How to get a little heat with crossovers...?
 

Given my recent situation, I know super cold heads and block played a roll in my destruction, I been running crossovers and no stats for YEARS with no issues, but knew certain things were set up for it, I will be setting the heads up for that but want to be safe so what works? I know if I just put stats in I will have fluxuating temps and possible water pressure issues, what will work good???

My opinion on it is this. If you want a crossover and some temperature buy the stainless marine crossover kit with the thermostat housing/ bypass and thermostat. Tried and true setup. Very expensive but it works. If you are using the regular old crossover that are mass produced in China I would set the whole motor up loose. Always better to loose than too tight. And run no thermostat. When I came to the crossroads with this dilemma I had to ask myself what is there to gain with a crossover and what is there to loose? With the question at hand I really can't see any benefit from running a crossover. I will stick with the circulating pump on the front of the motor. I know I know everyone has been running a crossover for thirty years with no issues. At the same time they have also been running them with the circulating pump for thirty years also and if you want temperature in the motor it's much easier to control with the pump than no pump.

The crossovers I have are Stainless marine, If I had regular pumps and all the other stuff I would consider that route, I am trying to make do with what I already have, when I bought the Baja years ago this was on it so I left well enough alone with no issues, I know there may be better options but I need to make what I DO have work...or just set my stuff up loose like planned and move on, just looking for more safety, I cannot do this again....

I did a bunch of dyno tests......full wet exhaust. 1 set of tests out of the many I did, was Factory recirc vs crossover. up to 5800rpm. About 2hp. HA ! Well within dyno error. Sea water pump I couldn't test because that would mean running the exhaust without water. I'm willing to bet by the massive water volume it passes plus the psi it can produce, this is the HP consumer...but nothing we can do about that.

I'm not concerned about hp or any of that, just happens to be what was on the boat when I got it so I kept it because it didn't cause issues, that being said it's playing a role in current issues, can't I get really low t stats and make it work?

I always ran crossovers with no stats in the past and never had any water temp. I have read on here in 100 places about people running stats with holes drilled in them.

I have put 140 stats with 2 3/16 holes drilled in them and a bypass to cool the headers. I am going in the water today hopefully and will let you know what results I have if you'd like. From following your posts the last few years though I will say I think we run differently - I rarely even see 4000 rpms. I believe you run a lot harder than I do....

I think at this point you should step away from the " I have to make due with what I have" and "I have to make what I have work" thinking. Your not building a 350 for grandpa's station wagon, your trying to build some pretty decent power that you admittedly are going to beat the phuck out of. Rushing it, trying to make stuff work, thinking it should be "good enough" and not paying exceptional eye to detail just bit you in the azz and its going to keep biting. Its going to keep frustrating you, its going to keep costing you money..... you need to change the thinking from "making it work" to making it bomb proof. Im not trying to dog on you Tim, Im not trying to be a dick, but Im not going to sugar coat things either. After something goes horribly wrong in the military, they do a stand down, they stop, figure out what happened and how to make it not happen again.

I run cp's high flow thermostats 120° w/ 3 holes drilled in the(3/16"),whippled charged 490 ci enginges.all the engines over 550hp get that set up.never a problem.and all run cross overs.
my friends chief 725hp engines in a 38 top gun runs no t-stats on afr 335's,,of course I did the heads,,but no issues there.before or after I touched them.

I get that but there are many guys running crossovers, with success and inwas one until recent and it's not the entire cause of my issue... May not play a role at all.... Just looking for knowing I got some heat.

if i was you tim i would be running a circulating pump.i know a crossover looks much better but imo,a na marine engine in your hp range does not need a crossover.espically in the cold water you run in.a circ pump and 140 deg t-stat will make your engine last longer.

I have a crossover with a bypass with a 140* thermostat with 2- 3/16 holes in it. I also have the back of the intake manifold taped for a #4 fitting and a hose run to the thermostat housing. AFR 315 heads with .00018 valve guides. All four corners of the engine stay very even. Works for me.

I`ve thought running the water thru the headers first then into the block but then I`d need 2 stage water pumps

So I can get temp with crossovers that's all I wanted to know really, I will work on this.

Do you have h2o pressure relief valves Tim?

do you mean .0018.?

Tim, first I would say that ideally Mike is correct in suggesting going back to the recirculating set up, with that said if you elect not to do that you might look into restrictors in place of the t-stat, they sell them in different sizes so you can adjust the out flow of water from the block, a few down sides to this is that you will have to watch your water pressures at WOT, and as the lake water gets warmer you may need to change to a larger size hole to reduce the heat, I'm not condoning this approach but it is another option that you can research.

