Please help: 2110cc stroker engine with 35.5mm exhast valves. Currently running with standard heat exchangers, bugpack header and 2.5" turbo muffler. There appear to be differing views on whether a big engine like this should be run with or without heat exchangers and i need to make a quick decision. Some say larger engines with 35.5mm exhaust valves will cause damage to cylinder heads if the exhaust flow is 'restricted' with heat exchangers. Others say there will be no issues except a very slight loss in power if i stick with my heat exchangers. Please share your experiences and any implications. I appreciate input from all, but will listen to those who have already done it. Options 1. Keep it as it is. Pros: warm van & no cost now. Cons: heads may eventually get damaged. 2. Big bore heat exchangers & new 1 5/8" 4 into 1 header. Pros: Less likely to damage heads, warm van. Cons: Cost, big bore heat exchangers not as good at heating? 3. J Tubes & new exhaust. Pros: No damage to cylinder heads. Cons: High Cost. No heat, unless I fit propex or Eberspascher The engine has plenty of power so that isn't a concern. I look forward to your replies. Thanks Paul
J tubes will cause the heads to run too warm if its a normal use bus They are ok for a quick run down the strip at the pod but the air flowing through heat exchangers actually cools the internal pipework and stops it radiating heat to the heads
Thanks that is useful to know. It is a normal use bus, in fact i've never been down the strip! I didn't realise that about the j tubes. So i now just need to decide between options 1 & 2. Option 1 costs me £ nothing, but i may need new heads in the future approx £600 ish Option 2 costs me: big bore heat exchangers x 2 & new 4 into one header. £500+ ish
Best way is to write a list of what you want from your bus in an ideal world then work from there When i get to the stage of building my ideal engine i dont want to go any faster than 70 mph however i want enough bottom end torque to allow me to pull a trailer full of logs behind me whilst going uphill
Your heads wont be damaged from using the bus normally with standard heat exchangers However if you spend a lot of time hammering it at the top end of the rev limit theres a chance you may blow the valve stem seals out This wont damage the heads it will just give you a smokey exhaust
I have been running heatx. on my 2,4 l. engine for 4 years,,,no probs what so ever,,,m8 has the same engine, he's got a phyton on his, = 16bhp more in his
Holmsen, thanks I'm swaying towards leaving it as it is. I don't need more power and a few people have said i won't have any probs. Thanks Paul
most valve stem seals if fitted are in your sump anyway , for me i`d run big bore J tubes or big heat exchangers depending wether you want heat or not , Its all about getting the air in and exhaust out other wise whats the point of such a large cc motor . J tubes are fine and shouldnt cause any issues other than cost
lhu1281 Thanks for your input, I appreciate it. Since posting this i have done some further research on valve and bore sizes My exhaust valves are 35.5mm My current header is 35mm (bugpack 4 into 1) My current stock heat exchangers are 33mm 'Big bore' heat exchangers are 35mm & cost £250 CSP do heat exchangers at 38mm. They cost £500, but i'd also need a new exhaust system at £745+, or at the very least a new header. I'm not going down the j tube route as i want heat in the van and they have other issues apparently I don't thrash the van, i went for a stroker with big cc's as i wanted to be able to get up hills and cruise along motorways with ease. Unless i thrash the engine i'm starting to think i'm unlikely to have issues with the heads/valves and even if i do they would cost approx £700 for new heads, as opposed to £1,200+ for bigger heat exchangers and new exhaust!
I have standard heat exchangers on Lime and run a CSP python. Never worried about it, rather have heat to be honest. Exhaust was 800 and heat exchangers 400 so yup a fair whack.
I have standard HX's and a beetle box on my 1955 with same valve sizes as you have. It runs out of beans at 55 in 3rd which annoys me a bit. But I think it's the jetting not the exhaust. Cost next to bugger all.
