. If you want to control temp a little bit and build more heat then experiment possibley with a restrictor plate. If one's concern is removing heat or air from the rear portion of the engine, or trying to balance the temp from the rear to front of the engine better then a line can be added on most intakes that goes from the rear intake water jacket to the front. This can also aid in relieving air from the system depending on how it is rigged, and it can also help to keep a more even temp.. :)

Jamie / Lakeside


Here is a link with some more illustrations:
Click here for link on cooling (http://forums.boatfreaks.org/showthread.php?t=6957&highlight=water+bleed)

Here is also a pic (not my pic, engine, or one that I did, but it shows the lines on the intake... :) )

fogducker III
10-08-2010, 09:37 AM
So basically two schools of thought here.....

Stock water pump gives a more "consistent" flow of water but does rob some power from the engine and I believe when I install the Procharger it might just be in the way.....:confused:

A crossover, as long as I plumb in a relief valve will work, but I should not install a thermostat?

Am I reading this correctly?

Thanks for the input boys.....:wink:

PS. The cost is not an issue, buying a new water pump, belt and hoses is about the same as a crossover kit.....

LKSD
10-08-2010, 09:50 AM
Jeremy, do be careful with what you choose to do cross over wise if you are going to run a procharger. Not all crossover systems will work & clear all procharger systems/kits.. Some used prochargers own design & crossover system.. ;) Jamie

fogducker III
10-08-2010, 09:59 AM
Jeremy, do be careful with what you choose to do cross over wise if you are going to run a procharger. Not all crossover systems will work & clear all procharger systems/kits.. Some used prochargers own design & crossover system.. ;) Jamie


Thanks for the heads up Jamie, I am going to have to change the stock Procharger mounting anyhow because my power steering pump and alt are on the "wrong" side because the raw water pump has the "built-in" fuel pump and fuel/water seperator is right above that.....:eek:

Basically, almost all my add-ons are in the wrong place for a standard Procharger application.....but I will make it work, I have all winter....:wink:

Just have to figure out the best water cooling solution.....:bonk:

LKSD
10-08-2010, 10:17 AM
Oh, OK.. :)

I was not aware of that.. If you are custom modding everything then you have more leeway to choose from.. :) Jamie

The Hedgehog
10-08-2010, 10:53 AM
Yo Fogducker,

Jamie has given good advice. Some of us own and have set up procharged engines, some have not. Jamie's setup is the route I went. My entire engine was setup to run cold. It was toleranced that way.

I am not disagreeing with the others on the whole pump and Tstat thing. I have seen that done right too.

Talk to the individual that is programming the ECU. The whole process has to work together.

fogducker III
10-08-2010, 11:30 AM
Yo Fogducker,

Jamie has given good advice. Some of us own and have set up procharged engines, some have not. Jamie's setup is the route I went. My entire engine was setup to run cold. It was toleranced that way.

I am not disagreeing with the others on the whole pump and Tstat thing. I have seen that done right too.

Talk to the individual that is programming the ECU. The whole process has to work together.

I spoke with Procharger and they stated that installing one of their M-1SC units with an AW324 intercooler set at 5lbs on my particular "stock" engine, there are no changes to the ECM required.....:confused:

They went on to say if I went higher then 7lbs boost or a larger unit like the M-3 or 4 then it might need to be reprogramed......

The Hedgehog
10-08-2010, 03:56 PM
I spoke with Procharger and they stated that installing one of their M-1SC units with an AW324 intercooler set at 5lbs on my particular "stock" engine, there are no changes to the ECM required.....:confused:

They went on to say if I went higher then 7lbs boost or a larger unit like the M-3 or 4 then it might need to be reprogramed......

Procharger knows much less about their systems in a marine evironment than the guys that tune them. Their customer service is horrible. I can back that up all day long.

Here is one example. Install the Procharger kit per their specs. It requires the crossover and dumping the t stat. In your neck of the woods (mine too), you will never get water temps above 110 degrees. Your ECM WILL be in cold start mode. Sure it will be fine under full boost. The rest of the time you will soot your transom, fowl your plugs and wash your cylinder wall down. It will be so bad you will smell the fuel in your oil after the first 10 hours. Lot's, maybe a half gallon. And no, there was nothing else wrong with my engine at the time. After tuning it right, I got many good hours. The problem is so well known that people came out with resisters to trick the temp senders back before the age or reprogramming. Procharger actually ended up marketing those at an extra expense. They dropped that after folks just started having them reprogrammed.