This is how mine is set up , N/A 540's 700hp water temp stays 140-150 & oil temp 200, gets to operating temp in less the 10 min
I used to run crossovers , but got tired of playing with different t stat set ups to keep it dialled in

I tried to run stats (with the cross over only no hose between) on an NA engine, drilled the holes ect ect I could never get the temp regulated, if I drilled the holes to keep the temp at 140 at WOT then at cruise the temp was super cold (wouldnt even read)

On the other side if I drilled the holes on the stat to be at 140 at cruise, then at WOT the engine would get super hot

Crossover with the thermostat hose

THen I tried the crossover with the tube between the cross over and the thermostat, that didnt seem to work well either, so the circ pumps went back on

Just my experience in Lake saint clair, now on the blower engines that I have the crossover seems to work just fine (but everything on this engine is cast iron)

Too early, yes

Just curious why there is no talk of switching to a closed cooling setup? I run closed cooling on my scarab and love the stable consistent temperatures!

I am guessing it's a cost thing?

I am not oppsed to water pumps and such but I don't have them parts I never did, these crossovers been on my boat way before I owned it...

If I can locate and have funds I would get them, but as inkjow it's a better way it's also not the only way to keep this alive, just loosening the guides and lifter bores will fix my issue alone, I think everyone can agree on that.

Kinda like when I had oiling issues 8 years ago.... Everyone here said it was my filter and it was not even close to the issue.... I love advice and listen to everyone but at the same time if I changed weekly what everyone said to I would never boat, i do appreciate the help and again I listen, mike T and I talked for half hour yesterday about my issues and ideas so if it seems I don't listen.... I do

When fixing engines and in June yes it's a cost thing... I am willing to spend what's availible and I did all winter I'm tapped guys, I will not miss a season that's just how I am, I will fix this and it will be ok I am sure I know where the 2 main causes are and I am addressig it

Tim, I have a circulating pump I would donate to the cause to help a brother out. It has a flat pulley on it from serpentine setup. Im pretty sure (not positive) you can put a vbelt on it and spin the other direction. I have to dig it out of my junk pile (shed) pretty sure I have a thermostat housing (if I didn't give it away) let me know what you want to do. I'm sure the pump would last you a few seasons.

Thx let me see what I decide there really is no reason this setup of over 20 years won't work to be honest...it's not like I just did this

I switched to the thermostat style crossover necks from the non thermostat style and they seem to work ok.

I have a 2 v belt pulley for the water pump if you need it Tim.

Tim, I was just looking at a photo of your engines. Have you considered simply installing a thermostat, with a bypass hose on your setup? Since you have the bypass's already. Make sure you get the high flow robert shaw style stats with the holes in them already.

My buddy bill was saying same thing, that's probably what I will do for now, you of all people know how much money I got to fix the actual issue here...

Ifyou are not already - check your water psi !

ok...seems your splitting the water at the cross over you start with splitting the water from the sea pump.tp the bottom of your exhaust manifolds..out the top from where it connects to the riser..from that part of the manifold to the front of the block..out the thermostat housing to the risers..that is good gor 40* with a restrictor plate which i know your not running...you have have some resistance there or the water is just going to run through the front of the block and the rear of the engine will get to over 200*

..

Robert shaw,,dont you mean the ranco ones??????

Tim, call Eddie Young. He recommended a certain stat housing that had an internal bypass mechanism but I cant remember who makes it.

Tim, you can buy the stats I was talking about here. They can be had with the holes in them already.

http://www.stewartcomponents.com/ind...tegory&path=61

I have a thermostat housing off a hp 500, ill donate. so with BB's water pump and if he that housing and big boats pulleys. your just a water pump away.

Since aluminum conducts heat better than cast iron, does it make the situation with valve guide clearance better or worse?

moroso makes a kit with 3 different size washers in it to restrict water flow. they are cheap

I believe my system is similar to S30's. Stainless Marine crossovers: I have 1 or 2 holes in my 140 thermostat, rear of the intakes dirlled out 1/8"NPT, and crossovers with the bypass. (I had to drill and tap my crossover to add the baypass) As you can see I take my water pressure at the intake and temp at the thermostat. Runs about 120*F idle and ~145*F at 6000RPM.

Completely understand man! I decided to lose a whole season retrofitting my scarab with kaama surface drives and hopefully EFI. I am already regretting it and it's only June! Good luck with getting her back together!

Definitely do Tim. On my old boat I went with the crossover with bypass and could never get any water pressure. I know of atleast 2 others local to me that had these same issues, both ended up adding external pickups to get water pressure, and unfortunately the one guy it cost a few, yes, a few motors (his were blower motors, and were getting steam pockets due to not having enough water pressure to get good circulations through the block. He added external pickups and dumps in the rear of the intake which fixed his issue). My thought always was that with this set up there isn't a whole lot of resistance forcing water into the block, and with the 1" bypass the water would just go the route of least resistance, so right through the bypass and out the exhaust resulting in a very weak flow in the block. I played and played untill I finally just pulled the tstat and blocked the crossover ports and ran a traditional crossover set up. I tested this by using compression pliers to restrict the bypass, and it literally took me damn near pinching that bypaass closed to get water pressure. Im not sure if you have a water pressure gauge in the boat or not, but definitely want to add one if you don't.

I never had water pressure gauges but I am adding them this year especially if stats are going in, like unsaid this setup have been run for years, just trying to fine tune things....