MikeJTR

What transmission and gear ratio are you using? The reason I ask is because there have been others on this forum who had overheating problems at freeway speeds, and I think it may be due to coolant foaming. If the coolant is foaming, an underdrive pulley may help.

The 180 lb weight gain is not surprising, but I believe there are other factors in the weight gain. Did the exhaust system also change? And if so, please describe the changes to the exhaust, and an estimate of the weight change due to the exhaust.

I have purchased a number of fans for various reasons. I have found the percentage of defective used fans to be quite high. The defective fans draw a lot of current, and do not move much air. You would not know the fans are defective until you have the problems you are experiencing, and you can compare it to other fans. The engine should run cool with the fan on low-speed, and the current draw should be about 15 amps. On high-speed, the fan will draw about 25-30 amps, and it will move a lot of air. Again, normally, it is not necessary to run the fan on high-speed. There are some inexpensive amp meters that simply lay over the wiring, and provide a direct reading. You can get these at most auto parts stores for under $20. I find these to be great for diagnosing problems. I have seen the defective fans draw over 50 amps. A better fitting fan for the Z with the JTR radiator is the fan from the 1992-1996 T-bird and Lincoln Mark 8. Just remember, these fans are fairly old, and about half of the used fans I have purchased off of ebay have been defective.

Sometimes, rebuilt water pumps have defective impellers, or it may be designed for reverse rotation (used with most serpentine belts). If you purchase a water pump, it may be a good idea to purchase the pump from a Chevrolet dealer, and make sure it is designed for the correct rotation. Also, it may be a good idea to put a restrictor in the heater hose -- this helps improve coolant flow through the radiator when the thermostat is open. Don't run more than 50% anti-freeze, as this can be too thick to run through the engine. It seems like you have been able to diagnose the problem that is similar to the problem Jason had when he used the JTR radiator, and had cooling problems at freeway speeds. Hopefully, you will come up with a solution and let us know what it is.

What transmission are you using? What gear ratio are you using?

I would like a copy. mike@jagsthatrun.com Thanks.

I am fully aware of the CC1LS1 header. However, after looking at how close it was to the starter, we decided it would be better to move the outlet forward, and avoid starter problems. The ribs on the outside of the engine block caused the outlet to interfere between the frame rail and the engine block, so the outlet was moved forward to position it between the ribs. Look at the engine block, and you will see what I mean.

45 degree spark plug boots will clear the headers. Mustang 5.0 engines use 45 degree boots. The Corvette LS2 uses 90 degree spark plug boots on one side of the engine, and these will provide better clearance than the straight boots.

The cast-iron block does not have the additional boss that needs to be ground down. Only the aluminum blocks have the extra bosses.

According to MAS280, who plans to use an LS2 oil pan in his next project, the Corvette LS2 oil pan provides better oil control than the Corvette LS1 oil pan. The LS2 pan eliminated the wings, and added baffling.

There could be any number of reasons why the JTR radiator doesn't perform well in some of the above listed applications. The JTR radiator is nothing more than the 1984-1986 Camaro V8 base radiator (non-heavy-duty), with a thicker core. The actual core is used in 3/4 vans. The actual core has more surface area than the 1984-1988 Corvette radiator that is used on the RX7 LS1 V8 swap. In the RX7's with LS1, LS2, and a 500 rwhp LS7 engine, the Corvette radiator has performed well, even when road racing. According to MAS280, who had roadraced his LS7 RX7, his car with the Corvette radiator, was running cooler than the C6 Corvettes. I suspect Gretchen/Jason's problem has to do with high-rpm and coolant foaming. In previous posts, he stated the temperature went down when he changed to a pulley that slowed down the water pump. When he is running the radiator with more rows, the coolant may be less foamy as it goes through the radiator, and this would improve the cooling. It is also possible that his engine had debris in it that clogged the JTR radiator. This can be checked by running the engine fully warmed up, with electric fan running, and feeling the core with your hand, to see if some sections of the core are cool. There is a lot more to cooling than the radiator. Sometimes overheating problems are not diagnosed properly, and this can lead to all kinds of incorrect theories. One more point. When I investigate an overheating problem, I always use an infrared thermometer to measure temperatures going into the radiator, and out of the radiator. Most of the infrared thermometers will not read correctly on uncoated aluminum. With aluminum engine parts and hose fittings, I normally paint the parts with black paint, which allow the infrared thermometers to provide accurate information.

I think bartman's idea of using the the expandable freeze plug is the best solution. If you ran another tee, it would create too much clutter and confusion.

Corvette water pumps don't have fitting #3. Hose # 3 goes to the oil cooler (on Camaro's with the oil cooler) or it goes into the inlet side of the Camaro radiator. You can plug the fitting or tee it into the upper hose. The best way to plug the fitting is to remove the fitting, tap it with a 1/2 npt (national pipe plug), and use a 1/2 npt plug. To remove the fitting from the water pump, twist and pull on it. I normally use a large screwdriver and insert it into the fitting and work it loose.

