TR2/3/3A 89 mm Piston and Liner Kit for TR3

I was following up Paul's recommendation of Payen gaskets from the "How has the best engine gasket sets?" thread.

I didn't want to hijack that thread so I thought I would start a new topic. While I was at the BPNW site I saw that they have a 89mm Piston and Liner Kit for TR3's. Since my car is in the shop and needs an engine rebuild anyway. It's at Her Majesty's Auto Service, Erik is going to start pulling the engine next week.

I did the math, that increases the engine from 2,188 with the 87mm pistons to 2,290 with the 89mm pistons. But, the cost for that extra 102CC's is $845. I'm wondering if it's worth it to get the 89mm sleeves and piston's instead of the more conventional 87mm pistons? So, some advice,what do you folks think, is the extra 102CC's worth the added $325? Has anybody gotten these for there TR3?

BPNW 89mm Piston and Liner kit

$325 extra is a lot of money. The money may be better spent on milling the head 0.090" (from stock) to increase compression the ratio, and possibly getting the cam reground. Those two items will yeild a lot more then the 2mm increase in bore for probably less expenditure.

It's most likely why most people (myself included) have opted for the 87mm sets. Of course, if cost is no object... :thumbsup:

Well, I've got a set of them (tho mine came from BFE) ... but I'd say no, not worth the extra money. Among other things, they reduce the size of the cooling passages somewhat, which can aggravate cooling problems. But those forged pistons (the others are cast) and thicker liners from better alloy should make a bullet-proof motor.

Don't go overboard on milling the head, just going to 87mm liners gives a big boost in compression ratio and the factory recommended 95 octane (research method) with the original 83mm liners. To really get much benefit from milling, you need to also open up the combustion chamber (and eliminate edges) per Kas Kastner's suggestions plus use a cam designed for the higher compression.

If I should ever get back around to my "hot rod" motor project, I also plan to have the head ported (by Uncle Jack Racing) and use a 4-2-1 header. Common wisdom seems to be that HS6 carbs are better on the street, but I'll likely still try out the DCOEs "just because".

It's a long, slippery slope; with a $10,000+ motor at the bottom. As Ken (and others) have said, "Speed costs money. How fast do you want to do ?"

You must ask yourself the question 'How am I going to use the car?'.

Do want the expierence of a TR3, or do you want to modify it?

One modification generally affects a bunch of other stuff. And like TR3driver said, you may be looking at a lot of money for the engine. Balancing, port matching the manifolds to the head, polishing the ports. deburring the block & a hundred of other seemingly little & very labor intensive items.

Balancing: worked with a guy years ago who had a nice Boss 302 Mustang. Rebuilt the engine, had the internals balances. The place that did the balancing would not take parts unless they were clean. Pretty much just short of eat-off-them clean. So even that cleaning costs you & has to be added into the equation.

You must ask yourself the question.

Colin

WA1KWA said:

You must ask yourself the question.
Colin

Click to expand...

I'm asking myself that question. :wink: I think from what I'm hearing it probably isn't worth the extra $300+. I'm really only planning on a daily driver. And as TR3driver mentioned it's a slippery slope. Where to stop? A hoter cam? tuned headers? It can end up costing a lot of money. I think I'll stick with the standard 87mm pistons.

Thanks for the advise guys!

I fitted 87mm pistons and liners when I rebuilt my engine several years ago. I also had the head converted to accept unleaded fuel and while I was at it I had the head skimmed and gas flowed with larger valves fitted.
I have left the cam as it was and have a standard exhaust manifold. The car pulls beautifully with lots of low-down torque and it revs nicely too.
Now I wish that I had balance it while it was apart.
A friend had a similar set up, but he had a lightened fly wheel and a race cam. Personally I thought he ruined the car because you had to keep the revs up to get the best out of it.
I prefer a nice torquey engine to one you have to rev.