Hi all I`m new to this group and have found this thread extremely interesting. I have much the same problem as Turbo dodge in that we have uprated a Ford Transit van
( standard 2.5 ltr non turbo diesel) with a Holden/Buick 3.8 ltr v6 petrol in doing so we retained the original radiator( recored as new of course)fitted a 14 in Thermo fan
( standard Transit was engine driven standard Holden is electric) the problem we have is that the Holden Parameters are 82deg C open thermostat 102deg C fan starts and whilst gentle highway running will see the engine sit at 96-98 deg C heavy use or towing bring it up to 110C straight away with little recovery on lite throttle periods. my next option is a thermostat controlled electric water pump allthough my thoughts are that this will not give a final solution. could any of you give me some advice or a site where I might be able to work out the thermal effectiveness of the standard Holden/Buick unit compared to the Transit one.
Thanks
Can you supply further details of the rad you've got fitted? ie face dimensions and number of tube rows.
Also before you go spending a small fotune on cooling the beast further have you tried either moving the rad? possibly downward ( a couple of inches can make a big difference!) or trying to duct the airflow into the rad a little more efficiently than good ol' Henry.
You don't say which Mk of Transit you're modifying but I know from experience that one of the models had cooling problems from lack of air flow due to bodywork.
I'm assuming that Buick/Holden means Rover for us UK bods so I'd start checking your motor before going too far as they're not mega hot runners.
Thanks Finman, No buick/holden doesn`t mean Rover the rover as you know is 4.4 litre all alloy the Holden is 3.8 litre all cast iron lump that was used as a front wheel drive engine in the US. The Transit I am talking about is an L190 it ran in the UK from 1986 to 1995 with the non turbo 2.5lt diesel The Standard transit Rad which we are running has a core size of 600X 335 X45 triple row with a 14in thermo fan ecu controlled start at 102degc the standard Holden unit is 550X 410 X 35 double row this is what has me confused the surface area of the Holden unit is about 10% bigger 2255-sqcm against 2010sqcm but the cubic capacity of the transit is abot 20% greater 9045cm3 against7892cm3 the transit rad as I said in my earlier post handles the temp fine until it asked to do any heavy work towing etc or has to wait around in traffic and doesn`t recover very well at all. Nobody seems to be able to answer me as to which is more important surface area or total capacity. and by the way the engine is fine new heads /gaskets/ water pump( nothing wrong with the old pump but I using the process of elimination method)rather than use the electric pump I`m leaning toward a custom core 680X 335X45 triple row as that will neatly fit in the existing position will give me slightly more surface area than the standard Holden unit and give me 10251cm3 triple rowed again with dual fans.Is there anywhere you know of that has a calculator to work out the capacity required to cool a 175kw petrol engine.any suggestion will be greatfully accepted.
Rule of thumb says it should all work fine but obviously doesn't......
Have you tried looking for air locks in the coolant side? usually up around the heater core.
If you havn't already done it, try "back flushing" the block, it may be worth popping a core plug to make sure the the motor hasn't got full of old dirt in the coolant passages.
I'm not the academic expert with the slide rule so I can't help with that side but, I used to work for a big UK aftermarket rad company so I've come across this sort of problem before.
Say the diesel is around 30% efficient, and the petrol engine is around 15% efficient at the same typical (rather low in the case of the petrol) power and speed. Where do you think that extra energy is going?
How does the fuel consumption compare?
Do you usually accelerate more quickly with the new engine? Or drive at higher speeds?
transitv6,
Improving airflow will improve cooling.
Agree with finman's suggestions re ducting, etc.
A fan shroud will help.
Also, try to improve flow out of engine compartment at rear of hood/base of windshield.
Remove the thermostat (re-install for winter season).
Another idea (for belt driven fan/water pump): Reduce the driven pulley size to speed up the fan and pump (or increase the drive pulley diameter).
Normally the air exit is underneath and out the wheel wells.
The bigger/wider engine may restrict airflow out of the engine compartment.