[quote name= JTR ?Nice guys' date=' great parts, but I am still waiting for my headers. QUOTE] I apologize for the wait. We are only back-ordered one set, which is obviously your set. We don't sell that many LS1 Z headers -- about 10 sets a year, which is the minimum order that Sanderson will make for us. I mention this so that people will have a better understanding of the low volume of people who purchase the parts from us. We ordered the headers over two months ago, sometimes Sanderson is a bit slow, but for the most part, we are happy with them. I was told the headers are going through the ceramic coating process, and will be ready by Monday.

This is just a shameless plug for JTR ZX V8 mounts. When using the MSA mounts, the shifter will be about 2" forward of the stock shifter hole. With the JTR mounts, the shifter will be further rearward, so less cutting of the shifter hole is required, and the shifter position will appear closer to stock. When using the power steering box (non-rack and pinion), the 1982-1992 Camaro exhaust manifold can be used on the driver's side. When using the rack and pinion steering (manual or power assist), I know of no headers, other than ours, that will fit. I would avoid the 3.9 gears and try to find the 3.54 R-200. Overdrive on the V8 Camaro T5 is normally .73, but some models came with .63 overdrive.

Here's some instructions and pictures for the ZX V8. http://www.jagsthatrun.com/Pages/Parts_DATZX_MountingInstructions.html

Improved cooling by reducing the water pump speed indicates that you have a coolant foaming problem. You need to get all of the air out of the cooling system, as well as any chemicals that can cause foaming. You should probably flush your cooling system and add an additive like Redline Water Wetter, which reduces foaming.

Did you block the heater hose fittings on the engine, or did you loop the hose from one fitting to the other?

I think the cooling problem you have with the JTR radiator is the cooling fan. I think you have the fan wired backwards. Easiest way to check is to put a piece of paper in front of the radiator with the fan running to see if it sticks to the radiator. If the paper blows off, you have the fan running backwards. Also, are you running the heater hoses to the heater core?

I read your posts in the miscellaneous section concering your cooling problems with the JTR radiator: http://forums.hybridz.org/showthread.php?t=115320 http://forums.hybridz.org/showthread.php?t=116270 http://forums.hybridz.org/showthread.php?t=115763 I never could understand why you couldn't make it run cool in cold weather. It was never clear to me if you ran the electric cooling fan backwards, or if there was some other problem. You mentioned you had a modified hood than may have affected the air flow through the engine compartment. I would like to see pictures of your current set-up, and I would like to know if there were any other changes you made when you switched radiators.

The hose fitting is pressed into the Camaro LT1 water pump. It can be removed by sticking a large screwdriver (or bar) into the fitting and twisting and pulling at the same time. The hole can then be tapped with a 1/2 npt, and plugged with a 1/2 npt plug. If you don't want to modify the water pump, you can run the oil cooler hose into the lower radiator hose using a 1-5/16" x 3/4" (or 5/8", I can't remember) hose tee. Also, since you have the LT1, you should get the radiator 1-5/16" X 3/8" hose tee for the steam vent tube. See the following link for hose tees: http://www.jagsthatrun.com/Pages/Parts_TPI-TBI_Brass-Tees.html

The stock Camaro transmission mount (rubber isolator) should work fine. The reason I recommended the old style mount (which is no longer available) is because it was inexpensive and soft enough to prevent normal driveline vibrations from going into the car. I do not like the aftermarket transmission mounts because they tend to be stiff, and this transmits noise and vibration into the car. The urethane transmission mounts, in my opinion, are too stiff. If you use the Caprice style transmission tailhousing shown in the book (to gain exhaust clearance), you should install spacers between the rubber mount and the tailhousing to raise the back of the transmission so that the output shaft is nearly parallel with the differential pinion shaft.

These are relatively new parts that were made for the cooling system for the RX7 LS1 V8 swap. The website (JTRpublishing.com) has not been updated, and may not be updated for several months. We plan on having a new line of hose splicers that go from one size to another, without the need for rubber reducer bushings. We currently use a 1-5/16" to 1-1/2" splicer in our 6-cylinder aluminum radiator kit (although the website shows a 1-5/16" hose splicer with a rubber bushing, http://www.jagsthatrun.com/Pages/Parts_DATZ_Radiator_Kit.html ) We now make hose splicers for intercooler applications, made from aluminum, and with beaded ends to keep the hoses from popping off with high boost pressures. These look the same as our radiator hose splicers, but are made with larger diameter tubing. If you need a specific diameter and length, let us know, we have intercooler splicers for 2", 2-1/4," 2-1/2", 3", 3-1/2", and 4" (although none of this is listed on our website). The typical length is 2-1/2" long overall, with about 1-3/4" between the beads. If you need a size (diameter or length) not listed, we might be able to make it.

JTR now has billet aluminum heater hose adapters for 5/8" to 3/4", and a 5/8" heater hose restrictor/splicer. Also, we now carry an LS1 upper radiator hose tee for the steam vent tube, and the tee also has an air-bleed valve to purge air out of the cooling system.