Try to order something from them. My 502 Mag kit came with an instruction manual for the carb version. The boost reference regulator was set for 7lbs. I figured that out when I took that apart and ordered a diaphram kit for 3,5 and 7 lbs. I can tell you what happens when you set it for 7 lbs and use the 5 lb wheel. It completely falls on its face when the boost comes on. NOBODY from Procharger figured that one out. They pointed the finger at a whole myriad of other problems before I figured out that they sent me a 7 lb regulator. Those parts were on my nickle. I had a few other screw ups but they did those on their dollar thanks to Jamie.

When tuning my 540, I went through 5 pulleys on the dyno. They were confident they would hit it right the first time. After pulley's 2 and 3, I started dumping money into other parts figuring (upgrading ignition etc)that it could not be that far off. Pulley #4 hit it. I still have a stack of them if anyone needs them. They were willing to take them back for a restocking fee. I was so pissed I kept them. I will sell them myself one day. Trust me, after digging around, I learned that I am not the only one with a stack of them.

I can go on and on but I hope that you are getting the point. Hell, I am getting so ticked that I need to go have a beer.

The blowers are fine but most of them are car folks and they don't know our world.

fogducker III
10-08-2010, 05:21 PM
Procharger knows much less about their systems in a marine evironment than the guys that tune them. Their customer service is horrible. I can back that up all day long.

Here is one example. Install the Procharger kit per their specs. It requires the crossover and dumping the t stat. In your neck of the woods (mine too), you will never get water temps above 110 degrees. Your ECM WILL be in cold start mode. Sure it will be fine under full boost. The rest of the time you will soot your transom, fowl your plugs and wash your cylinder wall down. It will be so bad you will smell the fuel in your oil after the first 10 hours. Lot's, maybe a half gallon. And no, there was nothing else wrong with my engine at the time. After tuning it right, I got many good hours. The problem is so well known that people came out with resisters to trick the temp senders back before the age or reprogramming. Procharger actually ended up marketing those at an extra expense. They dropped that after folks just started having them reprogrammed.

Try to order something from them. My 502 Mag kit came with an instruction manual for the carb version. The boost reference regulator was set for 7lbs. I figured that out when I took that apart and ordered a diaphram kit for 3,5 and 7 lbs. I can tell you what happens when you set it for 7 lbs and use the 5 lb wheel. It completely falls on its face when the boost comes on. NOBODY from Procharger figured that one out. They pointed the finger at a whole myriad of other problems before I figured out that they sent me a 7 lb regulator. Those parts were on my nickle. I had a few other screw ups but they did those on their dollar thanks to Jamie.

When tuning my 540, I went through 5 pulleys on the dyno. They were confident they would hit it right the first time. After pulley's 2 and 3, I started dumping money into other parts figuring (upgrading ignition etc)that it could not be that far off. Pulley #4 hit it. I still have a stack of them if anyone needs them. They were willing to take them back for a restocking fee. I was so pissed I kept them. I will sell them myself one day. Trust me, after digging around, I learned that I am not the only one with a stack of them.

I can go on and on but I hope that you are getting the point. Hell, I am getting so ticked that I need to go have a beer.

The blowers are fine but most of them are car folks and they don't know our world.

Points taken, I hear you, understand and appreciate the input.

Having said that, I am not "huffing" a 540 with high performance, high quality components, I am putting a M-1SC on a totally stock, freshly rebuilt 454 mag and staying at 5lbs of boost.....as long as I do the water circulation correctly, as pointed out, and make sure I install all the correct parts in the correct place I believe I will be good to go.....but hell... we all know that is a fantasy world when it comes to boats right........:wink:

Perhaps I might need to play with adjustments but reprograming or having the engine dyno'd is not in the cards around here.....christ, I ordered some parts and Fedex does not deliver to my neck of the woods, I have to go on Tuesday to pick them up from their closest office in Victoria...:nilly:

farmer tx
10-08-2010, 10:58 PM
If you have a crossover you won't have to search for three days to find this problem.:bonk:

The Hedgehog
10-10-2010, 08:38 AM
Points taken, I hear you, understand and appreciate the input.

Having said that, I am not "huffing" a 540 with high performance, high quality components, I am putting a M-1SC on a totally stock, freshly rebuilt 454 mag and staying at 5lbs of boost.....as long as I do the water circulation correctly, as pointed out, and make sure I install all the correct parts in the correct place I believe I will be good to go.....but hell... we all know that is a fantasy world when it comes to boats right........:wink:

Perhaps I might need to play with adjustments but reprograming or having the engine dyno'd is not in the cards around here.....christ, I ordered some parts and Fedex does not deliver to my neck of the woods, I have to go on Tuesday to pick them up from their closest office in Victoria...:nilly:

Make no mistake. What I am saying applies to stock and exotic power. My first go around was with a stock 502 mag.

