Hi Tiny86,
Yes, I have used the Fram 3600 with the spin-on adapter on my TR4, too. Right now I've got a KN HP-2005 on there. It's the same size as the Fram. With these two numbers, you can probably cross-reference just about any other brand of filter, if you wish.
I've got an oil cooler adapter, too. (Mocal SPT1 which can be seen at
www.racerpartswholesale.com) As mentioned, it's a separate item that just screws on and "sandwiches" in between the spin-on adapter and the spin-on filter, adding another 1-1/8" or so to the length of the entire assembly. This extra length isn't usually any problem on TR2/3/4, even with the longer filters we are using.
There are two possible concerns about a spin-on filter adapter. One has to do with how it was made, the other has to do with how it is fitted.
All those spin-on adapters use a special, central nut and bolt arrangement to hold them on. Most often these are made of brass. Occasionally these have pretty small holes that can restrict oil flow into the filter. That's one thing to watch out for.
When it comes to fitting it up, the original filter "can" uses a seal where it fits into the filter head on the block. There's a deep groove this rubber seal fits into. The spin-on adpaters also use this seal and have a flange machined into them to fit into the groove and make contact with the rubber seal. The most common problem is a leak that's caused by an old, damaged rubber seal or when someone accidentally stacks two of those rubber seals in the deep groove in the filter head (it's easy to forget to remove the hidden, old one), or pinches the rubber seal in the process of tightening. If there is any leakage around the top edge of the spin-on adapter, look for a replacement for this seal (it's included with original style cartridge filters, might be available separately from some vendors... it's a sort of square sectioned o-ring) and be sure to remove the old one before installing the new seal.
Finally, since the adapter is made of brass, don't overtighten it or it can be snapped off. Thanks to the rubber seal, it doesn't have to be terribly tight.
If you want to do something here to keep the whole assembly from unscrewing when you go to change the spin-on filter, I recommend using some Locktite Thread Sealant on carefully cleaned threads (remove all traces of oil), rather than overtightening the nut or the brass adapter.
I've still got the original oil filter "can" from my car stashed away, with a lot of the original paint on it. I mention this because some folks like to paint their spin-on filters to match the somewhat unique "light teal green" of the original filter can, for a somewhat original appearance. Search the archives for several postings here, with photos of the special color used, for comparison, if you are interested.
BTW, the original cannister filter really wasn't a bad setup, worked well. The spin-on is just a bit easier to service and is only really necessary if also using a typical oil cooler take-off and/or some sort of remote filter arrangement. (Note: There are some oil cooler take-offs that don't require a spin-on adapter, such as the one made by Greg Solow at The Engine Room in Santa Cruz, Calif. His design fits under the filter head, itself.)
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