Another thing I didn't see mentioned is: make sure that cooling air can't recirculate from the hot side of the radiator to the cool side. (many vehicles have a baffle or 'spoiler' along the lower edge of the radiator.)
Depending on the electric fan installation arrangement and diameter, you may not be pulling air through the entire core- most engine-driven fans are fitted with a shroud to pull through the entire area of the radiator. Many front-wheel-drive cars mount the fan right against the radiator and only the circle described by the fan sees the airflow.
Greg's comments regarding engine size and efficiency were good, but I expect that a cooling system that will handle the original engine at full power should at least recover the V6 (from high temp down to normal) under light load!
Thanks Gentlemen,
I have taken all your thoughts on board and may now proceed to fit some "full sick" vents in the bonnet if all else fails or maybe a few large washers under the hinges at the back like the weelly fast race cars had in the sixties. In all seriousness I`ll look at the baffle idea, I can`t see that changeing the pump speed will help but I might try it out or even use the electric pump as a test as it is speed/flow variable. I have all but commited myself to the larger core idea and with some judicious placement of ally tape I`ll make sure every scrap of available wind passes through the core as well as mounting a second thermo fan. Don`t you just love those "yeah mate it bolts straight in" jobs especially when they include the "don`t change the rad its plenty big enough just get it recored" so of course you do that so its ready when you fire up the new engine and proceed to p.... a couple of hundred up against the wall.
I`ll let you know the results
transitv6---
The idea of proper ducting both in and out is GOOD (mandatory in most cases). Sealing up the area around the rad to correct any reverse flow tendencies is GOOD. Electric fans can SOMETIMES help but they "suck" better than they "blow" (a properly ducted mechanical fan is usually more efficient but uses more hp to do it). Taking the T-stat out without using some sort of flow restriction is BAD (can increase cavitation due to loss of pressure build up and decrease dwell time in the rad). Jacking up the back of the bonnet without proper consideration for the HUGE stagnant area at the base of the windscreen is BAD.
Speeding up the fan/waterpump can cause excessive cavitation and result in a worsening condition---BAD.
Often slowing the pump down will give improved cooling via reduced cavitation and increased dwell (dubious as I have had mixed results from "dwell time" experiments, but I had to put it in) time in the rad. I have often found that multiple core rads are worse than single or double core/large tube rads mostly due to airflow restrictions in the four or five core units that were the hot setup in the 50's and 60's. Any good core mfgr can give you the heat rejection/hp capability of their products. Pull up some of their sites, especially the mfgrs in the SouthEast U.S. that do stock car (NASCAR) rads as they are pretty much cutting edge these days. Like I said last year, I have a LOT of experience in what does NOT work!!!
I agree that raising the rear of the hood (bonnet) is dangerous. The hot air leaving the engine compartment will be OK at low to moderate speeds, but as speed reaches a critical level (based on w/s rake angle, height, trim, etc.) high pressure developing at the w/s base will force cool air back into the compartment, and add its own volume to the other exit points.
I have a 1983 Mercedes 240D Manual Transmission. Cooling is not much of an issue, even here in New Orleans. Neither is salt
The radiator is saved the thermal load of an automatic transmission oil cooler.
The prior owner abused the radiator (not OEM) and I have the choice between a Behr/Valeo plastic tank w/Al or a Nissens plastic tank w/Cu radiator.
I am careful with maintenance. Which one will last the longest in my application. (I want at LEAST another dozen years). I am leaning towards the Danes.
BTW: I run a mix of 55% ethlyene glycol, 15% propylene glycol and 30% distilled water. Very close to optimum for heat transfer/volume. Also low corrision potential.
I have had great luck with Valeo.
are you sure it is plastic with Al?
mine is plastic with tin plated copper.
two things to throw into the discussion.
1. many people see shiny silver radiators and assume they are Al, many of these are tinned copper. tin plating eliminates the need to paint radiators, gives near perfect corrosion resistance, and is very thermaly conductive.
2. a lot of people seem to compare current high tech Al radiators to oem units from the 60's and 70's and assume that Al must be better than copper.