Do yourself a favor. Send your ECU to Mark Boos at PEMFI. The 300-400 you spend will be WELL worth it. You won't need to dyno it. He will mail it back to you with a base cal for your 454 MPI. Takes about a week. You can ask Tex about it. His has never been on the dyno and hits perfectly.

Or you can do it the Procharger way.....which sucks. That is why Vortec and Whipple sends their stuff with a new cal.

gcarter
10-10-2010, 01:27 PM
Just something to think about......

Since you want to run a crossover, here's a way to do it.
This company offers really good remote mount closed cooling systems.

http://www.perfprotech.com/store/catalog/High-Performance-Fresh-Water-Cooling-Systems,3203.aspx

I bought one good for 500 HP, there's a couple more for more power, up to 1,200 HP.
Griz has one on his Procharged Criterion.
Now, back to the crossover, If you run an electric remote mount circulation pump, you can use a crossover as part of the package;

http://www.donzi.net/forums/attachment.php?attachmentid=58810&stc=1&d=1284839214

If you have any questions, holler.
Would you believe all these parts are now painted red?

fogducker III
10-10-2010, 02:57 PM
Thanks for the suggestion Hedge....I will look into contacting Mr.Boos....:)


George, that is a great set-up but I have no plans of a closed cooling system, full or half, I don't believe in them. On top of that I don't have an extra $1000-1500+ in my budget....:eek:

My plan is a transom mounted low water pick-up with a shut off valve at the transom, into a sea strainer and then to a pressure relief valve leading to the intercooler and dumping overboard next to the bilge pump outlet.

The cooling system will be the regular Bravo leg pick-up to the strainer through the raw water pump, into a pressure relief valve and either through a cross-over or I will stick with the stock circulation pump, not sure yet which way I am going....:boggled:

There are valid points on both sides with pros and cons of each method, just have to do some more research and decide which is best for my set-up......:confused:

The Hedgehog
10-10-2010, 05:28 PM
Thanks for the suggestion Hedge....I will look into contacting Mr.Boos....:)


George, that is a great set-up but I have no plans of a closed cooling system, full or half, I don't believe in them. On top of that I don't have an extra $1000-1500+ in my budget....:eek:

My plan is a transom mounted low water pick-up with a shut off valve at the transom, into a sea strainer and then to a pressure relief valve leading to the intercooler and dumping overboard next to the bilge pump outlet.

The cooling system will be the regular Bravo leg pick-up to the strainer through the raw water pump, into a pressure relief valve and either through a cross-over or I will stick with the stock circulation pump, not sure yet which way I am going....:boggled:

There are valid points on both sides with pros and cons of each method, just have to do some more research and decide which is best for my set-up......:confused:

Good deal. It is always to have a backup plan.

FYI, I tried the Procharger band aid approach as well. I heard the warnings but figured that I may as well go ahead and give it a try. I was sending it off to get reprogrammed within a couple of weeks of tuning.

In your case, I think it is best to start a conversation with the tuner since you have it all torn down right now. There are a few things you can do that will help a good bit for a nominal extra penny.

BTW, my first go around I had a 502 MPI with a MEFI 1. It ran great once I got it tuned in right. Mark did an awesome job and I did not have to run to the dyno.

fogducker III
10-10-2010, 06:59 PM
Good deal. It is always to have a backup plan.

FYI, I tried the Procharger band aid approach as well. I heard the warnings but figured that I may as well go ahead and give it a try. I was sending it off to get reprogrammed within a couple of weeks of tuning.

In your case, I think it is best to start a conversation with the tuner since you have it all torn down right now. There are a few things you can do that will help a good bit for a nominal extra penny.

BTW, my first go around I had a 502 MPI with a MEFI 1. It ran great once I got it tuned in right. Mark did an awesome job and I did not have to run to the dyno.


10-4............that is one of my issues, there is no dyno even close to me.....and I am worried if I have the ECM reprogramed I will need to get a "lap-top" program and compatible cable to fine tune the ECM once the engine is in and up and running....:confused:

After a lot of research I really do understand your points about fine tuning....problem, as I have said before, is I do not have bottomless pockets nor access to people who have the time or knowledge to sort out this mess I have started.....:nilly::):wink: